Research On Control Strategy Of Single-phase Voltage Regulator With Controllable Phase And Amplitude

The operation principle and control strategy of single-phase voltage regulator withcontrollable phase and amplitude (VRCPA) were analyzed in detail in this paper. Thephase and amplitude of the output voltage are regulated respectively and continuously.The paper mainly explores the optimized relationship between the phase and amplitudeof output voltage VRCPA and the two-stage duty cycle about pre-stage and back-stage’scontrol parameters. The phase closed-loop control system was designed by using thecontrol chip TMS320F2812.First of all, the functions of single-phase PWM Buck type AC converter,single-phase PWM Boost type AC converter and single-phase π type AC converter wereintroduced briefly, all of which can only adjust the amplitude without being able toadjust the phase. Based on this, the VRCPA was introduced. The single-phase VRCPA iscomprised of pre-stage converter and back-stage converter, as for pre-stage converter, itis used to adjust the phase of the output voltage, while the back-stage converter is usedto adjust the amplitude of the output voltage with the pre-stage converter. It wassimulated and the simulation results verified the correctness of the theory.Secondly, a detailed analysis about the optimized relationship between the phaseand amplitude of output voltage VRCPA and the two-stage duty cycle about pre-stageand back-stage’s control parameters of VRCPA is included. For phase regulation, twomethods were explored to select optimal controll parameters dynamicly. The Curvesfollowed by two methods are crossed at the reference phase angle and have sameoriginal controll parameters.Thirdly, for the control objective of VRCPA, the software and hardware about thephase closed-loop system of the VRCPA are designed. The duty cycle of pre-stage wasproduced by the CMP2unit of the EVA module, the phase closed-loop control programwas build by the software programming, combined with synchronous detection of the grid voltage and the output voltage of pre-stage by the capture unit, the accurate phaseclosed-loop control was achieved. The results of two methods were compared and thecontrol accuracy was analyzed.At last, a prototype of single-phase VRCPA was manufactured based on the DSPcontrol, on which the open-loop and closed-loop experiments were debugged. Thewaveforms, experimental data and analytical results were given, and the experimentalresults verified the correctness of the theory and the feasibility of the control strategy.