| In the power plant and transformer substations, the DC operation power is supplied from high frequency switching power supply (HF SPS) and uses bulky batteries as alternative power.The paper analyze the present situation development of high frequency switching power supply domestically and overseas, study and research the basal principle of HF SPS and its application in electric power system, then design HF SPS applied in electric power system in order to replace the old supply controlled by phase angle. The full-bridge converter is made up of four IGBT. The system consists of the AC input stage, main inverter, output low-pass filter, auxiliary power supply, and load current sharing circuit, etc. The theory of PWM is used in the system, and single of PWM is offered by controller UC3825.The feedback voltage and current achieved from output is used to control the change of the output. The controller M57962L is used in the IGBT drive-circuit. The primary circuit and the control circuit are insulated by the transformer and photo-coupler,increasing the reliability of the system.System exceptions, such as over-voltage, over-current, over-temperature, etc, are dealt with by carefully designed protection circuits. These circuits provide various functions to protect the system, including soft start, drive signals mask, etc.By using master-slave load current sharing technique, modules can be parallelized easily, thus capacity-expansion is very convenient.Because of the high frequency operation, this switching mode power supply has many advantages: light weight, small physical size, high reliability, etc.Li Zhe(Power Electronics and Electric Drive) Directed by Tang Tianhao...
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