Patent ID: 6384553
Filing Date: 2002-05-07
Classification: B60L,Y02T

Abstract:
In a system that includes a battery, a motor, a switching circuit that interconnects the battery and the motor, a switch driving circuit that is connected to the switching circuit, and a controller that is connected to the switch driving circuit for controlling operation of the switching circuit in one of a first mode, wherein the motor is configured so as to draw power from the battery and wherein the motor rotates in a positive direction and with a positive torque, and a second mode, wherein the motor is configured so as to supply power to the battery and wherein the motor rotates in the positive direction and with a negative torque, a method of controlling current flow to the motor when the switching circuit is operated in the second mode, comprising the steps of:detecting actual rotational speed of the motor; and controlling the switch driving circuit to adjust duty cycle of control pulses provided by the switch driving circuit to the switching circuit in an inversely proportional relationship with respect to the actual rotational speed of the motor, thereby controlling the current flow to the motor to prevent damage to the switching circuit.