Analysis of inverter nonlinearity effects on sensorless control for permanent magnet machine drives based on High-Frequency Signal Injection

This paper reports on inverter nonlinearity effects on sensorless control methods based on high-frequency signal injection (HF-injection). Inverter output voltage distortions and their influence on position detection are described analytically and their compensation is discussed. Furthermore it is pointed out that the effects of inverter nonlinearities on sensorless control depend on whether the rotating or the pulsating HF-injection is applied. It is shown that their influence is small if pulsating HF-injection is used and the stator current at fundamental frequency is aligned with the q-axis of the rotor.