A Single-Stage Control Strategy of Wound-Rotor Synchronous Starter Generator Under Excitation Failure Conditions for Hybrid-Electric Propulsion Aircraft Application

The hybrid-electric propulsion aircraft has the advantages of extended range and superior load capacity, compared to the battery-powered electric aircraft. The wound-rotor synchronous machine (WRSM) is a promising candidate in aircraft hybrid-electric propulsion systems due to its mature aero application. In this article, a single-stage control strategy under excitation failure conditions is proposed. This control strategy employs the reluctance torque of WRSM to facilitate engine starting and power generation. Based on the analysis of inductance characteristics, the reluctance torque is calculated and analyzed in detail. Then, an analysis of the output characteristics is conducted. The characteristics of the induced voltage and current of the main generator (MG) field winding when subjected to stator harmonic current excitation are studied. Meanwhile, the influence of the shunt resistor which is connected in parallel to the field winding is analyzed. Furthermore, an analysis of the system in the starting mode and the generating mode under the proposed control strategy is conducted, respectively. According to simulation results, 43.8% rated torque and 14.2% rated electric power can be generated by the scaled WRSM under the proposed control strategy. At last, experiments are carried out on a scaled prototype. The accuracy of the analysis and the feasibility of the proposed control strategy is confirmed.

I. Introduction

The more electric aircraft (MEA) is a promising development trend of aircraft electrification. By replacing the hydraulic system and the pneumatic system with the electric system, the MEA gains substantial economic and environmental benefits [1], [2], [3]. Considering the fact that over 90% of the aircraft power is used for propulsion, the electrification of the aircraft’s primary power system providing propulsion has more potential for higher fuel efficiency and better emission performance [4], [5], [6], [7]. Therefore, electric propulsion aircraft has become the new development trend of aircraft electrification.