CN110198150A - A kind of permanent magnet synchronous motor multi-parameter on-line identification method - Google Patents

Abstract

A multi-parameter online identification method for a permanent magnet synchronous motor, comprising the following steps: step 1, establishing a mathematical model of the permanent magnet synchronous motor under a high-frequency voltage signal; step 2, calculating the current and dq-axis inductance of the PMSM under the excitation of a rotating high-frequency voltage signal ; Step 3, calculate the resistance of PMSM under excitation; Step 4, calculate the permanent magnet flux linkage of PMSM. The invention adopts the rotating high-frequency voltage signal injection to identify the dq-axis inductance of the permanent magnet synchronous motor online, adopts the square wave current signal to identify the resistance of the permanent magnet synchronous motor online, and adopts the model reference adaptive method to identify the permanent magnet flux linkage of the permanent magnet synchronous motor online. , to realize the multi-parameter online identification of the motor, which can be applied to the sensorless control to improve the control accuracy.

Description

A Multi-parameter Online Identification Method for Permanent Magnet Synchronous Motors

technical field

The invention belongs to the technical field of permanent magnet synchronous motor control, and relates to a multi-parameter online identification method of a permanent magnet synchronous motor.

Background technique

In recent years, with the development of power electronic technology and rare earth materials, permanent magnet synchronous motor (PMSM) has been widely used in industrial automation, aerospace and people's daily life. The high-performance permanent magnet synchronous motor speed control system needs the rotor position and speed signals to realize the speed closed-loop control. Although these signals can be accurately detected by mechanical sensors, mechanical position sensors are expensive and cumbersome, reducing the reliability of the system. In the field of high-reliability motor drive systems such as aerospace, due to their own space constraints, installing position or speed sensors not only increases the weight and complexity of the system, but also increases the failure rate of the system.

In order to realize the sensorless control of the permanent magnet synchronous motor speed control system, the motor parameters as accurate as possible are required. In practical situations, the motor parameters will change with the changes of environmental temperature, magnetic saturation effect, operating frequency and other factors. Therefore, the online parameter identification of the motor is very important for the realization of high-performance control strategies.

SUMMARY OF THE INVENTION

In order to solve the deficiencies mentioned in the above background art, the present invention provides a multi-parameter online identification method for a permanent magnet synchronous motor. The electrical parameters of the permanent magnet synchronous motor include stator resistance, rotor flux linkage, direct-axis inductance and quadrature-axis inductance. The multi-parameter identification problem described below refers to the identification of these four parameters. At present, the research on PMSM parameter identification mainly focuses on the identification of multiple parameters. First, due to the lack of rank of the established system model, most algorithms can only identify one or two parameters, and for the identification of three parameters, the convergence and uniqueness of the results lack theoretical basis; second, under the identification algorithm, using External signal injection, changing the motor running state and other methods to identify parameters are not suitable for online identification of motor parameters; third, the complexity of the algorithm and the amount of calculation make the solution difficult to implement.

The technical solutions proposed to solve the above technical problems are as follows:

A multi-parameter online identification method for a permanent magnet synchronous motor, the method comprises the following steps:

Step 1, establish the mathematical model of the permanent magnet synchronous motor under the high frequency voltage signal, the process is as follows:

1.1 In the dq two-phase synchronous rotation coordinate system, the voltage state equation of the built-in permanent magnet synchronous motor IPMSM is expressed in the form of a matrix as follows

where _ud , u _q , _id and i _q are the stator voltage and current in the synchronous rotating coordinate system, respectively, R _s is the stator resistance, L _d and L _q are the d and q-axis inductances, ω _e is the electrical angular velocity, ψ _f is the flux linkage amplitude of the permanent magnet rotor;

1.2 The frequency of the high-frequency injection signal is much higher than the fundamental frequency of the motor, so the three-phase PMSM is regarded as an RL circuit; because the resistance is very small relative to the reactance at high frequency, it can be ignored; at this time, the high frequency of the three-phase PMSM The frequency-voltage equation simplifies to

In the formula, u _dh , u _qh , i _dh , and i _qh are the high-frequency voltage and current components of the d and q axes, respectively; the subscript h represents the high-frequency quantity;

Step 2: Calculate the current and dq-axis inductance of the PMSM under the excitation of the rotating high-frequency voltage signal. The process is as follows:

