Design And Implementation Of Active Clamp Forward Converter Based On UC1715

Since entering twenty-first Century,the rapid development of high and new technology industry represented by aerospace.With the development of power electronic technology,switching power supply tends to be more and more high frequency.The weight of inductor and capacitor is reduced as the switching frequency increases.So high frequency can increase power density and reduce the weight of material,but the switching loss of power device is proportional to the switching frequency.In order to solve this problem,soft switching technology is proposed.The research object of thesis is active clamp forward converter.Using a novel soft switching technology to solves the problems of conventional forward converter,such as low utilization ratio of magnetic core,high switching losses,low switching frequency,low efficiency,strong EMI.This paper analyzes the working principle of active clamp forward converter,the working process of active clamp forward converter is divided into 8 stages,presents the necessary condition to realize the zero voltage turn-on of the active clamp forward converter switch.Through the analysis of the active clamp converter are zero voltage turn-on conditions,without increasing the excitation current situation,designed a novel ZVS active clamp forward converter circuit,only add a magnetic saturation inductance in the original source clamp circuit.According to the working process of active clamp forward converter,the main device parameters of converter circuit are designed,including the design of main transformer clamping capacitor,a main switch tube,tube,switch clamped output rectifier filter circuit,control circuit,driving circuit design etc..By using SABER simulation software,the parameters of the main circuit are simulated.Simulation results verify that the design of the active clamp ZVS forward converter with rationality and accuracy.Based on theoretical analysis and circuit simulation,using complementary MOS driver UC1715,debugging installed input voltage is 25V~50V,output voltage is 5V/10 A,the switching frequency of the ZVS 400 KHZ active clamp forward converter prototype.The experimental results prove the correctness of the scheme,the indicators meet the design requirements.