A Novel High Frequency Signal Injection Based Sensorless Control Method for Six-Phase FTPMSM System

A novel sensorless control method based on high frequency (HF) signal injection into any non-fault two phase windings is proposed for the six-phase fault tolerant permanent magnet synchronous motor (FTPMSM), which can guarantee the sensorless control performance of the system even in postfault operation. The essence of the proposed HF signal injection method is to inject HF signals directly into non-fault two windings, in which no coordinate transformation is required. Then the rotor position and speed information can be extracted from the phase inductance signals. First, the real-time inductance observer is proposed to estimate the real-time differential mode inductance through resolving the HF current signals, which consists of the band-pass filter (BPF), the envelop demodulation and the signal processing. Second, the nonorthogonal phase-locked loop (NPLL) is proposed, which can extract the information of the rotor position and speed from the estimated inductance signals. Finally, the proposed control scheme is demonstrated by the simulation of a FTPMSM drive, which can achieve the sensorless control in low speed range even in fault tolerant operation condition.