| With the growing power needs of electronic equipment, the three-phase AC power supply hasbeen widely used. In order to reduce the pollution to electric network, three-phase AC power requiresa power factor correction (PFC) converter. Well, the output voltage of three-phase PFC converter isusually about800V, the after DC-DC convert is hard to design. Many existing electronic equipmentsrequire low-voltage high-current output converters. How to improve the efficiency and power densityof the converter has been a hot study.The converter derivation is given in the thesis. Two three-level half-bridge converters arecompared firstly. Due to poor clamped diode problem on three-level half-bridge converter with flyingcapacitor and clamped diode, three-level half-bridge converter without clamped flying capacitor andclamped diode is adopted. Current-doubler-rectifer circuit is usually used in low-voltage high-currentoutput applications. Well, current-doubler-rectifier circuit has three magnetic components, the powerdensity is low. In order to improve power density, integrated magnetic is adopted secondly. Thederivation of integrated magnetics is given in details. At last, a converter suit for high-voltage-inputlow-voltage-high-current-output is presented. Based on the architecture of integrated magnetics, afamily of integrated current-doubler-rectifer converter is also proposed.In this thesis, the operational principle of the proposed converter is described, the main switch torealize ZVS and duty cycle loss at the secondary side are discussed, the self-driven circuit andvoltage-sharying circuit are given, the loss comparison between two half-bridge three-level converteris analysed. And the main design parameters are also given.A2.8kW prototype is built in the lab. The experimental results verify the theoretical analysis.The proposed converter which works at high efficiency under wide load range is very suitable forhigh-voltage-input low-voltage-high-current-output applications. |
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