Method and system for estimating charge state of power battery

Abstract

The invention relates to a method and system for estimating charge state of a power battery. The method includes the steps of selecting a Thevenin equivalent circuit model, exerting pulse current excitation to the power battery, collecting output voltage and current data of the power battery, obtaining a pulse current excitation response curve according to the relation of the output voltage and time, dividing the excitation response curve into an A section, a B section and a C section, obtaining a time constant through combination of a zero-input response expression of a resistance-capacitance return circuit and the least square method of the resistance-capacitance return circuit according to the A-section excitation response curve, according to the B-section excitation response curve, combining a zero-state response expression of the resistance-capacitance return circuit, substituting the time constant into the zero-state response expression, utilizing the least square method to obtain polarization resistance and polarization capacitance, obtaining ohm inner resistance by the utilization of the ohm law according to the C-section excitation response curve, and obtaining the estimated value of the charge state of the power battery by the utilization of the kalman filtering algorithm according to the polarization resistance, polarization capacitance and the ohm law. Therefore, the method can be used for recognizing parameters of the Thevenin equivalent circuit model accurately.

Description

technical field [0001] The invention relates to a method and system for estimating the state of charge of a power battery, in particular to a method and system for estimating the state of charge of a power battery for an electric vehicle, and belongs to the technical field of power batteries for electric vehicles. Background technique [0002] With the depletion of the world's oil resources, the power sources of automobiles, locomotives, and large construction machinery vehicles will have to gradually get rid of the shackles of oil resources and use some new energy drives. Power batteries, such as lithium-ion power batteries, because of With the advantages of high voltage, high capacity, good cycle performance, long cycle life, good safety performance and environmental protection, it is favored by people and has become one of the main development directions of power source technology. It has broad application prospects in many aspects such as portable electronic equipment, e...

AI Technical Summary

Problems solved by technology

[0009] The technical problem to be solved by the present invention is that in the prior art, due to the inaccurate estimation of the parameters of the equivalent circuit model of the power battery, the estimation of the state of charge of the power battery is inaccurate, thereby providing a method that can accurately estimate the equivalent circuit model of the power battery Method and system for estimating state of charge of power battery based on parameters

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