Soft-switching power converter for operation in discrete pulse modulation and pulse width modulation modes

摘要

A single-phase, soft-switching, ac-to-dc power converter comprises a rectifier for receiving and rectifying an ac voltage and providing the rectified ac voltage to a boost dc-to-dc converter, which in turn is coupled to an active clamped resonant dc link (ACRDCL). Resonant oscillations of the resonant dc link circuit comprising an inductor and a capacitor are maintained via control of an active clamp switching device. Soft-switching in a discrete pulse modulation scheme is achieved by controlling the switching instants of a boost switching device to occur at zero voltage instants of the resonant dc link. Alternatively, if a pair of snubber capacitors are added to the boost converter, soft- switching may be achieved in a pulse width modulation mode, resulting in reduced subharmonics even at higher frequencies and with smaller filter components.