Dual three-phase permanent magnet synchronous motor rotor magnetic pole position estimation method based on terminal voltage detection

Abstract

The invention discloses a dual three-phase permanent magnet synchronous motor rotor magnetic pole position estimation method based on terminal voltage detection, and the method employs a high-frequency pulsating square wave injection method based on terminal voltage detection, injects a voltage signal into a first set of winding, and employs the mutual inductance effect between the two sets of windings to estimate the rotor magnetic pole position of a dual three-phase permanent magnet synchronous motor. And extracting a high-frequency response envelope containing rotor position information from the open-circuit end voltage of the second set of windings. Compared with an existing high-frequency injection method based on carrier current detection, the voltage signal adopted as a position information carrier has the remarkable advantages that the high-frequency amplitude is irrelevant to the injection frequency, and large errors are not likely to be introduced in the signal separation and extraction process. Under the condition of the same injection amplitude, the signal-to-noise ratio can be effectively improved, so that the accuracy of rotor magnetic pole position estimation is remarkably improved, and the method has important application value in the field of industrial control.

Description

Technical Field

[0001] This invention belongs to the field of industrial control and relates to a sensorless control method for a dual three-phase permanent magnet synchronous motor, specifically a low-speed sensorless control method based on high-frequency square wave pulse injection. Background Technology

[0002] According to vector space decoupling theory, the mathematical model of a dual three-phase permanent magnet synchronous motor can be decoupled into a torque subspace model identical to that of a three-phase permanent magnet synchronous motor, and a harmonic subspace model independent of electromechanical energy conversion. Therefore, a direct approach to developing sensorless control of dual three-phase permanent magnet synchronous motors based on high-frequency injection is to extend existing methods to their torque subspace. However, the injection of high-frequency signals introduces additional noise, limiting its widespread application in noise-sensitive applications.

[0003] Existing noise suppression schemes can be mainly divided into three categories. The first category reduces the high-frequency signal energy by decreasing the amplitude of the injected signal, thereby achieving noise suppression. However, excessively low injection amplitude significantly reduces the signal-to-noise ratio, limiting the practical application of this scheme. The second category adjusts the injection frequency, setting it outside the range of human hearing to reduce audible noise. However, a low injection frequency hinders the separation and processing of high-frequency signals; while an excessively high injection frequency is limited by the switching characteristics of power devices. Furthermore, another category of schemes is based on the principle of randomization, redistributing the injected signal to disperse concentrated high-frequency energy across a wider frequency band, thereby suppressing noise peaks at specific frequencies. Summary of the Invention

[0004] This invention provides a rotor pole position estimation method for a dual three-phase permanent magnet synchronous motor based on terminal voltage detection. This method utilizes the mutual inductance between two sets of windings to amplify the high-frequency response signal, and then separates and extracts the high-frequency voltage envelope containing position information to achieve accurate position estimation. This invention can significantly improve the system's signal-to-noise ratio and estimation accuracy while effectively suppressing injected noise.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for estimating the rotor pole position of a dual three-phase permanent magnet synchronous motor based on terminal voltage detection includes the following steps:

[0007] Step (1) Generate a high-frequency square wave voltage signal:

[0008]

[0009] In the formula, and for High-frequency voltage signal in the reference coordinate system; The magnitude of the injected voltage. Injection frequency; The high-frequency square wave voltage signal is a unit square wave function; the high-frequency square wave voltage signal is then propagated along the estimated rotor reference coordinate system. The shaft is injected into the first set of windings of the motor;

[0010] Step (2) Ignore the resistance voltage drop, rotational voltage, and back electromotive force in the motor model, and derive the expressions for the injection voltage and the high-frequency voltage of the second set of windings according to Kirchhoff's laws:

[0011]

[0012] In the formula, , , , , , These represent the self-inductance and mutual inductance between the same set of windings in different reference frames; , , and These represent the mutual inductance between the two sets of windings; and It is the current component induced in the second winding; and It is the high-frequency voltage component induced by the second set of windings;

