Lear Corporation
METHOD AND SYSTEM FOR PRODUCING AN ACTIVE SHORT CIRCUIT CONDITION IN AN ELECTRIC MOTOR OF A HYBRID ELECTRIC VEHICLE

Abstract:

A method for producing an active short circuit condition in an electric motor of a hybrid electric vehicle including a traction battery, an inverter having switches in communication with the electric motor and the traction battery, and an inverter controller in communication with the inverter and configured to generate driver signals to operate the switches to produce three-phase alternating current for the electric motor to drive a vehicle propulsion system or to produce direct current for charging the traction battery. The method includes determining an electric motor speed threshold, wherein the electric motor speed threshold is continuously variable, comparing a monitored speed to the speed threshold, and generating, in response to the monitored speed exceeding the speed threshold, driver signals to operate the switches to produce an active short circuit condition in the electric motor to prevent overcharging of the traction battery.