AbstractA solid state, current source, polyphase inverter induction motor drive is disclosed wherein the current source is derived from a constant potential buss. Each side of the buss is connected to the inverter via a separate chopper. The choppers normally operate in unison to supply a controlled current to the inverter. Each time the inverter sequence is to be advanced, the chopper current is reduced to zero on the side of the inverter, either positive or negative, that requires a commutation. Chopper current is then reinstigated and feeds the next set of inverter thyristors in the inverter sequence. Alternative means for rendering the current source non-inductive during inverter commutations, and transformerless means for providing motor voltages well above rated voltage are also disclosed.