2.1 Define the frequency of the injected high-frequency signal as ω _h and the amplitude as U _h , then the injected high-frequency voltage signal is expressed as

In the formula, u _αh and u _βh are the high-frequency voltage components of the αβ axis, respectively;

2.2 u _αβh is transformed into a complex variable in the complex plane

2.3 Transform the formula (4) into the synchronous rotation coordinate system, we get

2.4 Substituting formula (5) into formula (2), the current response equation of the three-phase PMSM under the high frequency voltage excitation in the rotating coordinate system is:

2.5 Transforming formula (6) into the static coordinate system, we get

In the formula, I _cp is the amplitude of the positive phase sequence high-frequency current component, that is I _cn is the amplitude of the negative phase sequence high frequency current component, namely

It can be seen from formula (7) that the high-frequency current response contains two components: the first is the positive phase sequence component, whose rotation direction is the same as the direction of the injected voltage vector, and the amplitude is related to the average inductance; the second is the positive phase sequence component , its rotation direction is opposite to the direction of the injected voltage vector, and its amplitude is related to the semi-difference inductance;

The high-pass filter of the synchronous shaft system transforms the high-frequency current vector into a reference coordinate system that rotates synchronously with the injected high-frequency voltage vector through coordinate transformation. The high-pass filter filters it out; then the signal is restored through the inverse coordinate system of the previous reference coordinate system, and finally the amplitude of the negative-sequence current is extracted by transformation; similarly, the amplitude of the positive-sequence current is extracted; finally , the dq-axis inductance is calculated by the amplitude of the extracted positive and negative sequence currents;

Step 3, calculate the resistance of PMSM under excitation, the process is as follows:

3.1 The voltage equation of PMSM in the estimated dq coordinate system is given by

In the formula, is the Parker transform, To estimate the angle between the dq axis and the actual dq axis, θ _e is the actual rotor position, To estimate the rotor position, is the speed difference, ω _e is the actual speed, To estimate the speed, are the estimated voltage and current of the dq axis, respectively, L _Σ =(L _d +L _q )/2 is the average inductance, and L _Δ =(L _d -L _q )/2 is the difference inductance;

3.2 When the position error is small, formula (10) is simplified to

3.3 Since the d-axis voltage equation is relatively simple, it is used to identify the stator resistance

3.4 When the motor is running at a constant speed, Equation (12) simplifies to

3.5 In order to identify the resistance stably online, inject a periodic square wave current with alternating positive and negative amplitudes on the estimated d-axis, we get

In the formula,

3.6 After the estimated d-axis current reaches the reference value, the estimated voltage on the d-axis is stored and averaged; using the two averaged voltages, the estimated resistance is obtained

In the formula, "-" represents the average value;

Step 4, calculate the permanent magnet flux linkage of PMSM, the process is as follows:

4.1 The current equation of PMSM in the dq coordinate system is

4.2 According to formula (16), the current equation of PMSM in the estimated dq coordinate system is

In the formula, To estimate the permanent magnet flux linkage;

4.3 Definitions is the generalized error vector, and the error state equation is obtained by formula (16) and formula (17)

where A, B, and C are the coefficient matrices of the actual system, respectively, are the coefficient matrices of the estimated system, respectively, are the difference of the coefficient matrix, respectively;

4.4 Using formula (18), the linear compensation matrix D is introduced, and the MRAS is transformed into an equivalent feedback system as

4.5 Take D as the unit matrix E to ensure the strict positive real of the feedforward linear model, and then consider the Popov integral inequality

4.6 In order to satisfy the formula (20), according to the traditional form of self-adaptation rule, the self-adaptive law of the proportional plus integral structure is selected to obtain the self-adaptive law of the permanent magnet flux linkage.

According to formulas (8), (9), (15) and (21), the dq-axis inductance, resistance and permanent magnet flux linkage of the motor are obtained, and the multi-parameter online identification of permanent magnet synchronous motor is realized.

The invention adopts the rotating high-frequency voltage signal injection to identify the dq-axis inductance of the permanent magnet synchronous motor online, adopts the square wave current signal to identify the resistance of the permanent magnet synchronous motor online, and adopts the model reference adaptive method to identify the permanent magnet flux linkage of the permanent magnet synchronous motor online. , to realize the online multi-parameter identification of the motor.

