Permanent magnet synchronous motor rotor position filtering and zero calibration method and controller

Abstract

The invention discloses a permanent magnet synchronous motor rotor position filtering and zero position calibration method. The method comprises rotor position filtering, coordinate transformation vector angle calculation and rotor zero position calibration. Wherein the rotor position filtering and coordinate transformation vector angle calculation is used for filtering a rotor position and completing coordinate transformation vector angle calculation of a vector control system; and the rotor zero position calibration is used for realizing zero position deviation calibration of the permanent magnet synchronous motor rotor and the sensor and compensating the obtained rotor position. According to the scheme, the position of the rotor is stably and reliably obtained, and the zero position of the motor rotor is automatically calibrated.

Description

Technical Field

[0001] The present invention relates to the field of automobile electric drive systems, and in particular to a method for filtering and zero-position calibration of a permanent magnet synchronous motor rotor in an automobile electric drive system. Background Art

[0002] The electric drive system is the core component of new energy vehicle driving. Permanent magnet synchronous motors currently account for a large proportion of the domestic market. For the control of permanent magnet synchronous motors, the accuracy and anti-interference of rotor position acquisition are particularly important, and are the key factors to ensure the stable and reliable operation of the electric drive system.

[0003] At present, when the motor controller cannot obtain the zero position of the permanent magnet synchronous motor rotor, the representative methods for obtaining the zero position of the rotor are the high-frequency signal injection method and the back-electromotive force method. Among them, the high-frequency signal injection method depends on the motor type, and the effect is obvious for the salient pole motor, but not obvious for the hidden pole motor. In addition, the demodulation algorithm for the high-frequency current response signal often has the characteristics of large calculation amount, complex algorithm and strong theoretical nature, and poor versatility. The back-electromotive force law calculates the position of the rotor by detecting the voltage or current of the three-phase winding. The amplitude of the back-electromotive force is proportional to the speed. When the rotor is stationary or the speed is very low, the zero position of the motor cannot be detected, and an oscilloscope is needed to observe the waveform, which increases the hardware requirements and is inconvenient to operate. In addition, there are literatures that use neural networks, model reference adaptation and other methods to estimate the initial position of the rotor, but such methods require a lot of calculations and complex algorithms.

[0004] Nowadays, as the development trend of new energy vehicles is towards high voltage and high speed, in such a complex environment, there are many interference sources in the system. How to make the rotor position obtained by the sensor more stable and accurate to ensure the performance of the electric drive system is the current problem. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a permanent magnet synchronous motor rotor position filtering and zero position calibration method for realizing stable and reliable acquisition of the rotor position and automatic calibration of the motor rotor zero position.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a method for rotor position filtering and zero position calibration of a permanent magnet synchronous motor, including rotor position filtering and coordinate transformation vector angle calculation and rotor zero position calibration;

[0007] Among them: the rotor position filtering and coordinate transformation vector angle calculation are used to filter the rotor position and complete the coordinate transformation vector angle calculation of the vector control system; the rotor zero position calibration is used to realize the zero position deviation calibration of the permanent magnet synchronous motor rotor and the sensor, and compensate the acquired rotor position.

[0008] The rotor position filtering and coordinate transformation vector angle calculation includes the following steps:

[0009] S1, obtain the motor rotor position sensor signal and convert it into electrical angle;

[0010] S2, calculate the electrical angle difference between the rotor positions before and after;

[0011] S3, within a sampling period, determine whether the electrical angle difference △θ between the previous and the next two times exceeds the angle corresponding to the current speed;

[0012] S4, when the electrical angle difference △θ between the first and the last two exceeds the limit value, the angle error value is calculated and the angle correction flag is set to 1;

[0013] S5, determining whether the angle correction flag is set;

[0014] S6. If the judgment result of S5 is yes, determine whether the number of corrections is less than the number threshold;

[0015] S7, when the number of corrections in S6 is less than the number threshold, the current rotor position angle = the previous position angle + the estimated angle change within one cycle based on the current speed;

[0016] S8, assigning the current rotor position angle to the last electrical angle variable;

[0017] S9, calculating the difference between the two rotor electrical angles, and performing sliding average processing;

[0018] S10, calculating the coordinate transformation vector angle, coordinate transformation vector angle = current electrical angle change + previous electrical angle + zero position deviation angle.

