Digital-control DC/DC Converter

In recent years,the phase-shifted bridgeh as found many applications due to its distinct characteristis. This topology permits all switching devices to operate under ZVS by using circuit parasitic such as leakage inductance and power MOSFET junction capacitance to achieve resonant switching. The ZVS allows operation with much reduced switching losses and stresses, and eliminates the need for primary snubber. It enables high switching frequency operation for improved power density with good conversion efficiency. To implement Phase-shifting Full Bridge ZVS dc/dc converter, the conventional analogy controller UC3895 generally is used. However, the emergence of advanced microprocessors and digital signal processors has made it possible for power supply manufacturers to consider digital technology as a suitable option. As compared to analogy control,digital control provides a number of advantages, such as less susceptibility to aging and environmental variation, better noise immunity, ability to handle complex control schemes and monitoring functions, possibility to implement comunication functions for fault and status information. The digital control SMPS has been gaining attention, some chip manufacturers have introduced dedicated to the digital switching mode power supply controller, Microchip's dsPIC30F2020 is one such dedicated to the digital switching power supply controller (DSC), which integrates a precision internal DSC higher A / D converters, hardware implementation of digital PWM modules and SMPS comparator unit.In this paper, a 600W of digital PS PWM ZVS FB DC / DC converter based on dsPIC30F2020 is designed. And analysis phase—shifting ZVS full-bridge PWM DC / DC converter basic working principle and the process of work ,described in detail the main circuit of the converter design and control circuit design. And analysises the converter's small-signal model of average state space ,on this basis , analysises and designs double closed-loop control and control software of the converter.