阅读说明：本技术 基于解耦信号的三级式无刷交流同步电机位置估计方法 (Three-stage brushless alternating current synchronous motor position estimation method based on decoupling signals ) 是由 魏佳丹 王俊杰 鲁恒 周波 于 2021-07-20 设计创作，主要内容包括：本发明公开了一种基于解耦信号的三级式无刷交流同步电机位置估计方法,所述方法具体为：输入单相交流电源至主励磁机的励磁绕组中,使得主励磁机转子侧感应出三相交流电源,所述旋转整流器将三相交流电源整流成含有偶次谐波高频分量的直流电源,将旋转整流器的输出输入至主发电机中,为主发电机的励磁绕组提供直流励磁,根据在主发电机电枢绕组中检测到的感应电流和提取的高频响应信号,生成与高频响应信号同步的同步解耦信号,采用外差法对同步解耦信号进行解调,实现主发电机转子位置角的估计。本发明无需额外使用滤波器,易于实施,能够获得较为准确的同步解耦信号。(The invention discloses a decoupling signal-based three-stage brushless alternating current synchronous motor position estimation method, which comprises the following steps: the method comprises the steps of inputting a single-phase alternating current power supply into an excitation winding of a main exciter to enable a rotor side of the main exciter to induce a three-phase alternating current power supply, rectifying the three-phase alternating current power supply into a direct current power supply containing even harmonic high-frequency components by using a rotating rectifier, inputting the output of the rotating rectifier into the main generator to provide direct current excitation for the excitation winding of the main generator, generating a synchronous decoupling signal synchronous with the high-frequency response signal according to the induced current detected in an armature winding of the main generator and the extracted high-frequency response signal, and demodulating the synchronous decoupling signal by adopting a heterodyne method to realize estimation of a position angle of a rotor of the main generator. The invention does not need to additionally use a filter, is easy to implement and can obtain more accurate synchronous decoupling signals.)

1. The three-stage brushless alternating current synchronous motor position estimation method based on the decoupling signal is characterized in that the three-stage brushless alternating current synchronous motor comprises a main exciter, a rotary rectifier and a main generator which are sequentially and coaxially arranged; the method specifically comprises the following steps: the method comprises the steps of inputting a single-phase alternating current power supply into an excitation winding of a main exciter to enable a rotor side of the main exciter to induce a three-phase alternating current power supply, rectifying the three-phase alternating current power supply into a direct current power supply containing even harmonic high-frequency components by using a rotating rectifier, inputting voltage output by the rotating rectifier into the main generator to provide direct current excitation for the excitation winding of the main generator, generating a synchronous decoupling signal synchronous with the high-frequency response signal according to the induced current detected in an armature winding of the main generator and the extracted high-frequency response signal, and demodulating the synchronous decoupling signal by adopting an heterodyne method to realize estimation of a position angle of a rotor of the main generator.

2. The decoupled signal based three-stage brushless AC synchronous motor position estimation method of claim 1, wherein a field current i in a field winding of the main exciter_efComprises the following steps:

ω_exfor angular frequency of exciting current, I_efIs an effective value of the exciting current, and t is a time variable;

the induced potentials of the three-phase alternating current power supply are respectively e_exa,e_exb,e_exc；e_exa,e_exb,e_excThe expression of (a) is:

in the formula M_efIs the maximum value of mutual inductance between stator and rotor windings of the main exciter, theta_e0Electrical angle of the initial position of the main exciter;

output voltage u of the rotating rectifier_fComprises the following steps:

in the formula of U_fIs a direct current component, u_nIs the amplitude of the 2n harmonic voltage,is the phase of the 2n harmonic voltage.

3. The decoupling signal based three-stage brushless AC synchronous motor position estimation method of claim 2, wherein the synchronous decoupling signal u is a synchronous decoupling signal_fhComprises the following steps:

wherein sgn (.) is a sign function, u_αhAnd u_βhRespectively representing the alpha-axis component and the beta-axis component u of the high-frequency response signal in a two-phase stationary coordinate system_αhAnd u_βhThe expression of (a) is:

is the phase, u, of the high-frequency response signal_hTheta is the main generator rotor position angle for the amplitude component of the high frequency response signal.

4. The decoupling signal based three-stage brushless AC synchronous motor position estimation method of claim 3, wherein sgn (u) is determined when the three-stage brushless AC synchronous motor is in a zero-speed stationary phase_fh) The expression of (a) is:

wherein i_αAnd i_βThe alpha-axis component and the beta-axis component of the induced current detected in the armature winding of the main generator under the two-phase static coordinate system are obtained;

sgn (u) when the three-stage brushless AC synchronous motor is in the low-speed starting stage_fh) The expression of (a) is:

is an estimate of the main generator rotor position angle.