The technical idea of the present invention is as follows: for the multi-parameter online identification of the permanent magnet synchronous motor, a rotating high-frequency voltage signal is superimposed on the fundamental wave, then the current response in the permanent magnet synchronous motor is detected, and the signal is demodulated and processed to extract Negative phase sequence and positive phase sequence high-frequency current, and finally use the amplitude of positive and negative phase sequence high-frequency current to calculate the dq-axis inductance of the motor. By injecting a periodic square wave d-axis current with alternating positive and negative amplitudes, the d-axis voltage and q-axis current are detected, and then the resistance of the PMSM is calculated. Using the model reference adaptive method, the adaptive law of the permanent magnet flux linkage is obtained, and the permanent magnet flux linkage of the permanent magnet synchronous motor is calculated by collecting experimental data online.

The beneficial effects of the invention are as follows: through signal injection, the problem of lack of rank in the multi-parameter identification of the permanent magnet synchronous motor is solved, and the multi-parameter online identification of the permanent magnet synchronous motor can be realized, which can be applied to the position sensorless control and improve the control accuracy.

Description of drawings

Fig. 1 is the whole system structure block diagram of the present invention;

FIG. 2 is a schematic diagram of the positional relationship among the two-phase stationary coordinate system, the actual two-phase synchronous rotating coordinate system, and the estimated two-phase synchronous rotating coordinate system.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings.

1 and 2, a multi-parameter online identification method for a permanent magnet synchronous motor, the method includes the following steps:

Step 1, establish the mathematical model of the permanent magnet synchronous motor under the high frequency voltage signal, the process is as follows:

1.1 In the dq two-phase synchronous rotation coordinate system, the voltage state equation of the built-in permanent magnet synchronous motor IPMSM is expressed in the form of a matrix as follows

where _ud , u _q , _id and i _q are the stator voltage and current in the synchronous rotating coordinate system, respectively, R _s is the stator resistance, L _d and L _q are the d and q-axis inductances, ω _e is the electrical angular velocity, ψ _f is the flux linkage amplitude of the permanent magnet rotor;

1.2 The frequency of the high-frequency injection signal is much higher than the fundamental frequency of the motor, so the three-phase PMSM is regarded as a RL circuit; because the resistance is very small relative to the reactance at high frequency, it is ignored; at this time, the three-phase PMSM The high frequency voltage equation simplifies to

In the formula, u _dh , u _qh , i _dh , and i _qh are the high-frequency voltage and current components of the d and q axes, respectively; the subscript h represents the high-frequency quantity;

Step 2: Calculate the current and dq-axis inductance of the PMSM under the excitation of the rotating high-frequency voltage signal. The process is as follows:

2.1 Define the frequency of the injected high-frequency signal as ω _h and the amplitude as U _h , then the injected high-frequency voltage signal is expressed as

In the formula, u _αh and u _βh are the high-frequency voltage components of the αβ axis, respectively;

2.2 u _αβh is transformed into a complex variable in the complex plane

2.3 Transform the formula (4) into the synchronous rotation coordinate system, we get

2.4 Substituting formula (5) into formula (2), the current response equation of the three-phase PMSM under the high frequency voltage excitation in the rotating coordinate system is:

2.5 Transforming formula (6) into the static coordinate system, we get

In the formula, I _cp is the amplitude of the positive phase sequence high-frequency current component, that is I _cn is the amplitude of the negative phase sequence high frequency current component, namely

It can be seen from formula (7) that the high-frequency current response contains two components: the first is the positive phase sequence component, whose rotation direction is the same as the direction of the injected voltage vector, and the amplitude is related to the average inductance; the second is the positive phase sequence component , its rotation direction is opposite to the direction of the injected voltage vector, and its amplitude is related to the semi-difference inductance;

In order to extract the negative phase sequence high frequency current, the fundamental frequency current, low order harmonic current, PWM switching frequency harmonic current and positive phase sequence high frequency current of the motor terminal current must be well filtered; The amplitude of the frequency current is very different, and the carrier frequency is much higher than the injected high frequency frequency, both of which can be filtered out by a conventional band-pass filter; the positive phase sequence component and the negative phase sequence component of the carrier current rotate in opposite directions, Therefore, the positive sequence current component can be filtered out by the high-pass filter of the synchronous shaft system;

