Research On Three-phase VIENNA Rectifier Technology Applied In Electric Vehicle Charging

In recent years, with the continuous improvement of battery technology,electric vehicle industry is developing rapidly. It needs to build a lot of chargingstations in order to make the electric vehicles popularity. Since the chargers need toget large current from the grid quickly and it is a non-linear load, it brings greatharmonic pollution for grid. So the study with power factor correction converter hasimportant significance.In the three-phase rectifier topology, there are has good network side powerquality, less switching device, a small votage stress and no direct conduction for theDC bus for three-phase VIENNA rectifier. Therefore?this paper mainly analyzed onthe working principle, mathematical model and the control strategy in depth for thethree-phase VIENNA rectifier. Then it calculates parameters of the key componentfor the main topologies and designs the hardware circuit of the entire system.Finally, the control program is compiled.This paper studys the three-level space vector control method in detail andanalyzes the carrier phase shift control strategy. Its switching states are the samewith space vector modulation. Thse switching states are synthesized by the basicvector which the reference vector is located in the small triangle sector. Carrierphase shift control strategy attain the performance of applying space vector control.At the same time, the control method becomes more simplified. According to theDC link neutral point potential unbalance, it adds the neutral point potentialdifference to the reference voltage of current loop, to regulate the DC bus positiveand negative voltage balance dynamically. As the system doesn't have neutral lineand sample phase voltage directly, the paper sample the voltage between the inputterminal and the DC bus midpoint. Then each phase voltag is obtained by improvingcontrol algorithm and the hardware circuit is simplifyed.When theoretical analysis is completed, the paper builds simulation model ofthe system in Matlab and the simulation results verify the validity of the theoreticalanalysis. Finally, a prototype based on DSP control is designed. The experimentalresults show that the rectifier has good network side power quality, small harmoniccontent, and dynamically adjust the DC bus neutral balance under the control of thecarrier phase shift control strategy.