Sneak Circuit Phenomenon And Analysis In Zero-voltage-switching Phase-shifted Full-bridge Converter

Recently,with application of power electronics systems in various important areas,the system security and reliability are been concerned.Sneak circuit phenomenon in power electronic circuit is a newly discovered phenomenon. Sneak circuit is a kind of pathway or state which lurks in the converter. It appears under certain conditions and influences converter's overall operating performance and reliability. Therefore, this paper major studies zero-voltage-switching phase-shifted full-bridge converter and proposes its sneak circuit phenomenon and researches their characteristics.Main research are as follows:(1) The existing graph theory analysis method which is fit to analyzing sneak circuit phenomenon in non-isolated convertor is further promoted. Certain circuit model of zero-voltage-switching phase-shifted full-bridge converter is established to make the method be suit for its sneak circuit phenomenon research. According to the normal working principle of the convertor and the principle of a false path, possible sneak circuits in the convertor are gotten by using graph theory analysis method of sneak circuit phenomenon .(2) Operation Principle of zero-voltage-switching phase-shifted full-bridge converter is analyzed.Then, sneak circuit phenomenon is discovered in the convertor. Operation principle and occurring conditions of the phenomenon is analyzed particularly. The results show that if the circuit are disturbed, such as increase RL, increase resonant capacitor Cr of the lagging arm or decrease the resonant inductor Lr, diffirent sneak circuit phenomenons happen with different switching dead time of the lagging arm.(3) Prototype of zero-voltage-switching phase-shifted full-bridge converter is designed.Its experimental sneak circuit phenomenon which is in line with the theoretic analysis is analyzed particularly. The correction of the foregoing theoretical analysis is testified finally.