Inverters convert DC power to AC power at desired output voltage and frequency. Inverters are used for variable speed AC motor drives, induction heating, aircraft power supplies, UPS for computer.
The diagram of IGBT based single phase inverter is as shown. It consists of four IGBT. The current can be supplied to the load by proper gating the IGBTs. Only two diagonally opposite IGBTs will be ON at any one time.
When Q1 and Q4 are conducting, load current flows from X to Y in the path XQ1, ABQ4 Y and load voltage is +Edc. When Q2 and Q3 are conducting, load current flows from X to Y in the path XQ3 BAQ2 Y. Now, the load current direction changes and load voltage becomes -Edc Thus, AC square wave is generated.