阅读说明：本技术 永磁同步电机宽范围调速控制方法、装置、设备及介质 (Wide-range speed regulation control method, device, equipment and medium for permanent magnet synchronous motor ) 是由 章玮 袁心谷 吴新兵 于 2020-06-03 设计创作，主要内容包括：本发明公开了一种永磁同步电机宽范围调速控制方法、装置、设备及介质,方法包括：获取永磁同步电机d、q轴电流参考值查询表；选择d、q轴电流参考值计算方式；计算拟合数据点元素下标；获取拟合数据值；数据拟合获取d、q轴电流参考值；获取永磁同步电机IO参数矩阵估计律、电压参考差值估计律和电压动态限幅值估计律；获取当前控制周期的IO参数矩阵估计值；获取当前控制周期的d、q轴电压参考差值；获取当前控制周期的d、q轴动态电压限幅值；计算当前控制周期的d、q轴电压参考值；对d、q轴电压参考值进行动态限幅；控制永磁同步电机。该方法具有鲁棒性强、电流工作点连续、电流响应速度快、跟踪精度高、数据存储量小等优点。(The invention discloses a method, a device, equipment and a medium for controlling the wide-range speed regulation of a permanent magnet synchronous motor, wherein the method comprises the following steps: acquiring a look-up table of d-axis and q-axis current reference values of the permanent magnet synchronous motor; selecting a d-axis and q-axis current reference value calculation mode; calculating the index of the fitted data point elements; acquiring a fitting data value; d and q axis current reference values are obtained through data fitting; obtaining an IO parameter matrix estimation law, a voltage reference difference value estimation law and a voltage dynamic amplitude limiting value estimation law of the permanent magnet synchronous motor; obtaining an IO parameter matrix estimation value of a current control period; acquiring d and q axis voltage reference difference values of the current control period; acquiring dynamic voltage amplitude limits of d and q axes of a current control period; calculating d and q axis voltage reference values of the current control period; dynamically limiting the d and q axis voltage reference values; controlling the permanent magnet synchronous motor. The method has the advantages of strong robustness, continuous current working points, high current response speed, high tracking precision, small data storage capacity and the like.)

1. A wide-range speed regulation control method for a permanent magnet synchronous motor is characterized by comprising the following steps:

according to a data fitting table look-up method, obtaining d-axis and q-axis current reference values;

according to a model-free self-adaptive algorithm, obtaining an IO parameter matrix estimation law and a voltage reference difference value estimation law of the permanent magnet synchronous motor, and according to a global current optimal control theory, obtaining dynamic limiting value estimation laws of d-axis and q-axis voltages;

acquiring d-axis and q-axis voltage reference values according to an IO parameter matrix estimation law and a voltage reference difference estimation law of the permanent magnet synchronous motor and d-axis and q-axis current reference values;

acquiring d-axis and q-axis voltage dynamic amplitude limiting values according to a d-axis and q-axis voltage dynamic amplitude limiting value estimation law;

and carrying out amplitude limiting on the d-axis voltage reference value and the q-axis voltage reference value according to the d-axis voltage dynamic amplitude limiting value and the q-axis voltage dynamic amplitude limiting value, and controlling the permanent magnet synchronous motor according to the d-axis voltage reference value and the q-axis voltage reference value after dynamic amplitude limiting.

2. The method of claim 1, wherein obtaining d-axis and q-axis current reference values according to a data fitting lookup table comprises:

acquiring a look-up table of d-axis and q-axis current reference values of the permanent magnet synchronous motor;

acquiring an electromagnetic torque reference value and a rotating speed reference value of a permanent magnet synchronous motor in a current control period;

selecting a d-axis and q-axis current reference value calculation mode according to the rotating speed reference value of the current control period;

calculating the index of the d-axis current reference value and the q-axis current reference value according to the calculation mode of the d-axis current reference value and the q-axis current reference value, the rotating speed reference value and the electromagnetic torque reference value in the current control period, and acquiring a fitting data value by inquiring a d-axis current reference value lookup table and a q-axis current reference value lookup table;

and selecting a data fitting mode according to the d-axis and q-axis current reference value calculation mode of the current control period, and performing data fitting on the fitting data points to obtain the d-axis and q-axis current reference values of the current control period.

3. The method of claim 2, wherein calculating the d-axis and q-axis current reference value fitting data point element subscripts according to the d-axis and q-axis current reference value calculation mode, the rotating speed reference value and the electromagnetic torque reference value of the current control period, and obtaining the fitting data value by querying a d-axis and q-axis current reference value lookup table comprises:

when the calculation mode of the d-axis and q-axis current reference values is an MTPA mode, calculating the element subscripts of the fitting data points according to the electromagnetic torque reference values and the d-axis and q-axis current reference value subscripts in the current control period by using a function:

calculating and obtaining accurate subscript x of the d-axis and q-axis current reference values according to the electromagnetic torque reference value of the current control period and subscripts of the d-axis and q-axis current reference values of the MTPA working area; rounding the precise subscript x to obtain the lower limit value x of the subscript of the fitting data₁(ii) a Rounding the precise subscript x upwards to obtain the upper limit value x of the subscript of the fitting data₂(ii) a According to fittingLower limit value x of data subscript₁Obtaining an extension value x of fit data point subscript₃Let x₃＝x₁-1; or upper limit value x according to fit data subscript₂Obtaining the extension value x of the subscript of the fitting data point₃Let x₃＝x₂+1；

Thereafter, the lower limit value x is scaled according to the fitting data₁Upper limit value x₂And an extension value x₃Inquiring a d-axis and q-axis current reference value inquiry table of an MTPA working area to obtain a corresponding fitting data value v₁,v₂,v₃The three fitting data points are represented as (x)₁,v₁),(x₂,v₂),(x₃,v₃)；

When the calculation mode of the d-axis and q-axis current reference values is a weak magnetic mode, calculating the row subscript of the fitting data point according to the electromagnetic torque reference value and the row subscript of the d-axis and q-axis current reference values of the current control period, and calculating the column subscript of the fitting data point according to the rotating speed reference value and the column subscript of the d-axis and q-axis current reference values of the current control period:

according to the electromagnetic torque reference value of the current control period and the row subscripts of the d-axis and q-axis current reference values of the weak magnetic working area, calculating to obtain accurate row subscripts y of the d-axis and q-axis current reference values, and rounding the accurate row subscripts y downwards to obtain a lower limit value y of the subscripts of the fitted data point row₁And rounding the accurate row subscript y upwards to obtain the upper limit value y of the fitted data point row subscript₂；

According to the rotating speed reference value of the current control period and the column subscripts of the d-axis and q-axis current reference values of the weak magnetic working area, calculating to obtain the accurate column subscripts x of the d-axis and q-axis current reference values^*For precise column subscript x^*Rounding down to obtain lower limit value x of subscript of fitting data point column₁For precise column subscript x^*Rounding up to obtain upper limit value x of subscript of fitting data point column₂；

Then according to the combination of the column subscript and the row subscript, the corresponding fitting data value v is obtained by inquiring a d-axis and q-axis current reference value inquiry table of the weak magnetic working area₁,v₂,v₃,v₄And expressing the fitting point as (x)₁,y₁,v₁),(x₂,y₁,v₂),(x₁,y₂,v₃),(x₂,y₂,v₄) The row and column indices of the fitted data points are expressed as Q₁₁(x₁,y₁),Q₂₁(x₂,y₁),Q₁₂(x₁,y₂),Q₂₂(x₂,y₂)。

4. The method of claim 2, wherein selecting a data fitting mode according to the calculation mode of the d-axis and q-axis current reference values of the current control period, performing data fitting on the fitting data points, and obtaining the d-axis and q-axis current reference values of the current control period comprises:

when the calculation mode of the d-axis and q-axis current reference values of the current control period is an MTPA mode, performing data fitting on fitting data points by adopting a quadratic interpolation method to obtain the d-axis and q-axis current reference values of the current control period:

equating a look-up table of d and q axis current reference values for the MTPA operating region to a mapping from elemental subscripts to elemental values, fitting this mapping with a quadratic polynomial, and expressing the quadratic polynomial as a first fitting function P as described below₁(x)：

