System and method for precharging and discharging a high power ultracapacitor pack
First Claim
1. A method for rapidly discharging an ultracapacitor energy storage cell pack in a drive system, wherein the drive system includes a braking resistor and a power bus, and wherein the ultracapacitor energy storage cell pack and the braking resistor may be selectably connected to the power bus, the method comprising:
- determining the ultracapacitor energy storage cell pack requires discharging;
connecting the braking resistor to the power bus;
discharging the ultracapacitor energy storage cell pack through the braking resistor; and
cooling the braking resistor.
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Accused Products
Abstract
This invention is a system and a method that uses the braking resistor, commonly used and available in electrically or hybrid-electrically propelled vehicles, to limit the precharge current during the startup of a high power ultracapacitor pack energy storage device and/or safely and rapidly discharge an ultracapacitor pack for maintenance work or storage to lengthen the life of the individual ultracapacitor cells and, correspondingly, the whole pack. The use of the braking resistor for precharging an ultracapacitor energy storage pack is an effective and less expensive method compared to other methods such as a separate DC-to-DC converter. This method includes the control logic sequence to activate and deactivate switching devices that perform the connections for the charging and discharging current paths.
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Citations
26 Claims
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1. A method for rapidly discharging an ultracapacitor energy storage cell pack in a drive system, wherein the drive system includes a braking resistor and a power bus, and wherein the ultracapacitor energy storage cell pack and the braking resistor may be selectably connected to the power bus, the method comprising:
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determining the ultracapacitor energy storage cell pack requires discharging; connecting the braking resistor to the power bus; discharging the ultracapacitor energy storage cell pack through the braking resistor; and cooling the braking resistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A rapid discharge system for an ultracapacitor energy storage cell pack in a drive system, the system comprising:
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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. - View Dependent Claims (10, 11, 12, 13, 14)
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15. 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:
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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. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A rapid discharge system for an ultracapacitor energy storage cell pack in a drive system, the rapid discharge system comprising:
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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. - View Dependent Claims (23, 24, 25, 26)
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Specification