Patent ID: 7268521
Filing Date: 2007-09-11
Classification: B60L,F02D,F02N,Y02T

Abstract:
1. A method to discharge a capacitor in an automotive electric drive system of an electric vehicle, wherein the electric drive system includes a DC electric power source coupled by contactors to the capacitor for providing power to an electric motor coupled to a pair of wheels to drive the vehicle, the method comprising: determining a disconnect of the contactors; discharging the capacitor in response to the disconnect by controllably transferring energy from the capacitor to the electric motor without driving the wheels; wherein the electric drive system includes an electric motor controller coupled between the capacitor and the electric motor to controllably transfer energy from the capacitor to the electric motor by controlling current drawn from the capacitor and voltage provided to the electric motor; and wherein discharging the capacitor comprises controlling flux and torque produced by the electric motor to produce positive power flow from the capacitor to the electric motor.