P₁(x)＝a₀+a₁x+a₂x²

Fitting known data points (x)₁,v₁),(x₂,v₂),(x₃,v₃) Substituting the first fitting function with the unknown parameters, and solving to obtain the unknown parameters a₀,a₁,a₃Value of (A)Will be provided with

When the calculation mode of the d-axis and q-axis current reference values of the current control period is a weak magnetic mode, performing data fitting on fitting data points by adopting a biquadratic linear interpolation method to obtain the d-axis and q-axis current reference values of the current control period:

the d-axis and q-axis current reference value lookup table of the weak magnetic working area is equivalent to the mapping from the row-column subscripts of the elements to the element values, and the mapping relation is expressed as the following function, wherein v is_refD, q-axis current reference values:

v_ref＝f(x,y)

as shown below, for a fitted data point Q with a known data value₁₁(x₁,y₁),Q₂₁(x₂,y₁),Q₁₂(x₁,y₂),Q₂₂(x₂,y₂) Intermediate fitting data points R for which the data values are unknown₁(x*,y₁),R₁(x*,y₂) Interpolating in the column subscript direction to obtain the data value of the middle fitting data point;

as shown below, for the intermediate fit data point R₁(x*,y₁),R₁(x*,y₂) Interpolating in the row index direction to obtain d-axis and Q-axis current reference values v mapped by accurate data points Q (x, y)_ref；

5. The method of claim 1, wherein obtaining an IO parameter matrix estimation law and a voltage reference difference estimation law of the permanent magnet synchronous motor according to a model-free adaptive algorithm, and obtaining a d-axis and q-axis voltage dynamic limiting value estimation law according to a global current optimal control theory comprises:

acquiring a current model of the permanent magnet synchronous motor, and performing linearization processing on the current model to acquire a dynamic linearization current model;

acquiring a full-format dynamic linearized data model according to the dynamic current model;

obtaining a criterion function of IO parameter matrix estimation according to the full-format dynamic linearized data model, and analyzing the criterion function of the IO parameter matrix estimation to obtain the IO parameter matrix estimation law;

obtaining a criterion function of the voltage reference difference estimation according to the full-format dynamic linearized data model, and analyzing the criterion function of the voltage reference difference estimation to obtain a voltage reference difference estimation law;

and obtaining the estimation law of the dynamic amplitude limiting values of the d-axis voltage and the q-axis voltage according to the global current optimal control theory.

6. The method according to claim 5, wherein obtaining a criterion function of an IO parameter matrix estimation according to the full-format dynamic linearized data model, and analyzing the criterion function of the IO parameter matrix estimation to obtain the IO parameter matrix estimation law, comprises:

the IO parameter matrix estimation law is expressed by the following formula:

wherein the content of the first and second substances,

7. The method of claim 5, wherein obtaining the criterion function of the voltage reference difference estimate from the full-format dynamic linearized data model and parsing the criterion function of the voltage reference difference estimate to obtain the voltage reference difference estimate law comprises:

the voltage reference difference estimation law is expressed by the following formula:

wherein, is Δ V_ref(k) For the voltage reference difference vector of the kth control period to be estimated, I^*(k +1) is a desired d, q-axis current reference value vector, I (k) is a d, q-axis current feedback value vector of a k-th control period,

8. The method of claim 5, further comprising:

judging whether the IO parameter matrix estimation value of the current control period meets a preset reset condition or not;

if so, resetting the IO parameter matrix estimation value of the current control period, and estimating the voltage reference difference value of the current control period according to the reset IO parameter matrix estimation value;

if not, estimating the voltage reference difference value of the current control period directly according to the IO parameter matrix estimation value of the current control period;

IO parameter matrix for current control period

if it is notOrOrThen makeWherein the content of the first and second substances,is composed ofThe matrix index of (a) is the diagonal element of ii,

if it is notOrThen makeWherein the content of the first and second substances,is composed of

9. The method of claim 5, wherein obtaining a d-axis and q-axis voltage dynamic limiting value estimation law according to a global current optimal control theory comprises:

the lower limit value estimation law of the dynamic limiting value of the d-axis voltage is a quadratic function related to the motor rotating speed reference value and the electromagnetic torque reference value in the current control period, as shown in the following formula, wherein V is_{d_lower_lim}Dynamic lower limit, ω, of d-axis voltage values_refAs reference value of the speed of rotation, T_{e_ref}As reference value of electromagnetic torque, k₁Is a first estimated value parameter with a value range of k₁>0，k₂Is a second estimated value parameter with the value range of k₂>0：

10. A permanent magnet synchronous motor wide range speed regulation control device is characterized by comprising:

the current reference value acquisition unit is used for acquiring d-axis and q-axis current reference values according to a data fitting table look-up method;

the algorithm obtaining unit is used for obtaining an IO parameter matrix estimation law and a voltage reference difference value estimation law of the permanent magnet synchronous motor according to a model-free self-adaptive algorithm and obtaining dynamic limiting amplitude value estimation laws of d-axis and q-axis voltages according to a global current optimal control theory;

the first calculation unit is used for acquiring d-axis and q-axis voltage reference values according to an IO parameter matrix estimation law and a voltage reference difference estimation law of the permanent magnet synchronous motor and d-axis and q-axis current reference values;

the second calculation unit is used for acquiring the dynamic limiting values of the d-axis voltage and the q-axis voltage according to the estimation law of the dynamic limiting values of the d-axis voltage and the q-axis voltage;

and the amplitude limiting control unit is used for carrying out amplitude limiting on the d-axis voltage reference value and the q-axis voltage reference value according to the d-axis voltage dynamic amplitude limiting value and the q-axis voltage dynamic amplitude limiting value and controlling the permanent magnet synchronous motor according to the d-axis voltage reference value and the q-axis voltage reference value after dynamic amplitude limiting.

Technical Field

The invention relates to the technical field of motor control, in particular to a method, a device, equipment and a medium for controlling the wide-range speed regulation of a permanent magnet synchronous motor based on a data fitting table look-up method and a model-free self-adaptive algorithm.

Background

The permanent magnet synchronous motor is a novel motor controlled by electromechanical integration, has the advantages of high efficiency, excellent torque performance, small size and the like, and is widely applied to a plurality of fields of industrial automation control, aerospace, machinery and the like.

The permanent magnet synchronous motor is a high-order, nonlinear and strongly coupled system, is difficult to accurately model, the uncertainty of a current model of the permanent magnet synchronous motor is high, and meanwhile, the motor parameters are disturbed by external interference in the running process to influence the control performance. To ensure high dynamic performance and accurate tracking of the whole motor system, current response with high tracking speed, small static error and strong robustness is required.

Meanwhile, the permanent magnet synchronous motor adopts permanent magnet excitation, and the excitation magnetic field cannot be adjusted through an excitation winding, so that a weak magnetic control technology is required to realize the performance index of wide-range speed adjustment. Common weak magnetic control strategies include formula calculation, table lookup, negative d-axis current compensation, and the like. The formula calculation method describes the flux weakening speed regulation process of the permanent magnet synchronous motor from the angle of a current track, provides constraint conditions for current amplitudes of d and q axes, has high theoretical value, but is difficult to apply to actual engineering due to the fact that a large amount of complex calculation is involved; the method needs a large amount of data support, in addition, the conventional table look-up method is difficult to obtain continuous current tracks from the table, the current which is frequently mutated in engineering application can cause impact on a motor system, and the system can oscillate or even collapse in serious cases; the negative d-axis current compensation method is characterized in that a given value of stator voltage in a control loop is compared with a voltage limit value, and a negative compensation value of d-axis current is obtained through calculation of a PI (proportional-integral) controller, so that the purpose of widening the rotating speed range of the motor is achieved.

Disclosure of Invention

The embodiment of the invention aims to provide a method, a device, equipment and a medium for controlling the wide-range speed regulation of a permanent magnet synchronous motor, so as to solve the problems of discontinuous current reference value and low current response speed in the current flux weakening control method of the permanent magnet synchronous motor.

