Offshore Wind Farms

9.2. Semiconductors and switch valves

9.2.1. Semiconductor power losses

The power semiconductor devices (PSDs) used in WECS are operated as switches, taking on two possible static states, conducting or blocking, and two possible transition states, turn-on action or turn-off action. In any of these states, one energy dissipation component is generated, which heats the semiconductor and adds to the total power dissipation of the switch. Fig. 9.1 shows the simplified device switching waveforms (voltage and current) and the power losses associated with each possible operation state of the power switch.

9.2.1.1. Conduction loss

Static loss is determined by the non-linear voltage–current characteristic of the PSD. A typical voltage–current characteristic ...