High power insulated gate transistor circuitry - has additional capacitor and thyristor fired by rectifier overcurrent in series across DC voltage source

摘要

The circuitry for high power insulated gate bipolar transistors (IGBT) in an inverter is set up such that each a.c. voltage phase has its a.c. voltage terminal positioned between two series-arranged, alternatively driven transistors connected between the poles of a d.c. voltage source, a series-circuit of a capacitor and a diode connected in parallel with both transistors, and the node between the diode and capacitor connected via a resistor to one pole of the d.c. voltage source. The three-phase inverter is formed by the transistors (V7-V12). In each a.c. voltage phae (U,V,W) two transistors (IGBTs) i.e. (V7 and V10) or (V8 and V11) or (V9 and V12) are connected in series between the poles of the d.c. voltage source (C), with the a.c. voltage terminal (U,V,W) being provided at the node of the two transistors per phase. ADVANTAGE - Protects transistors against overvoltages during shorting of inverter.