Research On650VA Three-phase Voltage Regulator With Controllable Phase And Amplitude

With the development of economy and the improvement of people’s living standard,demand for power energy of society has grown rapidly. The contradiction of power supplyis becoming more and more serious. Improving the ability of power transmission is aneffective measure to alleviate the contradiction.Three-phase voltage regulator with controllable phase and amplitude (VRCPA) wereanalyzed in this paper. The three-phase VRCPA is comprised of two parts which are usedto continuously adjust the phase and amplitude of three-phase output voltage respectively.So three-phase VRCPA can control the transmission of active power and reactive powerflexibly, which had potential application prospect.First of all, the circuit structure and working principle of a three-phase VRCPAwithout3thharmonic notch filter were introduced. By analyzing its control parameterrelationship of extreme phase angle, select reasonable parameters of closed-loop control.The simulation results verified the correctness of the theory and the feasibility of thecontrol strategy.Secondly, analyze the process of phase closed-loop system of the three-phase VRCPApre-stage in detail. Capture zero crossing point signal of the input and output voltage anduse DSP software programming, then through related hardware circuit to produce phasecontrol duty cycle of pre-stage. The accurate phase closed-loop control was achieved.Thirdly, the amplitude closed-loop control strategy of three-phase VRCPA back-stagewas analyzed in detail. Three-phase VRCPA back-stage was a three-phase Boost typeAC/AC converter. The key to realize the converter control was the minimum phasejudgment of the three-phase output voltage. Three methods to judge the minimum phase ofthe three-phase output voltage were researched and compared and the three-phase Boosttype AC/AC converter was simulated. The simulation result show that the line voltagepolarity judgment method made the waveform of output voltage better than other methods.Finally, a prototype of three-phase VRCPA was designed, on which the load efficiency measurement and other related experiment were debugged. The experimentalresults and measured data show that three-phase VRCPA can regulate the phase andamplitude of the output voltage respectively. The conversion efficiency changes with thephase-shifting angle. When the phase-shifting angle becomes smaller, the conversionefficiency becomes higher.