Unscented particle filtering method for SOC estimation of lithium ion battery pack of large unmanned aerial vehicle

Abstract

The invention discloses an unscented particle filtering method for SOC estimation of a lithium ion battery pack of a large unmanned aerial vehicle. The unscented particle filtering method comprises the following steps: S01, constructing a battery model according to a relationship between influence factors of the SOC of the lithium ion battery pack and nonlinear working characteristics of the lithium ion battery pack due to internal parameter coupling; s02, collecting and integrating various data of the battery pack; s03, updating a particle set in particle filtering algorithm sampling according to the integrated data by using a mean value and a variance obtained by an unscented Kalman filtering algorithm; and S04, predicting the working characteristics of the lithium ion battery pack according to the calculation in the step S03. The invention has the advantages that unscented Kalman filtering is adopted, a good filtering effect is achieved, errors caused by a linearization process are ingeniously avoided by adopting probability density fitting of system state variables, estimation precision is further improved, and system robustness is better.

Description

technical field [0001] The invention relates to the field of battery detection, in particular to an unscented particle filter method for SOC estimation of a lithium-ion battery pack of a large unmanned aerial vehicle. Background technique [0002] In the design and implementation of the battery management system (Battery Management System, BMS) of large-scale unmanned aerial vehicle lithium-ion battery packs, SOC estimation is one of the key points and difficulties, because the charging and discharging of the battery has a serious nonlinear relationship, it cannot be simply The SOC of the lithium-ion battery can be reflected through a single variable such as voltage; however, only by accurately detecting the SOC of the lithium-ion battery pack in real time and giving feedback to the flight controller of the drone or the ground operator can the safe planning of operation time and Range, SOC estimation has become one of the key issues in BMS design. [0003] In order to meet ...

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Problems solved by technology

[0002] In the design and implementation of the battery management system (Battery Management System, BMS) of large-scale unmanned aerial vehicle lithium-ion battery packs, SOC estimation is one of the key points and difficulties, because the charging and discharging of the battery has a serious nonlinear relationship, it cannot be simply The SOC of the lithium-ion battery can be reflected through a single variable such as voltage; however, only by accurately detecting the SOC of the lithium-ion battery pack in real time and giving feedback to the flight controller of the drone or the ground operator can the safe planning of operation time and Voyage, SOC estimation has become one of the key issues in BMS design

[0003] In order to meet the needs of large-scale UAVs with large-capacity batteries, lithium-ion batteries are often combined in series and parallel. There may be inconsistency between batteries, which is unavoidable, which will reduce its use efficiency and shorten the service life of the battery; the inconsistency will intensify as the number of times of use increases, and relevant measures can only be taken to suppress its aggravation. Fundamentally remove this problem; because the battery management system can detect battery physical parameters, estimate state of charge (State of Charge, SOC) / state of health (State of Health, SOH) / power state (State of Power, SOP), Balance management, etc., was born in the field of drone development. Therefore, the battery management system can monitor the working status of lithium-ion battery packs, balance and control inconsistencies, and prevent ohmic polarization and concentration differences during the charging process. Polarization is a polarization phenomenon composed of polarization and electrochemical polarization; among them, the SOC value of a lithium-ion battery pack can represent the remaining power of the battery, and accurate estimation can help the battery management system to more accurately judge the timing of equilibrium, and predict Provide a reference basis for judging the remaining power; select the ternary lithium-ion battery pack as the research object of this paper, perform SOC estimation, and obtain the SOC value

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