A sensorless control method for permanent magnet synchronous motor

Abstract

The application relates to the technical field of motor control, and discloses a permanent magnet synchronous motor position sensorless control method, which comprises the following steps: constructing an extended back electromotive force disturbance observer and a dynamic error disturbance observer; based on a stator voltage instruction value and a stator current actual value, an extended back electromotive force estimation value is calculated by using the extended back electromotive force disturbance observer; an initial rotating speed estimation value is determined based on the extended back electromotive force estimation value; based on the extended back electromotive force estimation value, a dynamic error disturbance estimation value is calculated by using the dynamic error disturbance observer, and a rotating speed compensation amount is obtained based on the dynamic error disturbance estimation value; the initial rotating speed estimation value is dynamically error compensated by using the rotating speed compensation amount, a rotating speed estimation value is obtained, and a rotor position information estimation value is calculated based on the rotating speed estimation value; and the permanent magnet synchronous motor is vector controlled by using the rotor position information estimation value. The application improves the dynamic performance of the built-in permanent magnet synchronous motor position sensorless control.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, specifically a sensorless control method for a permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) offer advantages such as high efficiency, high power density, strong overload capacity, and convenient maintenance, leading to their widespread application in industrial fields such as new energy power generation, rail transportation, and electric vehicles. In the control of PMSMs, rotor position is crucial, and the accuracy of the estimated rotor position information directly impacts the accuracy and stability of the control. To obtain accurate rotor position estimates, position sensors are typically installed on the motor shaft. In some outdoor applications, harsh working environments, such as mechanical vibration, humidity, and temperature variations, can cause position sensor malfunctions, leading to failures in the entire control system and affecting its reliability and safety.

[0003] To address the problems caused by position sensor failure, research was conducted on sensorless control of permanent magnet synchronous motors. However, the relevant sensorless control methods for permanent magnet synchronous motors neglect the adverse effects of speed error and linearization error terms on the performance of estimating speed and rotor position during dynamic operation, resulting in deteriorated dynamic performance of sensorless control of permanent magnet synchronous motors. Summary of the Invention

[0004] In view of this, the present invention provides a sensorless control method for permanent magnet synchronous motors to solve the problem that the dynamic performance of related sensorless control methods for permanent magnet synchronous motors deteriorates during the dynamic operation of the motor.

[0005] In a first aspect, the present invention provides a sensorless control method for a permanent magnet synchronous motor, the method comprising:

[0006] Construct an extended back-EMF perturbation observer and a dynamic error perturbation observer;

[0007] Obtain the stator voltage command value and stator current actual value of the permanent magnet synchronous motor. Based on the stator voltage command value and stator current actual value, calculate the extended back EMF estimate value using the extended back EMF disturbance observer.

[0008] The initial rotational speed estimate is determined based on the extended back EMF estimate;

[0009] Based on the extended back EMF estimate, the dynamic error disturbance estimate is calculated using a dynamic error disturbance observer, and the speed compensation amount is obtained based on the dynamic error disturbance estimate.

[0010] The initial speed estimate is dynamically compensated by the speed compensation amount to obtain the speed estimate, and the rotor position information estimate is calculated based on the speed estimate.

[0011] Vector control of a permanent magnet synchronous motor is performed using rotor position information estimation.

[0012] This embodiment provides a sensorless control method for a permanent magnet synchronous motor. It constructs an extended back-EMF disturbance observer and a dynamic error disturbance observer, calculates the extended back-EMF estimate using the extended back-EMF disturbance observer, determines the initial speed estimate based on the extended back-EMF estimate, calculates the dynamic error disturbance estimate using the dynamic error disturbance observer, obtains the speed compensation amount based on the dynamic error disturbance estimate, and then uses the speed compensation amount to perform dynamic error compensation on the initial speed estimate. Finally, it uses the rotor position information estimate to perform vector control on the permanent magnet synchronous motor. By constructing the dynamic error disturbance observer and performing dynamic error compensation on the initial speed estimate, it considers the impact of speed error terms and linearization error terms on the performance of estimated speed and rotor position during dynamic motor operation, thus improving the dynamic performance of sensorless control of the built-in permanent magnet synchronous motor.

[0013] In one alternative implementation, an extended back-potential perturbation observer and a dynamic error perturbation observer are constructed, including:

[0014] The linear state equation of a permanent magnet synchronous motor in a two-phase synchronous rotating coordinate system is obtained. Based on the linear state equation of the permanent magnet synchronous motor in a two-phase synchronous rotating coordinate system, an extended back EMF disturbance observer and a dynamic error disturbance observer are constructed respectively.