In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

in a first aspect, an embodiment of the present invention provides a method for controlling a wide-range speed regulation of a permanent magnet synchronous motor, including the following steps:

according to a data fitting table look-up method, obtaining d-axis and q-axis current reference values;

obtaining an IO parameter matrix estimation law and a voltage reference difference value estimation law of the permanent magnet synchronous motor according to a model-free self-adaptive algorithm, and obtaining dynamic limiting value estimation laws of d-axis and q-axis voltages according to a global current optimal control theory;

acquiring d-axis and q-axis voltage reference values according to an IO parameter matrix estimation law and a voltage reference difference estimation law of the permanent magnet synchronous motor and d-axis and q-axis current reference values;

acquiring d-axis and q-axis voltage dynamic amplitude limiting values according to a d-axis and q-axis voltage dynamic amplitude limiting value estimation law;

and carrying out amplitude limiting on the d-axis voltage reference value and the q-axis voltage reference value according to the d-axis voltage dynamic amplitude limiting value and the q-axis voltage dynamic amplitude limiting value, and controlling the permanent magnet synchronous motor according to the d-axis voltage reference value and the q-axis voltage reference value after dynamic amplitude limiting.

In a second aspect, an embodiment of the present invention further provides a wide-range speed adjustment control device for a permanent magnet synchronous motor, including:

the current reference value acquisition unit is used for acquiring d-axis and q-axis current reference values according to a data fitting table look-up method;

the algorithm obtaining unit is used for obtaining an IO parameter matrix estimation law and a voltage reference difference value estimation law of the permanent magnet synchronous motor according to a model-free self-adaptive algorithm and obtaining dynamic limiting amplitude value estimation laws of d-axis and q-axis voltages according to a global current optimal control theory;

the first calculation unit is used for acquiring d-axis and q-axis voltage reference values according to an IO parameter matrix estimation law and a voltage reference difference estimation law of the permanent magnet synchronous motor and d-axis and q-axis current reference values;

the second calculation unit is used for acquiring the dynamic limiting values of the d-axis voltage and the q-axis voltage according to the estimation law of the dynamic limiting values of the d-axis voltage and the q-axis voltage; and the amplitude limiting control unit is used for carrying out amplitude limiting on the d-axis voltage reference value and the q-axis voltage reference value according to the d-axis voltage dynamic amplitude limiting value and the q-axis voltage dynamic amplitude limiting value and controlling the permanent magnet synchronous motor according to the d-axis voltage reference value and the q-axis voltage reference value after dynamic amplitude limiting.

In a third aspect, an embodiment of the present invention further provides an electronic device, including:

one or more processors;

a memory for storing one or more programs;

when executed by the one or more processors, cause the one or more processors to implement a method as described in the first aspect.

In a second aspect, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program is configured to, when executed by a processor, implement the method according to the first aspect.

The wide-range speed regulation control method and device for the permanent magnet synchronous motor adopt an improved data fitting table look-up method to calculate d-axis and q-axis current reference values, adopt a model-free self-adaptive current controller to realize d-axis and q-axis current following, can realize wide-range speed regulation control of the permanent magnet synchronous motor, are insensitive to sudden change and perturbation of motor parameters in the operation process of the motor system, effectively inhibit adverse effects on control effects caused by uncertain factors such as modeling errors and working condition sudden change, can stably operate constant cut-in power from constant torque, realize weak magnetic expansion, can keep stable operation of the system at both a weak magnetic cut-in point and a deep weak magnetic area, and have the advantages of strong robustness, high current response speed, high tracking precision, small calculation amount, no need of expert experience and the like.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a block diagram of a control system for a permanent magnet synchronous motor in one embodiment;

FIG. 2 is a flow chart of a method for controlling the wide-range speed regulation of a permanent magnet synchronous motor in one embodiment;

FIG. 3a is a d-axis current reference value simulation waveform of an experimental system;

FIG. 3b is a simulated waveform of d-axis current reference for a control system;

FIG. 3c is a d-axis current feedback value simulation waveform of the experimental system;

FIG. 3d is a simulation waveform of d-axis current feedback values for a control system;

FIG. 3e is a q-axis current reference value simulation waveform of the experimental system;

FIG. 3f is a q-axis current reference simulation waveform for the comparison system;

FIG. 3g is a q-axis current feedback value simulation waveform of the experimental system;

FIG. 3h is a q-axis current feedback value simulation waveform of the comparison system;

FIG. 3i is a simulation waveform of the feedback value of the rotation speed of the experimental system;

FIG. 3j is a waveform of a speed feedback simulation of a control system;

fig. 4 is a wide-range speed regulating control device of the permanent magnet synchronous motor in one embodiment.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

Fig. 1 is a block diagram of a control system of a permanent magnet synchronous motor according to an embodiment, and as shown in fig. 1, the control system of the permanent magnet synchronous motor includes a high-current portion and a control portion. The high-voltage part comprises a direct-current voltage source and a three-phase inverter, wherein the direct-current voltage source is used for supplying power to a system, the output end of the direct-current voltage source is connected with a voltage stabilizing capacitor in parallel and then connected with the three-phase inverter, and the three-phase inverter can be composed of a power switch tube (such as an IGBT) and a freewheeling diode and is used for inverting direct current output by the direct-current voltage source into alternating current to be input to the input end of a three-phase.

The control part comprises a rotor position angle detection unit, a stator current detection unit, an inverter drive unit and a control unit, wherein the rotor position angle detection unit usually consists of a Hall element or an encoder and is used for reading a rotor position angle signal theta (k) of the permanent magnet synchronous motor, inputting the rotor position angle signal theta (k) into the control unit, calculating through a first-order differential unit in the control unit to obtain an actual rotor mechanical angular velocity omega (k), and then calculating the actual rotor mechanical angular velocity omega (k) and a rotor mechanical angular velocity reference value omega (k) through the rotor mechanical angular velocity_ref(k) Making difference to obtain a rotation speed deviation signal delta omega (k), inputting the rotation speed deviation signal delta omega (k) to a PI speed controller, and outputting an electromagnetic torque reference value T after the rotation speed deviation signal is regulated by the PI speed controller_{e_ref}(k) In that respect Reference value T of electromagnetic torque_{e_ref}(k) And a rotor mechanical angular velocity reference value omega_ref(k) Inputting the current into an improved current distributor, and calculating and outputting a d-axis current reference value i through the improved current distributor based on a data fitting lookup table method_{d_ref}(k) And q-axis current reference value i_{q_ref}(k) In that respect Meanwhile, the stator current detection unit reads a three-phase stator current signal i of the permanent magnet synchronous motor in real time_abc(k) Inputting the current to a control unit, and obtaining a d-axis current feedback value i through Clark conversion and Park conversion_d(k) And q-axis currentValue i is fed_q(k) In that respect Then, the q-axis current is referenced to the value i_{q_ref}(k) D-axis current reference value i_{d_ref}(k) D-axis current feedback value i_d(k) And q-axis current feedback value i_q(k) Inputting the voltage into a model-free adaptive current controller, and calculating and outputting a d-axis voltage reference value V through the controller_{d_ref}(k) And q-axis voltage reference value V_{q_ref}(k) Then obtaining an alpha axis voltage reference value V through inverse Park conversion_{α_ref}(k) And a reference value V of the beta axis voltage_{β_ref}(k) The three-phase PWM control circuit is input to the SVPWM modulation unit, six paths of PWM control signals are output to the three-phase inverter after modulation, and the purpose of controlling the rotating speed and the current of the permanent magnet synchronous motor is achieved by driving the on and off of a power switch tube in the three-phase inverter. The current control part consists of an improved current distributor and a model-free adaptive current controller, and realizes the wide-range speed regulation of the permanent magnet synchronous motor together, which is specifically described as follows.

Fig. 2 is a flowchart of a method for controlling a wide-range speed regulation of a permanent magnet synchronous motor in an embodiment, as shown in fig. 2, including the following steps:

step 202, obtaining d-axis and q-axis current reference values according to a data fitting table look-up method, comprising:

acquiring a look-up table of d-axis and q-axis current reference values of the permanent magnet synchronous motor;

acquiring an electromagnetic torque reference value and a rotating speed reference value of a permanent magnet synchronous motor in a current control period;

selecting a d-axis and q-axis current reference value calculation mode according to the rotating speed reference value of the current control period;

calculating the index of the fitting data point elements of the d-axis and q-axis current reference values according to the calculation mode of the d-axis and q-axis current reference values, the rotating speed reference value and the electromagnetic torque reference value of the current control period, and acquiring a fitting data value by inquiring a d-axis and q-axis current reference value inquiry table;

and selecting a data fitting mode according to the d-axis and q-axis current reference value calculation mode of the current control period, and performing data fitting on the fitting data points to obtain the d-axis and q-axis current reference values of the current control period.

