The Research Of SWISS Rectifier Based On Predictive Control

With the rapid development of social economy,electric vehicles which can use electricity generated by renewable energy have a very large space for development.The problems of poor stability and continuity of renewable energy power generation slow the working efficiency of electric vehicle's battery charging device down and can't make the device run smoothly.Also,used as the charging device,the rectifier topology is easy to produce harmonics,which will affect the output power quality.Swiss rectifier,being as a new type of charging device topology,its' control strategy can greatly improve the output DC power quality.In this paper,based on the predictive control strategy of Swiss rectifier as the research object,its' working principle and control strategy are researched.Firstly,by analyzing the basic working principle of Swiss rectifier,according to the different conduction states of harmonic injection network and IGBTs in a switch cycle,the circuit topology of Swiss rectifier is equivalent to buck converter circuit.At the same time,using state space averaging method to make a small-signal model of the circuit,deducing transfer function of inductance current to duty cycle and inductor current to output voltage.Secondly,research on the basic principle of the predictive control strategy,based on its five components,design the controller suitable for the Swiss rectifier.Then,on the basis of LC filter,design a new LLR-C ? type filter,and the filter characteristics of a new LLR-C ? type filter are tested by analyzing the bode diagram of its transfer function from input voltage to output voltage.Finally,the simulation model of Swiss rectifier is built with Matlab / Simulink simulation platform,and carry out the simulation of the Swiss rectifier with the predictive control strategy and the improved LLR-C ? filter separately.Make a comparison between the predictive control based Swiss rectifier and the traditional PI controlled Swiss recrifier,simulation results effectively show that the predictive control strategy has better ripple suppression effect on the output power of the Swiss rectifier and shorter overshoot time in case of sudden load change.At the same time,through the analysis of the comparison between Swiss rectifier with the new LLR-C ? type filter and the Swiss rectifier with the LC filter,the simulation results highlight the advantages of the new LLR-C ? type filter in improving the input current quality.