Apparatus for interactively accelerating an electric drive vehicle

Abstract From the Canadian patent

Apparatus for controlling the supply of power to an electric drive motor normally controls the duty cycle of a power switching element to produce a variety of vehicle speeds. The apparatus typically controls the rate of change of the duty cycle to provide smooth vehicle operation. During periods of extended high speed, high load operation the apparatus bypasses the power switching element and connects the vehicle battery directly to the drive motor via a bypass contactor. Under normal operating conditions the bypass contactor is energized after a relatively short preselected delay; however, where the vehicle is heavily loaded, such that current limiting of the power switching element …