Device and method for measuring individual cell voltages in a cell stack of an energy accumulator
First Claim
1. A device for measuring individual cell voltages of cells in a cell stack of an energy accumulator, comprising:
- a series circuit of two diodes connected in parallel with each cell of the cell stack and connected to conduct current in a direction from a minus pole to a plus pole of the cell;
a changeover switch having a number of terminals assigned to switch positions corresponding to a number of the cells of the cell stack, and a capacitor connecting each of said terminals to a respective node between said diodes assigned to the cells;
a reference circuit having first and second diodes connected in series, said first diode having an anode connected to reference potential and to a cathode of said second diode;
a differential amplifier having a non-inverted input connected to an output of said changeover switch, an inverted input connected via a capacitor to a node between said first and second diodes of said reference circuit, and an output;
a controlled rectifier having an input connected to said output of said differential amplifier and an output carrying a direct current with a voltage, relative to reference potential, proportional to a cell voltage of the cell respectively selected with said changeover switch;
a first controlled alternating current source connected between said non-inverting input of said differential amplifier and reference potential;
a second controlled alternating current source connected between said inverting input of said differential amplifier and reference potential; and
a clock control having an oscillator outputting an oscillator clock signal and a frequency divider outputting a divider signal, wherein said first and second alternating current sources and said rectifier are controlled by the oscillator clock and said changeover switch is controlled by the divider signal.
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Accused Products
Abstract
A device and method enable measuring individual cell voltages of cells in a cell stack of an energy accumulator. To this end, a series circuit formed of two diodes is connected in parallel to each cell, the nodes between these diodes are connected to a changeover switch via a respective capacitor and to a differential amplifier via the changeover switch, and an alternating current of a specified frequency and amplitude is fed into these capacitors while generating an alternating voltage corresponding to the cell voltage. This alternating voltage, after rectifying, becomes a direct voltage to ground value for the cell voltage.
10 Citations
9 Claims
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1. A device for measuring individual cell voltages of cells in a cell stack of an energy accumulator, comprising:
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a series circuit of two diodes connected in parallel with each cell of the cell stack and connected to conduct current in a direction from a minus pole to a plus pole of the cell; a changeover switch having a number of terminals assigned to switch positions corresponding to a number of the cells of the cell stack, and a capacitor connecting each of said terminals to a respective node between said diodes assigned to the cells; a reference circuit having first and second diodes connected in series, said first diode having an anode connected to reference potential and to a cathode of said second diode; a differential amplifier having a non-inverted input connected to an output of said changeover switch, an inverted input connected via a capacitor to a node between said first and second diodes of said reference circuit, and an output; a controlled rectifier having an input connected to said output of said differential amplifier and an output carrying a direct current with a voltage, relative to reference potential, proportional to a cell voltage of the cell respectively selected with said changeover switch; a first controlled alternating current source connected between said non-inverting input of said differential amplifier and reference potential; a second controlled alternating current source connected between said inverting input of said differential amplifier and reference potential; and a clock control having an oscillator outputting an oscillator clock signal and a frequency divider outputting a divider signal, wherein said first and second alternating current sources and said rectifier are controlled by the oscillator clock and said changeover switch is controlled by the divider signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification