阅读说明：本技术 一种永磁同步电机霍尔传感器容错控制方法 (Fault-tolerant control method for Hall sensor of permanent magnet synchronous motor ) 是由 孟智超 魏海峰 张懿 王浩陈 李垣江 于 2020-11-23 设计创作，主要内容包括：本发明公开了一种永磁同步电机霍尔传感器的容错控制方法,涉及永磁同步电机控制技术领域,包括：步骤1：根据Clark变换和Park变换获取永磁同步电机的转矩电流；步骤2：根据永磁同步电机的机械运动方程以及转矩的定义式找到电机加速度和转矩电流的关系；步骤3：将估算角速度和转矩电流差引入估算角加速度计算；步骤4：根据电机运行状态估算转子位置和速度；步骤5：将系统故障加速度替换成估算加速度。基于永磁同步电机霍尔传感器的容错控制方法,可以在霍尔传感器故障时,精确的估算出转子的位置及加速度,提高了永磁同步电机运动的准确度。(The invention discloses a fault-tolerant control method of a permanent magnet synchronous motor Hall sensor, which relates to the technical field of permanent magnet synchronous motor control and comprises the following steps: step 1: obtaining the torque current of the permanent magnet synchronous motor according to Clark conversion and Park conversion; step 2: finding the relation between the motor acceleration and the torque current according to the mechanical motion equation of the permanent magnet synchronous motor and the torque definition formula; and step 3: introducing the estimated angular velocity and the torque current difference into the estimated angular acceleration calculation; and 4, step 4: estimating the position and the speed of a rotor according to the running state of the motor; and 5: the system fault acceleration is replaced with the estimated acceleration. The fault-tolerant control method based on the permanent magnet synchronous motor Hall sensor can accurately estimate the position and the acceleration of the rotor when the Hall sensor fails, and improves the accuracy of the movement of the permanent magnet synchronous motor.)

1. A fault-tolerant control method based on a permanent magnet synchronous motor Hall sensor is characterized by comprising the following steps:

the method comprises the following steps: converting a three-phase current value of a permanent magnet synchronous motor under a natural coordinate system into a current value i under a two-phase d-q rotating coordinate system through Clark conversion and Park conversion_d、i_q；

Step two: obtaining a linear relational expression of motor acceleration and quadrature axis current by using a relational expression and a defining expression of the electromagnetic torque and the load torque of the permanent magnet synchronous motor;

step three: introducing the estimated angular velocity and the torque current difference into the estimated angular acceleration calculation;

step four: estimating the position and the rotating speed of a rotor according to the variable acceleration of the running state of the motor;

step five: the system estimated acceleration is replaced with the estimated acceleration.

2. The fault-tolerant control method based on the permanent magnet synchronous motor Hall sensor according to claim 1, characterized in that in step two, a relation between motor acceleration and torque current is derived by using a definition formula of electromagnetic torque and load torque of the permanent magnet synchronous motor and a mechanical motion equation, and the specific derivation process is as follows:

wherein: t is_LFor load torque, T_eIs electromagnetic torque, J is moment of inertia, n_pIs the number of pole pairs; Ψ_fFor rotor flux linkage, theta^*For estimated rotor angle, a^*Acceleration is estimated for the torque current.

3. The fault-tolerant control method based on the permanent magnet synchronous motor Hall sensor according to claim 1, characterized in that in step three, the torque current difference and the actual torque current difference are set to be larger in the motor acceleration and deceleration operation stage, so that the torque current difference and the estimated angular velocity are introduced into the motor angular acceleration calculation, and the estimation result is more accurate.

4. The fault-tolerant control method based on the permanent magnet synchronous motor Hall sensor according to claim 1, characterized in that in step three, when the motor is stably operated, the estimated acceleration is approximately zero, and the position and the rotating speed of the rotor are estimated according to the variation acceleration of the motor operation state, so that the estimation of the position and the rotating speed of the rotor is more accurate, and the improved 1-order acceleration angle estimation algorithm is as follows:

5. the fault-tolerant control method based on the permanent magnet synchronous motor Hall sensor as claimed in claim 1, wherein a more accurate rotor position and rotation speed are estimated according to the initial position of the motor rotor and the estimated motor acceleration, and the derivation formula is as follows:

thereby enabling a more accurate estimation of the position and angular velocity of the rotor.

