On the behavior of a current fed synchronous machine drive without DC-link inductance

A drive system with synchronous machine and machine-commutated thyristor-inverter is discussed. The current source of this type of drive is realized by a fast switching transistor chopper, and the current is smoothed by the machine reactance and, atypically, by a choke in the DC link. It is shown that operation without link inductance affects the margin angle of the inverter. Hence, the reactive power of the machine has to be increased considerably. To overcome this disadvantage, a special method of control is presented, investigated, and verified by experimental results