270VDC Switching Power Supply Design And Experimental Research

With the rapid development of modern electronic technology and power electronics,high power electric equipment is more and more high to the requirement of power supply.High frequency,high efficiency and high power density,become the main development direction of dc switching power supply.To the high frequency switch and high power supply of soft switch technology,the key technology of high power density development has been widely research.ZVS phase-shift full bridge converter because its only on their own leakage inductance of the transformer and switch tube junction capacitance can achieve soft switch,is widely used in high power DC/DC conversion in the occasion.But ZVS phase-shift full bridge converter application also exist,such as the lagging arm of light load cases difficult to achieve soft switch,vice side duty cycle loss and parasitic oscillation problems of rectifier bridge.In this paper,aiming at the above problems for high power dc switching power supply system.That is commonly used two levels of structure transformation in the high-power power supply system.Level before using Boost circuit consisting of single phase active power factor correction circuit,level after using the transformer primary side add clamp diode moving to full bridge converter ZVS.And on the primary side clamp diode ZVS of the phase shifting full bridge converter are analyzed in detail,through the transformer primary side clamp diode successfully suppress the transformer rectifier bridge of parasitic oscillation.Based on main circuit based on state space method of small signal model is established,and on the basis of the small signal model of ZVS phase-shift full bridge converter feedback compensation network is designed,and use the special phase shift control chip of TI company UCC3895 built with voltage loop and current limiting protection current limiting ring double loop control system to meet the demands of the dynamic and static index.In order to verify the correctness of the theoretical analysis,and finally made a 270 VDC,the power of the 3 kw/80 KHZ experimental prototype.And the related experiments conducted on the experimental prototype.The experimental results show that reasonable parameter selection of main circuit design,both bridge arm in a wide range load realizes ZVS soft switch and effectively solved the problem of the rectifier bridge parasitic oscillation.To prove the correctness of the main circuit and control circuit design.