An Approximate Three-Phase AC Excitation Method With Parallel Capacitors for Aircraft Wound Rotor Synchronous Starter/Generator

In order to solve the excitation problem of wound rotor synchronous starter/generator (WRSSG) in the starting mode, an approximate three-phase ac excitation method with parallel capacitors is proposed. In this method, the main exciter (ME) is equipped with three-phase field winding and two parallel capacitors. The proposed method can realize the approximate effect of the three-phase ac excitation, only needing a single-phase ac excitation power source with constant voltage and constant frequency. Compared with the existing excitation methods, the proposed method has relatively high excitation efficiency and power factor. The variation range of ME output current during the starting process is narrowed by selecting appropriate parallel capacitor parameters so that there is no need for the control of the excitation power source. In this article, the 12-kVA WRSSG is taken as the research object, and the principle and characteristics of the proposed method are analyzed by theoretical method and finite element (FE) field-circuit coupling simulation. The multiobjective optimization method based on the Kriging approximation model combined with an evolutionary algorithm (EA) is utilized to determine parallel capacitor parameters. A 12-kVA WRSSG prototype is manufactured and tested. The simulation and experimental results verify the feasibility and advantages of the proposed method.