[0013] Step (3) disconnect the second winding during the low-speed phase, and the current... and Forced to 0, and considering that the injection frequency is much higher than the motor operating frequency, the high-frequency model is further simplified to:

[0014]

[0015] In the formula, This is the actual rotor position. This is the salient pole position error after considering the salient pole effect; It is a constant related to the amplitude of the high-frequency signal;

[0016] Step (4) Perform simple algebraic operations on the high-frequency voltage components induced by the second set of windings to obtain the high-frequency envelope. and With rotor position Relationship:

[0017]

[0018] In the formula, and Representing the Envelope signal for each control cycle;

[0019] Step (5) Collect the terminal voltage signal of the second set of windings , and The second set of windings is processed by performing a Clarke transformation to obtain... Voltage components in the reference coordinate system:

[0020]

[0021]

[0022] In the formula, , and This is the terminal voltage signal acquired from the second set of windings; Neutral point Voltage to ground; , and This is the phase voltage signal for the second winding. and for Voltage components in the reference coordinate system;

[0023] Step (6) from Voltage components in the reference coordinate system and High-frequency voltage envelope is separated from the source:

[0024]

[0025] In the formula, and Representing the Voltage components calculated per control cycle; It is the first The injection signal calculated in each control cycle; Represents a symbolic function;

[0026] Step (7) Based on the high-frequency envelope and rotor position relationship analyzed in step (4), the separated envelope signal is processed using the heterodyne method to obtain the equivalent position error signal:

[0027]

[0028] In the formula, Represents the equivalent position error signal. and For dq axis inductance; It is the rotor position error; It is to estimate the rotor position; Represents the mutual inductance amplitude;

[0029] After obtaining the equivalent position error in step (8), the rotor position and speed information are extracted using a phase-locked loop, and the estimated rotor position and speed signals are input into the motor closed-loop system to realize sensorless control of the dual three-phase permanent magnet synchronous motor.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] This invention proposes a high-frequency pulsed square wave injection method based on terminal voltage detection for sensorless control of dual three-phase permanent magnet synchronous motors. This method can be implemented in standard digital control chips (DSPs, microcontrollers, or FPGAs, etc.). Compared with existing high-frequency injection methods based on carrier current detection, the voltage signal used in this invention as the position information carrier has significant advantages: its high-frequency amplitude is independent of the injection frequency, and it is less prone to introducing large errors during signal separation and extraction. Under the same injection amplitude conditions, it can effectively improve the signal-to-noise ratio, thereby significantly improving the accuracy of rotor magnetic pole position estimation, which has important application value in the field of industrial control. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the voltage detection principle for the D-phase winding terminals.

[0033] Figure 2 Transient experimental waveforms under load change conditions based on carrier current detection method and terminal voltage detection method, (a) based on carrier current detection method, (b) based on terminal voltage detection method;

[0034] Figure 3 For the comparison of steady-state experimental waveforms based on carrier current detection method and terminal voltage detection method, (a) based on carrier current detection method, (b) based on terminal voltage detection method;

[0035] Figure 4 Experimental results on position estimation error and noise for the two methods under different injection amplitudes. Detailed Implementation

[0036] The technical solution of the present invention will be further described below with reference to the accompanying drawings, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0037] This invention provides a rotor pole position estimation method for a dual three-phase permanent magnet synchronous motor based on terminal voltage detection. The method employs a high-frequency pulsed square wave injection method based on terminal voltage detection. By injecting a voltage signal into the first winding and utilizing the mutual inductance between the two windings, a high-frequency response envelope containing rotor position information is extracted from the open-circuit terminal voltage of the second winding. This method uses the voltage signal as an information carrier, effectively improving the signal-to-noise ratio, thereby achieving higher accuracy rotor position estimation while suppressing noise. The specific implementation steps are as follows:

[0038] Step (1) generates a high-frequency square wave voltage signal, and then applies this high-frequency square wave voltage signal along the estimated rotor reference coordinate system. The shaft is injected into the first set of windings of the motor.

