Selective commutation circuit for an inverter

A selective commutation technique used with an inverter eliminates one of the two commutation pulses at those points at which there is a particular relationship of inverter operating characteristics. If the power factor angle 0, the voltage phase angle 6, and the voltage pattern notch angle are sensed to determine this particular relationship. Because at the switching point there is no current flowing througt the conducting thyristor, the conducting thyristor can then be transitioned to the nonconducting state merely by the removal of its gate signal. A single makeup pulse is then rung through the system to initialize the commutation capacitors for the next switch point.