Specifically, in one embodiment, obtaining a look-up table of d-axis and q-axis current reference values of a permanent magnet synchronous motor includes:

according to the permanent magnet synchronous motor weak magnetic control theory, the MTPA algorithm, the MTPV algorithm and the motor parameters, a d-axis and q-axis current reference value query table and a switching point judgment table of an MTPA working area are obtained, and an element subscript calculation function of each data table is obtained, so that a current working point track is planned, and the global current optimal control is realized.

The method for acquiring the electromagnetic torque reference value and the rotating speed reference value of the permanent magnet synchronous motor in the current control period comprises the following steps:

and calculating and acquiring an electromagnetic torque reference value and a rotating speed reference value of the current control period through software of the control unit.

Selecting a d-axis and q-axis current reference value calculation mode according to a rotating speed reference value of the current control period, wherein the d-axis and q-axis current reference value calculation mode comprises the following steps:

when the rotating speed reference value of the current control period is smaller than a first rotating speed limit value, judging that the current working point of the current control period is in an MTPA working area, wherein the calculation mode of the d-axis and q-axis current reference values is an MTPA mode; when the rotating speed reference value of the current control period is greater than the first rotating speed limit value and less than the second rotating speed limit value, judging that the current working point falls in a switching point judgment area, wherein the d-axis and q-axis current reference value calculation mode is a switching point judgment mode, and a switching point judgment table needs to be inquired to further judge the working area where the current working point is located; when the rotating speed reference value of the current control period is larger than the second rotating speed limit value, the current working point is judged to fall in the field weakening working area, and the calculation mode of the d-axis and q-axis current reference values is a field weakening mode.

Calculating the subscripts of the fitting data point elements of the d-axis and q-axis current reference values according to the calculation mode of the d-axis and q-axis current reference values, the rotating speed reference values and the electromagnetic torque reference values of the current control period, and acquiring a fitting data value by inquiring a d-axis and q-axis current reference value inquiry table, wherein the method comprises the following steps:

when the calculation mode of the d-axis and q-axis current reference values is an MTPA mode, calculating the element subscripts of the fitting data points according to the electromagnetic torque reference values and the d-axis and q-axis current reference value subscripts in the current control period by using a function:

calculating and obtaining accurate subscript x of the d-axis and q-axis current reference values according to the electromagnetic torque reference value of the current control period and subscript calculation functions of the d-axis and q-axis current reference values of an MTPA working area; rounding down the precise index x to obtain the lower limit value x of the index of the fitting data₁(ii) a Rounding the precise subscript x upwards to obtain the upper limit value x of the subscript of the fitting data₂(ii) a Lower limit value x according to fit data subscript₁(or upper limit value x of subscript of fitting data)₂) Obtaining an extension value x of fit data point subscript₃Let x₃＝x₁-1 (or x)₃＝x₂+1)；

Thereafter, the lower limit value x is scaled according to the fitting data₁Upper limit value x₂And an extension value x₃Inquiring a d-axis and q-axis current reference value inquiry table of an MTPA working area to obtain a corresponding fitting data value v₁,v₂,v₃The three fitting data points are represented as (x)₁,v₁),(x₂,v₂),(x₃,v₃)；

When the calculation mode of the d-axis and q-axis current reference values is a weak magnetic mode, calculating the row subscript of the fitting data point according to the electromagnetic torque reference value and the row subscript of the d-axis and q-axis current reference values of the current control period, and calculating the column subscript of the fitting data point according to the rotating speed reference value and the column subscript of the d-axis and q-axis current reference values of the current control period:

calculating function according to electromagnetic torque reference value of current control period and row subscripts of d-axis and q-axis current reference values of weak magnetic working area, obtaining accurate row subscript y of d-axis and q-axis current reference values through calculation, and obtaining lower limit value y of virtual data point row subscript by downwardly integrating accurate row subscript y₁And rounding the accurate row subscript y upwards to obtain the upper limit value y of the fitted data point row subscript₂；

According to the rotating speed reference value of the current control period and the column subscripts of the d-axis and q-axis current reference values of the weak magnetic working area, calculating to obtain the accurate column subscripts x of the d-axis and q-axis current reference values^*For precise column subscript x^*Rounding down to obtain lower limit value x of subscript of fitting data point column₁For precise column subscript x^*Rounding up to obtain upper limit value x of subscript of fitting data point column₂；

Then according to the combination of the column subscript and the row subscript, the corresponding fitting data value v is obtained by inquiring a d-axis and q-axis current reference value inquiry table of the weak magnetic working area₁,v₂,v₃,v₄And expressing the fitting point as (x)₁,y₁,v₁),(x₂,y₁,v₂),(x₁,y₂,v₃),(x₂,y₂,v₄) The row and column indices of the fitted data points are expressed as Q₁₁(x₁,y₁),Q₂₁(x₂,y₁),Q₁₂(x₁,y₂),Q₂₂(x₂,y₂)。

Selecting a data fitting mode according to the calculation mode of the d-axis and q-axis current reference values of the current control period, performing data fitting on fitting data points, and acquiring the d-axis and q-axis current reference values of the current control period, wherein the data fitting mode comprises the following steps:

when the calculation mode of the d-axis and q-axis current reference values of the current control period is an MTPA mode, performing data fitting on the fitting data points by adopting a secondary interpolation method to obtain the d-axis and q-axis current reference values of the current control period:

equating a lookup table of d and q-axis current reference values for the MTPA operating region to a mapping from elemental subscripts to elemental values, fitting this mapping with a quadratic polynomial, and expressing the quadratic polynomial as a first fitting function as shown in equation (1) below:

P₁(x)＝a₀+a₁x+a₂x²(1)

fitting known data points (x)₁,v₁),(x₂,v₂),(x₃,v₃) Substituting the first fitting function with the unknown parameters into the first fitting function to obtain the unknown parameters a₀,a₁,a₃Value of (A)Will be provided withThe value of (a) is substituted back to the first fitting function to obtain a second fitting function without unknown parameters; substituting the accurate subscripts x of the d-axis current reference values and the q-axis current reference values into a second fitting function to obtain the d-axis current reference values and the q-axis current reference values shown in the following formula (2):

when the calculation mode of the d-axis and q-axis current reference values of the current control period is a weak magnetic mode, performing data fitting on fitting data points by adopting a biquadratic linear interpolation method to obtain the d-axis and q-axis current reference values of the current control period:

the d-axis and q-axis current reference value lookup table of the weak magnetic working area is equivalent to mapping from element row-column subscripts to element values, and the mapping relation is expressed as an unknown function shown in the following formula (3):

v＝f(x,y) (3)

fitting data points Q for which the data values are known, as shown in equation (4) below₁₁(x₁,y₁),Q₂₁(x₂,y₁),Q₁₂(x₁,y₂),Q₂₂(x₂,y₂) Intermediate fitting data points R for which the data values are unknown₁(x*,y₁),R₁(x*,y₂) Interpolating in the column subscript direction to obtain the data value of the middle fitting data point;

as shown in the following equation (5), the intermediate fitting data points R₁(x*,y₁),R₁(x*,y₂) Interpolating in the subscript row direction to obtain d-axis and Q-axis current reference values mapped by accurate data points Q (x, y);

it should be noted that, the conventional table lookup method generally does not perform data fitting processing, or performs data fitting processing only in some current working regions, and mostly adopts a linear interpolation mode with relatively small calculation amount. The linear interpolation is to fit the mapping relation from the element subscripts to the element values in the d-axis and q-axis current reference value query tables by using a linear function, the mapping relation in a certain area is equivalent to a straight line, and actually, an MTPA curve is a curve which is positioned in a d-axis and q-axis current level plane and passes through a coordinate original point, so that in the control method, three fitting data points are obtained, the mapping from the element subscripts to the element values in the d-axis and q-axis current reference value query tables in an MTPA working interval is equivalent to a curve, and a quadratic polynomial is used for fitting a target curve, so that the problem that the current working points are discontinuous in the traditional table lookup method is solved, the data fitting precision is higher, and the control precision of the wide-range speed control method is further improved.