Technical Field

The invention belongs to the technical field of motor control

Background

The starting and power generation integrated system can save a special starting device, save cost and reduce the volume and weight of the system, and is the core technology of a multi-electric/full-electric airplane. The rotary rectifier type three-level brushless alternating current synchronous motor removes an electric brush slip ring structure, and the output of the main exciter is rectified by the rotary rectifier to provide excitation for the main generator, so that the reliability of the system is improved. At present, a main power supply system of a multi-electric airplane B787 uses 4 250kVA three-stage brushless alternating current synchronous motors to realize a starting and power generation integrated system.

At present, the power generation and voltage regulation technology of the three-stage brushless alternating current synchronous motor is mature, and starting control is a key technology for realizing starting/power generation integration of the three-stage brushless alternating current synchronous motor. The start control of the three-stage synchronous motor depends on an accurate rotor position angle, and the rotor position information can be generally acquired by a position sensor such as a photoelectric encoder or a resolver. However, in a complicated and severe aviation environment, the use of the position sensor is limited, and therefore, research on the starting control of the three-stage brushless alternating current synchronous motor without the position sensor needs to be carried out.

The position estimation of the traditional synchronous motor in the low-speed starting stage generally uses a high-frequency signal injection method, wherein a high-frequency signal is injected at the stator side of a main generator, a high-frequency response signal containing rotor position information is extracted at the same side, and the amplitude modulation is carried out by a heterodyne method to obtain the position of a motor rotor. In order to improve the signal-to-noise ratio and ensure the position estimation accuracy, the method of injecting the high-frequency signal at the stator side needs to increase the amplitude of the injected high-frequency signal, which causes torque ripple at the time of starting. According to the structural particularity of the three-level synchronous motor, a high-frequency signal can be indirectly injected into a rotor winding of the main generator from the side of a main exciter, however, the indirectly injected high-frequency signal and the generated response signal phase information are unknown, and the rotor position cannot be directly demodulated and calculated through a heterodyne method. Therefore, the method for generating the synchronous decoupling signal in the position estimation process of the three-stage brushless alternating current synchronous motor has great research significance.

Disclosure of Invention

The purpose of the invention is as follows: in order to solve the problems in the prior art, the invention provides a signal three-stage brushless alternating current synchronous motor position estimation method.

The technical scheme is as follows: the invention provides a three-level brushless alternating current synchronous motor position estimation method based on a decoupling signal, wherein the three-level brushless alternating current synchronous motor comprises a main exciter, a rotary rectifier and a main generator which are coaxially arranged in sequence; the method specifically comprises the following steps: the method comprises the steps of inputting a single-phase alternating current power supply into an excitation winding of a main exciter to enable a rotor side of the main exciter to induce a three-phase alternating current power supply, rectifying the three-phase alternating current power supply into a direct current power supply containing even harmonic high-frequency components by using a rotating rectifier, inputting voltage output by the rotating rectifier into the main generator to provide direct current excitation for the excitation winding of the main generator, generating a synchronous decoupling signal synchronous with the high-frequency response signal according to the induced current detected in an armature winding of the main generator and the extracted high-frequency response signal, and demodulating the synchronous decoupling signal by adopting an heterodyne method to realize estimation of a position angle of a rotor of the main generator.

Further, a field current i in a field winding of the main exciter_efComprises the following steps:

ω_exfor angular frequency of exciting current, I_efIs an effective value of the exciting current, and t is a time variable;

the induced potentials of the three-phase alternating current power supply are respectively e_exa,e_exb,e_exc；e_exa,e_exb,e_excThe expression of (a) is:

in the formula M_efIs the maximum value of mutual inductance between stator and rotor windings of the main exciter, theta_e0Electrical angle of the initial position of the main exciter;

output voltage u of the rotating rectifier_fComprises the following steps:

in the formula of U_fIs a direct current component, u_nIs the amplitude of the 2n harmonic voltage,is the phase of the 2n harmonic voltage.

Further, the synchronous decoupling signal u_fhComprises the following steps:

wherein sgn (.) is a sign function, u_αhAnd u_βhRespectively representing the alpha-axis component and the beta-axis component u of the high-frequency response signal in a two-phase stationary coordinate system_αhAnd u_βhThe expression of (a) is:

is the phase, u, of the high-frequency response signal_hTheta is the main generator rotor position angle for the amplitude component of the high frequency response signal.

