| 摘要 |
A digital UPS(Uninterruptible Power Supply) system for three phases is provided to prevent the disconnection of output voltage by rapidly detecting the voltage of three phases input/single phase output. In a digital UPS system for three phases, a first transformer(12) transforms power inputted through a three phases input switch(11) to a single phase. A distribution switch(13) switches the power inputted from the first transformer(12). A second transformer(10) outputs the power to a load side through a primary coil. A chopper circuit(20) controls the voltage/current of a secondary coil of the second transformer(10) and the output for input of the second transformer(10). A first inverter(30) controls the voltage and current of the chopper circuit(20). A battery(40) supplies uninterruptible power. A second inverter(50) transforms the battery power to AC power during the interruption of power. A third transformer(60) is connected between the second inverter(50) and an output load side of the second transformer(10). A high speed detecting unit(80) detects input voltage(Vi) and input current(Is) from the rear end of the input switch(11), output voltage(Vo) and output current(Ip) from the connecting end of the load side, and DC voltage from the battery(40). A microprocessor(900) controls the uninterruptible power, an automatic voltage regulating function, and various monitoring, displaying, and protections functions. A gate driver(70) outputs pulse width modulation control signals of the first inverter(30) and the second inverter(50). A key pad(100) is manipulated by an operator for setting various functions and monitoring control. An LCD(110) displays various states and menus for setting functions.
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