The Nonlinear Phenomena And Control In Phase-Shifting Full-Bridge Zero-Voltage Switched Converter

The paper studies systemically the circuit topology and operating modes of Phase-Shifting(PS) Full-Bridge(FB) Zero-Voltage Switched(ZVS) converter at first, then proves that the nonlinear phenomena such as bifurcation, chaos and intermittency does exist in PS FB ZVS converter through simulation and theoretic analysis, finally controls chaos in PS FB ZVS converter successfully by applying the method of resonant parametric perturbation.Buck converter, as one of the fundamental switching converters, has many linear and nonlinear phenomena, such as bifurcation and chaos, have been revealed to exist in Buck converter, and the chaos operation, as an irregular operation state, can be controlled effectively. PS FB ZVS converter is a kind of soft switching converter with constant frequency, which has found important applications in reality. It makes the four power switches of Full-Bridge PWM converter turn on under zero voltage in turn by utilizing the output capacitors of switches and the leakage inductance of output transformer as resonant components on the base of phase-shifting technology. Because the output parts of Buck converter and the PS FB ZVS converter are similar, it is reasonable to consider the Buck converter serve as the equilent topology of PS FB ZVS converter. Thus, those nonlinear phenomena in Buck converter, must also arise in PS FB ZVS converter. In order to validate the conclusion, the paper firstly establishes the simulation circuit and mathematical model of PS FB ZVS converter and sets the appropriate circuit parameters, based on the circuit model the corresponding results are deduced. Then relative figures are plotted using EWB and SIMULINK respectively after simulation. Secondly, the conclusion that there are nonlinear phenomena such as bifurcation, chaos and intermittency is confirmed with the theory of nonlinear dynamics. In the end, a kind of non-feedback controlling method, namely resonant parametric perturbation, is applied to control chaos in PS FB ZVS converter, so as to eliminate the unstable operation and then this way is proved to be accurate in theory.The paper studies PS FB ZVS converter, a complex converter by comparion with its simple equivalent Buck converter, accordingly, the conclusion can be concluded favorably as expected. This method has a certain use for reference in researches.