Direct initial position detection method for permanent magnet synchronous motor

Abstract

The application discloses a direct initial position detection method of a permanent magnet synchronous motor, wherein a sinusoidal high-frequency voltage signal is injected to a d-axis when the permanent magnet synchronous motor is static; a high-pass filter is used to extract a d-axis high-frequency current response of a stator winding; a sliding average filter counting method is used to obtain time of a positive half cycle and a negative half cycle of the d-axis high-frequency current response in a period, and the time of the positive half cycle and the negative half cycle are compared to judge a convergence polarity of a position detection result; and the polarity judgment result is compensated to an output of a phase-locked loop, so that direct and effective detection of an initial position of the permanent magnet synchronous motor is realized. The application can improve the precision and response speed of the initial position detection, and meets the control demand of a zero-speed sensorless control and a low-speed sensorless control.

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