Power circuit for variable frequency, variable magnitude power conditioning system

Abstract From the Canadian patent

A power circuit arrangement for a power conditioning system adapted to supply variable frequency variable magnitude, voltage to an electromagnetic device such as an electric motor having a center-tapped winding includes first and second inverting thyristors connected to the respective winding ends and connected in series with a transistor chopper across a unidirectional source so that the inverting thyristors may be gated on alternately at a relatively low modulation frequency while the chopper is time ratio controlled at a higher carrier frequency to selectively vary the voltage applied to the winding; a capacitor in shunt to the chopper which is overcharged due to winding leakage …