[0015] This embodiment provides a sensorless control method for a permanent magnet synchronous motor. Based on the construction of an extended back EMF disturbance observer, a dynamic error disturbance observer is constructed based on the linear state equation of the permanent magnet synchronous motor in a two-phase synchronous rotating coordinate system. The speed error term and linearization error term ignored in the construction of the extended back EMF disturbance observer are taken as the total system disturbance, and then the dynamic error disturbance observer is constructed. This lays the foundation for subsequent dynamic error compensation of the initial speed estimate and improves the dynamic performance of speed estimation and rotor position estimation.

[0016] In one optional implementation, an extended back EMF disturbance observer and a dynamic error disturbance observer are constructed based on the linear state equations of the permanent magnet synchronous motor in a two-phase synchronous rotating coordinate system, including:

[0017] The expression for the extended back-potential perturbation observer is shown below:

[0018]

[0019] in, This represents the first derivative of the current. Represents the first matrix coefficient, where i represents the actual value of the stator current, A. 12 Denotes the coefficients of the second matrix. This represents the extended back potential estimate, u. s Indicates the stator voltage command value. denoted by the derivative of the extended back EMF estimate, and G represents the first feedback gain;

[0020] The expression for the dynamic error disturbance observer is as follows:

[0021]

[0022] in, B1 represents the estimated value of dynamic error disturbance, and B1 represents the coefficients of the third matrix. Let L represent the derivative of the dynamic error disturbance estimate, and let L represent the second feedback gain.

[0023] In one alternative implementation, determining the initial rotational speed estimate based on the extended back EMF estimate includes:

[0024] The rotor position error estimate is calculated based on the extended back EMF estimate.

[0025] By controlling the rotor position error estimate, an initial speed estimate is obtained.

[0026] This embodiment provides a sensorless control method for a permanent magnet synchronous motor. By controlling the rotor position error estimate, an initial speed estimate is obtained, thus achieving accurate calculation of the initial speed estimate.

[0027] In one optional implementation, the rotor position error estimate is controlled to obtain an initial speed estimate; including:

[0028] A phase-locked loop (PLL) position observer is used to control the rotor position error estimate, thereby obtaining the initial speed estimate. The calculation formula for the initial speed estimate is shown below:

[0029]

[0030] in, k represents the initial speed estimate. p and k i This represents the PI control parameters for speed estimation, where 1 / s represents the integral. This indicates the rotor position error value.

[0031] In one optional implementation, based on the extended back EMF estimate, a dynamic error disturbance estimate is calculated using a dynamic error disturbance observer, and a speed compensation amount is obtained based on the dynamic error disturbance estimate, including:

[0032] Input the stator voltage command value, the actual stator current value, and the extended back EMF estimate value into the dynamic error disturbance observer to obtain the dynamic error disturbance estimate value;

[0033] The estimated value of d-axis disturbance is determined based on the estimated value of dynamic error disturbance, and PI control is applied to the estimated value of d-axis disturbance to obtain the speed compensation amount.

[0034] This embodiment provides a sensorless control method for permanent magnet synchronous motors. Based on the dynamic error disturbance estimation value, the method determines the d-axis disturbance estimation value and performs PI control on the d-axis disturbance estimation value to obtain the speed compensation amount. This achieves accurate calculation of the dynamic error disturbance corresponding to the speed error and linearization error, laying the foundation for subsequent dynamic error compensation of the initial speed estimation value and improving the dynamic performance of sensorless control of permanent magnet synchronous motors.

[0035] In one optional implementation, the d-axis disturbance estimate is determined based on the dynamic error disturbance estimate, and PI control is applied to the d-axis disturbance estimate to obtain the speed compensation amount. The calculation formula for the speed compensation amount is as follows:

[0036]

[0037] in, This indicates the amount of speed compensation. This represents the estimated d-axis disturbance value, k p_d and k i_d This represents the disturbance compensation PI control parameter, and 1 / s represents the integral.

[0038] In one optional implementation, vector control of the permanent magnet synchronous motor is performed using rotor position information estimates, including:

[0039] The three-phase current of the permanent magnet synchronous motor is collected by a current sensor, and the three-phase current is subjected to Clark transformation to obtain the current value in a two-phase stationary coordinate system.

[0040] Based on the rotor position information estimation, the current value in the two-phase stationary coordinate system is transformed by Park to obtain the actual current value in the two-phase synchronous rotating coordinate system.

