A new active dynamic voltage equalization technology for the series connected ultracapacitors used in EV

Ultracapacitor is needed to be series connected when it is used in electric vehicles (EVs) for its low terminal-voltage of single unit. Then, maintaining every unit in the same terminal-voltage is necessary in order to keep the whole ultracapacitor-system in safe and efficient working state. This paper proposes a new active dynamic voltage equalization technology for the series connected ultracapacitors used in EVs. The key is to design voltage equalization circuit and to develop proper control strategy for the circuit. Both the simulation and experiments are carried out, proving that the dynamic voltage equalization system can work efficiently.