Research On Key Techniques Of High Power Density VIENNA Rectifier Module

Three-phase PFC rectifiers with high-power density and high-efficiency are widely used in civil fields such as industrial control,data communications,network servers,and military fields such as phased array radar,warships,and aviation.Aiming at the application of 400 Hz intermediate frequency power supply in the aviation field,the three-phase three-wire Vienna rectifier was researched in the paper.Its topological characteristics and working principle were analyzed,and the research focused on the problem of decoupling of the control loop at high frequency input and the improvement of current waveform quality when the midpoint potential fluctuates greatly.A full brick module power of Vienna rectifier was finally designed.The specific research content is as follows:1.The working principle of the three-phase three-wire Vienna rectifier was studied,the mathematical model in the abc natural coordinate system and the dq rotating coordinate system was established,the parameter design method of the voltage and current double closed-loop PI control was given,and the method to realize the space vector modulation in the g-h coordinate system was introduced.Detailed analysis and simulation were carried on to verify it.2.In the case of low carrier ratio at high frequency input,the digital control delay caused the increased coupling of the dq axis of the Vienna rectifier current loop.The complex coefficient transfer function modeling was used to analyze it.On the basis of the traditional current feedforward decoupling,a current feedforward decoupling control method with phase compensation was proposed.The system loop performance of the proposed decoupling method and the traditional decoupling method were analyzed through the root locus.In high-power-density applications,the size of the Vienna rectifier was limited.Aiming at the problem of increased midpoint potential fluctuations caused by the reduction of its DC terminal capacitance,the reason for the deterioration of the input current waveform quality was analyzed from the perspective of vector modulation,and an improved space vector modulation strategy with midpoint potential fluctuations was proposed to solve this problem.For applications with higher power levels,a parallel current-sharing scheme using current-sharing busbars was proposed.Finally,the proposed methods were verified by simulation and experiment.3.A prototype of 1.5kW full-brick power supply size(116.8*61*12.7mm)based on LCL filter structure was built.The design idea of LCL filter was given,and a soft start method of Vienna rectifier with capacitor precharge was designed in terms of hardware design.At the software level,the operating architecture of the control program was introduced,and a pipeline execution method was designed in combination with the unique hardware resources of the controller,which can effectively improve program execution efficiency and increase computing speed.Finally,the experimental waveforms and performance test results of the prototype were given.