Research on excitation control method for the three-phase brushless asynchronous excitation system of wound-field synchronous starter/generators

This paper focuses on the control of three-phase brushless asynchronous excitation system (TBAES) of the aircraft wound-field synchronous starter-generator system. Since the closed-loop control of the field current of synchronous starter-generator is hard to achieve, generally, the TBAES is powered by the onboard three-phase power system during the low speed region and cut off one phase of the onboard three-phase power system during the high-speed region. The uncontrolled operation of TBAES increases the control complexity of starter-generator and affects the performance of the starter-generator. In order to control the field-current of starter-generator during the starting process, this paper presents an excitation control method which is based on the decoupled equivalent circuit model of TBAES. The proposed mathematical model and theoretical findings are verified by experimental results.