Low AC harmonic DC power supply

Abstract

A DC power supply which generates little or no harmonics on the supply line includes a bridge circuit having high frequency controlled unilateral switching devices in the four legs thereof and a high frequency filter capacitor connected across two opposed junction points of the bridge to which is also connected a source of input power. The other two opposed junction points of the bridge are connected to a DC loop circuit which in one embodiment maintains a constant current through a load device connected in the loop and in another embodiment maintains a constant voltage. In the constant current embodiment a storage inductor is provided and energy is transferred to and from the storage inductor in accordance with the high frequency switching of the unilateral switch devices. The on and off times of the switch devices are governed by a control circuit which measures the current in the DC loop and compares it with a desired value. In the constant voltage embodiment a DC storage capacitor is provided, across which is connected a load device and the voltage across the capacitor is maintained by a similar control circuit comparing the actual voltage with a desired voltage.

Dependencies are inferred from the claim text.