Patent ID: 9656556
Date: 2017-05-23
CPC Classifications: B60L,H02M,Y02T

Claim:
1. A drive system for an electric vehicle, comprising: an input capacitor; a contactor with an open state and a closed state for selectably coupling the input capacitor to a DC power source; a main capacitor; a variable voltage converter coupling the input capacitor to the main capacitor, the converter comprising a plurality of converter switches adapted for boost conversion; an inverter for coupling the main capacitor to a machine load, the inverter comprising a plurality of inverter switching devices in a bridge configuration; a controller coupled to the converter and the inverter to discharge the input capacitor and the main capacitor when the contactor goes from the closed state to the open state by A) operating the converter in the boost mode to transfer charge from the input capacitor to the main capacitor until the input capacitor discharges to less than a threshold voltage, B) deactivating the converter switches to prevent transferring charge from the main capacitor to the input capacitor, and C) discharging the main capacitor through the inverter switches.