18.1.1 Theory of Operation
(Ask a Question)The three-phase inverter is the core of any AC motor drive. PWM pulses generated by the three-phase PWM drive the inverter bridge.
The following figure shows the inverter bridge.
A three-phase two level inverter consists of three power electronic switches (Transistors), two in each leg for each phase of motor winding. The switches in each leg are driven by complementary pulses to switch the phase voltage between positive and negative DC voltage. The DC voltage passes through the transistor switches to the load when at least one of the three-phase pulses is active. Dead time is introduced between these high and low pulses of a phase or channel to allow the transistor to turn off completely, so that the DC source does not get shorted during operation.