Model Analysis And Controller Research Design For Medium And Low Power Interleaved PFC Circuit

With the development of digital control theory and power electronics technology,people not only pay attention to the problem of grid harmonic pollution caused by high-power equipment,but also put forward higher requirements on the current harmonic distortion rate of medium and low power equipment.In this paper,the medium and low power interleaved PFC circuit is selected as the controlled object,and the applicability and limitations of different control algorithms in medium and low power applications are discussed.Theoretical analysis and simulation verification of different control algorithms were carried out and compared to achieve the goal of low current harmonic distortion rate for low and medium power PFC circuits.And this paper uses the domestic digital control chip to carry out the experiment.The research results have two main points: First,this paper focus on completing the model analysis and controller research design of the traditional control algorithm and sliding mode control algorithm in the low and medium power PFC circuit.The simulation results show that the sliding mode control algorithm can make the system more excellent performance;Second,in the traditional control algorithm,this paper points out the limitation of the average current control algorithm in the low and medium power PFC circuit,and this paper focuses on verifying the practicality of a variable duty cycle control algorithm without current sampling to achieve low current harmonic distortion rate.Based on this algorithm,a prototype with a rated AC input of 90 V ? 264 V,a DC output of 390 V,and a capacity of 350 W was designed in this paper.The main work completed in this paper is as follows:1)In the traditional control algorithms,model analysis,controller research design and simulation verification of medium and low power interleaved PFC circuits based on the average current control algorithm are carried out,indicating limitations of this algorithm in medium and low power applications.At the same time,the theoretical research and simulation verification of the interleaved PFC circuit based on the single voltage loop fixed duty cycle control algorithm which is commonly used in traditional low power occasions are carried out,indicating its defects and causes.In order to improve the accuracy of the control algorithm,the feasibility of variable duty cycle control is theoretically explained;the model analysis,controller research design and simulation verification of the low and medium power interleaved PFC circuit based on the variable duty cycle control algorithm show the effectiveness of this algorithm in medium and low power applications.2)The sliding mode control algorithm is used to focus on the theoretical study of the sliding mode control of the interleaved PFC circuit.The model analysis,controller research design and simulation verification of the low and medium power interleaved PFC circuit based on the integrated sliding mode control and the double integrated sliding mode control are carried out,the results show that sliding mode control can achieve the advantage of lower current harmonic distortion rate.3)In order to realize the complete localization of low and medium power interleaved PFC circuits,the domestic digital chip processor was selected as the main control unit.The experimental prototype was designed based on the variable duty cycle control algorithm,and the prototype was tested under different load conditions.The experimental results show the effectiveness of the proposed control algorithm in low and medium power PFC circuits.