Sequencing switched single capacitor for automatic equalization of batteries connected in series

A battery charging system, comprising:

• a charger having an output to be coupled to at least two batteries coupled in series;
• and
• a first equalizer coupled to the charger to equalize an output of the at least two batteries, the first equalizer including
• a single capacitor,
• at least two switching circuits coupled to the single capacitor, each of the at least two switching circuits to be coupled to each of at least two batteries coupled in series,
• at least two driver circuits, each corresponding to one of the at least two switching circuits, and
• a controller coupled to the at least two driver circuits, wherein the controller is programmed to control the at least two driver circuits in order to drive the at least two switching circuits to sequentially couple the single capacitor to one of the at least two batteries coupled in series during charging and/or discharging of the at least two batteries, and wherein only one of the at least two switching circuits is turned on at a given time such that only one of the at least two batteries is coupled to the single capacitor at the given time.

A battery discharging system, comprising:

• an inverter having an input to be coupled to at least two batteries coupled in series;
• and
• a first equalizer coupled to the charger to equalize an output of the at least two batteries, the first equalizer including
• a single capacitor,
• at least two switching circuits coupled to the single capacitor, each of the at least two switching circuits to be coupled to each of at least two batteries coupled in series,
• at least two driver circuits, each corresponding to one of the at least two switching circuits, and
• a controller coupled to the at least two driver circuits, wherein the controller is programmed to control the at least two driver circuits in order to drive the at least two switching circuits to sequentially couple the single capacitor to one of the at least two batteries coupled in series during charging and/or discharging of the at least two batteries, and wherein only one of the at least two switching circuits is turned on at a given time such that only one of the at least two batteries is coupled to the single capacitor at the given time.