[0041] The current command value in the two-phase synchronous rotating coordinate system is obtained. Based on the current command value and the actual current value in the two-phase synchronous rotating coordinate system, the voltage command value in the two-phase synchronous rotating coordinate system is obtained through the current controller.

[0042] Based on the rotor position information estimation, the voltage command value in the two-phase synchronous rotating coordinate system is subjected to inverse Park transformation to obtain the voltage command value in the two-phase stationary coordinate system.

[0043] The voltage command value in the two-phase stationary coordinate system is processed to obtain the control voltage, which is used to control the permanent magnet synchronous motor.

[0044] This embodiment provides a sensorless control method for permanent magnet synchronous motors. In the vector control process of the permanent magnet synchronous motor, Park transformation and inverse Park transformation are performed using the rotor position information estimation value, thereby realizing sensorless control of the permanent magnet synchronous motor. This ensures that the vector control process of the permanent magnet synchronous motor fully considers the impact of the speed error term and linearization error term on the performance of estimating speed and rotor position during the dynamic operation of the motor, thus improving the dynamic performance of sensorless control of built-in permanent magnet synchronous motors.

[0045] In one optional implementation, the voltage command value in the two-phase stationary coordinate system is processed to obtain a control voltage for controlling the permanent magnet synchronous motor, including:

[0046] A modulation strategy is used to modulate the voltage command value in a two-phase stationary coordinate system to obtain a trigger pulse signal;

[0047] Based on the trigger pulse signal, the control voltage is obtained by the inverter, and the control voltage is used to control the permanent magnet synchronous motor.

[0048] In an optional implementation, before obtaining the current command value in the two-phase synchronous rotating coordinate system and, based on the current command value and the actual current value in the two-phase synchronous rotating coordinate system, obtaining the voltage command value in the two-phase synchronous rotating coordinate system through the current controller, the method further includes:

[0049] The current command value in the two-phase synchronous rotating coordinate system is determined by using the maximum torque-current ratio control strategy. Attached Figure Description

[0050] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0051] Figure 1 This is a schematic flowchart of a sensorless control method for a permanent magnet synchronous motor according to an embodiment of the present invention.

[0052] Figure 2 This is a control block diagram of a sensorless control method for a permanent magnet synchronous motor according to an embodiment of the present invention;

[0053] Figure 3 This is a schematic flowchart of another sensorless control method for a permanent magnet synchronous motor according to an embodiment of the present invention;

[0054] Figure 4 This is a schematic flowchart of another sensorless control method for a permanent magnet synchronous motor according to an embodiment of the present invention. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] To address the problems caused by position sensor failure, research was conducted on sensorless control of permanent magnet synchronous motors. The related sensorless control methods for permanent magnet synchronous motors are divided into two categories based on the speed range: one is a medium-to-high speed method based on the fundamental wave model, and the other is a zero-to-low speed method based on salient pole characteristics. Among the medium-to-high-speed methods based on the fundamental wave model, the method based on the extended back EMF model involves estimating the extended back EMF containing rotor position information estimates by constructing an observer, and then estimating the rotor position information estimates using the extended back EMF. The method based on the extended back EMF model includes: estimating the extended back EMF using a disturbance observer and a minimum-order observer; establishing a second-order linear extended state observer in a two-phase stationary coordinate system to extract the extended back EMF estimates, calculating the preliminary rotor position estimate angle, further using the preliminary rotor position estimate angle as the main state variable, the load torque of the permanent magnet synchronous motor as the overall external disturbance, and using the overall external disturbance as the extended state variable, establishing a third-order linear extended state observer to extract rotor position and speed observation values; designing a discretized sliding mode back EMF observer based on the precise discrete state space model of the permanent magnet synchronous motor to observe the back EMF of the motor, and then establishing a new phase-locked loop based on the discrete back EMF model to accurately estimate the rotor position.

[0057] The extended back EMF in the synchronous rotating coordinate system of the permanent magnet synchronous motor is shown below:

[0058]

[0059] Among them, e e_d e e_q L represents the extended back electromotive force along the d-axis and q-axis, respectively.d and L q These are the d-axis and q-axis inductances, i d i q These are the stator currents along the d-axis and q-axis, respectively, ω r Let ω be the rotor angular velocity, p be the differential operator, and ψ be the angular velocity. f For permanent magnet flux linkage, θ err For rotor position error, This is an estimated value for the rotor angular velocity.

