Test: Single Phase VSI

Inverter is a dc to ac converter.

A VSI is the one in which the internal impedance of the source is negligible. It has a stiff DC source at its input.

IGBT is a transistor family device. It can be turned off simply by removing the gate signal. All the transistor devices operated in the same way in inverters.

It is a half-wave circuit as it has only 2 SCRs are connected. It is a half wave bridge type thyristorised inverter.

Considering T1 as an ideal switch, the load is directly connected to the upper voltage source when T1 is on.

Line-commuted inverters are actually phase-controlled converters operated in the inverting mode. They cannot act as standalone inverters as they require a AC supply. It is to be noted that “line commutated inverter” is not the conventional inverter. The conventional inverters are forced or load commutated inverters.

GTOs are gate turn off SCRs in which turn-off is achieved by applying a negative gate pulse.

All the devices can be turned off by their gate/base singles expect SCR. SCRs require external commutation circuits.

They require two voltage sources Vs/2 and Vs/2.

Only one SCR is gated at a time, gating the both of them will short the supply.