System and method for precharging and discharging a high power ultracapacitor pack

A rapid discharge system for an ultracapacitor energy storage cell pack in a drive system, the system comprising:

• a power bus;
• a motor selectably connected to the power bus;
• a braking resistor selectably connected to the power bus;
• a pump configured to circulate cooling fluid through the braking resistor;
• a first switch configured to disconnect the ultracapacitor energy storage cell pack from the motor;
• a second switch configured to connect the ultracapacitor energy storage cell pack to the braking resistor;
• a controller configured to discharge the ultracapacitor energy storage cell pack by disconnecting the ultracapacitor energy storage cell pack from the motor via the first switch, and connecting the ultracapacitor energy storage cell pack to the braking resistor via the second switch.

A method for rapidly discharging an ultracapacitor energy storage cell pack in a drive system, wherein the drive system includes an engine, a generator, and a power bus, and wherein the ultracapacitor energy storage cell pack and the generator may be selectably connected to the power bus, the method comprising:

• determining the ultracapacitor energy storage cell pack requires discharging;
• determining the engine is not running;
• shutting off fuel to the engine;
• connecting the generator to the power bus;
• and
• discharging the ultracapacitor energy storage cell pack by driving the engine via the generator with the energy stored in the ultracapacitor energy storage cell pack.

A rapid discharge system for an ultracapacitor energy storage cell pack in a drive system, the rapid discharge system comprising:

• a power bus;
• a generator selectably connected to the power bus;
• an engine connected to the generator;
• a motor selectably connected to the power bus;
• a first switch configured to disconnect the ultracapacitor energy storage cell pack from the motor;
• a second switch configured to connect the ultracapacitor energy storage cell pack to the generator;
• a fuel shut-off;
• and,
• a controller configured to determine that the engine is not running, to shut off fuel to the engine via the fuel shut-off, and to discharge the ultracapacitor energy storage cell pack by disconnecting the ultracapacitor energy storage cell pack from the motor via the first switch, and connecting the ultracapacitor energy storage cell pack to the generator via the second switch.