Rapid demodulation of rotor position for high frequency voltage injection based IPM machine sensorless control

A rapid demodulation process of position sensorless control was investigated for Interior Permanent Magnet Synchronous Machine (IPMSM) drive system. In this method, the rotor position is derived with the demodulation of stator current based on high frequency rotating voltage injection. Fundamental component of rotor position signal is isolated from high frequency components containing useless information by synchronization with the angle of high frequency rotating voltage vector. With the comparison between the synchronizing angle deriving from the command voltage and the directly measured voltage value, the estimation performance is studied with respect to the effects introduced by inverter non-linearity. With instantaneous voltage measurement, the proposed method is superior in easiness of implementation, rapid estimation process and insensitivity to the effects on estimation accuracy arisen from the non-ideal behaviors of pulse width modulation and the voltage source inverter.