Voltage inputting for the rotor position estimation of a permanent magnet motor based on high-frequency signal injection

To estimate the rotor position of a permanent magnet synchronous machine by the method of high-frequency signal injection, the basic and high-frequency voltages should be input into the machine simultaneously. The feasibility to realize this idea by a pulse width modulation (PWM) inverter was discussed and simulated. The results show that this method works well with an appropriate ratio of carrier signal to modulation. The inverter's nonlinear behavior was also studied, and its effects only occur in the time domain as the phase currents cross zero. According to this feature, a simple compensation measure was presented and simulation results verified its correctness.