[0060] The first term on the right side of equation (1) contains rotor position error information, which can be used to estimate the rotor position error. The second term on the right side of equation (1) assumes that the estimated rotational speed is equal to the actual rotational speed, i.e. The rotational speed error term is ignored; similarly, the linearization error term is ignored during the construction of the observer. The formula for calculating the linearization error is shown below:

[0061]

[0062] Where W represents the linearization error, The first derivative of the q-axis current. It is the second derivative of the q-axis current.

[0063] The above assumptions hold true when the motor is running in a steady state. However, when the motor is running dynamically, such as during acceleration or deceleration, the neglected speed error term and linearization error term will adversely affect the performance of estimating speed and rotor position, resulting in poor dynamic performance.

[0064] This invention provides a sensorless control method for permanent magnet synchronous motors. By designing a dynamic error disturbance observer to perform dynamic error compensation on the estimated speed, the dynamic performance of sensorless control of built-in permanent magnet synchronous motors can be improved.

[0065] According to an embodiment of the present invention, a sensorless control method for a permanent magnet synchronous motor is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0066] This embodiment provides a sensorless control method for a permanent magnet synchronous motor, which can be used in server-type control devices. Figure 1 This is a flowchart of a sensorless control method for a permanent magnet synchronous motor according to an embodiment of the present invention, as shown below. Figure 1 As shown, the process includes the following steps:

[0067] Step S101: Construct an extended back EMF perturbation observer and a dynamic error perturbation observer.

[0068] Specifically, the linear state equation of the permanent magnet synchronous motor in a two-phase synchronous rotating coordinate system is obtained, and an extended back EMF disturbance observer and a dynamic error disturbance observer are constructed based on the linear state equation of the permanent magnet synchronous motor in a two-phase synchronous rotating coordinate system.

[0069] Furthermore, the linear state equation of the built-in permanent magnet synchronous motor in a two-phase synchronous rotating coordinate system is as follows:

[0070]

[0071] In the above formula, A 11 A 12 A 22 B1, O, and C represent the matrix coefficients in the linear state equation, where i = [i d i q ] T i d i q These represent the stator currents along the d-axis and q-axis, respectively. s =[u d u q ] T u d u q These represent the stator voltages along the d-axis and q-axis, respectively, e = [e e_d e e_q ] T e e_d e e_q These represent the extended back electromotive forces along the d-axis and q-axis, respectively.

[0072] in,

[0073]

[0074] C = [I 0] (9)

[0075] In the above formula, I and J represent matrices. R s L represents the stator resistance. d L q Represents the d-axis and q-axis inductance, ω r This represents the rotor angular velocity, with the symbol "^" indicating an estimated value. The first derivative of the q-axis current. Let θ be the second derivative of the q-axis current. err This indicates the rotor position error.

[0076] Furthermore, based on the above formula (3), an extended back EMF perturbation observer is constructed. The expression of the extended back EMF perturbation observer is as follows:

[0077]

[0078] in, This represents the first derivative of the current. Represents the first matrix coefficient, where i represents the actual value of the stator current, A. 12 Denotes the coefficients of the second matrix. This represents the extended back potential estimate, u. s Indicates the stator voltage command value. Let G represent the derivative of the extended back EMF estimate, and let G = gI, where g represents the positive real gain.

[0079] Furthermore, a dynamic error disturbance observer is constructed based on the above formula (3). The expression of the dynamic error disturbance observer is as follows:

[0080]

[0081] in, B1 represents the estimated value of dynamic error disturbance, and B1 represents the coefficients of the third matrix. Let L represent the derivative of the dynamic error disturbance estimate, and let L represent the second feedback gain.

[0082] Furthermore, to improve the dynamic performance of estimating rotational speed and rotor position, a dynamic error disturbance observer is designed based on the existing extended back EMF disturbance observer. The term neglected in the original assumption process is treated as the total system disturbance, which includes two parts: one is the disturbance caused by the rotational speed error, and the other is the disturbance caused by the linearization error term. For the linearization error term, the second-order differential term of the q-axis current is ignored as a higher-order term, meaning that this disturbance is mainly caused by the change in the d-axis current. Therefore, the dynamic disturbance term can be expressed as:

[0083]

[0084] In the above formula, For disturbances related to speed error, This refers to the perturbation related to the d-axis current variation, i.e., the perturbation related to the linearization error; where d = [d d d q ] T d d and d q These are the d-axis and q-axis perturbation terms, respectively.

