Analysis of an Application of the Extended Electromotive Force Model Based Position Sensorless Control on the Wound-Field Synchronous Motor with Dual-Three Phases in Standstill/Low Speed Region

Sensorless control has become a popular research area for ac drives. However, most of the works are attributed to conventional three-phase drives. Given that applications of multiphase machines keep spreading, studies of position sensorless for them are necessary. For the object in this paper, some studies for sensorless control in middle/high speed region are reported. To accomplish a full-speed range sensorless control, a study about the standstill/low speed sensorless control of the target motor is proposed in this paper. Particularly, conventional signal injection methods utilized in three-phase ac drives meet a new issue caused by the inner magnetic couplings of the system when applying to the object in this paper. It may lead to failure of sensorless control and torque ripple enlargement. Therefore, analyses to solve the issue become the main interest of this paper, simulation results are demonstrated in the last section.

I. Introduction

As an extension of variable speed ac drives, the history of multiphase electric machines can be dated back to the late 1960s. Multiphase drives have advantages over three phase drives in some aspects. Particularly, reduction of low-order harmonics, free degrees for fail-safe control, etc. Owing to these characteristics, they are preferable to many areas, such as electric/hybrid vehicles, electric propulsion of ships, more electric aircraft and many high-power electric applications^{[1] [2]}. Fig. 1.

Configuration of the W-DFSM