In addition, aiming at the weak magnetic working interval, a biquadratic linear interpolation method in the image processing field is introduced into the motor control field, so that data fitting processing in the row subscript and the column subscript is realized, the data fitting precision is greatly improved on the premise of not excessively increasing the calculated amount, and the control performance of a current loop is optimized.

Step 204, obtaining an IO parameter matrix estimation law and a voltage reference difference estimation law of the permanent magnet synchronous motor according to a model-free adaptive algorithm, and obtaining a dynamic limiting amplitude estimation law of d-axis and q-axis voltages according to a global current optimal control theory, including:

acquiring a current model of the permanent magnet synchronous motor, and performing linearization processing on the current model to acquire a dynamic linearized current model;

acquiring a full-format dynamic linearized data model according to the dynamic current model;

obtaining a criterion function of IO parameter matrix estimation according to the full-format dynamic linearized data model, and analyzing the criterion function of the IO parameter matrix estimation to obtain an IO parameter matrix estimation rule;

obtaining a criterion function of the voltage reference difference estimation according to the full-format dynamic linearized data model, and analyzing the criterion function of the voltage reference difference estimation to obtain a voltage reference difference estimation law;

and obtaining the estimation law of the dynamic amplitude limiting values of the d-axis voltage and the q-axis voltage according to the global current optimal control theory.

Specifically, in one embodiment, obtaining a current model of the permanent magnet synchronous motor, and linearizing the current model to obtain a dynamically linearized current model includes:

specifically, a current model in a continuous state of a permanent magnet synchronous motor is known as shown in the following equation (6):

wherein i_d、i_qD and q axis current feedback values, V_{d_ref}、V_{q_ref}Are d and q axis voltage reference values, R_sIs stator resistance, L_d、L_qD and q axis inductances, n_pIs the pole pair number of the motor, omega is the mechanical angular speed of the rotor, psi_fIs a permanent magnetic linkage.

By T_sTo control the period, discretizing the current model shown in the above equation (6), and calculating the difference value, i.e. making: Δ i_d(k+1)＝i_d(k+1)-i_d(k)，Δi_d(k)＝i_d(k)-i_d(k-1)，Δi_q(k+1)＝i_q(k+1)-i_q(k)， Δi_q(k)＝i_q(k)-i_q(k-1)，ΔV_{d_ref}(k)＝V_{d_ref}(k)-V_{d_ref}(k-1)，ΔV_{q_ref}(k)＝V_{q_ref}(k)-V_{q_ref}(k-1), obtaining a dynamic linearized current model of the permanent magnet synchronous motor, as shown in the following formula (7), and realizing the design of the model-free adaptive current controller based on the current model。

Wherein i_d(k+1)、i_q(k +1) are d-axis and q-axis current feedback values, i, of the (k +1) th control period_d(k)、i_q(k) D and q axis current feedback values, V, of the k control period_{d_ref}(k)、V_{q_ref}(k) The reference values of d-axis voltage and q-axis voltage of the k control period are respectively.

In this embodiment, since the dynamic linear current model of the permanent magnet synchronous motor includes the coupling term of the d-axis current and the q-axis current, the automatic decoupling control of the currents can be realized, the dynamic performance of the control is improved, and the mechanical angular velocity and the parameter term of the motor are combined into a whole to be estimated when the product term of the mechanical angular velocity and the current of the motor is processed, so that the independence of the rotation speed loop and the current loop can be ensured.

Acquiring a full-format dynamic linearized data model according to the dynamic current model, comprising:

specifically, the dynamic linearized current model of the permanent magnet synchronous motor shown in the above formula (7) may be first abbreviated as:

I(k+1)＝f(I(k),V_ref(k)) (8)

wherein I (k +1) is a vector of feedback values of d and q axes current (also called as current output vector) in the (k +1) th control periodI (k) is a vector of feedback values of d and q axes of current in the k control period, specifically

V_ref(k) A vector of reference values of d and q axes voltage (also called voltage input vector) of the k control periodAnd I (k +1), I (k) and V_ref(k)∈R^mAnd f (..) represents an unknown non-linear vector function of the system.

When the higher-order unmodeled dynamics in the current model of the permanent magnet synchronous motor is taken into consideration, the dynamic linearized current model shown in the above equation (8) may be rewritten as:

I(k+1)＝f(I(k),...,I(k-n_y),V_ref(k),...,V_ref(k-n_u)) (9)

wherein n is_y、n_uRepresenting the order of the system.

Then, defineIs a sliding time window [ k- (L) correlated at the input_u-1),k]All voltage input signals in and the associated sliding time window [ k- (L) at the output_y-1),k]The vector formed by all current output signals in the permanent magnet synchronous motor is called as an input/output vector of the permanent magnet synchronous motor, which is called as IO vector for short, and is specifically shown in the following formula (10):

wherein the content of the first and second substances,is the IO vector of the kth control period, L_y、L_uA first preset pseudo order and a second preset pseudo order respectively for representing the input and output data length of the system, and L is more than or equal to 0_y≤n_y,0≤L_u≤n_uAnd when k is less than or equal to 0, there is

At the same time, defineThe input and output difference vector of the permanent magnet synchronous motor is called IO difference vector for short, and is specifically shown in the following formula (11):

wherein the content of the first and second substances,is the IO difference vector for the kth control period,

is the IO vector of the kth control period,

is the IO vector of the k-1 control period, and is the d-axis and q-axis current feedback value difference vector of the k control period, and is Δ V_ref(k)＝V_ref(k)-V_refAnd (k-1) is a d-axis and q-axis voltage reference difference vector of the k control period.

Aiming at the current dynamic linearization model of the permanent magnet synchronous motor shown in the formula (9), the method comprises the following stepsThere will be a time-varying IO parameter matrixThe current model shown in the above equation (9) is equivalent to the following full-format dynamic linearized data model:

wherein the content of the first and second substances,the IO parameter matrix is the IO parameter matrix of the kth control period, and the IO parameter matrix is bounded for any control period (k is an arbitrary value).

Obtaining a criterion function of IO parameter matrix estimation according to the full-format dynamic linearized data model, and analyzing the criterion function of the IO parameter matrix estimation to obtain the IO parameter matrix estimation law, including:

specifically, for the full-format dynamic linearized current model shown in the above equation (12), a criterion function of the IO parameter matrix estimation can be obtained, as shown in the following equation (13):

then to

And (3) carrying out derivation, making the derivation function equal to zero, and calculating a minimum value point of the criterion function to obtain an IO parameter matrix estimation law, wherein the IO parameter matrix estimation law is represented by the following formula (14):

wherein the content of the first and second substances,is the IO parameter matrix of the kth control period to be estimated,

IO parameter matrix for k-1 control periodThe estimated value of (1) is called IO parameter matrix estimated value of k-1 control period for short, eta is a preset step length factor, and the purpose of adding the step length factor is to enable the design of a control algorithm to be more flexible, and eta belongs to (0,2)]In general, η ═ 1.9, μmay be a first predetermined weight, and μmay be a second predetermined weight>In order to improve the stability of the system, μ is usually a relatively large positive value, and may be generally 10.

Obtaining a criterion function of the voltage reference difference estimation according to the full-format dynamic linearized data model, and analyzing the criterion function of the voltage reference difference estimation to obtain the voltage reference difference estimation law, including:

in particular, for current control, the goal is to find a suitable input voltage such that the error between the target current and the actual current is

Gradually converging to zero with increasing time, the following input voltage criterion function can be considered:

to V_ref(k) And (3) carrying out derivation, making the derivation function equal to zero, and calculating a minimum value point of the criterion function to obtain a voltage reference difference value estimation law, wherein the minimum value point is represented by the following formula (16):

wherein the content of the first and second substances,

reference difference vector for d and q axis voltages of the kth control period to be estimated, I^*(k +1) is a d-axis and q-axis current reference value vector, and in practical application,

i_{d_ref}(k)、i_{q_ref}(k) d-axis and q-axis current reference values of a k-th control period, I (k) is a vector of d-axis and q-axis current feedback values of the k-th control period,is a sub-matrix of the estimated value of the IO parameter matrix of the kth control period, and delta I (k-I +1) is a d-axis and q-axis current feedback difference vector of the kth-I +1 control period, and delta V_ref(k-i + Ly +1) is a d-axis and q-axis voltage reference difference vector of a k-i + Ly +1 control period,

for a predetermined step-size factor orderThe purpose of adding the step factor sequence is to make the design of the control algorithm more flexible, each sub-matrix corresponds to a step factor with the same subscript, the values of the step factors can be equal, and the value range can be 0<ρ_i≤1，i＝1,2,...,L_y+L_uUsually, a positive number close to 1 can be taken, for example, in generalλ is a second predetermined weight, λ>0, and as lambda is the most critical parameter influencing the current control performance, when lambda is smaller, the current control response speed is fast, but overshoot is large; when the lambda is larger, overshoot is reduced but the response speed is correspondingly slowed down, and meanwhile, the convergence of the algorithm is greatly influenced by the value of the lambda, so that the value range of the lambda is 0 by combining theoretical analysis and experimental results<λ≤0.0001。

