Design of a high power-factor LiFePO₄ battery charger

• Main Authors: Zheng Yeh, 葉政
• Other Authors: Yong-Nong Chang
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/wasn33

碩士 === 國立虎尾科技大學 === 電機工程系碩士班 === 105 === 　　This thesis concluded a three-phase power supply conditioner with a high power lithium battery charger. The charger consists of three groups of single-phase charger, each group uses a two-stage circuit architecture. The front-end circuit adopts the continuous-conduction mode, designs the power facto correction circuit, the output voltage regulator’s interleaved CCM PFC boost converter enabling the converter to have power factor characteristics; the second-stage circuit adopts the full bridge converter regulator architecture, which utilizes the transformer to provide galvanic isolation function and through the leakage inductance and power switching’s parasitic capacitance resonance cause the power switch to have zero voltage switching characteristics. It can reduce the switching loss and improve the efficiency of the charger. This thesis first completed a single-phase 2kW charger modular design, using the CC-CV charging method, where the back-end current is responsible for regulation charging power. The input voltage is 220V, its power factor can reach 0.999 and efficiency can attain 91.5%. 　　This thesis completed a single-phase electric charger module that can integrate into a three-phase power supply to become a three-group single-phase electric charger with their independent input, parallel output form to combine into a three-phase electric power lithium battery charger. This charger, in order to avoid multi-module power supply in parallel output’s uneven current problem, the second-stage circuit adopts the continuous-conduction mode. When the multi-module is connected in parallel output, it has an active shunt circuit function, with the ability to regulate the power of each phase. Whenever the three-phase electric power is unbalanced, the charger will adjust the phase charge storage power, adjust the power grid three-phase power which enables the three-phase power to be balanced. We completed the three-phase electric power conditioner with high power lithium battery charger, which has an aggregate capacity that can reach 6kW, each phase factor can top 0.999. The output power of each phase can also be adjusted to achieve the three-phase electric power conditioner.