Fractional power battery SOC estimation method considering temperature and hysteresis effects

Abstract

The invention provides a fractional-order power battery SOC estimation method considering temperature and hysteresis effects, which can accurately estimate the battery SOC, has strong robustness, and can quickly converge in the case of initial errors in the system. The method is that the open circuit voltage of the battery is U OCV The voltage source, internal resistance R 0 , The polarization rings are connected in series to form a first-order fractional equivalent circuit model of the power battery. The capacitor in the polarization ring is a fractional-order CPE element, and the resistance is the polarization internal resistance R 1 ;CPE component capacitance is C 1 , the order is α 1 , U OCV Can be measured by experiment; U 0 Is the internal resistance terminal voltage; I is the total current; the current I on the CPE element 1 =C 1 D. α 1 u 1 ; Polarization ring terminal voltage U 1 =(I‑C 1 D. α1 u 1 )R 1 ;Battery terminal voltage U t =U OCV -U 0 -U 1 ; SOC (0) is the initial SOC value; η is the charge and discharge capacity conversion coefficient; Q N is the rated capacity of the battery.

Description

technical field [0001] This patent relates to a power battery SOC estimation method. Background technique [0002] For power battery SOC estimation, currently commonly used integer-order equivalent circuit models include Rint model, Thevein model and PNGV model. [0003] The integer-order equivalent circuit model is difficult to accurately simulate the resistance-capacitance characteristics of the battery charge and discharge and the static state of the terminal voltage, especially the accuracy of the output terminal voltage of the integer-order equivalent circuit model cannot be guaranteed in a wide temperature range; the estimated The SOC of the battery is accurate and low, and it is difficult to meet the needs of use. Contents of the invention [0004] The purpose of the present invention is to provide a fractional-order power battery SOC estimation method considering temperature and hysteresis effects, which can accurately estimate battery SOC, and has strong robustne...

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Problems solved by technology

[0003] The integer-order equivalent circuit model is difficult to accurately simulate the resistance-capacitance characteristics of the battery charge and discharge and the static state of the terminal voltage, especially the accuracy of the output terminal voltage of the integer-order equivalent circuit model cannot be guaranteed in a wide temperature range; the estimated The battery SOC is accurate and low, and it is difficult to meet the needs of use

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