Auxiliary circuit-assisted soft switching techniques and their application to power converters

The need to incorporate significant improvements in power supplies is driven by customer demands, industry requirements and regulatory standards. This thesis proposes novel high frequency auxiliary circuit assisted, (a) soft-switched boost converters and their application to DC-to-DC converters and AC-to-DC front-end power factor corrected converters; and (b) zero-voltage switching (ZVS) dc link DC-to-AC inverters.; In auxiliary circuit assisted soft transition converters, the auxiliary circuit processes the power during switching transitions, creating a soft transition path. A zero-current switching (ZCS) auxiliary circuit and ZVS auxiliary circuit are proposed in this thesis to achieve soft transitions for the main circuit.; A ZCS auxiliary circuit assisted soft transition boost converter is proposed. Operating intervals of the proposed technique in various intervals of operation are analyzed. Design constraints and considerations are discussed. A 300 W dc-to-dc boost converter and a 600 W, ac-to-dc power factor correction front-end boost converter prototype models are built in the laboratory. The experimental results confirm the theory.; A ZVS auxiliary circuit assisted soft transition boost converter is also presented. Operating intervals of the proposed converter in various intervals of operation are analyzed. As all the parasitic elements in the circuit are accounted, parasitic oscillations are eliminated. A 300 W dc-to-dc converter operating at 250 kHz is built in the laboratory to verify the theory. A modified gating scheme to utilize the soft switching auxiliary circuit in the main power processing is also proposed. A 600 W, 100 kHz, 380 V dc, operating with universal input line voltage, ac-to-dc power factor corrected (PFC) boost converter is built using the proposed technique with modified gating algorithm.; Large signal analysis to analyze the soft switching characteristics of the proposed technique during load and input voltage transients is also presented. PSPICE simulation results are presented to verify the theory. By integrating the proposed auxiliary network with a full bridge inverter, a ZVS dc link voltage source inverter (VSI) is obtained. Operating intervals of the proposed inverter in various intervals of operation for the forward power flow and reverse power flow are presented. A modified unipolar switching scheme to achieve ZVS during reverse power flow is also presented. As the proposed technique requires synchronized PWM operation, sine-ramp modulated PWM signals are used. Experimental results from a 120 V, 60 Hz, 300 VA, single phase VSI switching at 50 kHz are presented to verify the theory. (Abstract shortened by UMI.)...