| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 103 === Although battery management systems (BMS) have been developed in past decades, they start to attract massive attention till they are widely applied in electric vehicles (EVs). Battery packs of EVs are series-parallel combination of many battery modules such that battery management has become a task to beat. In addition, BMS must resist environmental variations to comply with stringent safety requirements. A BMS must at least provide functions of protection, cell balancing and monitoring circuitry. Notably, battery balancing and protection depend on reliable battery parameters such that the status estimation of battery packs is the key to BMS.
This thesis presents a battery monitor unit (BMU) using coulomb counting method with calibrated current estimation approach (CCEA) that avoids the variation of battery capacity at the initialization of different discharging currents. The value of SOC estimated with CCEA represent the ratio of residual charge and variation of battery capacity. Moreover, open-circuit voltage (OCV) method is added to the BMU to acquire the initial states from the battery parameters. Specially, OCV buffer mode is added to the BMU such that the BMU doesn''t start to estimate state of the battery by using OCV method until the OCV of the battery is stabilized. The proposed BMU is implemented using TSMC 0.25 μm HVG2 Design Kit, while a battery control unit (BCU) is implemented by DCcduino UNO to receive status of batteries from the BMU.
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