[0085] Step S102: Obtain the stator voltage command value and the actual stator current value of the permanent magnet synchronous motor. Based on the stator voltage command value and the actual stator current value, calculate the extended back EMF estimate value using the extended back EMF disturbance observer.

[0086] Specifically, such as Figure 2 As shown, the three-phase current of the permanent magnet synchronous motor is collected by a current sensor. The three-phase current is subjected to Clark transformation (a coordinate transformation technique) to obtain the current value in the two-phase stationary coordinate system. Based on the estimated value of the initial rotor position information, the current value in the two-phase stationary coordinate system is subjected to Park transformation (a coordinate transformation technique) to obtain the actual value of the stator current in the two-phase synchronous rotating coordinate system. Then, the current command value in the two-phase synchronous rotating coordinate system is obtained by the current controller. Based on the current command value in the two-phase synchronous rotating coordinate system and the actual value of the stator current in the two-phase synchronous rotating coordinate system, the stator voltage command value in the two-phase synchronous rotating coordinate system is determined.

[0087] Furthermore, the stator voltage command value and the actual stator current value are extended with the input data of the back EMF disturbance observer, and the extended back EMF estimate is obtained through the above formula (10). These represent the estimated extended back electromotive force values ​​for the d-axis and q-axis, respectively.

[0088] Step S103: Determine the initial rotational speed estimate based on the extended back EMF estimate.

[0089] Step S104: Based on the extended back EMF estimate, calculate the dynamic error disturbance estimate using the dynamic error disturbance observer, and obtain the speed compensation amount based on the dynamic error disturbance estimate.

[0090] Step S105: Dynamic error compensation is performed on the initial speed estimate using the speed compensation amount to obtain the speed estimate, and the rotor position information estimate is calculated based on the speed estimate.

[0091] Step S106: Vector control of the permanent magnet synchronous motor is performed using the rotor position information estimation value.

[0092] This embodiment provides a sensorless control method for a permanent magnet synchronous motor. It constructs an extended back-EMF disturbance observer and a dynamic error disturbance observer, calculates the extended back-EMF estimate using the extended back-EMF disturbance observer, determines the initial speed estimate based on the extended back-EMF estimate, calculates the dynamic error disturbance estimate using the dynamic error disturbance observer, obtains the speed compensation amount based on the dynamic error disturbance estimate, and then uses the speed compensation amount to perform dynamic error compensation on the initial speed estimate. Finally, it uses the rotor position information estimate to perform vector control on the permanent magnet synchronous motor. By constructing the dynamic error disturbance observer and performing dynamic error compensation on the initial speed estimate, it considers the impact of speed error terms and linearization error terms on the performance of estimated speed and rotor position during dynamic motor operation, thus improving the dynamic performance of sensorless control of the built-in permanent magnet synchronous motor.

[0093] This embodiment provides a sensorless control method for a permanent magnet synchronous motor, which can be used in the aforementioned server-type control devices. Figure 3 This is a flowchart of a sensorless control method for a permanent magnet synchronous motor according to an embodiment of the present invention, as shown below. Figure 3 As shown, the process includes the following steps:

[0094] Step S301: Construct the extended back EMF perturbation observer and the dynamic error perturbation observer. See details below. Figure 1 Step S101 of the illustrated embodiment will not be described again here.

[0095] Step S302: Obtain the commanded stator voltage and actual stator current values ​​of the permanent magnet synchronous motor. Based on these values, calculate the estimated extended back EMF using the extended back EMF disturbance observer. For details, please refer to [link to relevant documentation]. Figure 1 Step S102 of the illustrated embodiment will not be described again here.

[0096] Step S303: Determine the initial rotational speed estimate based on the extended back EMF estimate.

[0097] Specifically, step S303 includes:

[0098] Step S3031: Calculate the rotor position error estimate based on the extended back EMF estimate.

[0099] Specifically, the rotor position error estimate The calculation formula is as follows:

[0100]

[0101] Step S3032: Control the rotor position error estimate to obtain the initial speed estimate.

[0102] Specifically, a phase-locked loop position observer is used to control the rotor position error estimate to obtain the initial speed estimate; the calculation formula for the initial speed estimate is as follows:

[0103]

[0104] in, k represents the initial speed estimate. p and k i This represents the PI control parameters for speed estimation, where 1 / s represents the integral. This indicates the rotor position error value.

[0105] Furthermore, linear position observers, such as phase-locked loop position observers and Romberg position observers, or nonlinear position observers, such as sliding mode observers, can be used to control the rotor position error estimate.

