Reduction of Input Current Harmonics Using Dual Inverter for Motor Drive

Abstract

This paper proposes a control method to reduce the capacitance of an inverter driven motor system comprising two inverters and an open-end winding machine. In the proposed method, the inverter connected to the DC power supply switches based on the fundamental electric angular frequency of the motor. The other inverter is a pulse-width modulator controlled to generate a compensation voltage to supply a sinusoidal voltage waveform to the motor. Therefore, the carrier-frequency-order component of the input current harmonic can be reduced greatly, which helps reduce the current ripple of the filter capacitor across the DC-bus. Furthermore, this paper proposes a new control method to suppress the voltage fluctuation of the floating capacitor of the secondary-side inverter. The voltage fluctuation of the floating capacitor and hence its capacitance are reduced. The effectiveness of the proposed system is verified through experiments. The proposed control method suppresses the voltage fluctuations of the floating capacitor by 35.0% compared to the conventional driving method.