A method for compensating installation errors of Hall sensors in permanent magnet synchronous motors under disordered sequence

Abstract

A method for compensating installation errors of Hall sensors in a permanent magnet synchronous motor under disordered sequence includes the following steps: by energizing the three-phase stator windings in sequence and presetting a certain time, the back electromotive force of each phase is measured; the position of the rotor is obtained according to the back electromotive force value of each phase obtained in step 1; the value of the Hall sensor transferred to the corresponding sector is measured by injecting a fixed SVPWM, and the correct order of the Hall sensor is determined by the values ​​of the six groups of Hall sensors in step 3; when the motor starts normally, the position deviation of the Hall sensor is compensated. This method solves the problem that the Hall signal detects a rotor position that is inconsistent with the actual position due to the disordered sequence of the Hall sensor of the motor, and the rotor cannot be transferred to the corresponding sector and cannot start normally; through the position deviation compensation method of the Hall sensor, the sinusoidality of the current can be improved, the position deviation of the Hall sensor can be reduced, and the harmonic content of the current can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of permanent magnet synchronous motors, and in particular to a method for compensating installation errors of permanent magnet synchronous motors under disordered Hall sensors. Background Art

[0002] Permanent magnet synchronous motor control systems have broadened many fields. Permanent magnet synchronous motors have the characteristics of high power efficiency, high power factor, small size and low noise. They have been widely used in civil, aerospace and military fields.

[0003] Permanent magnet synchronous motors currently generally use switch-type Hall components. Whenever the rotor magnetic pole passes near the Hall sensor, a high or low level signal will be received, indicating that the north and south magnetic poles are passing through the Hall sensor. The precise order of commutation can be determined based on the signal combination of the three Hall sensors. When there is a deviation in the installation position of the Hall sensor, there is a deviation between the rotor position detected by the Hall sensor and the ideal rotor position, which will cause the electrical angle of each sector to no longer be 60°, which will cause current distortion and torque pulsation, and in severe cases, the motor will burn out. Summary of the invention

[0004] The purpose of the present invention is to provide a method for compensating the installation error of the Hall sensor in a permanent magnet synchronous motor under disordered sequence, so as to solve the problem in the prior art that the rotor position detected by the Hall signal is inconsistent with the actual position due to the Hall disordered sequence, and the corresponding SVPWM cannot be transferred to the corresponding sector, and solves the situation that there is a deviation in the initial installation position of the Hall position sensor; the present invention determines the rotor position by back electromotive force, and then determines the position of the Hall sensor by looking at the Hall value of the corresponding sector through a given SVPWM, thereby compensating for the Hall sensor position deviation and achieving the purpose of correcting the Hall sensor position deviation.

[0005] A method for compensating installation errors of Hall sensors in a permanent magnet synchronous motor under disordered sequence comprises the following steps:

[0006] Step 1: By energizing the three-phase stator windings in sequence and presetting a certain time, the back electromotive force of each phase is measured;

[0007] Step 2: Obtain the position of the rotor according to the back electromotive force value of each phase obtained in step 1;

[0008] Step 3: Measure the value of the Hall in the corresponding sector by injecting a fixed SVPWM;

[0009] Step 4: Determine the correct order of the Hall sensors based on the values ​​of the six Hall sensors in step 3;

[0010] Step 5: When the motor starts normally, based on the principle of least squares method, by calculating the absolute reference position and establishing the absolute position deviation correction equation, the absolute position deviation correction value of the Hall sensor is expressed, and the position deviation compensation of the Hall sensor is performed.

[0011] Furthermore, in step 1, the preset time is 100ms to 400ms.

[0012] Furthermore, the value of the back electromotive force in step 1 is obtained by comparing the terminal voltage of the non-conducting phase with the calculated virtual midpoint voltage, thereby obtaining the zero-crossing point of the back electromotive force. After the two phases are turned on, the currents of the two phases are equal in magnitude and opposite in direction. In addition, the current of the non-energized phase is 0. Assuming that the voltage of the non-energized phase is A voltage, the specific calculation formula is:

[0013] U A =E A +U N

[0014] Among them, U A is the A phase voltage in volts, E A is the point potential of phase A, in volts, U N is the neutral point voltage, and so on to get U B and U C , the specific calculation formula is:

[0015] U B =E B +U N

[0016] U C =E C +U N

[0017] Among them, U B is the B phase voltage in volts, U C is the C phase voltage in volts, E B is the point potential of phase B, in volts, E C is the point potential of phase C, in volts, U N is the neutral point voltage in volts;

[0018] byU A , U B and U C The voltage calculation formula is used to get the neutral point voltage equation, and the A phase electromotive force zero-crossing detection equation is obtained. The specific calculation formula is:

[0019]

[0020]

[0021] Among them, U N is the neutral point voltage in volts, U A is the A phase voltage in volts, U B is the B phase voltage in volts, U C is the C phase voltage in volts, E A is the point potential of phase A, in volts. By analogy, the zero-crossing detection equation of the electromotive force of phases B and C can be obtained. The specific calculation formula is:

[0022]

[0023]

[0024] Among them, U A is the A phase voltage in volts, U B is the B phase voltage in volts, U C is the C phase voltage in volts, E B is the point potential of phase B, in volts, E C is the point potential of phase C, in volts.