Further, sgn (u) when the three-stage brushless AC synchronous motor is in the zero-speed stationary phase_fh) The expression of (a) is:

wherein i_αAnd i_βThe alpha-axis component and the beta-axis component of the induced current detected in the armature winding of the main generator under the two-phase static coordinate system are obtained;

sgn (u) when the three-stage brushless AC synchronous motor is in the low-speed starting stage_fh) The expression of (a) is:

is an estimate of the main generator rotor position angle.

Has the advantages that:

(1) the method is applied to the position estimation process of the three-stage brushless alternating current synchronous motor in the starting stage, and can accurately generate the synchronous decoupling signal.

(2) The method does not need an additional filter, avoids using the filter to cause phase shift to the generated synchronous decoupling signal, and has higher phase precision of the generated synchronous decoupling signal.

(3) The method only detects the induced current at the stator side of the main generator and the armature winding voltage at the stator side, is easy to implement and reduces the complexity of system control.

Drawings

FIG. 1 is a schematic structural diagram of a three-stage brushless AC synchronous motor suitable for the method of the present invention;

FIG. 2 is a block diagram of a three-stage brushless AC synchronous motor position sensorless start control based on the method of the present invention;

FIG. 3 is a flow chart of a method of the present invention;

FIG. 4 is a simulation waveform diagram of a high-frequency response signal of a main generator stator side alpha shaft and a generated synchronous decoupling signal in a zero-speed static stage;

FIG. 5 is a simulation waveform diagram of a main generator stator side alpha shaft high-frequency response signal and a generated synchronous decoupling signal in a low-speed starting stage;

FIG. 6 is a graph of the simulation results of the comparison of the speed, position estimation angle and actual rotor angle and position estimation error for the three-stage brushless AC synchronous motor position sensorless start control based on the method of the present invention; wherein (a) is a plot of the rotational speed of the primary generator; (b) a comparison graph of the position angle estimated by the method of the invention and the actual rotor position angle is adopted; (c) the simulation result graph of the estimation error is obtained.

Detailed Description

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention.

The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

The structure schematic diagram of the three-level brushless alternating current synchronous motor applicable to the method of the present invention is shown in fig. 1, and the permanent magnet auxiliary exciter, the main exciter, the rotating rectifier and the main generator are coaxially connected. The main exciter stator side is a single-phase exciting winding, a single-phase alternating current with a certain frequency is introduced into the exciting winding (the main exciter adopts single-phase alternating current for excitation), the three-phase alternating current induced by the rotor side is rectified by a rotating rectifier to generate direct current containing even harmonic high-frequency components, excitation is provided for the main generator, and a second harmonic component in the direct current containing the even harmonic high-frequency components is a high-frequency excitation signal indirectly injected into the exciting winding of the main generator. A synchronous decoupling signal synchronized with the high frequency response signal is generated in conjunction with the sensed induced current on the stator side of the main generator and the extracted high frequency response voltage. And demodulating the synchronous decoupling signals by adopting a heterodyne method to realize the estimation of the rotor position angle.

As shown in fig. 2, the three-stage brushless ac synchronous motor sensorless start control block diagram according to the present invention omits the permanent magnet sub-exciter since the permanent magnet sub-exciter does not participate in the start process. The high-frequency response signal extracted by the band-pass filter is multiplied by the synchronous decoupling signal generated based on the method of the invention to carry out amplitude modulation, the high-frequency part is filtered by the low-pass filter to obtain the low-frequency component containing the rotor position information, and the low-frequency component is input into a phase-locked loop to calculate the rotor position. The specific process is as follows:

when the three-level brushless alternating current synchronous motor is started, the excitation mode of the main exciter is single-phase alternating current excitation with constant amplitude and frequency, and the excitation current is as follows:

I_efeffective value of exciting current, omega_exIs the angular frequency of the exciting current;

the three-phase induced potential generated on the rotor side is:

in the formula, M_efIs the maximum value of mutual inductance between stator and rotor windings of the main exciter, I_efEffective value of exciting current, omega_exFor angular frequency of exciting current, omega_erIs the main exciter rotor electrical angular frequency, theta_e0Electrical angle of the initial position of the main exciter. Since the frequency corresponding to the rotation speed is too low in the initial phase of the start-up, the cutting potential proportional to the rotation speed can be ignored, and the simplified induced potential is:

after the voltage is rectified by the rotating rectifier, the voltage injected into the excitation winding of the main generator is as follows:

in the formula of U_fIs a DC component in the excitation voltage, u_nIs the amplitude of the 2n harmonic voltage,is the phase of the 2n harmonic voltage, where the second harmonic is the high frequency excitation signal used for rotor position estimation. The main generator stator side armature winding induces a high frequency response signal containing rotor position information, which can be expressed on a two-phase stationary coordinate system as:

