← All revision guidesSEMESTER 5 · DI05000171
6FLASHCARDSPower Electronics
Power semiconductor devices, converters and inverters.
Power devices
Q1How is an SCR turned on?
Forward-bias it and apply a sufficient gate pulse, or raise anode voltage beyond breakover.
Q2Why does an SCR not turn off when its gate signal is removed?
After latching, anode current maintains conduction until it falls below holding current or reverse bias is applied.
Q3What is PWM?
Pulse-width modulation controls average output by varying the duty ratio of switching pulses.
Converters
Q1What is a controlled rectifier?
A converter using controllable devices such as SCRs to obtain adjustable DC from AC.
Q2What is inverter dead time?
A short delay between complementary switch transitions that prevents shoot-through.
Q3What does a freewheeling diode do?
It provides a path for inductive load current when the main supply device turns off.