System and Method for Discharging HVDC Capacitors

A drive system for an electric vehicle, comprising:

• a DC link capacitor configured and arranged to couple with a positive and negative DC bus;
• an active discharge circuit connected across the link capacitor, the active discharge circuit comprising at least two resistors in series with at least one MOSFET configured to operate in its linear region so as to selectively maintain a constant current discharge of the link capacitor;
• an operational amplifier in connection with turn on logic and a negative feedback loop arranged in series with one of the at least two resistors and configured to provide the operational amplifier with a first voltage indicative of a voltage level within the DC link capacitor, the turn on logic configured and arranged to provide the operational amplifier with a reference voltage, and the operational amplifier configured and arranged to make a comparison between the reference voltage and the first voltage, generate a control signal in response to the comparison and direct the control signal to the MOSFET;
• and
• wherein the MOSFET is driven by the control signal generated from the operational amplifier.