Single-phase On-line Ups Parallel Technology

Multi-UPS redundant parallel operation is a good solution to realize high reliability and large capacity of power system and it is one of the vital regions in power electronics. Because of the output of the UPS (or Inverter) is AC, its parallel operation is more difficult than DC supplies. With the rapid development of information technology, the redundant parallel operation of UPS has been become of the research hot point and difficult point of the domain of power electronics.In this thesis, depending on the theoretical analysis , computer simulation and physical experiments, the operation of typical on-line UPS is analyzed at first; Based on this, applying the latest research achievements of the parallel operation of the inverter, the problems such as following bypass and bypass control have been solved, the redundant parallel operation of UPS has been developed. A novel parallel operation system based on current instantaneous regulated inverters is proposed in this thesis. The system operation is analyzed, with the circuits given. The system is proved to be feasible by theoretical analysis, computer simulation and physical experiments. This is no master-slave parallel operation with some interconnection. The UPS, which has been paralleled, is identical with others. Each module works equally and symmetrically, without extra control circuits. The synchronization and current sharing are realized through a few signal lines among the modules. The modules can work separately or in parallel, theoretically without limit for the number of modules. The thesis based on the redundant parallel operation of UPS with resistor analyses the operations of system with inductor and rectifier bridge load at first. The thesis gives the MATLAB simulation models and waveforms of the different loads. Simulation and experiment results are given at the end. The results show this solution is reliably, and the performance is good.