Research On Digital PFC Based On Predictive Current Control

At present,the rapid development of power electronics technology has aroused the progress of power electronic equipment.But there are many nonlinear elements in power electronic equipment.These elements lead to the distortion in the input current generating harmonics,which will cause the serious pollution of the power grid.Power factor correction technology is an effective method to restrain the current harmonics current and reactive power.It has been widely used in AC-DC converter.With the development of integrated circuit and digital control chip,digital power factor correction has become the one of the hot topics in power electronics field.Aiming at the problem of poor control effect of power factor correction,slow dynamic response and large computation,a high-performance digital control power factor correction proposed in this paper.The PFC system consists of two circuits:The former circuit adopts Boost PFC topology,and the control method adopts the predictive current control method.In this paper,the algorithm is simulated by Saber software,and compared with the most commonly used double closed loop control method.Simulation results show that the algorithm has the following advantages that it has a good control effect to the input current,the input current can track the input voltage well and fast,and the power factor and the dynamic response speed of the converter can be effectively improved and the THD value of the input current can be reduced.In the second stage,the interleaving Two-Transistor forward(ITTF)converter is adopted.By analyzing the circuit parameters,the compensation network is designed to meet the requirements of static and dynamic characteristics of the system.Finally,based on the theoretical analysis,an experimental prototype is designed.The first circuit is 280W Boost PFC prototype,using STM32F103RCT6 digital control chip to achieve digital control.The second circuit is 250W ITTF 250W prototype,using TL494 to achieve analog control.The validity and feasibility of the control scheme are verified by the experimental results.