Protection of power transistors in electric vehicle drives

Presently, transistor choppers are being applied in electric vehicle tractive drives. However, during transistor turn-off, the energy stored in the inductance of battery and cables must be redistributed in order to avoid device overvoltage. In this paper, several transient energy suppression circuits are discussed and a novel, nondissapative, energy catch network is identified. Operating data from an experimental 240V, 400A, transistor chopper is also presented.