Current harmonics reduction of square wave inverter by using adjustable filter for high speed motor power supply

The square wave inverter with adjustable filter is proposed for high speed motor power supply. The six-step square wave inverter can reduce the switching frequency which is beneficial to high frequency inverter due to the switching frequency limitation. The adjustable filter combines low-pass filter with band-blocking filters which have adjustable inductance. The band-blocking filters can adjust the band width following the output current frequency of the inverter. The simulation results show that the proposed adjustable filter can reduce the harmonic components of output inverter current effectively.