Compensation of dead-time effects based on adaptive harmonic filtering in the vector-controlled AC motor drives

A new dead-time compensation method for vector-controlled ac motor drives is proposed. The method only compensates the fundamental and sixth harmonic component of the inverter-output distortions in synchronous reference frame. The fundamental component is compensated by feedforwardly adding a predetermined compensation signal to the voltage reference of ac motor drive. To compensate the harmonic distortions, the harmonic compensator with all-pass-based adaptive bandpass filter is proposed and builds up the feedback loop with current controllers in order to minimize the distortions due to dead-time effects. The method is software intensive and independent of the polarity of the phase currents and nonlinear-switching characteristics varied with operating conditions of the inverter. It is simulated and implemented on a 750-W laboratory ac motor drive, where its effectiveness is verified.