[0039]

[0040] In the formula, and for High-frequency voltage signal in the reference coordinate system; The magnitude of the injected voltage. Injection frequency; The unit square wave function is defined as:

[0041]

[0042] In the formula, It is the set of natural numbers.

[0043] Step (2) Ignoring the resistance voltage drop, rotational voltage, and back electromotive force in the motor model, the expressions for the injection voltage and the high-frequency voltage of the second set of windings can be derived according to Kirchhoff's laws:

[0044]

[0045] In the formula, , , , , , These represent self-inductance and mutual inductance (between the same set of windings) in different reference frames. , , and These represent the mutual inductance between the two sets of windings; and It is the current component induced in the second winding; and This is the high-frequency voltage component induced by the second winding. The expressions for some of the self-inductance and mutual inductance values ​​are as follows:

[0046]

[0047] In the formula, and These represent the average inductance and differential inductance of the stator winding, respectively. and For dq axis inductance; It is the rotor position error; It is to estimate the rotor position; Represents the mutual inductance amplitude; It estimates the rotor angular frequency.

[0048] Step (3) To simplify the high-frequency model, the second winding is disconnected during the low-speed phase, and the current... and Forced to 0. Meanwhile, considering that the injection frequency is much higher than the motor's operating frequency, the high-frequency model is further simplified to:

[0049]

[0050] In the formula, This is the actual rotor position. This is the salient pole position error after considering the salient pole effect; It is a defined constant related to the amplitude of a high-frequency signal.

[0051]

[0052] Step (4) Perform simple algebraic operations on the high-frequency voltage components induced by the second set of windings to obtain the high-frequency envelope. and With rotor position Relationship:

[0053]

[0054] In the formula, and Representing the The envelope signal for each control cycle.

[0055] Step (5) Collect the terminal voltage signal of the second set of windings , and To process, Figure 1 This is a schematic diagram of the sampling principle for the terminal voltage of phase D winding. To eliminate the influence of the neutral point voltage, the second set of windings is subjected to a Clarke transformation to obtain... Voltage components in the reference coordinate system:

[0056]

[0057]

[0058] In the formula, , and This is the terminal voltage signal acquired from the second set of windings; Neutral point Voltage to ground; , and This is the phase voltage signal for the second winding. and for Voltage components in the reference coordinate system.

[0059] Step (6) from Voltage components in the reference coordinate system and High-frequency voltage envelope is separated from the source:

[0060]

[0061] In the formula, and Representing the Voltage components calculated per control cycle; It is the first The injection signal calculated in each control cycle; Represents a symbolic function;

[0062] Step (7) Based on the high-frequency envelope and rotor position relationship analyzed in step (4), the separated envelope signal is processed using the heterodyne method to obtain the equivalent position error signal:

[0063]

[0064] In the formula, This represents the equivalent position error signal.

[0065] After obtaining the equivalent position error in step (8), the rotor position and speed information are extracted using a phase-locked loop, and the estimated rotor position and speed signals are input into the motor closed-loop system to realize sensorless control of the dual three-phase permanent magnet synchronous motor.

[0066] Steps (2) to (8) above constitute the high-frequency pulse square wave injection method based on terminal voltage detection, which is also the core content of this invention that can improve the signal-to-noise ratio.

[0067] To verify the effectiveness of the method of the present invention, Figure 2 The transient experimental waveforms based on carrier current detection method and terminal voltage detection method are shown in the case of sudden load change. Figure 3The experimental waveforms for the two methods under steady-state operation are shown. Experimental results show that, during steady-state operation, the peak-to-peak value of the rotor position error fluctuation of the proposed method is only 5.23°, approximately 50% lower than the carrier current detection method. During dynamic load changes, the high-frequency envelope signal extracted by the proposed method is smooth and glitch-free, exhibiting superior transient performance. Furthermore, Figure 4 The comparison of position estimation errors and noise levels between the two methods under different injection amplitudes is presented. Experiments confirm that, at the same noise level, the method of this invention can achieve higher estimation accuracy. In summary, a series of experimental results demonstrate that the high-frequency pulsed square wave injection method based on terminal voltage detection proposed in this invention can effectively improve the system signal-to-noise ratio, thereby improving the rotor position estimation accuracy and controlling the estimation error fluctuation to a low level.