[0019] If the judgment result of S5 is no, the process proceeds to step S11, in which the variable of the number of angle corrections is reset to zero, and after the reset is completed, the process proceeds to step S8.

[0020] If the judgment result of S6 is no, the process proceeds to step S12, in which the angle value of the position sensor is read and converted into an electrical angle, and the number of angle corrections is reset. After the reset is completed, the process proceeds to step S8.

[0021] The number threshold is set by pre-calibration, and the number threshold setting range is between 1-10.

[0022] The rotor zero position calibration includes the following steps:

[0023] S13, a voltage vector is given with a gradient of 60° in electrical angle, the corresponding rotor position is locked, and the zero position deviation between the position sensor and the d-axis is calculated respectively, and the test of the pole pair number of electrical cycles is completed in total, the zero position deviation is accumulated, and the average value is calculated and assigned to the zero position deviation variable, where the d-axis is the excitation axis;

[0024] S14, in the current mode, a d-axis current is given to make the motor run at no load;

[0025] S15, determining whether the motor's no-load speed is within a set speed range;

[0026] S16, when the no-load running speed of the motor reaches the set speed range, the d-axis and q-axis currents id=0, iq=0 are given to reduce the motor speed, wherein the q-axis is the torque axis;

[0027] S17, when the no-load speed is decreasing, the rotor position alignment angle θ_al i gn is calculated, and the value of θ_al i gn is recorded;

[0028] S18, accumulating the θ_a li gn value M times and averaging it as its value;

[0029] S19, judging whether the θ_a li gn value is within ±2°;

[0030] S20, when the θ_a li gn value is within the range of ±2°, the zero position deviation locked by S13 is assigned to the corresponding zero position deviation value variable and stored in the memory to provide a zero position deviation value for the coordinate transformation vector angle calculation.

[0031] In S15, the speed range is set to 1000rpm-2000rpm.

[0032] In step S17 , the rotor position alignment angle θ_align=ATAN(Ud, Uq) is calculated, where Ud represents the d-axis voltage and Uq represents the q-axis voltage.

[0033] A motor controller, wherein the electrical appliance controller runs the method described to achieve position filtering and zero position calibration of a permanent magnet synchronous motor rotor.

[0034] The advantages of the present invention are: based on the above-mentioned motor rotor position filtering and zero position calibration method, when using a position sensor in a vector control system to obtain the rotor position, the anti-interference ability of the rotor position calculation can be effectively improved, and corrections can be made in real time, thereby improving the robustness of the system; and through the above-mentioned method, the automatic learning calibration of the motor rotor zero position can be realized quickly and accurately, which can be effectively implemented in the motor performance test and mass production stages. In a complex environment with high voltage and high speed and strong coupling, the acquired rotor position can be made more stable and accurate, ensuring the high efficiency and robustness of the permanent magnet synchronous electric drive system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0036] Figure 1 The block diagram of the permanent magnet synchronous motor rotor position filtering and zero position calibration method.

[0037] Figure 2 This is the flow chart of rotor position filtering and coordinate transformation vector angle calculation.

[0038] Figure 3 Flowchart for rotor zero position calibration. DETAILED DESCRIPTION

[0039] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0040] The present invention is based on the motor structure and its mathematical model, does not rely on the motor parameters, does not require the design of complex estimation algorithms and additional hardware equipment, combines the two modules of detection and verification of zero position, does not require human intervention, and the motor controller automatically executes the detection and verification process to obtain the rotor zero position of the permanent magnet synchronous motor. The technical advantages of this solution are: 1. The rotor position obtained by the resolver sensor is more stable and accurate, ensuring the efficiency and reliability of the electric drive system;

[0041] 2. It can quickly and accurately realize the automatic learning and calibration of the motor rotor zero position, and can be effectively implemented in the motor performance test and mass production stages.

[0042] The present invention provides a permanent magnet synchronous motor rotor position filtering and zero position calibration method, which can make the rotor position acquired by a sensor more stable and accurate, so as to ensure the high efficiency, stability and robustness of the electric drive system.

