An improved development of four-switch low cost inverter on voltage equilibrium with magnetic flux control method

A typical inverter topology is always made up of six switches (GTO, GTR or IGBT) and one shunt electrolytic capacitor. Compared to it, the four-switch inverter mentioned in this paper consists of four switches and two capacitors. It can be made at a lower cost, but its performance becomes worse. Through overall theory analyses and detailed lab data on the four-switch inverter, it is concluded that the main reason for the bad performance is the voltage disequilibrium between the two capacitors. In this paper, an improved magnetic flux control method to control the four-switch inverter is introduced. The method can solve the voltage disequilibrium between the two capacitors.