Novel Compensation Method of Digital Delay for High-speed Permanent Magnet Synchronous Motor Under Low Carrier Ratio

This study proposes a new compensation method of digital delay for permanent magnet synchronous motor (PMSM) under low carrier ratio. This method compensates the current sampling delay and the pulse width modulation (PWM) update delay respectively. The current sampling delay is compensated by one sampling period in the design of the current regulator. The PWM update delay observer is designed to get the delay angle resulted by the PWM update. The output of the PWM update delay observer is used to compensate the angle of the inverse Park transformation. The method proposed in this paper is simple to implement and performances good dynamic performance in sensorless vector control under low carrier ratio. Finally, the load step, speed step, and parameter sensitivity experiments performed on a 100kW 30000rpm surface permanent magnet synchronous motor verified the practicability and availability of the method.