Power battery SOC (state of charge) estimation system and method based on ARMAX (autoregressive-moving-average exogenous) model

Abstract

The invention discloses a power battery SOC (state of charge) estimation system and method based on ARMAX (autoregressive-moving-average exogenous) model. The method comprises the steps of representing polarization reaction of a battery base on RC (resistor-capacitor) structure, discretizing a Thevenin battery model, and introducing the ARMAX model; identifying parameters of the Thevenin battery model; calculating the parameters of the Thevenin battery model based on a least squares estimation method; establishing a following linear relationship between open-circuit voltage and SOC of the battery, and acquiring an estimated value of the SOC. The ARMAX model is introduced based on the RC equivalent circuit model; a recursive least squares method with forgetting factors is used to identify parameters of the model; the estimated value of SOC is found according to an OCU (Uoc)-SOC relation table, and accordingly, the problems of difficulty in establishing a battery mathematic model and precisely predicting SOC are solved; influences of model errors upon parameters are fully considered, and SOC estimation accuracy is improved.

Description

technical field [0001] The invention mainly relates to a system suitable for estimating the state of charge of a power lithium battery of an electric vehicle, and mainly belongs to the technical field of intelligent control. Background technique [0002] With the increasingly prominent problems of energy crisis and environmental pollution, lithium batteries have gradually replaced traditional batteries due to their advantages such as high energy density, high working voltage, high specific energy, low pollution, low self-discharge rate and no memory effect. In automotive, aerospace, shipbuilding and other fields. In order to prevent the occurrence of battery overcharge and overdischarge, prolong the service life of the battery, and improve the performance and safety of the vehicle, the battery management system is required to be able to accurately estimate the battery state of charge (State of Charge, SOC) in real time, so accurate Battery models and SOC estimation methods ...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the following deficiencies in the prior art: 1. Difficulty in establishing a mathematical model of the storage battery; 2. Inaccurate estimation of the state of charge of the power battery of an electric vehicle, etc., the present invention discloses a state of charge estimation of the power battery based on the ARMAX model Method, in the estimation of the SOC of the power battery state of charge, the influence of the model error on each parameter is fully considered, and the ARMAX model is introduced on the basis of the establishment of the Thevenin battery model, and the model parameters are identified online by the least square method including the forgetting factor. Improving the Estimation Accuracy of State of Charge SOC

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