Research On Modular Power Supply Based On HVDC

There are great advantages in solving the non-synchronous interconnection in grid, high voltage power transmission over long distance, adjusting itself quickly by applying HVDC Light technique. Traditional HVDC Light systems adopt park coupled topology in dc connection, which lift the voltage by industrial frequency transformer and need many power electronics devices in direct series in bridge rectifier. In this case the reliability and stability of the converter are reduced, while the loss in the wires and the area of the converter are increased. In this paper, a modular input-parallel output-series (IPOS) high voltage converter topology which is used for cluster coupled with common DC Bus overcomes these drawbacks above effectively, and it focuses on the design of switching-mode power supply for high output voltage and key technologies under high voltage pressure.The Electric DC-Transformer works at nearly 100% dutycylce without filter inductance ouput. The output voltage is proportional to input voltage, and the switches are ZVS in the DC transformer which can lift the voltage and power. The operation principle of the DC-Transformer based on full-bridge topology is analyzed theoretically. The output characteristics and the influence of the relatively parameters are analyzed. Simulation results are given and a prototype rated 6kW is built to verify the design method.The series resonant phase-shifted full bridge converter which employs fixed-frequency includes the advantages of both the resonant converters and the pulse-width modulation converters, and it is suited to regulate the output power. The operation principle of resonant converter is analyzed in this paper. A comprehensive design procedure for the converter is proposed based on its steady model, and the stresses of the voltage and the current are discussed. A 6kW prototype is designed on this basis, and simulation and experimental results are given to verify the effectiveness of the converter.Some key technologies under high voltage pressure are studied. The design of the transformer with high voltage and high frequency is illustrated. The problem of the voltage sharing in series coupled diodes for high voltage and high frequency rectifier applications is discussed, and the main factors that influence this problem are gotten. Then, the phenomenon of unequal distribution of each diode in bridge rectifier circuit is resolved. The problem of the output voltage sharing of the IPOS converter is analyzed and simulated, and the experimental results are given to verify the effectiveness of the proposed strategy. An IPOS prototype consisting of two DC-DC modules is built in the lab. Simulation and Experimental results are given to vertify the effectiveness of the propose design.