Technical Field

The invention relates to the technical field of permanent magnet synchronous motor control, in particular to a fault-tolerant control method of a permanent magnet synchronous motor under the condition that a Hall sensor is damaged.

Background

The permanent magnet synchronous motor has the advantages of simple structure, high power density, simple control and the like. In recent years, permanent magnet synchronous motors are increasingly widely used in the industrial fields of high-performance speed regulation systems, servo control systems and the like.

A PMSM system which relies on a three-phase Hall position sensor to carry out rotor position estimation can cause damage to the Hall position sensor due to influences of high temperature, high humidity, salt fog and the like after working for a long time in a severe environment. Or lead to problems such as broken sensor wiring, internal aging, etc. due to long-term use. After a Hall element has a problem, the traditional observation algorithm cannot complete the estimation of the position of a rotor, and the motor cannot change the phase. The method has the following advantages that the method can cause the consequences which cannot be estimated in certain environments such as vehicle transportation and aviation and navigation.

The permanent magnet synchronous motor estimates the position of a rotor by using a position estimation method based on zero order speed at present, an algorithm for observing the position of the rotor by using the zero order speed can obtain a good effect when the motor runs in a steady state, but in a complex motor control system, under the working conditions of large disturbance or frequent acceleration and deceleration and the like, the zero order speed of a previous Hall interval is adopted to replace the instantaneous speed of the current Hall interval, and the accuracy of an estimation result is greatly reduced. Based on the method, in order to obtain high-precision speed and position estimation values, motor acceleration can be introduced to adapt to the running environment of the dynamic motor, and then the position of the rotor is estimated, so that the aim of accurately estimating the position of the rotor is fulfilled.

Disclosure of Invention

The invention provides a fault-tolerant control method of a permanent magnet synchronous motor, which aims to solve the problem that the permanent magnet synchronous motor in the prior art cannot be driven normally because the position of a rotor is difficult to estimate accurately after a Hall sensor fails.

The invention provides a fault-tolerant control method for a permanent magnet synchronous motor Hall sensor, which is characterized in that when the permanent magnet synchronous motor Hall sensor is damaged, the position of a rotor is estimated by acquiring the relation between motor quadrature axis current and motor running acceleration, and the fault-tolerant control method comprises the following steps:

step 1: obtaining an estimation method of the rotating speed of an inner rotor in a current Hall section by utilizing a three-phase Hall commutation principle of a permanent magnet synchronous motor;

step 2: obtaining a motor quadrature axis current value by Clark conversion and Park conversion;

and step 3: acquiring a relational expression of torque components according to a mechanical motion equation and definitions of electromagnetic torque and mechanical torque of the permanent magnet synchronous motor;

and 4, step 4: obtaining a relational expression of quadrature axis current and motor acceleration of the permanent magnet synchronous motor;

and 5: and estimating the position and the rotating speed of the rotor according to the variable acceleration of the running state of the motor.

Step 6: during the operation of the motor, the fault acceleration of the rotor is replaced by a more accurate estimated acceleration.

Optionally, in step 1, one electrical cycle of the permanent magnet synchronous motor is divided into six regions by the three-phase hall sensor of the permanent magnet synchronous motor, as shown in fig. 1, 6 regions are equally spaced by 60 electrical angles, and 6 accurate reference phases are located at the region boundary, and the rotor speed in the current hall region can be calculated assuming that the running time is the same in adjacent regions and the rotor speed is unchanged in a single hall region;

optionally, in step 2, since the permanent magnet synchronous motor is a complex nonlinear system, in order to simplify a mathematical model thereof and implement decoupling in control, corresponding coordinate system transformation, namely Clark transformation and Park transformation, needs to be established;

the three-phase current value of the permanent magnet synchronous motor in a natural coordinate system is converted into the current component of a d-q axis in a two-phase d-q rotating coordinate system through Clark conversion and Park conversion, namely, the decoupled exciting current i_dComponent, torque current i_qA component;

optionally, in step 3, in the operation process of the permanent magnet synchronous motor, the mechanical motion equation and the electromagnetic torque expression are as follows:

wherein: t is_LIs load torque, J is moment of inertia, T_eIs electricityMagnetic torque, #_fIs the rotor flux linkage.

