Stupidist Plan yet to save gas -- muzzling the alternator

Inductive Balancing: Through a common inductor, the energy from a higher charged cell is transmitted to a lower charged cell in inductive balancing. The energy flow between the cells is handled by controlled switches, and therefore, efficiently balance the charge.

I don't understand the common inductor term, surely each cell would need it's own inductor coil.

T1 Terry

 

Looking at the diagram in #60, the inductor L1 is common to cell 1 and cell 2. Not at the very same time: you wouldn't want S1 and S2 both conducting. But if, say, you wanted to move charge from cell 1 to cell 2, you could have S1 conduct briefly, enough to get a good current flowing in L1—the energy it took to do that is now stored in the magnetic field around L1—and then let S2 conduct and S1 not. L1 will make sure the same current keeps flowing in the same direction—which you see is the charging direction for cell 2—until the energy in that magnetic field has been spent. The voltage across L1 will rise to whatever is needed to dump that current into cell 2, so it ends up being possible to move energy quickly between the cells even if their open-circuit voltages are not far different.

If the various inductors in that diagram magnetically interact—say, maybe they're wound on a common core (I'm not sure if that's what the curved arrows are getting at)—then you could even switch off S1 and switch on one of the switches further down, and let the magnetic field be dumped through a different coil into a different cell.

 

Common inductors are closely related to transformers. In the smaller image, titled "Fig 1. Flyback type ...", it looks to me exactly like a transformer, used in almost the same topology as a flyback dc-dc converter.

That is how I'm viewing it. The dual dotted lines next to L1, together with the curved arrows to all the Ls, point to that. The M12, M13, and M14 indicators on those arrows further support that view, with M signifying "mutual inductance".

In a common transformer, the coils are very tightly coupled. But these Ls and Ms suggest that these coils are more loosely coupled than in common transformers, and more energy gets stored in the core's (or cores's) magnetic field(s), e.g. by including an air gap in the magnetic path.