Super capacitor SOC calculation method

Abstract

The invention discloses a super capacitor SOC calculation method. The method comprises the steps of 1, establishing a first-order RC model of a super capacitor; step 2, selecting open-circuit voltageOCV of the super capacitor as a characteristic parameter, and establishing a dynamic balance voltage model to obtain DEV = OCV + eta ps; establishing a DEV-SOC relation function model: fDEV (SOC) = x1, i (SOC-SOCmin, i ) + x2, i + x3, iln (SOC-SOCmin, i ) + x4, iln (SOCmax, i-SOC); 3, describing a dynamic equivalent circuit model by using a discretized nonlinear state space equation and a measurement equation; taking the working current Ibat of the super capacitor monomer as an input quantity; taking the terminal voltage Ubat as an observed quantity, taking the nonlinear state-space equation in the step 3 as a state equation of extended Kalman filtering, taking the measurement equation in the step 3 as a measurement equation of extended Kalman filtering, and calculating the SOC of the super capacitor by using an extended Kalman filtering algorithm. According to the method, a good closed-loop SOC optimal estimation effect can be formed, the SOC calculation precision is high, and the stability is good.

Description

technical field [0001] The invention particularly relates to a method for calculating the SOC of a supercapacitor. Background technique [0002] In the field of road transportation, supercapacitors have become the preferred power source for new energy vehicles in rail transportation due to their high energy density, high power density, long cycle life and maintenance-free characteristics. In the actual operation process, it is particularly important to accurately monitor the state of charge (SOC) of the supercapacitor. Supercapacitor SOC cannot be measured directly, and is restricted by factors such as ambient temperature, working conditions, and capacitance characteristics. Accurate SOC estimation can not only provide the current power reference for the vehicle control system, but also avoid range anxiety. At the same time, effective SOC estimation can also avoid the danger of overcharging and overdischarging of energy storage modules. Comprehensive consideration of supe...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a supercapacitor SOC calculation method for the low accuracy and poor stability of SOC estimation in the prior art, which can form a good closed-loop SOC optimal estimation effect, high SOC calculation accuracy and good stability

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