Study on nonlinear phenomena in dual buck full-bridge inverter

Dual buck full-bridge inverter has the following advantages: it has no shoot-through problem, but receives highutilization of DC input voltage, high efficiency and optimum selection of the freewheeling diodes, hence it attracts more and more attention in high power applications. In this paper, the bifurcation and chaos in the dual buck full-bridge inverter is studied. The two-dimensional discrete iterated mapping model under proportional control is established and stroboscopic maps in different periods of time are obtained. Effects of the proportional coefficient k on system performance are analyzed by using bifurcation diagram and folded diagram. A simulation model of dual buck full-bridge inverter is established based on Matlab/Simulink and the time domain waveforms and phase-space portraits for different proportional coefficient k are obtained. Besides, the effects of the bifurcation and chaos on the spectrum of the system are analyzed. Finally, the nonlinear behavior in the inverter caused by the variation of other circuit parameters such as input voltage E, inductance L, and the switching period of carrier wave T is discussed through bifurcation diagrams. Results show that the correct choice of circuit parameters of dual buck full-bridge inverter is very important for its stable operation.