Accurate estimation of battery state of charge (SOC) is of great significance for extending battery life, improving battery utilization, and ensuring battery safety. Aiming to improve the accuracy of SOC estimation, in this paper, a temperature-dependent second-order RC equivalent circuit model is established for lithium-ion batteries, based on the battery electrical characteristics at different ambient temperatures. Then, a dual Kalman filter algorithm is proposed to estimate the battery SOC, using the proposed equivalent circuit model. The SOC estimation results are compared with the SOC value obtained from experiments, and the estimation errors under different temperature conditions are found to be within ±0.4%. These results prove that the proposed SOC estimation algorithm, based on a temperature-dependent second-order RC equivalent circuit model, provides accurate SOC estimation performance with high temperature adaptability and robustness.

In this paper, a new backstepping-based adaptive stabilization of a fractional-order system with unknown parameters is investigated. We assume that the controlled system is perturbed by external disturbance, the bound of external disturbance to be unknown in advance. Moreover, the effects of sector and dead-zone nonlinear inputs both are taken into account. A fractional-order auxiliary system is established to generate the necessary signals for compensation the nonlinear inputs. Meantime, in order to deal with these unknown parameters, some fractional-order adaption laws are given. The frequency-distributed model is used so that the indirect Lyapunov theory is available in designing controllers. Finally, simulation results are presented to verify the effectiveness and robustness of the proposed control strategy.

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Based on the existing data accumulation and process of stock management of a Steel pipe enterprise, a general analysis for its current inventory structure is done, then a classification research for hardware inventory is done with the theory of cluster-algorithm. Finally, a visualizing stock query function which is the main contribution of this paper is developed based on the research above.

Combined with the local climate characteristics, peasants existing living conditions and economic development level in the mountains of eastern Jilin, the paper analyzed with energy conservation transformation method of the existing grange and expounded the operative technology of energy conservation transformation of auld grange from the point of envelop enclosure, heating system and renewable energy resource, which is now suitable for the new grange in the mountains of eastern Jilin.