[0106] This embodiment provides a sensorless control method for a permanent magnet synchronous motor. By controlling the rotor position error estimate, an initial speed estimate is obtained, thus achieving accurate calculation of the initial speed estimate.

[0107] Step S304: Based on the extended back EMF estimate, calculate the dynamic error disturbance estimate using the dynamic error disturbance observer, and obtain the speed compensation amount based on the dynamic error disturbance estimate.

[0108] Specifically, step S304 includes:

[0109] Step S3041: Input the stator voltage command value, the actual stator current value, and the extended back EMF estimate value into the dynamic error disturbance observer to obtain the dynamic error disturbance estimate value.

[0110] Specifically, the stator voltage command value, the actual stator current value, and the extended back EMF estimate are input into the above formula (11) to obtain the dynamic error disturbance estimate. and These are the estimated dynamic error disturbance values ​​for the d-axis and q-axis, respectively.

[0111] Step S3042: Determine the d-axis disturbance estimate based on the dynamic error disturbance estimate, and perform PI control on the d-axis disturbance estimate to obtain the speed compensation amount.

[0112] Specifically, in order to improve the dynamic performance of the estimated speed and rotor position, the estimated speed (i.e., the initial speed estimate) is compensated by the estimated dynamic error disturbance value. The compensation amount is obtained by the d-axis disturbance estimate through the PI controller, and the calculation formula for the speed compensation amount is as follows:

[0113]

[0114] in, This indicates the amount of speed compensation. This represents the estimated d-axis disturbance value, k p_d and k i_d This represents the disturbance compensation PI control parameter, and 1 / s represents the integral.

[0115] Step S305: Dynamic error compensation is performed on the initial speed estimate using the speed compensation amount to obtain the speed estimate, and the rotor position information estimate is calculated based on the speed estimate.

[0116] Specifically, the estimated rotational speed The calculation formula is as follows:

[0117]

[0118] Furthermore, the rotor position information estimate The calculation formula is as follows:

[0119]

[0120] Step S306: Vector control of the permanent magnet synchronous motor is performed using the estimated rotor position information. For details, please refer to [link to relevant documentation]. Figure 1 Step S106 of the illustrated embodiment will not be described again here.

[0121] This embodiment provides a sensorless control method for permanent magnet synchronous motors. Based on the dynamic error disturbance estimation value, the method determines the d-axis disturbance estimation value and performs PI control on the d-axis disturbance estimation value to obtain the speed compensation amount. This achieves accurate calculation of the dynamic error disturbance corresponding to the speed error and linearization error, laying the foundation for subsequent dynamic error compensation of the initial speed estimation value and improving the dynamic performance of sensorless control of permanent magnet synchronous motors.

[0122] This embodiment provides a sensorless control method for a permanent magnet synchronous motor, which can be used in the aforementioned server-type control devices. Figure 4 This is a flowchart of a sensorless control method for a permanent magnet synchronous motor according to an embodiment of the present invention, as shown below. Figure 4 As shown, the process includes the following steps:

[0123] Step S401: Construct the extended back-EMF perturbation observer and the dynamic error perturbation observer. See details below. Figure 3 Step S301 of the illustrated embodiment will not be described again here.

[0124] Step S402: Obtain the commanded stator voltage and actual stator current values ​​of the permanent magnet synchronous motor. Based on these values, calculate the estimated extended back EMF using the extended back EMF disturbance observer. For details, please refer to [link to relevant documentation]. Figure 3 Step S302 of the illustrated embodiment will not be described again here.

[0125] Step S403: Determine the initial rotational speed estimate based on the extended back EMF estimate. For details, please refer to [link to relevant documentation]. Figure 3 Step S303 of the illustrated embodiment will not be described again here.

[0126] Step S404: Based on the extended back EMF estimate, the dynamic error disturbance estimate is calculated using a dynamic error disturbance observer, and the speed compensation amount is obtained based on the dynamic error disturbance estimate. For details, please refer to [link to relevant documentation]. Figure 3 Step S304 of the illustrated embodiment will not be described again here.

[0127] Step S405: Dynamic error compensation is performed on the initial speed estimate using the speed compensation amount to obtain the speed estimate, and the rotor position information estimate is calculated based on the speed estimate. For details, please refer to [link to details]. Figure 3 Step S305 of the illustrated embodiment will not be described again here.

[0128] Step S406: Vector control of the permanent magnet synchronous motor is performed using the rotor position information estimation value.