[0025] Furthermore, in step 2, when the back electromotive force of a phase winding passes through zero, the direct axis of the rotor coincides with the axis of the phase winding, and the position of the rotor is obtained.

[0026] Furthermore, in step 3, by injecting SVPWM, when the rotor rotates one cycle, one Hall sensor completes one cycle of detection and outputs a square wave signal with a duty cycle of 50%. The three Hall signals differ by 120° electrical angle from each other. Six rotor positions are detected in one cycle, that is, one cycle is divided into six sectors, and each sector corresponds to a different Hall combination value.

[0027] Furthermore, in step 4, the specific power-on sequence and power-on state of the Hall sensor are determined by the six Hall combination values ​​"111", "110", "100", "101", "001" and "011", thereby achieving normal motor start-up.

[0028] Furthermore, in step 5, the position compensation of the Hall sensor is based on the principle of least squares method. An absolute reference position is calculated by the controller to correct the absolute deviation of the three Hall sensors. Three consecutive sectors are selected to reflect all the information of the absolute error. The minimum variance estimation of the absolute position deviation is established to express the complete absolute position deviation correction equation. The relative position deviation of the Hall sensor is obtained by measuring the corresponding time through the timer of the controller, thereby expressing the absolute position deviation correction value of the Hall sensor. The specific formula is as follows:

[0029]

[0030] in, is the estimated value of the absolute position deviation of Hall sensor A in degrees, is the estimated value of the absolute position deviation of Hall sensor B in degrees, is the estimated value of the absolute position deviation of Hall sensor C in degrees, is the relative deviation between Hall sensor A and Hall sensor C, in degrees, is the relative deviation between Hall sensor B and Hall sensor A, in degrees, is the relative deviation between Hall sensor C and Hall sensor B, in degrees;

[0031] The three Hall sensors all have absolute position deviations during the installation process, which will cause the motor to fail to start normally. The estimated correction term of the Hall sensor absolute position deviation is to compensate for and correct the absolute position deviation of the Hall sensor during the installation process in actual operation. Therefore, during the control process, the time of the first three sectors is used for real-time calculation to obtain the estimated correction term of the Hall sensor absolute position deviation, as shown in the following formula:

[0032]

[0033] Among them, θ com is the estimated correction term for the absolute position deviation of the Hall sensor, expressed in degrees, T i and T i-2 T is the detected sector time in milliseconds. av The average time of the detected sectors in milliseconds.

[0034] Beneficial effects of the present invention:

[0035] (1) Solved the problem that the rotor position detected by the Hall signal was inconsistent with the actual position due to the disordered Hall sequence of the motor, and the rotor could not be turned to the corresponding sector and could not start normally;

[0036] (2) Through the position deviation compensation method of the Hall sensor, the sinusoidality of the current can be improved, the position deviation of the Hall sensor can be reduced, and the harmonic content of the current can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The present invention is a flowchart of a method for compensating installation errors of a permanent magnet synchronous motor under disordered Hall sensor sequence.

[0038] Figure 2 A schematic diagram of six sectors for a specific implementation of the present invention.

[0039] Figure 3 This is a diagram of the position deviation results of a Hall sensor after least squares compensation according to a specific implementation of the present invention. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings.

[0041] The present invention provides a method for compensating installation errors of Hall sensors in a permanent magnet synchronous motor under disordered sequence. Figure 1 As shown, the following steps are included:

[0042] Step S1: The three-phase stator windings are energized in sequence and a certain time is preset to measure the back electromotive force of each phase; the preset time is 100ms to 400ms.

