Research on Initial Rotor Position Estimation for DSEM Based on Excitation Field Building

This paper proposes an initial position estimation method for doubly salient electromagnetic motor (DSEM) based on excitation field building. During the rise of excitation current, the induced electromotive force (EMF) of three phases is sampled and the initial rotor position is estimated through coordinate transformation and normalization. Compared with traditional method based on excitation field building, this method takes the nonlinear factors of inductance into account and improves the estimation accuracy. Compared with methods based on pulse injection, this method has no current in armature winding, which does not generate current loss and electromagnetic torque. Besides, with no need to calculate current slopes, the method is convenient and less affected by sampling errors. Finally, the feasibility and correctness of this method is verified by experiment.