New two-quadrant chopper with simultaneous control

A two-quadrant chopper circuit equipped with an improved commutation scheme and capable of giving variable positive voltage and current in either direction is described. Saturable reactors are used to support the direct bus voltage during the commutation interval. This commutation scheme has the advantages of low trapped energy, self-healing capability, low cost, etc. This chopper circuit has been designed, fabricated and tested on a 2·2 kW, 220 V separately excited DC motor. Theoretical deductions and their experimental verification are presented in the normalized form.