[0129] Specifically, such as Figure 2 As shown, step S406 above includes:

[0130] Step S4061: The three-phase current of the permanent magnet synchronous motor is collected by the current sensor, and the three-phase current is subjected to Clark transformation to obtain the current value in the two-phase stationary coordinate system.

[0131] Specifically, two phases of the three-phase input current of the permanent magnet synchronous motor can be collected using a current sensor, and the third phase can be calculated. For example, the current of phase a, i... a and phase b current i b The current in phase c is i c =-i a -i b Thus, the current in the three-phase stationary coordinate system is obtained.

[0132] Furthermore, the current in the three-phase stationary coordinate system is transformed into the current i in the two-phase stationary coordinate system through Clark transformation (a coordinate transformation method). α and i β .

[0133] Step S4062: Based on the rotor position information estimate, perform Park transformation on the current value in the two-phase stationary coordinate system to obtain the actual current value in the two-phase synchronous rotating coordinate system.

[0134] Specifically, the expression for the Park transform is as follows:

[0135]

[0136] In the above formula, i d and i q These are the stator currents along the d-axis and q-axis, i.e., the actual current values ​​in the two-phase synchronous rotating coordinate system (dq coordinate system).

[0137] Step S4063: Obtain the current command value in the two-phase synchronous rotating coordinate system. Based on the current command value and the actual current value in the two-phase synchronous rotating coordinate system, obtain the voltage command value in the two-phase synchronous rotating coordinate system through the current controller.

[0138] Specifically, the maximum torque per ampere (MTPA) control strategy is used to determine the current command value in the two-phase synchronous rotating coordinate system. and

[0139] Furthermore, the actual current value i in the two-phase synchronous rotating coordinate system is... d and i q and the current command value in a two-phase synchronous rotating coordinate system. and In the input current controller, the output voltage command value is in a two-phase synchronous rotating coordinate system. and

[0140] Step S4064: Based on the rotor position information estimation value, perform inverse Park transformation on the voltage command value in the two-phase synchronous rotating coordinate system to obtain the voltage command value in the two-phase stationary coordinate system.

[0141] Specifically, the inverse Park transform can be expressed as:

[0142]

[0143] In the above formula, and This represents the voltage command value in a two-phase stationary coordinate system.

[0144] Step S4065: Process the voltage command value in the two-phase stationary coordinate system to obtain the control voltage, so as to control the permanent magnet synchronous motor.

[0145] In some optional embodiments, step S4065 above includes:

[0146] Step a1: Modulate the voltage command value in the two-phase stationary coordinate system using a modulation strategy to obtain a trigger pulse signal.

[0147] Step a2: Based on the trigger pulse signal, the control voltage is obtained using the inverter, and the control voltage is used to control the permanent magnet synchronous motor.

[0148] This embodiment provides a sensorless control method for permanent magnet synchronous motors. In the vector control process of the permanent magnet synchronous motor, Park transformation and inverse Park transformation are performed using the rotor position information estimation value, thereby realizing sensorless control of the permanent magnet synchronous motor. This ensures that the vector control process of the permanent magnet synchronous motor fully considers the impact of the speed error term and linearization error term on the performance of estimating speed and rotor position during the dynamic operation of the motor, thus improving the dynamic performance of sensorless control of built-in permanent magnet synchronous motors.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A sensorless control method for a permanent magnet synchronous motor, characterized in that, The methods applied include: Construct an extended back-EMF perturbation observer and a dynamic error perturbation observer; Obtain the stator voltage command value and the actual stator current value of the permanent magnet synchronous motor. Based on the stator voltage command value and the actual stator current value, calculate the extended back EMF estimate value using an extended back EMF disturbance observer. The initial rotational speed estimate is determined based on the extended back EMF estimate; Based on the extended back EMF estimate, the dynamic error disturbance estimate is calculated using a dynamic error disturbance observer, and the speed compensation amount is obtained based on the dynamic error disturbance estimate. The initial speed estimate is dynamically compensated using the speed compensation amount to obtain a speed estimate, and a rotor position information estimate is calculated based on the speed estimate. The estimated rotor position information is used to perform vector control on the permanent magnet synchronous motor.

2. The method according to claim 1, characterized in that, The construction of the extended back-potential perturbation observer and the dynamic error perturbation observer includes: Obtain the linear state equation of the permanent magnet synchronous motor in a two-phase synchronous rotating coordinate system, and construct the extended back EMF disturbance observer and the dynamic error disturbance observer based on the linear state equation of the permanent magnet synchronous motor in the two-phase synchronous rotating coordinate system.