[0043] The value of the back electromotive force in step S1 can be obtained by comparing the terminal voltage of the non-conducting phase with the calculated virtual midpoint voltage, thereby obtaining the zero-crossing point of the back electromotive force. After the two phases are turned on, the currents of the two phases are equal in magnitude and opposite in direction. In addition, the current of the non-energized phase is 0. Assuming that the voltage of the non-energized phase is A voltage, the specific calculation formula is:

[0044] U A =E A +U N

[0045] Among them, U A is the A phase voltage in volts, E A is the point potential of phase A, in volts, U N is the neutral point voltage, and so on to get U B and U C , the specific calculation formula is:

[0046] U B =E B +U N

[0047] U C =E C +U N

[0048] Among them, U B is the B phase voltage in volts, U C is the C phase voltage in volts, E B is the point potential of phase B, in volts, E C is the point potential of phase C, in volts, U N is the neutral point voltage in volts;

[0049] byU A , U Band U C The voltage calculation formula is used to get the neutral point voltage equation, and the A phase electromotive force zero-crossing detection equation is obtained. The specific calculation formula is:

[0050]

[0051]

[0052] Among them, U N is the neutral point voltage in volts, U A is the A phase voltage in volts, U B is the B phase voltage in volts, U C is the C phase voltage in volts, E A is the point potential of phase A, in volts. By analogy, the zero-crossing detection equation of the electromotive force of phases B and C can be obtained. The specific calculation formula is:

[0053]

[0054]

[0055] Among them, U A is the A phase voltage in volts, U B is the B phase voltage in volts, U C is the C phase voltage in volts, E B is the point potential of phase B, in volts, E C is the point potential of phase C, in volts.

[0056] Step S2: Obtain the position of the rotor according to the back electromotive force value of each phase obtained in step S1.

[0057] In step S2, the position of the rotor is determined by the back electromotive force. When the back electromotive force of a phase winding passes through zero, the direct axis of the rotor coincides with the axis of the phase winding. Therefore, as long as the back electromotive force of each phase winding is detected to pass through zero, the position of the rotor can be known.

[0058] Step S3: inject a fixed SVPWM to measure the value of the Hall of the corresponding sector.

[0059] like Figure 2 As shown, in step S3, by injecting SVPWM, when the rotor rotates one cycle, one Hall sensor completes one cycle of detection and outputs a square wave signal with a duty cycle of 50%. The three Hall signals differ by 120° electrical angle from each other. Six rotor positions can be detected in one cycle, that is, one cycle is divided into six sectors, and each sector corresponds to a different Hall combination value.

[0060] Step S4: Determine the correct order of the Hall sensors based on the Hall values ​​in step S3.

[0061] In step S4, the specific power-on sequence and power-on state of the Hall sensor can be determined through the six Hall combination values ​​"111", "110", "100", "101", "001" and "011", so as to achieve normal motor start-up;

[0062] Step S5: When the motor starts normally, position deviation compensation of the Hall sensor is performed.

[0063] In step S5, the position compensation of the Hall sensor is based on the principle of least squares method. An absolute reference position is calculated by the controller to correct the absolute deviation of the three Hall sensors. By selecting three consecutive sectors to reflect all the information of the absolute error, the minimum variance estimation of the absolute position deviation is established to express the complete absolute position deviation correction equation. The relative position deviation of the Hall sensor can be obtained by measuring the corresponding time through the timer of the controller, thereby expressing the absolute position deviation correction value of the Hall sensor. The specific formula is as follows:

[0064]

[0065] in, is the estimated value of the absolute position deviation of Hall sensor A in degrees, is the estimated value of the absolute position deviation of Hall sensor B in degrees, is the estimated value of the absolute position deviation of Hall sensor C in degrees, is the relative deviation between Hall sensor A and Hall sensor C, in degrees, is the relative deviation between Hall sensor B and Hall sensor A, in degrees, is the relative deviation between Hall sensor C and Hall sensor B, in degrees;

[0066] The three Hall sensors all have absolute position deviations during the installation process, which will cause the motor to fail to start normally. The estimated correction term of the Hall sensor absolute position deviation is to compensate for and correct the absolute position deviation of the Hall sensor during the installation process in actual operation. Therefore, during the control process, the time of the first three sectors is used for real-time calculation to obtain the estimated correction term of the Hall sensor for the position deviation, as shown in the following formula:

[0067]

[0068] Among them, θ com is the estimated correction term for the absolute position deviation of the Hall sensor, expressed in degrees, T i and T i-2T is the detected sector time in milliseconds. av The average time of the detected sectors in milliseconds.

[0069] The following is an embodiment:

[0070] like Figure 3 As shown, the specific process is as follows:

[0071] When T i 3ms, T i-1 4ms,T i-2 When it is 5ms, The calculated value is the estimated correction value of the absolute deviation. The position deviation of the Hall sensor is greatly reduced, which proves the effectiveness of the method and the accuracy of the control.

[0072] The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modifications or changes made by ordinary technicians in this field based on the contents disclosed by the present invention should be included in the protection scope recorded in the claims.

