| Summary: | 碩士 === 國立成功大學 === 電機工程學系 === 103 === Compared with other power generation forms, most renewable energy resources are hard to supply stable power even though they are more sustainable and environmental friendly. Therefore, a hybrid backup supply system is proposed to amend this problem. Interfacing the microgrid with current-fed full-bridge isolated DC-DC converter, fuel cell can provide stable backup power for microgrid. Interfacing with the dual-active-bridge bidirectional DC-DC converter, lead-acid battery can control the bidirectional power flow to balance power source and demand. However, the working time of the battery might be reduced due to the limited battery capacity. For this reason, this thesis proposes a power distribution strategy to set output power of the fuel cell for reducing the battery burden. Furthermore, DC-Bus management scheme is employed to control battery output power for balancing generation and demand. Moreover, a state of charge (SOC) regulation scheme is proposed to prevent battery from overcharging or overdischarging. A 450W base-load fuel cell with a 1.5kW lead-acid battery are integrated for the control test. Simulation and experimental results validate the effectiveness of the energy management control and strategy.
SUMMARY
This thesis proposes an energy management strategy for a hybrid power supply system which includes a backup supply in the distributed renewable generation system. The hybrid power system is composed of a 500W proton exchange membrane fuel cell and a series of seven 40Ah lead-acid battery bank. Interfacing the microgrid with current-fed full-bridge isolated DC-DC converter, fuel cell can provide stable and controllable backup power for microgrid. Interfacing with the dual-active-bridge bidirectional DC-DC converter, lead-acid batteries can control the bidirectional power flow with DC-Bus. As a main energy source, the fuel cell must provide most of backup supply power for reducing the battery burden. For this reason, this thesis proposes a power distribution strategy to set the fuel cell output power. On the other hand, the battery bank has to compensate the dynamic energy variation. Therefore, DC-Bus management scheme is employed to control battery output power for balancing generation and demand. Moreover, a state of charge (SOC) regulation scheme is proposed to prevent battery from overcharging or overdischarging. Finally, a 450W base-load fuel cell system with a 1.5kW lead-acid battery storage system are integrated for the control test.
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