Characteristics of series-resonant AC link inverter for capacitor motor drives

This paper presents a control method for a series-resonant AC link inverter for capacitor motor drives and discusses its characteristics. This inverter is a type of resonant inverter using zero current switching (ZCS). Conventionally this inverter is controlled by pulse density modulation (PDM), but this generates the lower order harmonic components that do not arise with PWM inverters. To solve this problem, the authors have previously proposed solutions combining PDM and pulse amplitude modulation (PAM) controls. For resistance loads, they have demonstrated that this method can reduce the lower harmonic components and improve the waveform of the output current. In this paper, they present the basic characteristics and experimental results of this inverter for capacitor motor drives.