On-Line computation of T/sub J/ for EV battery chargers

Abstract

Since electric vehicle (EV) batteries need frequent recharging, it is usually desirable to do this as rapidly as possible. In general, the charging process can be divided into two periods referred to as the "bulk" charge and the "trickle" charge. Since the trickle charge is restricted to relatively low battery currents, the ability to reduce the charging time depends on delivering as much current as possible during the bulk charging period. This is especially true for those instances where the trickle charge occurs infrequently or not at all. It is expected that this will be the case where some mechanism other than a trickle charge is used to equalize the individual battery voltages. Here, the authors calculate the IGBT junction temperature of electric vehicle battery chargers in order to maximize charging current delivery.