直流對直流電源轉換器與超級電容在電動車電力分配上的應用

Abstract

為降低石化燃料使用與減少廢氣排放造成的空氣汙染，電動車成為市場上的熱門話題，目前許多廠商都致力於電動車輛的開發。在電池與電源系統方面，為了提高能源效率與降低成本，必須提高電池的穩定度與使用壽命。對電動公車來說，電池需求量大，成本也相當昂貴，一個好的供電管理系統尤其重要。 電池壽命除了取決於溫度的控制外，充放電速度過快，也就是電流太大，同樣會損壞電池而減少電池壽命。在電動車行駛的過程中，車輛加減速會使電池大電流放電與充電，而不同電池間的電壓差異，會造成電池互相充電，也可能使電池的電流過大。 本研究的電動車系統，同時存在電池與超級電容，利用DC/DC converter做電流輸出的控制，來限制電池輸出電流，並藉由功率分配，使電池不會有大電流輸出。本研究以實驗的方式，模擬此系統在車輛行駛模式下的情況，並且量測電池輸出的電流，從而驗證並分析本研究所提出方法的效果。結果顯示，依負載增減造成的電流改變，可得知DC/DC converter應提供之電流輸出改變，若依據此電流變化進一步控制DC/DC converter，即可達到超級電容SOC值修正的效果。

In order to reduce air pollution caused by the using of fossil fuel and the exhaust gas emission, electric car becomes a hot topic on the market. Many manufactures are committed to the development of electric vehicles. However, in order to improve energy efficiency and reduce costs, improving stability and circle life of the battery is an important key. For electric buses, the cost is quite huge caused by batteries. Accordingly, effect management of power supply systems is important. Battery life not only depends on the temperature control, but also depends on charging and discharging speed, which means the charging/discharging current. If there is too large current, it will damage the battery and reduce circle life. During the electric car driving, vehicle acceleration and deceleration cause large current charging. Also, the voltage differences between the cells cause the battery to charge each other. All these situation can damage the battery badly . The electric vehicle system in this study consists of batteries, a super capacitor, and a DC/DC converter. This study uses the DC/DC converter to control and limit the output current of the battery. Base on power distribution, the battery does not generate too large current output. This study uses an experimental approach to simulating this system during vehicle driving, and measures the output current of batteries, so as to validate the proposed method in this study. The results show that, depends on the load increases caused by current changes, we can verify current output DC/DC converter should be provided. If we use this current change in the DC/DC converter in a control system, supercapacitor SOC value can be appropriately adjusted.