| This dissertation investigates the principles and design of an digital controlled bi-directional DC-DC converter with synchronous rectifier, which was used for the administration of storage battery in hybrid electrical vehicle.The storage battery is the core part of hybrid electrical vehicle. It is necessary to analyze the battery' s characteristic and choose a suitable charging and discharging strategy that will influence the working patterns of the converter.Some DC-DC topologies that could be applied for the vehicle were discussed and compared. Based on the analyses, the Buck converter with synchronous rectifier was selected. For Buck mode, the converter is mainly operated in high-current state. Some research was made to compare the digital controlled synchronous rectifier and the schottky diode rectifier.Moreover, another main job is the realization of bi-directional converter in different control modes. A control method base on algorithm was proposed for digital average-current control in boost mode. The dissertation also investigates the design of digital controller by modeling the converter.Based on theoretical analyze, a topology is realized. The result proved that the digital controlled Buck converter with synchronous rectifier is valuable for the application in the vehicle because it can improve the efficiency and reduce the cost, compared with separated buck and boost converter which used schottky diode as rectifier. |
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