Research On Three-phase Series-parallel Compensated UPS

With the development of power electronics technology, a new UPS topology is proposed, that is series-parallel compensated UPS. This type of UPS is getting an advantage over others, not only retain online features of the traditional full-time UPS but also make a lot of improvement in key performance indicators. It makes power factor of the input equals nearly 1, but also it has strong output capacity and high reliability. So it can be said the ideal UPS system.The paper analyzes firstly function, sorts and development trends in future of UPS. And then analyzes the structure, working status of the UPS. Mathematical models of Delta converter and main converter are built. Analysis are centered on how to control the Delta converter as a sinusoidal current source and to control the main converter as a sinusoidal voltage source and the introduce of repetitive control into main converter. For the Delta converter, direct current control scheme are selected; while for the main converter, based on the multiple-loop of voltage and current control scheme, the repetitive control scheme are introduced. Analyze the theory of the two schemes for the main converter and do simulations for this, by comparing we can know that it has a better voltage control consequent by using compound control method when loads are nonlinear loads.Finally, give the system hardware circuit and the main program flow chart based on control schemes mentioned and simulations by MATLAB. And carry out the relevant experiments, simulation and experimental results verify basically that series-parallel compensated UPS increases power factor of the input, has voltage and current adjustment and compensation for power grid and has better output idiosyncrasy.Figure [62] table [5] reference [33]...