Study On Control Method Of Vienna And Swiss Rectifiers

With the increasing use of Power electronic products,more and more harmonic and reactive Power are brought to the Power grid,which makes people begin to pay attention to three-phase Power Factor Corrector(PFC).At present,there are four kinds of threephase PFC rectifier including voltage type PWM rectifier,Vienna rectifier,three-phase six-switch Buck rectifier and Swiss rectifier,among which the research on voltage type PWM rectifier and three-phase six-switch Buck rectifier is more perfect.In this paper,the control methods of Vienna rectifier and Swiss rectifier are studied,and the solution strategy is put forward to solve the problems of Vienna rectifier current zero crossing distortion and Swiss rectifier current sector boundary distortion.First,the background of three-phase PFC technology is summarized,the working principle and performance of several rectifiers are briefly introduced.The topological structure and control methods of Vienna rectifier and Swiss rectifier are introduced emphatically.According to the operation principle of Vienna rectifier,the ProportionIntegral(PI)control method of double closed loop and two modulation methods of Vienna rectifier are introduced.Sine Pulse Width Modulation(SPWM)and Space Vector Pulse Width Modulation(SVPWM)are given.Through the qualitative analysis of the midpoint voltage balance model,the active control method of midpoint voltage is adopted.Then this paper analyzes the causes of input current distortion in Vienna rectifier at zero crossing,and proposes a control method that the output voltage and input current(UI)of Vienna rectifier are in the same phase.This method eliminates the input current distortion in Vienna rectifier at zero crossing at the cost of reducing the power factor on the power supply side.The above Vienna rectifier control method is verified by simulation and experiment.Nextly the working principle of Swiss rectifier is analyzed.According to its mathematical model,two indirect current control methods are given: double closed loop PI control method and input current harmonic reduction control method.By analyzing the inductive current ripple of DC side and the conduction loss of harmonic injection network,the synchronous drive method and the interleaved drive method are compared.Finally,the reason of input current distortion at sector boundary of Swiss rectifier is analyzed,and a direct current control method and a new modulation strategy are proposed.Both methods can solve the problem of input current distortion.The power loss of the two modulation strategies is compared by calculating the current stress of each switching device.Finally,the control method of Swiss rectifier is simulated and verified.