In one embodiment, the first predetermined weight μ is [10, + ∞ ], the embodiment takes μ as 10 for example, the predetermined step-size factor η is (0,2) for example, the embodiment takes η as 1.9 for example, and the predetermined step-size factor sequence isThe range of each step factor in (1, 0), which is equal to 0.98 in this embodiment, for example, the range of the second predetermined weight λ may be (0, 0.0001)]And experiments and simulation results can confirm that the value taking method is suitable for both high-voltage motors and low-voltage motors and has strong universality.

In the embodiment, the IO parameter matrix estimation rule and the voltage reference difference value estimation rule of the permanent magnet synchronous motor are obtained by adopting a full-format dynamic linearized data model, the high-order uncertain items which are not modeled in the permanent magnet synchronous motor model are fully considered, and the dynamic performance and the steady-state precision of current control are effectively improved. Meanwhile, the full-format dynamic linearized data model considers the historical current feedback value difference value delta I (k-1)_y-1)) and a historical voltage reference difference Δ V_ref(k-1),...,ΔV_ref(k-(L_y-1)) on the control performance, and thus the dynamic performance of the system can be effectively improved.

According to the global current optimal control theory, obtaining the estimation law of the dynamic limiting values of the d-axis voltage and the q-axis voltage, which comprises the following steps:

specifically, the case of the permanent magnet synchronous motor with variable load in forward rotation is taken as an example, and the case of reverse rotation can be analogized. The current working point when the permanent magnet synchronous motor stably rotates forwards is always positioned in the third quadrant of the d-axis and q-axis current planes, so that the q-axis current feedback value is always a positive value, the d-axis current feedback value is always a negative value, and the following discussion about the increase or decrease of the current value refers to the increase or decrease of the absolute value of the current.

When the permanent magnet synchronous motor operates in a constant torque area, the q-axis current feedback value increases along with the increase of the load, the d-axis current feedback value increases along with the increase of the q-axis current feedback value, and the increase rate is k₁The current working point is on the MTPA curve of the third quadrant of the d-axis and q-axis current plane; as the rotating speed of the permanent magnet synchronous motor rises, the voltage limit ellipse contracts towards the circle center, the current working point is forced to be separated from the MTPA curve and enter a weak magnetic I area, at the moment, the q-axis current feedback value is reduced along with the rise of the rotating speed of the motor, and the d-axis current feedback value is increased along with the rise of the rotating speed of the motor; when the rotating speed of the permanent magnet synchronous motor continuously rises, the current working point will fall on an MTPV curve, the q-axis current feedback value is reduced along with the rising of the rotating speed of the motor, and the d-axis current feedback value is reduced.

According to the theoretical analysis and experimental data, the magnitude of the current feedback value of the permanent magnet synchronous motor is related to the motor rotating speed and the load magnitude, and the load magnitude can be reflected by an electromagnetic torque reference value in a control loop of the permanent magnet synchronous motor. Therefore, the output clipping values (i.e., the clipping values for the d and q-axis voltage reference values) of the model-less adaptive current controller may be expressed as a function of the motor speed reference value and the electromagnetic torque reference value.

It should be noted that, since the q-axis current feedback value has a relatively small influence on the magnetic flux of the motor and is mainly related to the load capacity of the motor, in order to reduce the calculation amount of the control module, the limiter value of the q-axis voltage reference value is selected as an appropriate constant value, as shown in the following equation (17):

wherein, V_{q_lim}For limiting the reference value of the q-axis voltage, V is generally taken_{q_lim}＝V_{s_max}，V_{s_max}The voltage output limit for the inverter, also called the stator voltage limit.

The d-axis current feedback value can affect the magnetic flux of the motor to a great extent, and the excessive negative d-axis current is suddenly increased at the weak magnetic cut-in point to cause the excessive weakening of the magnetic flux of the motor, the mechanical characteristics of the motor become soft, the rotating speed rapidly rises, and finally the motor is out of control, so that dynamic amplitude limiting is necessary to be carried out on the d-axis voltage reference value.

According to the analysis and experimental data, when the current working point of the motor falls in the field weakening I area, the d-axis current feedback value increases along with the increase of the rotating speed of the motor, and in the deep field weakening area (namely MTPV working area), the d-axis current feedback value decreases along with the increase of the rotating speed of the motor, and meanwhile, the d-axis current feedback value has a certain correlation with the load size. Therefore, the lower limit value estimation law in the d-axis voltage dynamic limiting value estimation law is equivalent to a quadratic function related to the motor speed reference value and the electromagnetic torque reference value, the upper limit value estimation law is a given constant, and the constant is usually taken as the stator voltage limit value V_{s_max}As shown in the following formula (18), wherein V_{d_lower_lim}Dynamic lower limit of d-axis voltage value, V_{d_upper_lim}Upper limit of d-axis voltage value, ω_refAs reference value of the speed of rotation, T_{e_ref}As reference value of electromagnetic torque, V_{s_max}Is the stator voltage limit value, k₁Is a first estimated value parameter, which takes a value range of k₁>0，k₂Is a second estimated value parameter with the value range of k₂>0：

Step 206, obtaining d-axis and q-axis voltage reference values according to an IO parameter matrix estimation law and a voltage reference difference estimation law of the permanent magnet synchronous motor and d-axis and q-axis current reference values, and the method comprises the following steps:

acquiring d-axis and q-axis current feedback values, d-axis and q-axis current feedback values and d-axis and q-axis voltage reference values of a previous control period through a data acquisition unit;

estimating an IO parameter matrix according to d and q axis current feedback values of a current control period, d and q axis current feedback values of a previous control period, an IO difference vector and an IO parameter matrix estimation law to obtain an IO parameter matrix estimation value of the current control period;

estimating a voltage reference difference value according to an IO parameter matrix estimation value, d-axis and q-axis current reference values and feedback values of a current control period and a d-axis and q-axis voltage reference difference value estimation law so as to obtain d-axis and q-axis voltage reference difference values of the current control period;

and calculating and acquiring the d-axis voltage reference value and the q-axis voltage reference value of the current control period according to the d-axis voltage reference difference value and the q-axis voltage reference value of the current control period and the d-axis voltage reference value and the q-axis voltage reference value of the previous control period.

Specifically, in one embodiment, the obtaining, by the data acquisition unit, the d-axis and q-axis current feedback values and the d-axis and q-axis voltage reference values of the last control cycle includes:

in the running process of the motor, current feedback values of d and q axes in the current control period are obtained through a stator current detection unit, a Clark conversion unit and a Park conversion unit; acquiring d-axis and q-axis current reference values calculated in the step 202; and acquiring the d-axis and q-axis current feedback values and the d-axis and q-axis voltage reference values of the last control period through the storage variables in the control program.

