Research And Design On High Power Factor VIENNA Rectifier Employed In DC Charging Power

As the society's development and progress,the power electronic equipment has been widely used.But at the same time,it can generate lots of harmonic disturbance due to its nonlinear characteristics.Under the trend of the development of electric vehicle,lots of harmonic pollution will be generated by the charging equipment.Therefore,the electric car charging equipment does not only need to meet high power,charging fast,the characteristics of high reliability,but also to meet the high power factor,harmonic content,less switch stress,less power switching devices,etc.For matching the development of the electric car charging power,this paper discussed the front-end rectifier module based on the VIENNA rectifier.The module has high power factor,less switching device,high reliability,strong anti-interference,good harmonic suppression,and therefore has the value of utility.This paper mainly discussed the working principle and control method of the three-phase VIENNA rectifier.First,this paper discussed the three-phase VIENNA mathematical model in the abc and dq coordinates.For comparison,the control system is simplified in the dq synchronous coordinates.Secondly,this paper analyzed the control strategy of VIENNA.By contrast,this paper proposed the double closed-loop PI controller,which has well stability and fast transient response.Considering the current inner loop to achieve hi-speedy,voltage outer loop to obtain the strong stability and anti-interference ability,so the current inner loop was designed according to the typical I system,the voltage outer loop was designed according to the typical II system.And then,the traditional three-level SVPWM was analyzed in detailed.Combining with the working principle of the VIENNA rectifier,this paper put forward the suitable improved SVPWM modulation method for the three-phase VIENNA rectifier.The control tactics of space voltage vector are investigated,and the simplified algorithm which judges the sector location of reference vector and calculates switch operation time is put forward.Finally,this paper put forward a kind of equilibrium strategy based on SVPWM modulation,which can balance the voltage of the two DC-side capacitor.In the last part,the paper designed the hardware and software platform.The system is verified with Matlab simulations,and the results are presented to show the validity of the adaptive inverse control strategies.