A fast and accurate estimation of the state-of-charge (SOC) of lithium batteries is critical for the battery management system. Aimed at the problem that the Kalman filter algorithm lacks reasonable constraints on the resistance-capacitance (RC) parameters when estimating the SOC of lithium batteries, an optimization method of RC parameters filtering is proposed, and it is combined with unscented Kalman filter (UKF) to achieve the fast and accurate convergence of lithium battery SOC estimation. First, an equivalent circuit model of lithium battery is established by combing the polynomial equation. Then, forgetting factor recursive least squares is used to obtain the time-varying and time-invariant model RC parameters. The expression of RC parameters filtering relationship is established by setting the Kalman gain threshold, and an RC optimization UKF algorithm is proposed for lithium battery SOC estimation. Finally, hybrid pulse-power characteristic experiment, intermittent constant-current discharge experiment and dynamic stress test experiment were designed to verify the convergence and robustness of the proposed algorithm. The maximum estimation error of SOC was less than 1.0%, and the reference range of gain threshold was also given.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |