Research On Optimization Method Of Input Current Distortion Of VIENNA Rectifier Based On On-line Inductance Identification

In the field of rectifiers,VIENNA rectifiers have high power factor,low current THD,and fewer switching tubes and low losses.The VIENNA rectifier are commonly used in medium and large applications where many energy single-phase flows.However,the filter inductance in the VIENNA rectifier topology causes distortion of the three-phase input current at zero crossings.In order to improve the performance of the VIENNA rectifier,the input current is sinusoidal and in phase with the input voltage.This paper proposes an optimization scheme of the input current distortion of the VIENNA rectifier based on online identification of the inductor.Firstly,based on the background and research significance of the topic,this paper introduces the current control strategies and modulation methods of VIENNA rectifiers,as well as some research status of input current zero-crossing distortion and online identification of inductors.Then the topology and working principle of VIENNA rectifier are analyzed.Based on this,the mathematical model of abc natural coordinate system and dq two-phase synchronous rotating coordinate system is established.Then the analysis of the voltage drop on the filter inductor leads to the distortion of the input current zero-crossing point.Therefore,the on-line identification system of the inductor is established.After the distortion region is analyzed,the identified inductance value is brought into the calculation to obtain the accurate distortion angle.The SPWM modulated wave injected into the zero-sequence component is compensated in the distortion region,so that the input current is sinusoidal,so as to suppress the distortion of the input current zero-crossing point.The system uses double closed loop PI control to ensure that the system can maintain stable output performance when the load is abrupt or the inductance value changes.In order to verify the proposed scheme,a VIENNA simulation model based on inductive online identification is built in Matlab/Simulink and the physical platform of VIENNA rectifier is built with FPGA as the main control chip.The simulation and experimental verification of the input current distortion optimization scheme of VIENNA rectifier based on online identification of the inductor are presented.Both simulation and experimental results show the feasibility and effectiveness of the method.