Improvement of power regeneration efficiency in the electronic vehicle using charge switching by the current value

Improvement of brake energy regeneration in the electric vehicle (EV) using the EDLC (Electrical Double Layer Capacitor) is studied. In order to save the battery and increase the driving range of the EV, improvement of power regeneration efficiency is important. The power regeneration system for the EV has been developed. The system consists of the EDLC as the energy storage, the synchronous motor and the rotational load. The rotational load simulates the kinetic energy of the EV. It is necessary that the regeneration voltage is larger than that of the charge system. The regular time intervals switching circuit is considered. Using this circuit, dysfunctional period is reduced and power regeneration efficiency is improved compared with that without switching. However, as each the EDLC unit is switched at regular time intervals, the dysfunctional state is occurs before switching under some condition. In order to solve this problem, the current value switching circuit is considered. The EDLC units are switched when the current value reaches nearly equals to zero in the system. Using this switching principle, the regenerating brake dysfunctional period is not observed, and power regeneration efficiency is improved compared with that using charge switching at regular time intervals.