This applet demonstrates commutation of thyristor converters. As an example we show the three-phase half bridge rectifier. The load is a constant current source, and stray inductances of the transformer are taken into account. Basically, it is shown that the stray inductances increase the commutation time, which results in a reduced output voltage.

• Change the stray inductance. If stray inductances are increased, the commutation needs more time for the current to change the phase. During this commutation time, the load current is partially flowing in two parallel thyristors. If you set high values for the stray inductance and place the red time slider within the commutation (yellow area), you will see two conducting thyristors. During commutation the output voltage is zero. Due to this voltage loss the average output voltage is reduced.
• Change the triggering angle to a small value. The voltage will be reduced. Since the voltage drives the current change in the stray inductor, with a smaller voltage the commutation takes longer. Therefore, the output voltage loss is also dependent on the triggering angle.
• Drag the red point in the ud(i0)-diagram in order to change the constant load current. With higher current the commutation takes longer and the output voltage loss is increased.
• Drag the red time slider to visualize the current paths at certain operating states.