Zero-voltage Soft-switching PWM Research Articles

Current polarity detection and current compensation strategy for PAC based three-phase ZVS PWM converter

A novel software implementation for current polarity detection and current compensation is presented. For a three-phase zero-voltage soft-switching (ZVS) PWM converter based on phase and amplitude control (PAC), when saw-tooth carriers with alternate positive and negative slopes are adopted, the positive or negative slopes are chosen according to the phase current polarity. Since polarity reversal causes current distortion, current at the instant of reversal should be compensated for. Based on the characteristic of unity power factor converter in rectification and regeneration modes, a software implementation for current polarity detection is proposed. Distortion of current zero-crossing caused by using saw-tooth carriers with alternate positive and negative slopes is analyzed, and the relevant compensation method is proposed. Experimental study with a 1.5 kW device shows that phase current has a small harmonic content and power factor is high both in rectification and regeneration modes.

High frequency PWM controlled step-up chopper type DC–DC power converters with reduced peak switch voltage stress

An advanced two-quadrant PWM controlled chopper type DC–DC power converter with lowered peak switch voltage stress, which is effectively used for parallel processing type small-scale UPS applications and utility interactive new energy interface distributed power supplies, is presented. In addition, a coupled inductor-assisted zero-voltage soft-switching PWM step-up chopper controlled type DC–DC power converter is also proposed and discussed. These two DC–DC converter circuit topologies are evaluated and compared on the basis of simulation and experimental results by a 1 kW 50 kHz breadboard setup using MOSFETs. The electromagnetic conductive noise characteristics of both converter circuits are also compared through experimentation.

Zero voltage soft switching PWM high-frequency inverter using IGBTs for induction heated fixing roller

A prototype of the active voltage clamped edge resonant ZVS-PWM high-frequency inverter using IGBTs for the electromagnetic induction eddy-current-based fixing rolling drum heating in the new generation copy and printing machines is presented. Its operating principle and unique features are described. The constant frequency duty cycle (asymmetrical PWM) controlled edge-resonant ZVS high-frequency inverter that can achieve stable complete soft commutation over widely specified power regulation ranges is proposed. The operating performances of this high-frequency inverter using the latest IGBTs is discussed and evaluated on the basis of simulation and experimental results as an induction heated roller of the fixing equipment in a high-speed copy machine.

Novel Transformer-Assisted Quasi-Resonant DC Link Circuit Family Operating under No Predictive Load Current Control Scheme for Soft-Switching Realization and Its Optimum Design.

In this paper, proposed is the state-of-the art auxiliary high-frequency transformer-assisted quasi-resonant DC link (Transformer-assisted Quasi-Resonant DC Link; TQRDCL) with and active voltage-clamping function, which is able to exclude a predictive load current feedback control scheme for maintaining a zero-voltage soft-switching operation in the DC bus line. This new conceptional advanced quasi-resonant circuit topology operated under the principle of zero-voltage soft-switching is actually demonstrated in order to achieve the minimized switching losses of all the power semiconductor devices incorporated into the three-phase voltage-fed PWM inverters and/or PWM converters, together with lowered electrical dynamic stresses as well as reduced EMI noise level. The basic operating principle of a novel type of TQRDCL circuit family for ZVS-PWM inverter and converter are presented and its related theoretical and practical considerations of the optimum circuit design procedure are discussed including its promising remarkable and unique features. Its operating characteristics are illustrated and evaluated on the basis of using the computer-aided circuit simulating results. The experimental results of this trially-produced TQRDCL circuit which is more acceptable and suitable for the zero-voltage soft-switching PWM CVCF inverter and active AC/DC converter systems are demonstrated and evaluated from a practical point of view as compared with simulating ones.