Dual and joint estimation

Example

Use in Lemonergy

Distinguish internal states from noisy measurement estimates.

This is a reference concept. No executable Lemonergy block has been verified for this term.

Connected concepts

Related concepts from the knowledge graph. Connections show context, not cause and effect. Hover or focus a linked term for its definition.

Kalman filter

A recursive estimator that blends a model prediction with noisy measurements according to how much each is trusted. In a BMS an extended Kalman filter combines coulomb counting with a voltage model to track SOC and sometimes resistance.

Recursive least squares

An online fitting method that updates model parameters with each new sample instead of refitting all past data. A forgetting factor set just below 1, such as 0.99, discounts old samples so the estimate follows a cell’s resistance and time constants as temperature, SOC and aging change them; the BMS then hands the parameters to its state estimator.

State observer

An algorithm that reconstructs internal states such as SOC by running a model alongside the cell and correcting it with the measured voltage error. A Luenberger observer uses a fixed gain, a sliding-mode observer a switching term robust to model error, an H-infinity filter bounds the worst-case error, and an adaptive observer also updates the model parameters.

State of charge

How full a cell is, as a fraction of its available capacity. State of charge, like temperature, affects how fast a stored cell ages.

State of health

A summary of how far a cell has aged, often expressed through remaining capacity or increased resistance compared with when it was new. By convention a cell has reached end of life at 80 % of its rated capacity.

References & further reading

Further reading on this topic

These sources provide broader context; they are not presented as citations for every statement in this entry.

1. Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs: Part 3. State and parameter estimation

   Gregory L. Plett · Journal of Power Sources · 2004

   Topic background · Model-based battery state-of-charge and parameter estimation with extended Kalman filtering, including uncertainty and model dependence.

2. Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs: Part 2. Modeling and identification

   Gregory L. Plett · Journal of Power Sources · 2004

   Topic background · Battery charge balance, open-circuit voltage, ohmic loss, polarization dynamics and model identification; parameters require cell-specific data.