Active charge balancing circuit

A charge balancing circuit, comprising:

• a switch arrangement comprising a first terminal and a second terminal, at least one control input for receiving at least one control signal, and a plurality of cell terminals, each of the cell terminals being configured to be connected to a tap of a charge storage arrangement that comprises a plurality of charge storage cells connected in series;
• a first inductive storage element coupled to the first and second terminals of the switch arrangement, wherein the switch arrangement is configured to selectively connect the first terminal with one of the plurality of cell terminals, and is operable to selectively connect the second terminal with one of the plurality of cell terminals dependent on the at least one control signal, and is configured to enable a current flow from the first and second terminals to the cell terminals either in a first direction or in a second direction opposite the first direction depending on a voltage between the first and second terminals;
• and
• a control circuit configured to provide the at least one control signal dependent on a state of charge of at least one of the charge storage cells, and configured to operate the switch arrangement in a first charge balancing mode providing electrical charge exchange through the first inductive storage element from any first charge storage cell of the plurality of storage cells to any second charge storage cell of the plurality of storage cells, wherein the switch arrangement comprises
• a first group of n+1 switches, with n>1, each switch having a first and a second load terminal, the first load terminal being coupled with one tap,
• a second group of n switches, each of the second switches being connected between the second load terminals of two switches of the first group,
• a first internal node formed by the second load terminal of one of the switches of the first group, and
• a second internal node formed by the second load terminal of another one of the switches of the first group, wherein the first and the second internal nodes are operable to be connected with at least one of the first and second terminals of the switch arrangement.

An energy storage arrangement, comprising:

• a charge storage arrangement comprising a plurality of charge storage cells connected in series, and a plurality of taps;
• a switch arrangement comprising a first terminal and a second terminal, at least one control input for receiving at least one control signal, and a plurality of cell terminals, each cell terminal being connected to a respective one of the taps of the charge storage arrangement;
• a first inductive storage element coupled to the first and second terminals of the switch arrangement, wherein the switch arrangement is configured to selectively connect the first terminal with one of the plurality of cell terminals, and is operable to selectively connect the second terminal with one of the plurality of cell terminals dependent on the at least one control signal, and is configured to enable a current flow in both directions from the first and second terminals to the cell terminals;
• and
• a control circuit configured to provide the at least one control signal dependent on a state of charge of at least one of the charge storage cells, and configured to operate the switch arrangement in a first charge balancing mode providing electrical charge exchange through the first inductive storage element from any first charge storage cell of the plurality of storage cells to any second charge storage cell of the plurality of storage cells, wherein, during the first charge balancing mode, the control circuit is configured to cause the switch arrangement to connect the first inductive storage element between terminals of the first charge storage cell during a first step and then connect the first inductive storage element between terminals of the second charge storage cell during a second step.

An energy storage arrangement, comprising:

• a charge storage arrangement comprising a plurality of charge storage cells connected in series, and a plurality of taps;
• a switch arrangement comprising a first terminal and a second terminal, at least one control input for receiving at least one control signal, and a plurality of cell terminals, each cell terminal being connected to a respective one of the taps of the charge storage arrangement;
• a first inductive storage element coupled to the first and second terminals of the switch arrangement, wherein the switch arrangement is configured to selectively connect the first terminal with one of the plurality of cell terminals, and is operable to selectively connect the second terminal with one of the plurality of cell terminals dependent on the at least one control signal, and is configured to enable a current flow in both directions from the first and second terminals to the cell terminals;
• and
• a control circuit configured to provide the at least one control signal dependent on a state of charge of at least one of the charge storage cells, and configured to operate the switch arrangement in a first charge balancing mode providing electrical charge exchange through the first inductive storage element from any first charge storage cell of the plurality of storage cells to any second charge storage cell of the plurality of storage cells, wherein the switch arrangement comprises
• a first group of n+1 switches, with n>1, each switch having a first and a second load terminal, the first load terminal being coupled with one tap,
• a second group of n switches, each of the second switches being connected between the second load terminals of two switches of the first group,
• a first internal node formed by the second load terminal of one of the switches of the first group, and
• a second internal node formed by the second load terminal of another one of the switches of the first group, wherein the first and the second internal nodes are operable to be connected with at least one of the first and second terminals of the switch arrangement.

A method of operating a charge balancing circuit comprising:

• determining at least one control signal for a switch arrangement based on a state of charge of at least one energy storage element of a plurality of energy storage elements;
• reconfiguring the switch arrangement according to the at least one control signal;
• and
• configuring the switch arrangement to perform a first charge balancing mode providing electrical charge exchange through a first inductive storage element from any first energy storage element of the plurality of energy storage elements to any second energy storage element of the plurality of energy storage elements, wherein configuring the switch arrangement to perform the first charge balancing mode comprises
• causing the switch arrangement to connect the first inductive storage element between terminals of the first energy storage element during a first step, and
• causing the switch arrangement to connect the first inductive storage element between terminals of the second energy storage element during a second step after the first step.