Switching losses reduction in current-controlled single-phase inverters

This paper introduces an effective technique for reducing semiconductor switching losses, and evenly distributing them, in current-controlled single-phase inverters. The current switching frequency is reduced taking advantage of three-level commutation by a double hysteresis-band current-control strategy imported from multilevel converters studies. Furthermore, an additional reduction of the semiconductor switching frequency is accomplished by modifying the standard semiconductor switching pattern for balancing power dissipation between upper and lower devices. An overall reduction of switching losses in a factor of 2 to 4 is achieved in this manner. The system control strategies are exposed in detail and experimental results for a 200 kVA grid-side converter of a switched reluctance drive are presented to better show the concepts involved.