A Research On Circuit Topology Of New Single-phase Dual Inverters UPS

This dissertation put forward a new series-parallel dual inverters-UPS topology based on analyzing existing UPS circuit topology, principles and characteristics, applying the method that pulse wave inverter and harmonic compensation to dual inverters-UPS system. When the power supply is in order, the two inverters are working in the state of PWM with high frequency, and providing power to the load together. Thereinto, inverter 1 works in the mode of current source, compensating harmonic and reactive power of the system and charging the battery at the same time; and inverter 2 works in the mode of voltage source, adjusting the voltage between input and output. When the power supply is cut off, the two inverters are working in the mode of voltage source, and inverter 1 works in the state of switch with low frequency, providing pulse wave with 50Hz; meanwhile, inverter 2 works in the state of PWM with high frequency, providing the compensation wave, so the output of the system is equal to series of the two inverters, and is the sine wave. The proposed UPS system can reduce the switch wastage and enhance the whole efficiency of the system under condition of the two inverters.Describe the principles of the new UPS system in detail, analyse and calculate in theory, educe the relation curve of each correlative parameters; provide the structure of the system, power circuit diagram and its control strategy.The topology of the proposed UPS system is simulated by the Simulink of MATLAB 6.5, and the feasibility of the scheme has been proved.