Estimating an IO parameter matrix according to d and q axis current feedback values of a current control period, d and q axis current feedback values of a previous control period, an IO difference vector and an IO parameter matrix estimation law, and acquiring an IO parameter matrix estimation value of the current control period, wherein the method comprises the following steps:

specifically, the IO parameter matrix estimation law and the voltage reference of the permanent magnet synchronous motor are obtained through a model-free adaptive algorithmAfter the difference estimation rule, it may be stored in the control system in advance. Then in the control process, obtaining d and q axis current feedback values i of the current control period_d(k)、i_q(k) And obtaining the d and q axis current feedback values i of the previous control period from the database_d(k-1)、 i_q(k-1), and then calculating a difference value of the current feedback valuesAccording to the delta I (k), the IO parameter matrix of the current control period is estimated according to the IO parameter matrix estimation law shown in the formula (14) to obtain the IO parameter matrix estimation value of the current control period

Estimating a voltage reference difference value according to an IO parameter matrix estimation value, a d-axis current reference value, a q-axis current reference value, a feedback value and a d-axis voltage reference difference value estimation law of the current control period to obtain a d-axis voltage reference difference value and a q-axis voltage reference difference value of the current control period, wherein the method comprises the following steps:

specifically, d and q axis current reference values i according to the current control period_{d_ref}(k)、i_{q_ref}(k) And d, q axis current feedback values i_d(k)、i_q(k) And IO parameter matrix estimation

Estimating the d-axis and q-axis voltage reference difference values of the current control period according to the voltage reference difference value estimation law shown in the formula (16) to obtain the d-axis and q-axis voltage reference difference value delta V of the current control period_{d_ref}(k)、ΔV_{q_ref}(k)。

Calculating and acquiring the d-axis and q-axis voltage reference values of the current control period according to the d-axis and q-axis voltage reference difference values of the current control period and the d-axis and q-axis voltage reference values of the previous control period, wherein the method comprises the following steps:

specifically, d-axis and q-axis voltage reference difference value delta V of the current control period is obtained_{d_ref}(k)、ΔV_{q_ref}(k) And then, acquiring the d and q axes of the previous control period from the databaseVoltage reference value V_{d_ref}(k-1)、V_{q_ref}(k-1) to calculate d and q axis voltage reference values V for obtaining the current control period_{d_ref}(k)、V_{q_ref}(k) As shown in the following equation (19):

and 208, acquiring the dynamic limiting values of the d-axis voltage and the q-axis voltage according to the estimation law of the dynamic limiting values of the d-axis voltage and the q-axis voltage.

Specifically, according to the estimation law of the dynamic amplitude limiting values of the d-axis and q-axis voltages described in the above formula (18) and the electromagnetic torque reference value and the current reference value acquired by the data acquisition unit, the dynamic amplitude limiting values V of the d-axis and q-axis voltages in the current control period are estimated_{d_lower_lim}。

And step 210, carrying out amplitude limiting on the d-axis voltage reference value and the q-axis voltage reference value according to the d-axis voltage dynamic amplitude limiting value and the q-axis voltage dynamic amplitude limiting value, and controlling the permanent magnet synchronous motor according to the d-axis voltage reference value and the q-axis voltage reference value after dynamic amplitude limiting.

In particular, if V_{d_ref}<V_{d_lower_lim}Then order V_{d_ref}＝V_{d_lower_lim}If V is_{d_ref}>V_{d_upper_lim}Then order V_{d_ref}＝V_{d_upper_lim}Otherwise, no modification is made; if V_{q_ref}<V_{q_lower_lim}Then order V_{q_ref}＝V_{q_lower_lim}If V is_{q_ref}>V_{q_upper_lim}Then order V_{q_ref}＝V_{q_upper_lim}Otherwise, no modification is made.

The dynamic amplitude limiting is carried out on the d-axis and q-axis voltage reference values output by the model-free self-adaptive controller, so that the faults of current oscillation, motor overspeed and the like at a weak magnetic cut-in point and a deep weak magnetic area can be prevented, the system can stably run, and the robustness of the control method is enhanced.

And controlling the permanent magnet synchronous motor according to the d-axis and q-axis voltage reference values after dynamic amplitude limiting in the current control period. For details, reference may be made to the foregoing description, which is not repeated here

In the embodiment, the wide-range speed regulation control of the permanent magnet synchronous motor can be realized by the current control method based on the data fitting table look-up method and the model-free adaptive algorithm, the permanent magnet synchronous motor system is insensitive to the sudden change and the shooting of motor parameters in the operation process, the adverse influence of uncertain factors such as modeling errors and working condition sudden changes on the control effect is effectively inhibited, the constant-power operation can be stably switched from the constant-torque operation, the weak-magnetic speed expansion is realized, the stable operation of the system can be maintained in both a weak-magnetic switching-in point and a deep weak-magnetic area, and the method has the advantages of strong robustness, high current response speed, high tracking precision, small calculated amount, no dependence on expert experience and the like.

In one embodiment, the above method for controlling wide-range speed regulation of a permanent magnet synchronous motor further includes: and initializing the IO difference vector and the IO parameter matrix estimation value.

Specifically, when the permanent magnet synchronous motor is controlled, the related control parameters of the system may be initialized first, and specifically, the first preset pseudo-order L may be initialized_yA second predetermined pseudo-order L_uA preset step factor eta, a first preset weight mu and a preset step factor sequence rho_iA second preset weight lambda, an IO difference vector

And IO parameter matrix estimationInitialization is performed.

In addition, IO difference vector is also neededAnd IO parameter matrix estimation

Initialization is performed. For example, in the pair IO difference vector

When initializing, the difference value delta i of the feedback values of the d and q axes current under the initial state is considered_d(0)、 Δi_q(0) And dQ-axis voltage reference difference value delta V_{d_ref}(0)、ΔV_{q_ref}(0) Are all zero, at this time, the IO difference vectorInitial value of (2)Each element in (a zero vector) is zero. In-pair IO parameter matrix estimationWhen initialization is performed, the parameters corresponding to the control period before the 0 th control period are all zero, and the difference value Δ i of the d-axis current feedback value is the parameter corresponding to the 0 th control period_d(0) Corresponding parameter (i.e. IO parameter) is based onCalculating to obtain the difference value delta i of the feedback value of the q-axis current_q(0) Corresponding parameter is based onCalculating to obtain a d-axis voltage reference difference value delta V_{d_ref}(0) Corresponding parameters are based on

Calculating to obtain a q-axis voltage reference difference value delta V_{q_ref}(0) Corresponding difference value according toAnd (6) calculating and obtaining. The above-mentioned motor parameter R_s、 L_dAnd L_qOnly the magnitude of the order is known, and no precise value needs to be determined. Moreover, the algorithm convergence can be accelerated, the system stability can be enhanced, and the peak current during the motor starting can be restrained through the initialization mode.

In one embodiment, the above method for controlling wide-range speed regulation of a permanent magnet synchronous motor further includes: judging whether the IO parameter matrix estimation value of the current control period meets a preset reset condition or not; if so, resetting the IO parameter matrix estimation value of the current control period, and estimating the voltage reference difference value of the current control period according to the reset IO parameter matrix estimation value; and if not, estimating the voltage reference difference value of the current control period directly according to the IO parameter matrix estimation value of the current control period.

Specifically, the IO parameter matrix estimation value of the current control period of the permanent magnet synchronous motor is obtained through the IO parameter matrix estimation law shown in the above formula (14)

And if the preset reset condition is met, resetting the parameter matrix, so that the convergence speed of the algorithm is accelerated by limiting the IO parameter matrix estimation value.

In one embodiment, the determining whether the IO parameter matrix estimation value of the current control period satisfies a preset reset condition includes: sub-matrix for judging IO parameter matrix estimated value of current control period

Whether each element satisfies a preset reset condition and resets the element satisfying the reset condition to an initial value. Submatrix only requiring estimation of IO parameter matrixThe reset judgment and reset operation are carried out, the calculation amount is small, and the estimated value of the IO parameter matrix can be obtainedCorrections are made to speed up the algorithm convergence.

In one embodiment, the IO parameter matrix estimation value of the current control period is judged

Is sub-matrix ofAnd resetting the elements satisfying the preset reset condition to initial values, including:

if it is not

OrOrThen makeWherein the content of the first and second substances,is a sub-matrix

Diagonal element of b₂Is a first preset upper limit value, c is a first preset lower limit value,

is a sub-matrix

The initial value of the diagonal element of (1); if it is notOrThen makeWherein the content of the first and second substances,is a sub-matrixOff diagonal element of b₁Is the second preset lower limit value and is,is a sub-matrixThe initial value of the off-diagonal element of (a).

It should be noted that, since the sub-matrix

Diagonal line element ofIs d-axis voltage reference difference Δ V_{d_ref}(k) And q-axis voltage reference difference Δ V_{q_ref}(k) Parameter (d), thus Δ V_{d_ref}(k) The upper and lower limits of the corresponding parameter (i.e., IO parameter) may be based onCalculated to obtain, Δ V_{q_ref}(k) The upper and lower limits of the corresponding parameters can be based on

And calculating to obtain, wherein in the calculation, the motor parameter only needs to know the order of magnitude, and an accurate value does not need to be measured.

