Power transfer device

Abstract

Apparatus for transferring electrical power between a power supplying apparatus and power consuming apparatus and having a separable high frequency transformer with a primary permanently mounted to the power supply apparatus and a secondary mounted about the power consuming apparatus. A charging control circuit mounted on the consuming apparatus, e.g. a mobile vehicle includes means for detecting current and voltage delivered through the transformer, and also for monitoring storage batteries within the vehicle. The power supply apparatus includes a power supply circuit comprising a ferrite core transformer and capacitor forming a parallel resonant circuit. The primaries of the transformer are alternately driven by a driver about opposing polarities. The drivers are controlled by a voltage-controlled pulse-width modulator which provides a square wave input to the drivers to cause them to alternatively energize the ferrite core transformer. Power is transferred across the inductor to the resonant circuit as portions of a sine wave. The power supply circuit also includes an internal current sensing circuit to shut current build-up down when current in the resonant circuit becomes too high, and an external control loop which senses power demands of the charging control circuit delivered via an optical communications link within the separable transformer.