Battery state of charge (SOC) estimation with the fuzzy logic approach.

摘要

In today's automobile world, electric and hybrid electric vehicles (EVs and HEVs) are revolutionary inventions; their heart is the battery, which is a constant source for the vehicle to run. In short, if we know the amount of charge left in the battery then we can easily predict the performance of EVs and HEVs and for that there are many techniques available in the current world, which are included in the upcoming chapters. While dealing with the estimation of the state of charge of a battery, the conventional methods like direct method or coulomb counting or even with the specific gravity method the factor of inaccuracy will always remain in existence and it will cause error sum results. Above all, the battery aging is also an important factor.;The emphasis of this work lies in the estimation of SOC with the fuzzy logic approach. Fuzzy logic approach is accurate, robust, and feasible to implement in most cases. Here, we generate a pulse with the use of 555timer and LM317 voltage regulator circuit and will give the pulse to the battery which is constantly discharging. The voltage response is being measured by an oscilloscope. Through the process three input variables, mean voltage, the difference of maximum voltage and mean voltage, and the difference of mean voltage and minimum voltage, we will have the SOC. That can be done by giving the three inputs to the Handy Board, which is a useful device for any embedded control system application. The Handy Board works on the Interactive C, which is the application based C language. Next we will download the Interactive C program in the Handy Board, which has the fuzzy based logic and processes the given data and generates the output in terms of the state of charge of the battery. This simulation in the proposed work is done with the VC++ program and Interactive C program. The results are useful in analyzing the accuracy of such models compared to other techniques.