EXPERIMENTAL IMPLEMENTATION OF SINGLE-PHASE, THREE-LEVEL, SINUSOIDAL PULSEWIDTH MODULATION (SPWM) VOLTAGE SOURCE INVERTER (VSI) WITH R-L LOAD

Abstract

The quest to achieve less-distorted dc-ac power conversion has resulted in the proliferation of many multilevel inverter configurations. This paper presents an experimental report of a simplified topology for single-phase, SPWM, three-level voltage source inverter wit R-L load. To keep the power circuit component count to a minimum, the three-level topology simplifies the conventional three-level inverter configuration to that of a full-bridge, two-level inverter, with only one added clamping power switch. Operational principles, with experimental switching functions are given. Laboratory prototypes of the simplified three-level inverter and the conventional full-bridge, two-level inverter were built. Assessment of the 3-level inverter is done by comparing its experimental voltage waveforms and the corresponding FFT analyses with those of the conventional full-bridge, 2-level inverter under the conditions of identical supply dc voltage, switching frequency and loading.