An efficient three‐phase two‐level voltage source inverter with the suppression of the dead time effect

Abstract

The paper carries out the research on a novel two‐level voltage source inverter to further improve the output power quality of the inverter under the premise of efficient operation. Main switches can realize zero‐voltage switching in a wide load range to ensure the efficient operation of the designed inverter. Total harmonic distortion (THD) of the output current at low output frequencies can be improved by the modification of resonant tanks in the designed inverter. In the dead time, the modified resonant tanks can result in a shorter duration of nonlinear changes in the output phase voltage at lower load current, which is beneficial for reducing the output voltage error caused by dead time. The improved power quality at low output frequencies is conductive to the use of the designed inverter in the drive system of the low‐speed AC motor. The paper expounds every operating status during a switching period. The experiment manifests that switches realize soft switching. The efficiency of the designed inverter reaches 98.6% at rated operation state, which is 0.3% and 0.5% more than that of two comparison objects, respectively. Moreover, when the output frequency reduces to 5 Hz, the THD of the output current is only 2%, which is also less than that of comparison objects. Hence, the designed inverter has advantages in the efficiency and the output power quality.