The high-pass filter of the synchronous shaft system transforms the high-frequency current vector into a reference coordinate system that rotates synchronously with the injected high-frequency voltage vector through coordinate transformation. The high-pass filter filters it out; then the signal is restored through the inverse coordinate system of the previous reference coordinate system, and finally the amplitude of the negative-sequence current is extracted by transformation; similarly, the amplitude of the positive-sequence current is extracted; finally , the dq-axis inductance is calculated by the amplitude of the extracted positive and negative sequence currents;

The reason why the high-frequency signal is injected into the αβ axis instead of the dq axis is to consider that the identification of the inductance in the static coordinate system will not cause errors due to the inaccurate coordinate system of the dq axis, and the expression of the inductance does not contain electrical angular velocity, etc. Physical quantity, the amount of calculation is relatively small, and it is easy to implement in engineering;

Step 3, calculate the resistance of PMSM under excitation, the process is as follows:

3.1 The voltage equation of PMSM in the estimated dq coordinate system is given by

In the formula, is the Parker transform, To estimate the angle between the dq axis and the actual dq axis, θ _e is the actual rotor position, To estimate the rotor position, is the speed difference, ω _e is the actual speed, To estimate the speed, are the estimated voltage and current of the dq axis, respectively, L _Σ =(L _d +L _q )/2 is the average inductance, and L _Δ =(L _d -L _q )/2 is the difference inductance;

3.2 When the position error is small, formula (10) is simplified to

3.3 Since the d-axis voltage equation is relatively simple, it is used to identify the stator resistance

3.4 When the motor is running at a constant speed, Equation (12) simplifies to

3.5 In order to identify the resistance stably online, inject a periodic square wave current with alternating positive and negative amplitudes on the estimated d-axis, we get

In the formula,

3.6 After the estimated d-axis current reaches the reference value, the estimated voltage on the d-axis is stored and averaged; using the two averaged voltages, the estimated resistance is obtained

In the formula, "-" represents the average value;

Step 4, calculate the permanent magnet flux linkage of PMSM, the process is as follows:

4.1 The current equation of PMSM in the dq coordinate system is

4.2 According to formula (16), the current equation of PMSM in the estimated dq coordinate system is

In the formula, To estimate the permanent magnet flux linkage;

4.3 Definitions is the generalized error vector, and the error state equation is obtained by formula (16) and formula (17)

where A, B, and C are the coefficient matrices of the actual system, respectively, are the coefficient matrices of the estimated system, respectively, are the difference of the coefficient matrix, respectively;

4.4 Using formula (18), the linear compensation matrix D is introduced, and the MRAS is transformed into an equivalent feedback system as

4.5 Take D as the unit matrix E to ensure the strict positive real of the feedforward linear model, and then consider the Popov integral inequality

4.6 In order to satisfy the formula (20), according to the traditional form of self-adaptation rule, the self-adaptive law of the proportional plus integral structure is selected to obtain the self-adaptive law of the permanent magnet flux linkage.

According to formulas (8), (9), (15) and (21), the dq-axis inductance, resistance and permanent magnet flux linkage of the motor are obtained, and the multi-parameter online identification of permanent magnet synchronous motor is realized.

Claims (1)

