Analysis of the Initial Alignment Process for Doubly Salient Electromagnetic Machine Position Sensorless Startup

Abstract

Align and go is a position sensorless startup control strategy which has the advantage of low price and easy-implementation, it has been widely applied in practice. This paper studies the initial alignment process in position sensorless doubly salient electromagnetic machine (DSEM) system, which plays an important role for the initial sensorless startup performance. By analyzing the electromagnetic torque of all possible alignment pulses in three-phase full-bridge converter, the relationship between alignment pulses and stable positioning position is studied. Then, to improve the initial startup performance, the alignment pulse of switching on two upper transistors and one lower transistor is proposed to be applied due to the benefit of the better selection of initial exciting phases. On this basis, the whole process of sensorless startup align and go is explored, and numerous experimental results verify the correctness and flexibility of the analysis.