in the formula u_hIn order to be the amplitude of the high frequency response signal,theta is the phase of the high frequency response signal and theta is the main generator rotor position angle. u. of_αhAnd u_βhRespectively representing alpha-axis component and beta-axis component of high-frequency response signal in two-phase static coordinate system, and alpha-axis component u and beta-axis component u output from current loop of main generator_αAnd u_βIn which two identical band-pass filters are used to extract the high-frequency response signal u_αhAnd u_βhAnd obtaining the absolute value of the synchronous decoupling signal by carrying out square operation on the sum of squares of the two signals, and then carrying out positive and negative polarity reduction on the absolute value signal to obtain a final synchronous decoupling signal:

the positive and negative polarities of the synchronous decoupling signal are the polarities of the high-frequency response signal divided by the polarities of the sine and cosine values of the rotor position angle of the main generator:

sgn (.) is a sign function.

The synchronous decoupling signal polarity restoring comprises the following two stages:

(1) zero speed rest phase

At zero-speed standstill, the polarity of the initial position angle is determined by detecting the polarity of the stator-side induced current during the main generator excitation build-up. The judgment basis is as follows:

when i is_α< 0 and i_βAt < 0, the initial angle is between (0, 0.5 π), cos θ₀>0，sinθ₀>0；

When i is_αIs greater than 0 and i_βWhen < 0, the initial angle is between (0.5 pi, pi), cos theta₀<0，sinθ₀>0；

When i is_αIs greater than 0 and i_βAt > 0, the initial angle is between (pi, 1.5 pi), cos θ₀<0，sinθ₀<0；

When i is_α< 0 and i_βAt > 0, the initial angle is between (1.5 π, 2 π), cos θ₀>0，sinθ₀<0；

In the formula i_αAnd i_βIs the component of the induced current on the stator side of the main generator on the alpha axis and the beta circumference respectively on the two-phase static coordinate system₀The rotor position angle when the main generator is at rest. The above criteria can be summarized as follows:

due to u_αhAnd u_βhThere are many zero-crossing points, and the polarity judgment may fail near the zero-crossing point, so | u needs to be judged first_αhI and I u_βhAnd selecting the phase with larger amplitude value to carry out polarity reduction. The final calculated polar reduction formula is:

(2) low speed start phase

In the low-speed starting stage, the calculation formula of the polarity of the synchronous decoupling signal is as follows:

in the formula (I), the compound is shown in the specification,is the estimated rotor position angle. Likewise, selecting|u_αhI and I u_βhAnd (4) carrying out polarity reduction with larger amplitude in I. The final calculated polar reduction formula is:

FIG. 3 is a flow chart of the method of the present invention for generating a synchronous decoupling signal, including two phases, a stationary phase and a low speed phase.

In order to verify the effectiveness of the method, MATLAB/Simulink simulation is carried out on the three-stage brushless alternating current synchronous motor and the corresponding working condition in the embodiment. The working conditions are as follows: the excitation frequency of the main exciter is 100Hz, and the stator current i of the main generator is given_d ^*＝0，i_q ^*＝25A。

Fig. 4 is a simulation waveform diagram of the zero-speed stationary-stage alpha-axis high-frequency response signal and the generated synchronous decoupling signal obtained by MATLAB simulation, the solid line is the high-frequency response signal, the dotted line is the generated synchronous decoupling signal, and the phases of the two signals are consistent.

Fig. 5 is a simulation waveform diagram of the alpha-axis high-frequency response signal and the obtained synchronous decoupling signal at the low-speed starting stage obtained by MATLAB simulation, the solid line is the high-frequency response signal, the dotted line is the generated synchronous decoupling signal, and the phases of the two signals are consistent.

FIG. 6 is a diagram of simulation results of comparison of rotation speed, position estimation angle and actual rotor angle, and position estimation error based on the method of the present invention. In the rotor position-to-simulation result diagram, the dotted line represents the actual position, and the solid line represents the estimated position. And reducing the calculated synchronous decoupling signal polarity according to the detected induced current polarity at 0.2s to estimate the initial position of the rotor at rest, finishing the initial position estimation after 0.2s, starting the motor to rotate, and reducing the synchronous decoupling signal polarity by using the estimated rotor position. From simulation results, in the process that the motor is started from a static state to 200rpm, the estimation error of the rotor position is always maintained within 0.05rad, and the phases of the generated synchronous decoupling signal and the high-frequency response signal have good consistency.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.