[0043] The technical solution is as follows: a method for rotor position filtering and zero position calibration of a permanent magnet synchronous motor, including rotor position filtering and coordinate transformation vector angle calculation and rotor zero position calibration;

[0044] Wherein: the rotor position filtering and coordinate transformation vector angle calculation are used to filter the rotor position and complete the coordinate transformation vector angle calculation of the vector control system;

[0045] The rotor zero position calibration is used to calibrate the zero position deviation between the permanent magnet synchronous motor rotor and the sensor, and to compensate for the acquired rotor position.

[0046] Furthermore, the rotor position filtering and coordinate transformation vector angle calculation includes the following steps:

[0047] S1, obtain the motor rotor position sensor signal and convert it into electrical angle;

[0048] S2, calculate the electrical angle difference between the rotor positions before and after;

[0049] S3, within a sampling period, determine whether the electrical angle difference △θ between the previous and the next two times exceeds the angle corresponding to the current speed;

[0050] S4, when the electrical angle difference △θ between the first and the last two exceeds the limit value, the angle error value is calculated and the angle correction flag is set to 1;

[0051] S5, determining whether the angle correction flag is set;

[0052] S6, if the judgment result of S5 is yes, then determine whether the number of corrections is less than 2;

[0053] S7, when the number of corrections in S6 is less than 2, the current rotor position angle = the previous position angle + the estimated angle change within one cycle according to the current speed is assigned to the current rotor position angle;

[0054] S8, assign the current rotor position angle to the previous electrical angle variable;

[0055] S9, calculating the difference between the two rotor electrical angles and performing sliding average processing;

[0056] S10, calculating the coordinate transformation vector angle, coordinate transformation vector angle = current electrical angle change + previous electrical angle + zero position deviation angle.

[0057] Furthermore, if the judgment result of S5 is no, the process proceeds to step S11 to reset the angle correction times variable, and after the reset is completed, the process proceeds to step S8.

[0058] Furthermore, if the judgment result of S6 is no, the process proceeds to step S12, where the angle value of the position sensor is read and converted into an electrical angle, and the number of angle corrections is reset. After the reset is completed, the process proceeds to step S8.

[0059] Further, the rotor zero position calibration includes the following steps:

[0060] S13, a voltage vector is given with a gradient of 60° in electrical angle, the corresponding rotor position is locked, and the zero position deviation between the position sensor and the d-axis is calculated respectively, and the test of the pole pair number electrical cycles is completed in total, the zero position deviation is accumulated, and the average value is calculated and assigned to the zero position deviation variable, and the d-axis is the excitation axis;

[0061] S14, in the current mode, a d-axis current is given to make the motor run at no load;

[0062] S15, determining whether the motor's no-load speed is within a set speed range;

[0063] S16, when the no-load running speed of the motor reaches the set speed range, the d-axis and q-axis currents id=0 and iq=0 are given to reduce the motor speed, and the q-axis is the torque axis;

[0064] S17, when the no-load speed is decreasing, the rotor position alignment angle θ_a li gn=ATAN(Ud, Uq) is calculated, and the value of θ_a li gn is recorded, where Ud represents the d-axis voltage and Uq represents the q-axis voltage;

[0065] S18, accumulating the θ_a li gn value M times and processing the average value thereof;

[0066] S19, judging whether the θ_a li gn value is within ±2°;

[0067] S20, when the θ_a li gn value is within the range of ±2°, the zero position deviation locked by S13 is assigned to the corresponding variable and stored in the memory to provide a zero position deviation value for the coordinate transformation vector angle calculation.

[0068] Furthermore, in S15, the speed range is set to 1000 rpm-2000 rpm.

[0069] Furthermore, in S18, M is 100.

[0070] like Figures 1 to 3 As shown, the permanent magnet synchronous motor rotor position filtering and zero position calibration method of the present invention includes rotor position filtering and coordinate transformation vector angle calculation and rotor zero position calibration; wherein: the rotor position filtering and coordinate transformation vector angle calculation are used to filter the rotor position and complete the coordinate transformation vector angle calculation of the vector control system; the rotor zero position calibration is used to calibrate the zero position deviation between the permanent magnet synchronous motor rotor and the sensor, and compensate for the acquired rotor position. The rotor position filtering and coordinate transformation vector angle calculation include the following steps:

[0071] S1, obtains the motor rotor position sensor signal and converts it into electrical angle.

