Research On Phase-Shift Full-Bridge ZVS Converter Based On DSP

Switching Power Supply(SPS) is growing rapidly in the application area instead of Linear Power Supply with the development of power electronics technology. High efficiency, high power density, high frequency and small size is the advantage of SPS, however, electromagnetic interference caused by SPS is also a new problem. SPS can achieve zero-voltage-switch(ZVS) or zero-current-switch(ZCS) by using soft switching technology, and it can improve the power efficiency and reduce the electromagnetic interference. Phase-Shifted Full-Bridge(PS-FB) converter is widely used in high-power field with its simple structure, convenient control and not very high switching stress among all soft-switching circuits.In this paper, the PS-FB-ZVS converter is researched, also the inherent disadvantage and key problem of this converter is discussed, and some common and useful improving topology is presented to deal with these problem. The small signal model of PS-FB-ZVS converter is established based on Buck converter. The PI controller based on pole assignment method is designed according to the dynamic response of system, also the dynamic response of sudden-addition-load and sudden-reduction-load is presented. The simulation and experiment match the theory. In this paper, the digital controller based on DSP is designed, and a new controller including Bang-Bang and PI is used. A simplest Phase-Shift PWM pulse producer without any external devices is presented, and it is simple and effective.In this paper, the power factor correction methods is discussed, and the multi-pulse rectifier on high power field is focused on. DC-ripple re-injection technology is researched based on the 12 pulse rectifier with autotransformer, and it can double or triple the pulse number of 12 pulse. In this paper, 24 pulse rectifier with small THD and high power factor of the network side of input current is achieved.All experiments is implemented on a 20kW experimental equipment. The experimental results prove that the system achieves good ZVS and good dynamic response, also the oscillation suppression on the secondary rectifier diode is reduced, and the output voltage is stable with small ripple.