EQUALIZING METHOD AND CIRCUIT FOR ULTRACAPACITORS
First Claim
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1. An ultracapacitor charging method for charging a series connected string of ultracapacitor cells having a plurality of balancing circuits, said method comprising the steps of:
- a. specifying a voltage balance hysteresis as variable V_BAL_HYST;
b. charging said string of ultracapacitor cells;
c. turning all balancing circuits off;
d. measuring the voltage of each ultracapacitor cell to determine the smallest measured cell voltage;
e. storing said smallest measured cell voltage as variable Vmin; and
f. for each ultracapacitor cell in the series connected string iteratively performing the following steps;
i) measuring the voltage of the ultracapacitor cell to set Vcell;
ii) computing the difference of Vcell and Vmin;
iii) comparing difference of Vcell and Vmin to V_BAL_HYST, wherein if the difference of Vcell and Vmin>
V_BAL_HYST, then turning on the balancing circuit for the cell, draining current from the cell.
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Abstract
An equalizing method for ultracapacitor cell packs and/or series connected ultracapacitors.
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Citations
18 Claims
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1. An ultracapacitor charging method for charging a series connected string of ultracapacitor cells having a plurality of balancing circuits, said method comprising the steps of:
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a. specifying a voltage balance hysteresis as variable V_BAL_HYST; b. charging said string of ultracapacitor cells; c. turning all balancing circuits off; d. measuring the voltage of each ultracapacitor cell to determine the smallest measured cell voltage; e. storing said smallest measured cell voltage as variable Vmin; and f. for each ultracapacitor cell in the series connected string iteratively performing the following steps; i) measuring the voltage of the ultracapacitor cell to set Vcell; ii) computing the difference of Vcell and Vmin; iii) comparing difference of Vcell and Vmin to V_BAL_HYST, wherein if the difference of Vcell and Vmin>
V_BAL_HYST, then turning on the balancing circuit for the cell, draining current from the cell. - View Dependent Claims (2, 3, 4, 5)
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6. An ultracapacitor charging method for charging a series connected string of ultracapacitor cells having a plurality of balancing circuits, said method comprising the steps of:
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a. specifying a voltage balance hysteresis as variable V_BAL_HYST; b. charging said string of ultracapacitor cells; c. establishing a predetermined time interval; and d. performing the following steps for a period of time equal to said time interval; i. turning all balancing circuits off; ii. measuring the voltage of each ultracapacitor cell to determine the smallest measured cell voltage; iii. storing said smallest measured cell voltage as variable Vmin; iv. for each ultracapacitor cell in the series connected string iteratively performing the following steps; a) measuring the voltage of the ultracapacitor cell to set Vcell; b) computing the difference of Vcell and Vmin; c) comparing difference of Vcell and Vmin to V_BAL_HYST, wherein if the difference of Vcell and Vmin>
V_BAL_HYST, then turning on the balancing circuit for the cell, draining current from the cell; ande. repeating step d after said period of time has passed. - View Dependent Claims (7, 8, 9)
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10. An apparatus for charging a series connected string of ultracapacitor cells, said apparatus comprising:
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a charger for charging said string of ultracapacitor cells; a plurality of balancing circuits for draining current from the cell; and a digital controller, said digital controller specifying a voltage balance hysteresis as variable V_BAL_HYST, said digital controller turning all balancing circuits off, determining which cell has the smallest cell voltage (Vmin), wherein as the ultracapacitor cells charge said digital controller monitors the voltage of each of the ultracapacitor cells, turning the corresponding balancing circuit on for any ultracapacitor cells where the difference between the voltage of the ultracapacitor cell and Vmin>
V_BAL_HYST. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification