Circuits and circuit elements for high efficiency power conversion

Abstract

Several novel zero voltage switching (ZVS) cells and a ZVS dc to dc transformer circuit are revealed. A U core transformer structure for use with the dc to dc transformer circuit is also revealed. An optimal gate drive circuit that achieves optimal switch timing for ZVS switches is revealed. The optimal gate drive circuit achieves optimal timing for the case in which there is sufficient energy available to drive a zero voltage transition and also for the case in which there is insufficient energy to drive a zero voltage transition providing turn on current to the switch at the minimum drain voltage of the switch. A magnetically coupled multi-phase converter cell structure is revealed which achieves reduced switch ripple current and fast transient response for multi-phase systems with three or more cells. A ZVS active reset switch drive scheme is revealed for providing zero voltage switching in bi-directional power flow converters for both directions of power flow using a single active reset circuit. A primary switching network that applies only one quarter of the input dc source voltage to a winding network connected to the switching network is revealed. The primary switching network is useful for planar magnetic circuit elements which benefit from lower applied voltages and suffer from windings with high number of turns.