3. The method according to claim 2, characterized in that, The extended back EMF disturbance observer and the dynamic error disturbance observer are constructed based on the linear state equations of the permanent magnet synchronous motor in the two-phase synchronous rotating coordinate system, respectively, including: The expression for the extended back EMF perturbation observer is as follows: in, This represents the first derivative of the current. Represents the first matrix coefficient, where i represents the actual value of the stator current, A. 12 Denotes the coefficients of the second matrix. This represents the extended back potential estimate, u. s Indicates the stator voltage command value. denoted by the derivative of the extended back EMF estimate, and G represents the first feedback gain; The expression for the dynamic error disturbance observer is as follows: in, B1 represents the estimated value of dynamic error disturbance, and B1 represents the coefficients of the third matrix. Let L represent the derivative of the dynamic error disturbance estimate, and let L represent the second feedback gain.

4. The method according to claim 1, characterized in that, The step of determining the initial rotational speed estimate based on the extended back EMF estimate includes: The rotor position error estimate is calculated based on the extended back EMF estimate. The rotor position error estimate is controlled to obtain the initial speed estimate.

5. The method according to claim 4, characterized in that, The step of controlling the rotor position error estimate to obtain the initial speed estimate includes: A phase-locked loop position observer is used to control the rotor position error estimate to obtain the initial speed estimate; wherein, the calculation formula for the initial speed estimate is as follows: in, k represents the initial speed estimate. p and k i This represents the PI control parameters for speed estimation, where 1 / s represents the integral. This indicates the rotor position error value.

6. The method according to claim 1, characterized in that, The step of calculating a dynamic error disturbance estimate using a dynamic error disturbance observer based on the extended back EMF estimate, and obtaining a speed compensation amount based on the dynamic error disturbance estimate, includes: The stator voltage command value, the actual stator current value, and the extended back EMF estimate are input into the dynamic error disturbance observer to obtain the dynamic error disturbance estimate. Based on the dynamic error disturbance estimate, the d-axis disturbance estimate is determined, and the d-axis disturbance estimate is subjected to PI control to obtain the speed compensation amount.

7. The method according to claim 6, characterized in that, The step involves determining the d-axis disturbance estimate based on the dynamic error disturbance estimate, and then applying PI control to the d-axis disturbance estimate to obtain the speed compensation amount. The calculation formula for the speed compensation amount is as follows: in, This indicates the amount of speed compensation. This represents the estimated d-axis disturbance value, k p_d and k i_d This represents the disturbance compensation PI control parameter, and 1 / s represents the integral.

8. The method according to claim 1, characterized in that, The vector control of the permanent magnet synchronous motor using the rotor position information estimation includes: The three-phase current of the permanent magnet synchronous motor is collected by a current sensor, and the three-phase current is subjected to Clark transformation to obtain the current value in a two-phase stationary coordinate system. Based on the estimated rotor position information, the Park transformation is performed on the current value in the two-phase stationary coordinate system to obtain the actual current value in the two-phase synchronous rotating coordinate system. Obtain the current command value in the two-phase synchronous rotating coordinate system. Based on the current command value and the actual current value in the two-phase synchronous rotating coordinate system, obtain the voltage command value in the two-phase synchronous rotating coordinate system through the current controller. Based on the rotor position information estimation value, the voltage command value in the two-phase synchronous rotating coordinate system is subjected to inverse Park transformation to obtain the voltage command value in the two-phase stationary coordinate system. The voltage command value in the two-phase stationary coordinate system is processed to obtain the control voltage, which is used to control the permanent magnet synchronous motor.

9. The method according to claim 8, characterized in that, The process of processing the voltage command values ​​in the two-phase stationary coordinate system to obtain the control voltage for controlling the permanent magnet synchronous motor includes: The voltage command value in the two-phase stationary coordinate system is modulated using a modulation strategy to obtain a trigger pulse signal; Based on the trigger pulse signal, the control voltage is obtained using an inverter, and the permanent magnet synchronous motor is controlled using the control voltage.

10. The method according to claim 8, characterized in that, Before obtaining the current command value in the two-phase synchronous rotating coordinate system, and before obtaining the voltage command value in the two-phase synchronous rotating coordinate system through the current controller based on the current command value and the actual current value in the two-phase synchronous rotating coordinate system, the process further includes: The current command value in the two-phase synchronous rotating coordinate system is determined using the maximum torque-current ratio control strategy.

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