CN-121984398-A - Sensorless static initial position identification method for permanent magnet synchronous motor

CN121984398ACN 121984398 ACN121984398 ACN 121984398ACN-121984398-A

Abstract

The application discloses a method for identifying a static initial position of a permanent magnet synchronous motor without a sensor, which comprises the steps of firstly calculating pulse voltage amplitude based on a motor mathematical model theory to replace a traditional heuristic method, ensuring current controllability and detection precision under a low sampling period from the source, then adopting a two-stage pulse injection strategy, firstly carrying out rough identification on a locking area in a large angle range, then carrying out fine identification on the result in a small range, controlling calculated amount while guaranteeing precision through connection of front and back steps, finally checking the result by judging whether the fine identification current is larger than a threshold value, and readjusting parameters if the fine identification current is not passed, thereby forming closed loop check and improving reliability. The application effectively solves the problem of identification failure caused by current out of control or inaccurate detection under low sampling frequency.

Inventors

Zhang Shirunxian
PENG XUAN
DING WEI
ZHU BINGQUAN
WANG AONENG
XU XIAOLONG

Assignees

中冶南方（武汉）自动化有限公司

Dates

Publication Date: 20260505
Application Date: 20260109

Claims (10)

1. The sensorless static initial position identification method for the permanent magnet synchronous motor is characterized by comprising the following steps of: based on a mathematical model of the permanent magnet synchronous motor, acquiring a pulse voltage amplitude for injecting a d axis so as to enable a current response to be within a preset range; Injecting a first group of pulse voltage vectors in a first angle range, recording response values of d-axis currents in all directions, and determining a first maximum current and a first angle corresponding to the first maximum current; injecting a second group of pulse voltage vectors in a second angle range by taking the first angle as the center, recording the response value of d-axis current in each direction, and determining a second maximum current and a second angle corresponding to the second maximum current; judging whether the second maximum current is larger than a preset current threshold value, if so, taking the second angle as the initial position of the rotor, and if not, returning to the step of acquiring the pulse voltage amplitude.
2. The method of claim 1, wherein the obtaining of the pulse voltage amplitude is based on a desired current response value, including a first maximum current value and a second maximum current value, and the voltage set point is obtained by a reverse-extrapolation of the motor model.
3. The identification method according to claim 1, wherein the mathematical model is a simplified model based on d-axis inductance and current change rate, the simplified model ignoring the effect of resistance drop.
4. The identification method according to claim 1, wherein the injection of the two sets of pulse voltage vectors is based on magnetic saturation effect such that the current response is maximized in the magnetic pole direction.
5. The identification method according to claim 1, wherein the identification method is applicable to an embedded permanent magnet synchronous motor and a surface-mounted permanent magnet synchronous motor with saturated saliency.
6. The identification method according to claim 1, wherein the two sets of injected pulse voltage vectors are implemented by PWM control of a frequency converter inverter module.
7. The identification method of claim 1 wherein the injection of the second set of pulse voltage vectors does not cause rotation of the motor shaft.
8. The identification method according to claim 1, wherein the identification method is integrated in a drive control unit of a permanent magnet synchronous motor without changing an original hardware platform and software architecture.
9. An electronic device, comprising: One or more processors; A memory for storing one or more programs; the one or more programs, when executed by the one or more processors, enable the one or more processors to implement the steps in the identification method of any one of claims 1 to 8.
10. A computer readable medium having a computer program stored thereon, which, when executed by a processor, is capable of implementing the steps in the identification method according to any of claims 1 to 8.

Description

Sensorless static initial position identification method for permanent magnet synchronous motor Technical Field The application relates to the technical field of motor control, in particular to a sensorless static initial position identification method for a permanent magnet synchronous motor. Background Permanent Magnet Synchronous Motors (PMSM) are widely used in the fields of industrial driving, household appliances, electric automobiles and the like due to the advantages of high power density, high efficiency and the like. In order to achieve high-performance closed-loop control, it is important to accurately acquire the initial position of the rotor. In applications where cost or environmental constraints are imposed, sensorless control techniques are typically employed. In the prior art, the high-frequency signal injection method can only identify the axis of the rotor and can not judge the polarity of the magnetic poles, while the traditional vector pulse injection method can solve the polarity judgment problem, the traditional vector pulse injection method generally relies on heuristic injection to determine a proper voltage amplitude so as to ensure that the current response is in a measurable and safe range. However, in the low sampling frequency controller, the probing process becomes difficult due to the rarity of sampling points, which is very easy to cause current runaway (overcurrent) or severely reduce detection accuracy, thereby affecting the reliability and accuracy of identification and even damaging the power device. Therefore, a method capable of ensuring current controllability and realizing high-precision initial position identification under a low sampling period is urgently needed. Disclosure of Invention The application aims to overcome the defects of the prior art and provides a sensorless static initial position identification method for a permanent magnet synchronous motor. The identification method is used for predetermining the pulse voltage amplitude through theoretical calculation, and adopts a two-stage injection strategy combining coarse identification and fine identification, so that the high-precision and high-reliability initial position identification under the low sampling frequency is realized. In order to achieve the above purpose, the application adopts the following technical scheme: In a first aspect, an embodiment of the present application provides a method for identifying a sensorless static initial position of a permanent magnet synchronous motor, including: based on a mathematical model of the permanent magnet synchronous motor, acquiring a pulse voltage amplitude for injecting a d axis so as to enable a current response to be within a preset range; Injecting a first group of pulse voltage vectors in a first angle range, recording response values of d-axis currents in all directions, and determining a first maximum current and a first angle corresponding to the first maximum current; injecting a second group of pulse voltage vectors in a second angle range by taking the first angle as the center, recording the response value of d-axis current in each direction, and determining a second maximum current and a second angle corresponding to the second maximum current; Judging whether the second maximum current is larger than a preset current threshold value, if so, taking the second angle as the initial position of the rotor, otherwise, returning to the step of acquiring the pulse voltage amplitude, adjusting the applied pulse voltage amplitude according to the actual sampling current value, and then repeating the identification process. Further, the acquisition of the pulse voltage amplitude is based on expected current response values, including a first round maximum current value and a second round maximum current value, and the voltage set value is obtained through the back-extrapolation of the motor model. Further, the mathematical model is a simplified model based on d-axis inductance and current change rate, which ignores the effect of resistance drop. Further, the injection of the two sets of pulse voltage vectors is based on the magnetic saturation effect, so that the current response is maximized in the pole direction. Further, the identification method is suitable for embedded permanent magnet synchronous motors and surface-mounted permanent magnet synchronous motors with saturated salient poles. Further, the two groups of injected pulse voltage vectors are realized through PWM control of a frequency converter inversion module. Further, the injection of the second set of pulse voltage vectors does not cause the motor shaft to rotate. Furthermore, the identification method is integrated in a drive control unit of the permanent magnet synchronous motor, and the original hardware platform and software architecture are not required to be changed. In a second aspect, an embodiment of the present application provides an electronic device, including one or m