Battery SOC (state of charge) estimation method by utilizing vehicle-mounted charging machine identification battery parameter

A technology of battery state of charge and on-board charger, which is applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., and can solve problems such as difficult implementation, nonlinear attenuation of battery capacity, and difficult operation

CN105068008AInactive Publication Date: 2015-11-18NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2015-11-18
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a battery SOC (state of charge) estimation method by utilizing a vehicle-mounted charging machine identification battery parameter. A battery model parameter is identifies through a pulse experiment which is performed by an electric automobile vehicle-mounted bidirectional charging machine on a battery, the battery capacity is recalibrated by utilizing the bidirectional charging machine to perform deep charging and discharging on the battery, extended Kalman filtering is performed then according to an updated battery parameter to estimate a state of charge (SOC) of the battery, and then an influence of a battery parameter changed, which is caused by aging, on battery SOC estimation precision is overcome. A changing battery parameter can be effectively tracked, and a selection of initial data is not depended on; the battery parameter is identified through charging and discharging which are performed by the vehicle-mounted bidirectional charging machine on the battery, and an advantage that an electric automobile is provided with a power electronic conversion device is fully used; in the whole parameter identification process, an electric energy released by the battery is grid-connected in a feedback manner, and energy loss is small; and the method is simple and practicable, and tedious operation that a traditional off-line identification battery parameter method needs to detach a battery box is prevented.
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Description

technical field

[0001] The invention relates to the technical field of electric vehicle power battery management systems, in particular to a method for estimating the state of charge of a battery using a vehicle-mounted bidirectional charger to identify battery parameters. Background technique

[0002] The power battery is a key component that affects the service life, safety and economy of electric vehicles. Efficient and reliable management through the battery management system (Battery Management System, BMS) is an important guarantee for the safe driving of vehicles. The accurate estimation of the battery state of charge (State of Charge, SOC) is the core technology of the battery management system, which has an important impact on the safe and efficient use of power batteries.

[0003] At present, the SOC estimation methods mainly include the classic open circuit voltage method and the ampere-hour integration method, intelligent algorithm and extended Kalman filter met...

Examples

Embodiment Construction

[0088] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings.

[0089] The specific process of the joint estimation algorithm of the present invention using the vehicle-mounted bidirectional charger to identify the battery parameters and estimating the battery SOC based on the extended Kalman filter algorithm is as follows:

[0090]Step 1: Use the vehicle-mounted bidirectional charger to conduct a pulse test on the battery, and identify the battery model parameters according to the electrochemical characteristics of the battery.

[0091] 1) Establish the equivalent circuit model of the power battery

[0092] This algorithm adopts the improved PNGV equivalent circuit model. like figure 1 As shown, the circuit consists of two parallel equivalent polarization resistors and equivalent polarization capacitors connected ...