HYBRID BATTERY-ULTRACAPACITOR ENERGY STORAGE SYSTEMS FOR NEXT GENERATION SHIPBOARD POWER SYSTEMS

Batteries and ultracapacitors are likely to be candidates as excellent energy storage technologies for future shipboard power systems. This dissertation explores a hybrid Battery-Ultracapacitor Energy Storage System (BUCESS) for next generation shipboard application. Based on the power requirements of combat ships, a new configuration of the battery and ultracapacitor combined system is introduced for propulsion systems and pulse power loads. For one BUCESS unit, batteries and ultracapacitors are charged and discharged at high voltage level and high power level through a dual active bridge and a double-boost bidirectional converter. The converters are optimally designed to control the bidirectional power flow for batteries and ultracapacitors separately, and to ensure constant voltage regulation of ultracapacitors during charging and discharging. High-frequency switching devices are selected to achieve dc-dc conversion at high voltage and high power levels. The design guidelines and control schemes for simulations are provided for the proposed new topology. Finally, a double-input BUCESS unit is designed, analyzed and simulated to investigate different operation modes of the hybrid energy storage system.M.S. in Electrical Engineering, May 201