| Summary: | 碩士 === 國立虎尾科技大學 === 電機工程系碩士班 === 105 === This thesis has accomplished a lithium battery charger with high power factor based on a single-stage full-bridge converter. The developed charger comprises a full-bridge converter along with two power factor inductors operating in interleaved way, thus having outstanding power-factor correction capability. Meanwhile, the power switches of the charger are featured with soft switching operation to reduce the switching loss. Further, for preventing the energy storage capacitor from experiencing excessive voltage stress during power regulation, the duty-cycle control of the power switches is employed to regulate the output power. The developed single-stage full-bridge high power-factor, lithium battery charger is carried out in two directions, one is the non-isolated type and another one is the isolated type. The non-isolated type charger possesses the advantage of positive/negative pulse charging (ReflexTM) profile without needing additional control circuit. On the other hand, the isolated type charger can definitely meet the safety standard for the isolation requirement of electricity charger.
In this thesis, one non-isolated type and one isolated type of 1kW single-stage full-bridge high power factor, lithium battery chargers are fulfilled by using the lithium iron phosphate battery pack as load. According to the experiments, the charging efficiency of the non-isolated type charger can approach 94.33% and the isolated type one can reach 92.03%, while both possessing power-factor higher than 0.99. In the meantime, the measurements indicate that the power storage of the lithium iron phosphate battery can be enhanced by using ReflexTM charging technique. The test results real that the power storage efficiency of 0.5C battery can be raised by 0.73% while 0.25C battery can be increased by 0.21%.
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