A Rotor Position Identification Method for Permanent Magnet Synchronous Motor in Low Speed ​​Range

Abstract

The invention discloses a rotor position identification method in a low-speed range of a permanent magnet synchronous motor, which belongs to the field of permanent magnet synchronous motor control. In order to solve the problem that the use of multiple filters in the traditional pulse vibration signal injection method causes the superposition of hysteresis effect, the decrease of the dynamic performance of the system and the increase of the position estimation error. The present invention proposes a new low-speed position sensorless control strategy, specifically on the basis of injecting the high-frequency pulse vibration square wave voltage signal into the two-phase stationary coordinate axis system, through a generalized second-order integrator (SOGI) to β The current in the shaft is subjected to signal separation and amplitude demodulation to obtain two orthogonal signals containing rotor position information, and then the rotor position information is extracted by heterodyne method and rotor position observer. No filtering is used in the whole signal demodulation process device. The dynamic performance of the control system and the estimation accuracy of the rotor position are effectively improved.

Description

technical field [0001] The invention relates to the field of permanent magnet synchronous motor control, in particular to a position sensorless rotor position identification method in the low speed field of permanent magnet synchronous motors. Background technique [0002] Permanent magnet synchronous motors are widely used in wind power generation, electric vehicles, aerospace and other fields due to their advantages of high power density, high efficiency and low noise. In order to achieve high-performance vector control, it is necessary to obtain accurate rotor position information. The rotor position can be accurately obtained by installing a high-resolution mechanical sensor, but it increases the size of the motor and hardware cost, and cannot be used in some special occasions. Therefore, it is of great significance to study the position sensorless control technology with high reliability and high precision to replace the mechanical sensor. [0003] For the control of t...

AI Technical Summary

Problems solved by technology

However, the traditional high-frequency signal injection methods, that is, the rotating voltage injection method and the pulse vibration voltage injection method, both need to use one or more filters in the process of current loop and signal demodulation, and the use of filters will bring different degrees of damage. Amplitude attenuation and phase lag will not only reduce the bandwidth of the current loop, affect the dynamic performance of the system, but also increase the position estimation error

In addition, the traditional pulse vibration signal injection method injects high-frequency voltage signals into the estimated d-axis, which has the advantages of simple algorithm and small torque ripple. However, the traditional rotating signal injection method injects high-frequency voltage signals into the two-phase stationary coordinate system, which has good stability, but the signal demodulation process is complicated, and multiple filters use to degrade the dynamic performance of the system

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