Further, aiming at the control method of the permanent magnet synchronous motor provided by the application, the inventor also provides a simulation comparison experiment. The experimental system adopts a PI controller for a rotating speed ring, the current ring adopts a motor system of a model-free self-adaptive controller for data fitting table look-up, the comparison system adopts a PI controller for the rotating speed ring, the current ring adopts a motor system of a conventional table look-up PI controller, the structure, parameters and data of the rotating speed ring PI controller of the experimental system and the rotating speed ring PI controller of the comparison system are kept completely consistent with those of a d-axis current reference value look-up table and a q-axis current reference value look-up table, and simulation comparison experiments are carried out under the same working condition. In the simulation process, the motor runs with a load of 0.1N m, the rotating speed reference value is given in a slope mode, the increasing rate is 2400RPM/s, the upper limit value is 13500RPM, and the total simulation running time is 6 s.

Fig. 3a is a d-axis current reference value simulation waveform of the experimental system, and fig. 3b is a d-axis current reference value simulation waveform of the control system. As can be seen from fig. 3a and 3b, at the weak magnetic cut-in point, the d-axis current reference value of the experimental system adopting the current control method of the present application decreases suddenly due to the action of dynamic amplitude limiting, and is only-1.25A, and then decreases with a fixed slope as the motor speed increases, and remains unchanged after the motor speed reaches 13500RPM and the speed increase process is completed. Because the data of the d-axis current reference value query table is subjected to fitting processing by the experimental system, the d-axis current reference value has smooth waveform, no burrs, peaks or oscillations, small impact on a motor system and contribution to stable operation of the system. The sudden drop of the d-axis current reference value of the comparison system at the weak magnetic cut-in point is large and reaches-2.25A, and in the subsequent accelerating process, the current working point of the d-axis current reference value lookup table is discontinuous, so that the d-axis current reference value repeatedly oscillates between two adjacent numerical values, which brings large impact to a motor system and is not beneficial to the stable operation of the system.

Fig. 3c is a simulation waveform of d-axis current feedback value of the experimental system, and fig. 3d is a simulation waveform of d-axis current feedback value of the comparative system. As can be seen from fig. 3c and 3d, the d-axis current feedback waveform of the experimental system has small fluctuation, the current spike at the weak magnetic cut-in point is small, and the current response is fast; the fluctuation range of the d-axis current feedback waveform of the experimental system is large, the current peak at the weak magnetic cut-in point is large, and the motor system is possibly impacted, so that the fluctuation of the motor rotating speed at the weak magnetic cut-in point is caused.

FIG. 3e is a q-axis current reference value simulation waveform for the experimental system, and FIG. 3f is a q-axis current reference value simulation waveform for the control system. As can be seen from fig. 3e and 3f, the simulated waveform of the q-axis current reference value of the experimental system is smooth and has no falling peak, and the waveform of the q-axis current reference value of the contrast system oscillates violently and has a severe falling peak. In addition, the q-axis current of the experimental system in a constant torque area is given to be smaller, corresponding loss is smaller, and the overall efficiency is higher.

Fig. 3g is a q-axis current feedback value simulation waveform of the experimental system, and fig. 3h is a q-axis current feedback value simulation waveform of the comparative system. As can be seen from fig. 3g and 3h, the peak of the q-axis current feedback waveform of the experimental system at the weak magnetic cut-in point is small, the fluctuation range of the q-axis current feedback value is small, and the current response speed is high; compared with a q-axis current feedback waveform of a weak magnetic entry point, the q-axis current feedback waveform of the system has obvious peak, the fluctuation range of the q-axis current feedback value is large, and a lot of burrs occur at a weak magnetic acceleration section, which brings adverse effects on the stable operation of the system.

Fig. 3i is a simulation waveform of the feedback value of the rotation speed of the experimental system, and fig. 3j is a simulation waveform of the feedback value of the rotation speed of the comparison system. As can be seen from fig. 3i and 3j, in the whole speed increasing process of the experimental system, the waveform of the speed feedback value is smoother, the speed increasing rate is consistent with the speed reference value, and no obvious fluctuation occurs; the waveform of the rotating speed feedback value of the experimental system fluctuates to a certain extent at the weak magnetic cut-in point and the rising speed ending point, which can bring adverse effect on the performance of the whole machine.

Therefore, it can be seen from the above simulation comparison experiment that the control method of the permanent magnet synchronous motor of the present application has the advantages of small data prestore amount, small calculated amount, fast convergence speed, smooth and non-oscillating waveforms of the reference values of the d-axis and q-axis currents, and can realize the automatic decoupling control of the d-axis and q-axis currents, ensure the fast tracking of the q-axis currents and the stable adjustment of the d-axis currents, and simultaneously suppress the current spikes at the starting and weak magnetic cut-in points of the motor, thereby being beneficial to the stable operation of the system. In addition, the motor control method provided by the invention has the capability of self-adaptive adjustment of IO parameters, so that the method has excellent robustness, strong adaptability to the change of motor parameters, insensitivity to uncertain factors caused by environmental change and strong anti-interference capability.

In summary, the method for controlling the wide-range speed regulation of the permanent magnet synchronous motor obtains the d-axis and q-axis current reference value query tables of each working area according to the MTPA algorithm, the MTPV algorithm and the weak magnetic control theory, and selects the secondary interpolation method and the biquadratic linear interpolation method to perform fitting processing on the data in the d-axis and q-axis current reference value query tables aiming at different working areas, so that the calculated d-axis and q-axis current reference values have smooth waveforms and have no sudden change or oscillation, dynamically linearizes the current model of the nonlinear permanent magnet synchronous motor into a full-format dynamic linear data model, realizes the control of the motor current according to the model-free adaptive algorithm on the basis, has the characteristics of small calculated amount and high convergence speed, can realize the automatic decoupling control of the d-axis and q-axis currents, and ensures the quick tracking of the q-axis current and the stable adjustment of the d-axis current, the dynamic limiting value estimation method has the advantages that the dynamic performance is excellent, the current fluctuation is small, in addition, the estimation law of the dynamic limiting values of the d-axis voltage and the q-axis voltage is obtained according to the global current optimal control theory, the dynamic limiting values of the d-axis voltage and the q-axis voltage are calculated in real time according to the rotating speed reference value and the electromagnetic torque reference value, the dynamic limiting values of the d-axis voltage and the q-axis voltage are subjected to dynamic limiting processing, and the stability of the system is further. The motor system applying the method is insensitive to uncertain factors caused by environmental changes, has strong anti-interference capability and strong adaptability to the change of motor parameters, and does not need to re-adjust the relevant model-free adaptive controller parameters when the controlled motor is replaced.

Fig. 4 is a wide-range speed regulation control device of a permanent magnet synchronous motor in an embodiment, as shown in fig. 4, including: the device comprises a current reference value acquisition unit 10, an algorithm acquisition unit 20, a first calculation unit 30, a second calculation unit 40 and a limiting control unit 50.

The current reference value obtaining unit 10 is configured to obtain d-axis and q-axis current reference values according to a data fitting table look-up method;

the algorithm obtaining unit 20 is configured to obtain an IO parameter matrix estimation law and a voltage reference difference estimation law of the permanent magnet synchronous motor according to a model-free adaptive algorithm, and obtain dynamic amplitude limiting value estimation laws of d-axis and q-axis voltages according to a global current optimal control theory;

the first calculating unit 30 is configured to obtain d-axis and q-axis voltage reference values according to an IO parameter matrix estimation law and a voltage reference difference estimation law of the permanent magnet synchronous motor and d-axis and q-axis current reference values;

the second calculating unit 40 is configured to obtain d-axis and q-axis voltage dynamic amplitude limiting values according to a d-axis and q-axis voltage dynamic amplitude limiting value estimation law;

and the amplitude limiting control unit 50 is used for carrying out amplitude limiting on the d-axis voltage reference value and the q-axis voltage reference value according to the d-axis voltage dynamic amplitude limiting value and the q-axis voltage dynamic amplitude limiting value, and controlling the permanent magnet synchronous motor according to the d-axis voltage reference value and the q-axis voltage reference value after dynamic amplitude limiting.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.