Soft-Switching DC-DC Converter Based On MERS And Its Application

With the development of power electronics technology,power electronic devices such as switching mode power supply,uninterruptible power supply and so on can be seen everywhere in life,the resulting harmonic problems of the power grid are widely concerned,Power Factor Correction(Power Factor Correction,PFC)has become one of research hotspots because it can reduce the switching mode power supply and other power electronic devices on the harmonic pollution and improve the input side of the power factor.This paper mainly focus on the research on magnetic energy recovery switch(Magnetic Energy Recovery Switch,MERS)soft-switching DC converter and its application in single-phase power factor correction,and it proposes a new high-gain,high efficiency boost converter topology-MERS-boost converter,and compared its voltage gain characteristics with the traditional boost converter;A new type of digital control method based on MERS-boost converter-MERS PFC circuit is proposed,The simulation and experiment results verify the correctness of the algorithm and the soft switching characteristics of the MERS PFC circuit.This paper firstly introduces the development of DC converter,soft switching technology and power factor correction technology,and then describes the basic concept,the basic topology the common control method of power factor correction technology.Then,the structure of MERS,the topology and working principle of MERS-boost converter are analyzed in detail,and the voltage gain performance is compared and analyzed.Then,the MERS-PFC circuit based on MERS-boost converter is introduced.The simulation model of single-phase MERS PFC circuit based on average current control and one cycle control is built by using PSIM simulation software.The simulation results verify that the MERS PFC circuit's soft switching characteristics and the function of power factor correction.Also this paper points out the shortcomings of these two kinds of control methods and introduces a digital control method for duty cycle prediction of current sensorless analyzing in detail the control principle of the algorithm.The dynamic stability of the MERS PFC circuit controlled by the algorithm is simulated by using PSIM simulation software.The simulation results verify the correctness of the algorithm.Finally,this paper introduces the realization of MERS PFC system based on DSP-TMS320F2812,including the parameters selection of main circuit,the design of the whole control system software and the external circuit.From the experimental results of MERS PFC system,the duty cycle predictive control the MERS PFC circuit realizes the input voltage and the input current in the same phase.At the same time,the experimental results verify the soft switching characteristics of the MERS PFC circuit and theoretically compared the efficiency of the MERS PFC circuit with the traditional boost PFC circuit.