1. a multi-parameter online identification method for permanent magnet synchronous motor, is characterized in that: described method comprises the following steps: Step 1, establish the mathematical model of the permanent magnet synchronous motor under the high frequency voltage signal, the process is as follows: 1.1 In the dq two-phase synchronous rotation coordinate system, the voltage state equation of the built-in permanent magnet synchronous motor IPMSM is expressed in the form of a matrix as follows where _ud , u _q , _id and i _q are the stator voltage and current in the synchronous rotating coordinate system, respectively, R _s is the stator resistance, L _d and L _q are the d and q-axis inductances, ω _e is the electrical angular velocity, ψ _f is the flux linkage amplitude of the permanent magnet rotor; 1.2 The frequency of the high-frequency injection signal is much higher than the fundamental frequency of the motor, so the three-phase PMSM is regarded as an RL circuit; because the resistance is very small relative to the reactance at high frequency, it is ignored; at this time, the high The frequency-voltage equation simplifies to In the formula, u _dh , u _qh , i _dh , and i _qh are the high-frequency voltage and current components of the d and q axes, respectively; the subscript h represents the high-frequency quantity; Step 2: Calculate the current and dq-axis inductance of the PMSM under the excitation of the rotating high-frequency voltage signal. The process is as follows: 2.1 Define the frequency of the injected high-frequency signal as ω _h and the amplitude as U _h , then the injected high-frequency voltage signal is expressed as In the formula, u _αh and u _βh are the high-frequency voltage components of the αβ axis, respectively; 2.2 Transform u _αβh into a complex variable in the complex plane 2.3 Transforming formula (4) into the synchronous rotation coordinate system, we get 2.4 Substituting formula (5) into formula (2), the current response equation of the three-phase PMSM under the high-frequency voltage excitation in the rotating coordinate system is: 2.5 Transforming formula (6) into the static coordinate system, we get In the formula, I _cp is the amplitude of the positive phase sequence high-frequency current component, that is I _cn is the amplitude of the negative phase sequence high frequency current component, namely It can be seen from formula (7) that the high-frequency current response contains two components: the first is the positive phase sequence component, whose rotation direction is the same as the direction of the injected voltage vector, and the amplitude is related to the average inductance; the second is the positive phase sequence component , its rotation direction is opposite to the direction of the injected voltage vector, and its amplitude is related to the semi-difference inductance; The high-pass filter of the synchronous shaft system transforms the high-frequency current vector into a reference coordinate system that rotates synchronously with the injected high-frequency voltage vector through coordinate transformation. The high-pass filter filters it out; then the signal is restored through the inverse coordinate system of the previous reference coordinate system, and finally the amplitude of the negative-sequence current is extracted by transformation; similarly, the amplitude of the positive-sequence current is extracted; finally , the dq-axis inductance is calculated by the amplitude of the extracted positive and negative sequence currents; Step 3, calculate the resistance of PMSM under excitation, the process is as follows: 3.1 The voltage equation of PMSM in the estimated dq coordinate system is given by In the formula, is the Parker transform, To estimate the angle between the dq axis and the actual dq axis, θ _e is the actual rotor position, To estimate the rotor position, is the speed difference, ω _e is the actual speed, To estimate the speed, are the estimated voltage and current of the dq axis, respectively, L _Σ =(L _d +L _q )/2 is the average inductance, and L _Δ =(L _d -L _q )/2 is the difference inductance; 3.2 When the position error is small, formula (10) is simplified to 3.3 Since the d-axis voltage equation is relatively simple, it is used to identify the stator resistance 3.4 When the motor is running at a constant speed, Equation (12) simplifies to 3.5 In order to identify the resistance stably online, inject a periodic square wave current with alternating positive and negative amplitudes on the estimated d-axis, we get In the formula, 3.6 After the estimated d-axis current reaches the reference value, the estimated d-axis voltage is stored and averaged; using the two averaged voltages, the estimated resistance is obtained In the formula, "" represents the average value; Step 4, calculate the permanent magnet flux linkage of PMSM, the process is as follows: 4.1 The current equation of PMSM in the dq coordinate system is 4.2 According to formula (16), the current equation of PMSM in the estimated dq coordinate system is In the formula, To estimate the permanent magnet flux linkage; 4.3 Definitions is the generalized error vector, and the error state equation is obtained by formula (16) and formula (17) where A, B, and C are the coefficient matrices of the actual system, respectively, are the coefficient matrices of the estimated system, respectively, are the difference of the coefficient matrix, respectively; 4.4 Using formula (18), the linear compensation matrix D is introduced, and the MRAS is transformed into an equivalent feedback system as 4.5 Take D as the unit matrix E to ensure the strict positive real of the feedforward linear model, and then consider the Popov integral inequality 4.6 In order to satisfy formula (20), according to the traditional form of self-adaptation rule, the self-adaptive law of the proportional plus integral structure is selected to obtain the self-adaptive law of the permanent magnet flux linkage According to formulas (8), (9), (15) and (21), the dq-axis inductance, resistance and permanent magnet flux linkage of the motor are obtained, and the multi-parameter online identification of permanent magnet synchronous motor is realized.