| Soft-switching techniques use the resonance principle to eliminate overlap of voltage and current during switching in order to achieve the objective of reducing losses and noise. Thesis researches phase-shifted full-bridge ZVS soft switching technology based on DSP control in the DC/DC converter applications.This paper discusses the conditions of phase-shifted full-bridge ZVS soft switching technology to achieve, to take current control mode based on PWM modulation, forming a current inner, voltage outer dual- loop control system, according indicators voltage loop and current loop adjustment factor has been designed and using the PI regulator to correct output parameters. Secondly, the full-bridge driver circuit, voltage sampling circuit, over-current detection circuit, and the external circuit of DSP control system has been designed. Finally, choose the high-performance digital signal processor TMS320F2812 as the control center, write a main program, interrupt subroutine and PI regulator subroutines of control system, use whole comparison unit generates two complementary PWM driving signal with a dead zone, by changing the phase angle α to adjust the output voltage. Through modeling and simulation in Simulink environment has verified the reasonableness of the circuit design parameters, PI regulator with software control to adjust the phase angle α, can be effective for real-time correction to obtain a stable output, improve efficiency, achieve the expected design goals.Experimental results show that, DC/DC converter can smoothly achieve soft switching, the conversion efficiency is obviously improved, by adjusting the phase shift control pulses can get a wide range of adjustment of the DC output, having a high practical value. |
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