PROTECTING CIRCUIT DEVICE FOR MOTOR CONTROL UNIT OF ELECTRIC VEHICLE, CONCERNED WITH RESTRICTING CURRENT FLOWING INTO CONTROL UNIT BY USING PTC RESISTOR

摘要

PURPOSE: A protecting circuit device for a motor control unit of an electric vehicle is provided to protect the motor control unit in hardware by restricting the current flowing into the control unit by using a PTC(Positive Temperature Constant) resistor. CONSTITUTION: A protecting circuit device for a motor control unit of an electric vehicle is implemented between a main battery(21) and the motor control unit(22) and is driven by a free charge relay(23) and a main relay(24,25). The protecting circuit lowers a voltage of a DC link capacitor(26) of the motor control unit to a voltage level of the main battery. The protecting circuit further includes a temperature-variable resistor(31) on one side of the free charge relay. The temperature-variable resistor restricts the amount of current flowing to the motor control unit when the DC link capacitor is short-circuited.