Research On Three-phase Voltage Regulator With Controllable Phase And Amplitude

With the rapid development of world economy, there have been more and morerequirements of power energy to all walks of life, which directly leaded to the severesituation of power supply. In order to alleviate this contradiction, on the one hand allaround the world have increased the investment on several kinds of power station; on theother hand some technical reformations and innovations have been carried out to improvethe transmission capacity of the power transmission line.Three-phase voltage regulator with controllable phase and amplitude (VRCPA) hasstudied in this paper, which is comprised of three Buck type AC choppers and athree-phase Boost type AC chopper. The Buck type AC part regulates the phase and theBoost type AC chopper does the amplitude, so the phase and amplitude of the outputvoltage are regulated respectively. By using the three-phase symmetric relation, thepreceding3rdharmonic voltage could be canceled. Compared with the single-phaseVRCPA, the3rdharmonic trap could be canceled in the three-phase VRCPA, which has themuch simpler structure. Three-phase VRCPA with wide application prospects whichprovided a new idea for improving the transmission capacity of the power transmissionline.First of all, several common kinds of three-phase non-isolated type PWM translationcircuit are introduced in this paper. Three-phase Boost type AC/AC translation circuit hasbeen selected to become the boosted circuit of Three-phase VRCPA, and the circuitstructure、operation principle and control strategy of three-phase Boost type AC/ACconverter were analyzed in detail, furthermore, some simulations and experiments werealso carried out.Secondly, three-phase VRCPA was deduced from the single-phase VRCPA, thecircuit structure、 operation principle and control parameters of three-phase VRCPA were analyzed in detail, and the results of simulation were provided. Moreover, the process ofusing the DSP to generate the control signal with the Buck type AC choppers and eachother part of the three-phase VRCPA have described detailedly.Finally, a prototype was designed. The waveforms and data from the experimentshave verified the correctness of the theory and the feasibility of the control strategy.