[0072] S2, calculate the electrical angle difference between the rotor positions before and after.

[0073] S3, within a sampling period, determine whether the electrical angle difference △θ between the two previous and subsequent times exceeds the angle corresponding to the current speed, where the current speed is 500 rpm.

[0074] S4, when the electrical angle difference △θ between the previous and the next two exceeds the limit value, the angle error value is calculated and the angle correction flag is set to 1.

[0075] S5, determining whether the angle correction flag is set.

[0076] S6: If the judgment result of S5 is yes, then determine whether the number of corrections is less than 2.

[0077] S7, when the number of corrections in S6 is less than 2, the current rotor position angle = the previous position angle + the estimated angle change within one cycle according to the current speed is assigned to the current rotor position angle.

[0078] S8, assign the current rotor position angle to the previous electrical angle variable.

[0079] S9, calculates the difference between the two rotor electrical angles and performs sliding average processing; the sliding average processing process is: take the difference between the two times as data each time, obtain N data by accumulating the difference between the two times, arrange the N data into a queue, the length of the queue is fixed at N, accumulate new data each time and put it at the end of the queue, and discard the data at the head of the original queue, add the values ​​of the N data in the queue and divide by N.

[0080] S10, calculating the coordinate transformation vector angle, coordinate transformation vector angle = current electrical angle change + previous electrical angle + zero position deviation angle.

[0081] If the judgment result of S5 is no, then go to step S11 to reset the angle correction times variable, and then go to step S8. If the judgment result of S6 is no, then go to step S12 to read the position sensor angle value, convert it to electrical angle, and complete the angle correction times reset, and then go to step S8.

[0082] The rotor zero position calibration comprises the following steps:

[0083] S13, give a voltage vector with a gradient of 60° in electrical angle, lock the corresponding rotor position, and calculate the zero position deviation between the position sensor and the d-axis respectively, complete the test of the pole pair number of electrical cycles in total, accumulate the zero position deviation, calculate the average value, and assign it to the zero position deviation variable, where the d-axis is the excitation axis.

[0084] S14, in current mode, sets the d-axis current to make the motor run at no-load.

[0085] S15, judging whether the speed of the motor running at no load is within the set speed range; in S15, the set speed range is 1000rpm-2000rpm.

[0086] S16, when the no-load running speed of the motor reaches the set speed range, the d-axis and q-axis currents id=0 and iq=0 are given to reduce the motor speed, and the q-axis is the torque axis.

[0087] S17, when the no-load speed is decreasing, calculate the rotor position alignment angle θ_a li gn = ATAN (Ud, Uq), and record the value of θ_a li gn, where Ud represents the d-axis voltage and Uq represents the q-axis voltage; wherein, the rotor position alignment angle θ_a li gn = ATAN (Ud, Uq) is calculated by the inverse tangent values ​​of Ud and Uq.

[0088] S18, accumulate θ_a lign values ​​M times and process them as the average value; M is 100.

[0089] S19, determine whether the θ_a li gn value is within ±2°.

[0090] S20, when the θ_a li gn value is within the range of ±2°, the zero position deviation locked by S13 is assigned to the corresponding variable and stored in the memory to provide a zero position deviation value for the coordinate transformation vector angle calculation.

[0091] This solution can realize the anti-interference processing of the permanent magnet synchronous motor rotor position and make real-time corrections, which can ensure the normal operation of the system and improve the stability of the system. The invention can also complete the self-learning and effectiveness judgment of the motor rotor zero position deviation, ensuring the accuracy of the rotor zero position deviation, and can be effectively implemented in the motor testing and mass production stages. Through the above invention, the accuracy and anti-interference ability of the vector control system rotor position acquisition can be guaranteed, especially in the high-voltage and high-speed development trend of new energy vehicles. In this strongly coupled interference environment, there is

[0092] It effectively improves the anti-interference ability and robustness of the electric drive system.

