Simplified rotor position estimation method for aircraft starter/generator based on harmonic signal self-injection

This paper proposes a simplified rotor position estimation method for aviation three-stage synchronous starter/generator (TSSG) to enhance the sensorless starting control performance. The self-injected 2nd harmonic in the field winding of main machine (MM) caused by the rotating rectifier is employed as indirectly injected high-frequency (HF) signal and the rotor position angle is demodulated from the response HF signal in armature winding of MM. A specific band-pass filter (BPF) is designed for error signal extraction in the proposed rotor position demodulation method with elimination of low-pass filter (LPF). The effectiveness and feasibility of the proposed method are validated by simulation and experiment investigations on a TSSG.