How does IGBT works in frequency inverter for ac motor control?
change motor to a 3 phase motor (very cheap) , buy an ac tech drive
The IGBTs act as switches to provide a series of DC pulses to the motor. Since most AC motor frequency controls are for 3-phase motors, there are six IGBTs, two for each phase. One IGBT connects each motor terminal to the positive side of the DC supply and one connects each motor terminal to the negative side of the DC supply. In that way, each terminal to terminal or line to line voltage can be either positive or negative. By controlling the switching sequence of the IGBTs, the control provides a simulated 3-phase sine voltage with frequency and voltage control. The waveform is composed of DC pulses and doesn't look too much like a sine wave, but the effective value is a reasonably good simulation of a sine wave. Each IGBT has a diode in parallel but positioned to conduct current in the opposite direction. The anti-parallel diodes conduct the portion of the motor current waveform that lags the voltage. Look at the Wikipedia article for more details and diagrams.