[0093] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A method for filtering and zero-position calibration of a permanent magnet synchronous motor rotor, characterized in that: Including rotor position filtering and coordinate transformation vector angle calculation and rotor zero position calibration; Among them: the rotor position filtering and coordinate transformation vector angle calculation are used to filter the rotor position and complete the coordinate transformation vector angle calculation of the vector control system; the rotor zero position calibration is used to realize the zero position deviation calibration of the permanent magnet synchronous motor rotor and the sensor, and compensate the acquired rotor position.

2. A method for filtering and zeroing the rotor position of a permanent magnet synchronous motor according to claim 1, characterized in that: The rotor position filtering and coordinate transformation vector angle calculation includes the following steps: S1, obtain the motor rotor position sensor signal and convert it into electrical angle; S2, calculate the electrical angle difference between the rotor positions before and after; S3, within a sampling period, determine whether the electrical angle difference △θ between the previous and the next two times exceeds the angle corresponding to the current speed; S4, when the electrical angle difference △θ between the first and the last two exceeds the limit value, the angle error value is calculated and the angle correction flag is set to 1; S5, determining whether the angle correction flag is set; S6. If the judgment result of S5 is yes, determine whether the number of corrections is less than the number threshold; S7, when the number of corrections in S6 is less than the number threshold, the current rotor position angle = the previous position angle + the estimated angle change within one cycle based on the current speed; S8, assigning the current rotor position angle to the last electrical angle variable; S9, calculating the difference between the two rotor electrical angles, and performing sliding average processing; S10, calculating the coordinate transformation vector angle, coordinate transformation vector angle = current electrical angle change + previous electrical angle + zero position deviation angle.

3. A method for filtering and zeroing the rotor position of a permanent magnet synchronous motor according to claim 2, characterized in that: If the judgment result of S5 is no, the process proceeds to step S11, in which the variable of the number of angle corrections is reset to zero, and after the reset is completed, the process proceeds to step S8.

4. A method for filtering and zeroing the rotor position of a permanent magnet synchronous motor as claimed in claim 2, characterized in that: If the judgment result of S6 is no, the process proceeds to step S12, in which the angle value of the position sensor is read and converted into an electrical angle, and the number of angle corrections is reset. After the reset is completed, the process proceeds to step S8.

5. A method for filtering and zero-position calibration of a permanent magnet synchronous motor rotor according to claim 2, characterized in that: The number threshold is set by pre-calibration, and the number threshold setting range is between 1-10.

6. A method for filtering and zeroing the rotor position of a permanent magnet synchronous motor according to any one of claims 1 to 5, characterized in that: The rotor zero position calibration includes the following steps: S13, a voltage vector is given with a gradient of 60° in electrical angle, the corresponding rotor position is locked, and the zero position deviation between the position sensor and the d-axis is calculated respectively, and the test of the pole pair number of electrical cycles is completed in total, the zero position deviation is accumulated, and the average value is calculated and assigned to the zero position deviation variable, where the d-axis is the excitation axis; S14, in the current mode, a d-axis current is given to make the motor run at no load; S15, determining whether the motor's no-load speed is within a set speed range; S16, when the no-load running speed of the motor reaches the set speed range, the d-axis and q-axis currents id=0, iq=0 are given to reduce the motor speed, wherein the q-axis is the torque axis; S17, when the no-load speed is decreasing, calculating the rotor position alignment angle θ_align and recording the value of θ_align; S18, accumulating the θ_align value M times and taking the average value thereof as its value; S19, judging whether the θ_align value is within ±2°; S20, when the θ_align value is within the range of ±2°, the zero position deviation locked by S13 is assigned to the corresponding zero position deviation value variable and stored in the memory to provide the zero position deviation value for the coordinate transformation vector angle calculation.

7. A method for filtering and zeroing the rotor position of a permanent magnet synchronous motor as claimed in claim 6, characterized in that: In S15, the speed range is set to 1000rpm-2000rpm.

8. A method for filtering and zero-position calibration of a permanent magnet synchronous motor rotor according to claim 6, characterized in that: In step S17 , the rotor position alignment angle θ_align=ATAN(Ud, Uq) is calculated, where Ud represents the d-axis voltage and Uq represents the q-axis voltage.

9. A motor controller, characterized in that: The electrical controller runs the method described in any one of claims 1 to 8 to achieve rotor position filtering and zero position calibration of the permanent magnet synchronous motor.

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