Reserch On UPS Based On Delta Converter And Its Control-the Part Of Series

The delta converter UPS power system as one of the compensating UPS power hasthe advantage of large capacity, low loss and high efficiency. It can satisfy theuninterrupted power supply for important load, and improve the power quality of thesystem. The series part of delta converter UPS power is discussed in this paper.Firstly a detailed introduction of the principle and characteristic has been made forthe series of delta converter UPS power. A model for the series of delta converter based onthe d-q coordinates is established. A load current detection circuit has been designed in thecase of the nonlinear and unbalanced load. The delta converter is controlled as an idealcurrent source with the voltage and current double closed-loop control using the directlycontrol method,to make sure the power factor is1.Then due to the characteristics of the three-phase four-line system, the largecenterline current make a serious influence on cycling life of the dc side battery when thesystem is with unbalanced and nonlinear loads. A double half bridge circuit topology isproposed, then the PI, PR controller is used to control the dc side centerline current, andthe control precision of the voltage loop has been improved. The validity of the seriesconverter and the dc side control is verified by means of the MATLAB/Simulinksimulation software.Finally, the hardware circuit is designed and the system experiment platform is set upusing the TMS320F28335. A part of the experiment of the system has been carried out.