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.

Abstract

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.