Abstract: A high efficiency static voltage clamped parallel resonant converter for converting power between two AC and/or DC circuits includes a link circuit between an input switch circuit and an output switch circuit. The link circuit comprises a parallel resonant circuit and link switch elements which are switched to generate a unipolar train of link voltage pulses. All of the switches are "soft-switched" on and off at substantially zero voltage or zero current. Each link voltage pulse consists of a zero segment and a non-zero segment. The duty cycle of these voltage pulses is controllable by the link switches and such that the duration of the zero and non-zero segments are independently controllable. Pulse width modulation (PWM) and pulse area modulation (PAM) can be applied for reduced filtering requirements and maintaining high efficiency for operation at fractional load conditions. The link voltage is clamped to a maximum voltage during the non-zero segment of each link voltage pulse.

Abstract: A high efficiency static series resonant converter and method for converting power between two electric AC and/or DC circuits includes a resonant tank coupled to a link current synthesizer for generating a train of unipolar link current pulses with controllable duration zero and nonzero current segments. A blocking switch deactivates oscillation of the resonant tank in initiating each link current pulse, which is subsequently clamped by a buffer inductor. Each pulse is terminated by natural commutation through resonant oscillation. The pulses are substantially squarewave and have a high duty cycle leading to minimal peak current values. Minimal switching losses are incurred by switching at substantially zero voltage and zero current.