Research Of Control Strategy Based On High Power Factor VIENNA Rectifier

With the development of power electronic devices and the widespread application in each kind of electricity situation, reactive power pollution and grid harmonic pollution problems are becoming increasingly serious. Therefore, research with high power factor, low Harmonic Distortion rate(Total Harmonic Distortion, THD) of the rectifying device becoming a key subject in the power electronics application technology. VIENNA rectifier with unity power factor, low input current harmonic content, less switching devices, low switch stress, and high reliability advantages, have higher research and application value. This paper introduces the basic working principles of VIENNA rectifier, and carries out in-depth study on the basis of special topology structure of VIENNA. To deduce the design parameters of the control loop in the end.First, this paper introduces the working principles of the VIENNA rectifier, and establishes the system respectively under ABC natural coordinate system and dq synchronous rotating coordinate system in order to get the mathematical expressions of switching function under different coordinate research.In the meantime building the foundation for further control algorithm.Secondly, this paper studies an improved SVPWM algorithm to VIENNA suitable topology. When we study the traditional SVPWM control method, the complex current interval is must be considered. This paper puts forward the interval judgment method with a kind of voltage(i.e., the input rectifier), and to simplify the calculation steps at the same time. On this basis, the analysis of the design process of the double loop structure is deduced, and the selection of key parameters for the theoretical proof and simulation validation.Again, in view of the inherent problems of tri-level midpoint clamping structure of the Boost converter in the neutral voltage fluctuations. To study the mechanism of its fluctuations, design the equalizing regulating module to suppress neutral voltage fluctuations, optimize the control strategy and modulation algorithm according to the characteristics of the space vector modulation SVPWM algorithm.Finally, this paper sets up a system simulation based on Matlab/Simulink platform, with giving a complete double loop controller parameters,the software process and so on. Then set the prototype experiment platform, and the experimental results were analyzed. The experimental results show that the proposed control strategy has the feasibility and effectiveness, which can significantly improve the efficiency and reliability of the rectifier.