A sensorless control system of permanent magnet synchronous motor for electric locomotive based on improved high-frequency rotating injection method

Abstract

The mechanical sensor of electric locomotive is easy to lose, leading to position measurement error, which deteriorates the performance of permanent magnet synchronous motor (PMSM) drive system. Therefore, a limp-home mode based on high-frequency injection sensorless strategy is proposed. The signal processing of conventional high-frequency rotating injection needs several filters, and the delay has an impact on estimated position, which is phase-based demodulation. In this paper, an amplitude-based demodulation strategy is proposed, which needs only one low-pass filter, meanwhile the digital control delay can be canceled automatically. Accordingly, the position estimation precision and robustness can be enhanced with the aid of proposed method. The feasibility and effectiveness of theoretical analysis is verified on an 18-kW PMSM drive system experimental platform.