Claims

1. A method for estimating the rotor pole position of a dual three-phase permanent magnet synchronous motor based on terminal voltage detection, characterized in that... The method includes the following steps: Step (1) generates a high-frequency square wave voltage signal, and then applies this high-frequency square wave voltage signal along the estimated rotor reference coordinate system. The shaft is injected into the first set of windings of the motor; Step (2) Ignore the resistance voltage drop, rotational voltage, and back electromotive force in the motor model, and derive the expressions for the injection voltage and the high-frequency voltage of the second set of windings according to Kirchhoff's laws: In the formula, and for High-frequency voltage signal in the reference coordinate system; , , , , , These represent the self-inductance and mutual inductance between the same set of windings in different reference frames; , , and These represent the mutual inductance between the two sets of windings; and It is the current component induced in the second winding; and It is the high-frequency voltage component induced by the second set of windings; Step (3) disconnect the second winding during the low-speed phase, and the current... and Forced to 0, and considering that the injection frequency is much higher than the motor operating frequency, the high-frequency model is further simplified to: In the formula, This is the actual rotor position. This is the salient pole position error after considering the salient pole effect; It is a constant related to the amplitude of the high-frequency signal; Step (4) Perform simple algebraic operations on the high-frequency voltage components induced by the second set of windings to obtain the high-frequency envelope. and With rotor position Relationship: In the formula, and Representing the Envelope signal for each control cycle; Step (5) Collect the terminal voltage signal of the second set of windings , and The second set of windings is processed by performing a Clarke transformation to obtain... Voltage components in the reference coordinate system: In the formula, , and This is the terminal voltage signal acquired from the second set of windings; Neutral point Voltage to ground; , and This is the phase voltage signal for the second winding. and for Voltage components in the reference coordinate system; Step (6) from Voltage components in the reference coordinate system and High-frequency voltage envelope is separated from the source: In the formula, and Representing the Voltage components calculated per control cycle; It is the first The injection signal calculated in each control cycle; Represents a symbolic function; Step (7) Based on the high-frequency envelope and rotor position relationship analyzed in step (4), the separated envelope signal is processed using the heterodyne method to obtain the equivalent position error signal: In the formula, Represents the equivalent position error signal. and For dq axis inductance; It is the rotor position error; It is to estimate the rotor position; Represents the mutual inductance amplitude; After obtaining the equivalent position error in step (8), the rotor position and speed information are extracted using a phase-locked loop, and the estimated rotor position and speed signals are input into the motor closed-loop system to realize sensorless control of the dual three-phase permanent magnet synchronous motor.

2. The method for estimating the rotor pole position of a dual three-phase permanent magnet synchronous motor based on terminal voltage detection according to claim 1, characterized in that... In step (1), the high-frequency square wave voltage signal is: In the formula, and for High-frequency voltage signal in the reference coordinate system; The magnitude of the injected voltage. Injection frequency; It is a unit square wave function.

3. The method for estimating the rotor pole position of a dual three-phase permanent magnet synchronous motor based on terminal voltage detection according to claim 2, characterized in that... The Defined as: In the formula, It is the set of natural numbers.

4. The method for estimating the rotor pole position of a dual three-phase permanent magnet synchronous motor based on terminal voltage detection according to claim 1, characterized in that... In step (2), , , , , The expression is as follows: In the formula, and These represent the average inductance and differential inductance of the stator winding, respectively. It estimates the rotor angular frequency.

5. The method for estimating the rotor pole position of a dual three-phase permanent magnet synchronous motor based on terminal voltage detection according to claim 1, characterized in that... In step (3), and The expression is as follows: 。

Images