Alternatively, step 4 is obtained from step 3, ignoring the start-up load torque (T)_L0), an estimated acceleration a during operation of the motor can be obtained^*And quadrature axis current i_qThere is a linear relationship between them.

Optionally, in step 5, the position and the rotational speed of the rotor are estimated according to the variation and acceleration of the operating state of the motor, so that the estimation of the position and the rotational speed of the rotor is more accurate, and the estimation algorithm of the acceleration and the angle is as follows:

alternatively, in step 6, in step five, a more accurate rotor position and angular velocity may be estimated. When the single-phase Hall position sensor has a fault, the estimated accurate acceleration is introduced into the switching time estimation so as to improve the control performance of the acceleration and deceleration stage when the Hall position sensor has a fault.

The invention at least comprises the following beneficial effects:

1. the invention provides a fault-tolerant control method of a permanent magnet synchronous motor, which solves the problem that the position of a rotor of the permanent magnet synchronous motor is difficult to accurately estimate after a Hall sensor fails in the prior art

2. The device solves the problem of low accuracy of the traditional rotor position estimation method in the acceleration and deceleration process of the permanent magnet synchronous motor.

Drawings

The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and not to be construed as limiting the invention in any way, and in which:

FIG. 1 is a three-phase Hall signal for one cycle;

FIG. 2 is an expanded view of a single-phase Hall fault section in the invention;

FIG. 3 is a fault tolerance diagram for a Hall position sensor;

FIG. 4 is a flow chart of the method of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a fault-tolerant control method for a permanent magnet synchronous motor Hall sensor, which comprises the following steps as shown in figure 4:

step S1: the permanent magnet synchronous motor is generally provided with three symmetrically-mounted hall sensors, and a coded signal generated by the three-phase hall sensors can divide one electric period (a linear relation is formed between the electric period and a physical period, and a proportionality coefficient of the coded signal depends on the number of pole pairs of the motor) of the permanent magnet synchronous motor into six regions, as shown in fig. 1. The coded signals are respectively: 101(5), 001(1), 011(3), 010(2), 110(6), 100(4), 6 areas are equally spaced by 60 electrical angles, and 6 accurate reference phases (phase 0-phase 5) are present at the boundary of the areas. The accurate rotor phase is very important for a permanent magnet synchronous motor control strategy, the accuracy of the phase directly influences the vibration, noise and efficiency of the motor in the operation process, and the rotating speed of the rotor in the current Hall interval can be calculated on the assumption that the operation time in adjacent intervals is the same and the rotating speed in a single Hall interval is unchanged; assuming that the operation time in the adjacent interval is the same and the rotating speed in the single Hall interval is unchanged, the rotating speed of the rotor in the current Hall interval can be calculated as follows:

ω(n)＝π/3(t-t_n)

wherein t is_nThe operating time of the rotor in the adjacent Hall intervals is shown, and n is the number of the Hall intervals.

Step S2: the permanent magnet synchronous motor is a complex nonlinear system, and corresponding coordinate system transformation, namely Clark transformation and Park transformation, needs to be established in order to simplify a mathematical model and realize decoupling on control.

Clark transformation: because the three-phase original dynamic model of the asynchronous motor is quite complex, the decomposition and the solution of the nonlinear equations are quite difficult, and the simplification needs to be realized in practical application, the basic idea of the simplification is to decompose the complex problem into a simple and easy-to-process problem, convert the complex three-phase coordinate system into an easily-understood two-phase coordinate system, namely convert the natural coordinate system ABC into a stationary coordinate system under alpha-beta.

Recording the phase currents of the three-phase alternating current system as follows:

wherein i_a、i_b、i_cRefer to instantaneous values, I, of ABC three-phase currents, respectively_mRefers to the three-phase current amplitude.

The instantaneous values of the ABC three-phase current are converted into values in an alpha-beta coordinate system through specific matrix transformation, namely, the change between the coordinate systems is carried out through Clark transformation.

