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Charge equalization system for batteries

  • US 9,490,639 B2
  • Filed: 02/04/2011
  • Issued: 11/08/2016
  • Est. Priority Date: 02/05/2010
  • Status: Active Grant
First Claim
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1. An apparatus comprising a battery equalization system for a battery, said battery comprising at least two accumulator stages arranged in series, each of said at least two accumulator stages having a negative pole, a positive pole, and at least one accumulator placed between said negative pole and said positive pole;

  • said battery equalization system comprising;

    a voltage generator comprising a positive terminal and a negative terminal and configured to apply a voltage between said positive terminal and said negative terminal;

    for each accumulator stage, a charging device, wherein each accumulator stage is associated with its own charging device, powered by said voltage generator, said charging device comprising at least one inductor, a first capacitor, a second capacitor, a first diode, a second diode, and a switch, wherein said first capacitor has a first end connected to a terminal of said voltage generator and a second end linked to said at least one inductor, wherein said second capacitor has a first end connected to a terminal of said voltage generator and a second end linked to said at least one inductor, wherein said first diode has an anode connected to said negative pole of the accumulator stage and a cathode connected to said second end of said first capacitor, wherein said second diode has an anode connected to said negative pole of the accumulator stage and a cathode connected to said second end of said second capacitor, wherein at least one diode in said charging device has an anode connected to said negative pole of the accumulator stage and has a cathode connected to one end of said at least one inductor, so as to allow, when said at least one diode is on, a charging current to flow through the accumulator stage, said at least one diode and said at least one inductor, and wherein said switch is linked to said at least one inductor and linked to a pole of the accumulator stage, such that said switch is connected in series with one of said at least one inductor and one of said first and second capacitors of said charging device between a terminal of said voltage generator and a pole of the accumulator stage; and

    a control device, wherein said control device is configured to control each one of the at least two accumulator stages to be charged with the following steps in order;

    during a first conduction time interval to close the switch of the charging device associated with the accumulator stage to be charged and to apply a positive voltage between said terminals of said voltage generator such that a current passes from said positive terminal through said first capacitor, said at least one inductor, the accumulator stage associated to said charging device, and said second capacitor to said negative terminal;

    said switch being passed through by an increasing power supply current originating from said voltage generator and that said at least one inductor stores energy;

    during a freewheel phase, upon completion of said first conduction time interval, by opening the switch of the charging device associated with the accumulator stage to be charged, interrupting said power supply current through said at least one inductor and allow transfer of said energy stored in said at least one inductor to the accumulator stage to be charged by circulation of a decreasing charging current through said at least one diode in said charging device and said at least one inductor, a zero voltage or no voltage being imposed on said positive terminal and said negative terminal by the voltage generator; and

    during a second conduction time interval, to close the switch of the charging device associated with the accumulator stage to be charged and to apply a negative voltage between said terminals of said voltage generator such that a current passes in opposite direction with respect to the first conduction time interval from said negative terminal through said second capacitor, the accumulator stage to be charged, said at least one inductor, and said first capacitor to said positive terminal;

    said switch being passed through by an increasing power supply current originating from said voltage generator and that said at least one inductor stores energy.

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