MTPA Control of Wound-Rotor Synchronous Start/Generator Drives Based on Virtual Signal Injection Considering Cross-Coupling Effect in Low-Speed Range

The cross-coupling effect is the most common phenomenon in the electric machinery operation. It has the influence on the machine efficiency and control scheme. However, the cross-coupling effect is ignored in the existing virtual signal injection (VSI) maximum torque per ampere (MTPA) control. In this article, the online searching MTPA control based on the VSI scheme for integrated starter/generator system considering the cross-coupling effect is proposed. For obtaining the accurate torque gradient with respect to the torque angle online, the torque equations in the existing VSI schemes are extended by the cross-coupling effect and the influence of the iron loss and temperature rise is studied. In this article, the partial parameters method is proposed. A prototype is set up, and the experiments are carried out to verify the effectiveness of the proposed control scheme.

I. Introduction

With the development of more electric aircraft, the integrated starter/generator (ISG) system based on the wound-rotor synchronous start/generator (WRSSG) becomes more and more popular due to the merits of high safety. This ISG system consists of a pre-exciter, a three-phase asynchronous main exciter (ME), a rotating rectifier (RR), and the main machine (see Fig. 1) [1], [2].