Thus, a current i in an α - β coordinate system is obtained_α、i_β。

Since the PID controller has a better tracking effect on the dc reference signal, the stationary α, β coordinate system needs to be transformed into a rotating d-q coordinate system after the Clark transformation, and Park becomes the transformation of the stationary α - β coordinate system into a synchronously rotating d-q coordinate system. Physically, Park transform is to transform i_a、i_b、i_cAnd current projection is equivalent to a d-q axis of rotation, and the currents on the stator are equivalent to a direct axis and a quadrature axis. For steady state, after such an equivalence, i_q、i_dIs exactly one constant.

After the matrix transformation, namely Clark transformation and Park transformation, the quadrature axis current i is obtained_q。

Obtaining the current component of the d-q axis under a two-phase d-q rotating coordinate system, namely the decoupled torque current i, through Clark conversion and Park conversion_qComponent, excitation current i_dA component;

step S3: in a permanent magnet synchronous motor, electromagnetic torque is a rotating torque formed on a rotor by interaction of magnetic fluxes of poles of a rotating magnetic field of the motor and rotor current, and is one of the most important physical quantities of the motor for converting electric energy into mechanical energy; the load torque is the torque (torque or moment) required by the motor to drive the rotating load. In the case of neglecting the load torque, there are expressions of the mechanical equation of motion and the electromagnetic torque:

wherein: t is_LFor load torque, T_eIs electromagnetic torque, J is moment of inertia, n_pIs the number of pole pairs; Ψ_fFor rotor flux linkage, theta^*Is the estimated rotor angle;

step S4: and (4) obtaining a linear relation between the acceleration and the quadrature axis current according to the equation set in the step (3).

Wherein: n is_pIs the number of pole pairs; Ψ_fIs a rotor flux linkage; j is moment of inertia; a is^*Acceleration is estimated for the torque current. Combining the above equation set to obtain the linear relation between the estimated acceleration and the torque current, i_qIs in direct proportion.

Step S5: from step 4, the motor acceleration and Δ i_q＝i_q ^*-i_qA linear relationship exists. Setting torque current i in motor acceleration and deceleration running stage_q ^*With the actual torque current i_qDifference Δ i_q＝i_q ^*-i_qGreater, so will Δ i_q＝i_q ^*-i_qAnd an angular acceleration estimation formula is introduced, and the control performance in the acceleration and deceleration stage is improved. When the motor is running at low speed, i.e. estimating the speedn is rated speed, so as to reduce errorThe difference with the torque current introduces an estimated angular acceleration calculation. I.e. estimating the angular accelerationComprises the following steps:

step S6: and 4, estimating the position and the rotating speed of the rotor according to the variable acceleration of the running state of the motor, so that the estimation of the position and the rotating speed of the rotor is more accurate, wherein an acceleration angle estimation algorithm is as follows:

step S7: in step 6, more accurate rotor position and angular velocity can be obtained, and system fault acceleration a is obtained by assuming that the permanent magnet synchronous motor performs uniform acceleration motion and performs uniform motion in 2 intervals in the fault large interval_hReplaced by the estimated acceleration a^*。

Optionally, under the fault of the single-phase Hall position sensor, based on an improved system fault-tolerant control algorithm of a traditional 1-order acceleration estimation algorithm, the rotor position θ (t), the angular velocity ω (t), and the fault acceleration a (t) at the current moment:

optionally, when the single-phase Hall position sensor fails, an accurate estimated acceleration is introduced into the switching time estimation, so as to improve the control performance of the acceleration and deceleration stage when the Hall position sensor fails.

It is obvious that those skilled in the art can obtain various effects not directly mentioned according to the respective embodiments without trouble from various structures according to the embodiments of the present invention. While the invention/embodiments of the invention have been disclosed above, it is not limited to the applications listed in the description and the embodiments. It can be applied to all kinds of fields suitable for the present invention. Additional modifications will readily occur to those skilled in the art. It is therefore intended that the invention not be limited to the exact details and illustrations described and illustrated herein, but fall within the scope of the appended claims and equivalents thereof.