Claims

1. A method for compensating installation errors of Hall sensors in a permanent magnet synchronous motor under disordered sequence, characterized in that: The steps include: Step 1: By energizing the three-phase stator windings in sequence and presetting a certain time, the back electromotive force of each phase is measured; The value of the back electromotive force in step 1 is obtained by comparing the terminal voltage of the non-conducting phase with the calculated virtual midpoint voltage, thereby obtaining the zero-crossing point of the back electromotive force. After the two phases are turned on, the currents of the two phases are equal in magnitude and opposite in direction. In addition, the current of the non-energized phase is 0. Assuming that the voltage of the non-energized phase is A voltage, the specific calculation formula is: IN A =E A +U N Among them, U A is the A phase voltage in volts, E A is the point potential of phase A, in volts, U N is the neutral point voltage, and so on to get U B and U C , the specific calculation formula is: IN B =E B +U N IN C =E C +U N Among them, U B is the B phase voltage in volts, U C is the C phase voltage in volts, E B is the point potential of phase B, in volts, E C is the point potential of phase C, in volts, U N is the neutral point voltage in volts; byU A , U B and U C The voltage calculation formula is used to get the neutral point voltage equation, and the A phase electromotive force zero-crossing detection equation is obtained. The specific calculation formula is: Among them, U N is the neutral point voltage in volts, U A is the A phase voltage in volts, U B is the B phase voltage in volts, U C is the C phase voltage in volts, E A is the point potential of phase A, in volts. By analogy, the zero-crossing detection equation of the electromotive force of phases B and C can be obtained. The specific calculation formula is: Among them, U A is the A phase voltage in volts, U B is the B phase voltage in volts, U C is the C phase voltage in volts, E B is the point potential of phase B, in volts, E C is the point potential of phase C, in volts; Step 2: Obtain the position of the rotor according to the back electromotive force value of each phase obtained in step 1; Step 3: Measure the value of the Hall in the corresponding sector by injecting a fixed SVPWM; In step 3, by injecting SVPWM, when the rotor rotates one cycle, one Hall sensor completes one cycle of detection and outputs a square wave signal with a duty cycle of 50%. The three Hall signals differ by 120° electrical angle from each other. Six rotor positions are detected in one cycle, that is, one cycle is divided into six sectors, and each sector corresponds to a different Hall combination value. Step 4: Determine the correct order of the Hall sensors based on the values ​​of the six Hall sensors in step 3; Step 5: When the motor starts normally, based on the principle of least squares method, by calculating the absolute reference position and establishing the absolute position deviation correction equation, the absolute position deviation correction value of the Hall sensor is expressed, and the position deviation compensation of the Hall sensor is performed; In step 5, the position compensation of the Hall sensor is based on the principle of least squares method. An absolute reference position is calculated by the controller to correct the absolute deviation of the three Hall sensors. Three consecutive sectors are selected to reflect all the information of the absolute error. The minimum variance estimation of the absolute position deviation is established to express the complete absolute position deviation correction equation. The relative position deviation of the Hall sensor is obtained by measuring the corresponding time through the timer of the controller, thereby expressing the absolute position deviation correction value of the Hall sensor. The specific formula is as follows: in, is the estimated value of the absolute position deviation of Hall sensor A in degrees, is the estimated value of the absolute position deviation of Hall sensor B in degrees, is the estimated value of the absolute position deviation of Hall sensor C in degrees, is the relative deviation between Hall sensor A and Hall sensor C, in degrees, is the relative deviation between Hall sensor B and Hall sensor A, in degrees, is the relative deviation between Hall sensor C and Hall sensor B, in degrees; The three Hall sensors all have absolute position deviations during the installation process, which will cause the motor to fail to start normally. The estimated correction term of the Hall sensor absolute position deviation is to compensate for and correct the absolute position deviation of the Hall sensor during the installation process in actual operation. Therefore, during the control process, the time of the first three sectors is used for real-time calculation to obtain the estimated correction term of the Hall sensor absolute position deviation, as shown in the following formula: Among them, θ com is the estimated correction term for the absolute position deviation of the Hall sensor, in degrees, T i and T i-2 T is the detected sector time in milliseconds. av The average time of the detected sectors in milliseconds.

2. The method for compensating installation errors of Hall sensors in a permanent magnet synchronous motor under disordered sequence according to claim 1 is characterized in that: In step 1, the preset time is 100ms to 400ms.

3. The method for compensating installation errors of Hall sensors in a permanent magnet synchronous motor under disordered sequence according to claim 1 is characterized in that: In step 2, when the back electromotive force of a phase winding passes through zero, the direct axis of the rotor coincides with the axis of the phase winding, and the position of the rotor is obtained.

4. The method for compensating installation errors of Hall sensors in a permanent magnet synchronous motor under disordered sequence according to claim 1 is characterized in that: In step 4, the specific power-on sequence and power-on state of the Hall sensor are determined by the six Hall combination values ​​"111", "110", "100", "101", "001" and "011", so as to achieve normal motor start-up.

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