Research On Compensated UPS Based On Delta Inverter

With the development of power electronics technology, a new UPS topology is proposed, that is Delta transform type UPS. This UPS include two converters, not only retain online features of the traditional full-time UPS but also make a lot of improment in key performance indicators. It eliminates the pollution of power grid, more importantly; it has strong output capacity and high reliability. So it can be said the ideal UPS system.The paper analyzes firstly current situation and development trends of UPS. In connection with the disadvantage of traditional-line UPS, researches the design of Delta transforms type UPS, divides it into two parts: Delta inverter and main inverter functionally and structurally, and researches the work mechanism of Delta convertor and main convertor and the compensation of the fluctuantion of voltage, current and harmonious deeply. Then analyzes and simulated the instruction signal check mode and the control plan of two convertors. Delta convertor introduces DC current closed-loop control. Through researching the dectection technique of the harmonic and reactive power and giving an implementation of the real-time detection of harmonic and reactive current based on three-phase instantaneous reactive power theory, obtains modulation-wave current instruction signal in which variation of harmonic and reactive current is reflected. Main convertor introduces instantaneous value comparison control. By d-q conversion and comparision, the instruction signal is obtained of modulation-wave voltage in which variation of harmonic wave and fundamental wave voltage is reflected.Finally, the simulation model of the entire system is builded and debugged in the PC by MATLAB/Simulink as the simulation tool. Give the system hardware sircuit and the main program flow chart of the software, and carry out the relevant experiments combining with the existing experimental conditions. Simulation and experimental results verify basically that Delta transform type UPS has voltage and current adjustment and compensation for power grid.