Maximizing life of capacitors in series modules
First Claim
1. A method for use in a series module of capacitors, each capacitor having a respective relative capacitance, each capacitor at a particular moment having a respective charge, each capacitor at a particular moment having a respective voltage, the method comprising:
- arriving at an estimate of the respective relative capacitance of each capacitor by measuring voltages at each of the capacitors;
identifying a first capacitor in the series module having an estimated relative capacitance smaller than the estimated relative capacitance of a second capacitor in the series module; and
causing the first capacitor to be charged to a respective level of charge lower than the respective level of charge of the second capacitor.
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Accused Products
Abstract
A device (1) monitors and/or balances an ultracapacitor (3) and/or a module (4) comprising a plurality of ultracapacitors (3) connected in series, the module (4) being connectable in series or in parallel with other modules (4). The device comprises an electronic board (2) comprising digital control and/or command means, such as a microcontroller (5), executing a program for monitoring and balancing the ultracapacitor (3) and/or the module (4). The relative capacitances of the capacitors are measured, and this information is employed to determine when to carry out a controlled discharge of particular capacitors. Temperature information is also employed to determine when to carry out a controlled discharge of particular capacitors. In this way the lifetime of any particular capacitor is, desirably, extended to be no shorter than the lifetime of other longer-lived capacitors in the module.
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Citations
12 Claims
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1. A method for use in a series module of capacitors, each capacitor having a respective relative capacitance, each capacitor at a particular moment having a respective charge, each capacitor at a particular moment having a respective voltage, the method comprising:
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arriving at an estimate of the respective relative capacitance of each capacitor by measuring voltages at each of the capacitors; identifying a first capacitor in the series module having an estimated relative capacitance smaller than the estimated relative capacitance of a second capacitor in the series module; and causing the first capacitor to be charged to a respective level of charge lower than the respective level of charge of the second capacitor. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for use with a series module of capacitors, each capacitor having a respective relative capacitance, each capacitor at a particular moment having a respective charge, each capacitor at a particular moment having a respective voltage, the apparatus comprising:
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means for arriving at an estimate of the respective relative capacitance of each capacitor by measuring voltages at each of the capacitors; means for identifying a first capacitor in the series module having an estimated relative capacitance smaller than the estimated relative capacitance of a second capacitor in the series module; and means for causing the first capacitor to be charged to a respective level of charge lower than the respective level of charge of the second capacitor. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification