Study On Parallel System Of PWM Rectifier

Along with the development of social economy and industrial engineering, peopleincreasingly make high demands on power supplies, high-capacity, high-performance, highsafety which become a trend mainly technical development of power. Parallel PWM rectifiercan improve the power factor, has the advantage of two-way exchange of energy has becomea potential research field of power electronics. Parallel PWM rectifier coupling can performlarge-capacity power supplies, backup power supplies which improve flexibility andreliability of the system. In the aviation industry, data centers, the financial sector and thesector that has high requirements for power supply parallel PWM rectifiers is to be welcomed,it has important research value and practical application.Firstly, thesis establish a mathematical model of PWM rectifier in three-phasecoordinates(a, b, c), through conversion coordinates to move to the second phase(d, q).Through analysis object model, and make plans for control-oriented grid voltage vector,design controls two close circuit using space vector PWM controller to proceed, energy is atwo-way exchange, normalize the power factor controllers and other control purposes.Secondly, the thesis analyzed the structure diagram parallel system and control methods,selected methods independently controlling. Rectifier connected parallel exist balancedcurrent and current sharing problems, gave vector modulation method and sync signals tocontrol the balanced current and control method of maximum discharge current. Based on thatbuilding block diagram and simulation software matlab/Simulink have been done.Simulationresults demonstrate parallel rectifier technique are feasible and effective.Finally, based on DSP + CPLD, established central control circuit of the experimentalsystem PWM rectifiers in parallel, introduced to hardware and software, perform experimentswith a single PWM rectifier and two parallel PWM rectifier. Experimental results havedemonstrated, the thesis gave the technical two parallel paired PWM rectifier can be actuallyexecuted, meaning in practical applications.Besides theses rectifier systems, thesis adds networking functionality and WEBmonitoring functions that create favorable conditions for the operation and maintenancesystem rectifiers in parallel, consistent with the development of network theory.