Abstract: An electric vehicle control apparatus fixed onto an electric vehicle body and including at least a main semiconductor device and a flywheel diode comprises a base member thereof fixed onto said vehicle body being in close contact therewith, a heat sink made of a metallic plate and fixed onto a portion of said base member through a thin sheet of an insulating material intervening therebetween, at least two pellets fixed directly onto said heat sink which pellets constitute at least said main semiconductor device and said flywheel diode, connecting terminals each thereof mounted on each of said pellets, and at least one auxiliary electric device fixed onto said heat sink.

Abstract: A chopper control system for controlling the amount of power supplied from a DC power source to a load having inductance. The chopper control system comprises a chopper circuit for accomplishing the on-off control of main current flowing from a DC power source to a load having inductance, and a duty cycle control circuit for controlling the duty cycle of the chopper circuit. A flywheel circuit including a series-connected circuit of a flywheel diode and a reactor is connected in inverse parallel with the load. The counter electromotive force induced in the flywheel circuit is detected by a detecting circuit and the output of the detecting circuit is applied to the duty cycle control circuit to prevent the main current from exceeding a predetermined value.

Abstract: A DC motor control system is provided which is useful for plugging action in an electric-powered vehicle. In the system, a saturable transformer is employed as a means of increasing the reverse biasing time of a thyristor without increasing the capacity and voltage proof of a capacitor. As a result, an increased biasing time of the thyristor can be ensured.