Novel soft switching methods for high frequency link converters and power transistor drive

Abstract

A new approach for zero voltage switching high frequency dc/dc converter is proposed, and it is applied to drive power transistor efficiently, and a secondary side regulation method is presented to control zero voltage switched pulse-width modulation converter effectively in the high voltage isolation conditions, and simple structure of soft recovery drive which can alleviate the loss and electromagnetic interference noise due to reverse recovery of diode is proposed. To reduce size and weight of the converter, the switching frequency must be increased. By zero voltage switching, the switching losses and stresses can be remarkably reduced. New zero voltage switching dc/dc converter is proposed, which provides zero voltage switching conditions to secondary rectifying diodes as well as primary main devices. As a result, the proposed converter can be operated much higher frequency and can be improved reliable operation of the converter and can be reduced noise. A secondary side regulated zero voltage switched pulse-width modulation converter is proposed the measured output voltage is commonly transmitted to the primary side for the output voltage regulation. The signal transmitting give rise to be time delay because the measured voltage signal is usually converted to frequency for the signal transmitting through fiber optical cable, which results in slow response and unstable condition of the converter. However, the secondary side regulation method is that all the analog signal processing is done at the secondary side. The total response of the converter is very fast and becomes almost equal to on-line converter and the bandwidth of the converter is much wider in the high voltage isolation conditions. Several small size and high efficiency current source type base drive schemes are proposed using high frequency converter with zero voltage switching converters. By using these base drives, the performance of switching power transistor is enhanced because the transis...