Active cell pack equalization control system based on cell energy state estimation

Abstract

The invention discloses an active cell pack equalization control system based on cell energy state estimation. According to the system, an equalization circuit topology based on multiple transformers can employ multiple control variables, direct parallel operation of an equalization charging and discharging process can be carried out, and equalization efficiency is improved. SOE energy can more accurately reflect an actual cell state, a cell SOE is employed as a control variable to solve disadvantages generated as a voltage or SOC is simply taken as an equalization control variable in an equalization control strategy in the prior art, equalization control precision is improved, cell energy after equalization can be precisely kept to be consistent, and an energy utilization rate of a cell pack can be maximized. A dual invariant embedding method is utilized to realize online identification of cell parameters and estimate a cell state in real time, SOE estimation precision can be effectively improved, equalization control precision is further guaranteed, and the equalization effect is optimized.

Description

technical field [0001] The invention relates to the technical field of active balancing of battery packs, in particular to an active balancing control system of battery packs based on battery energy state estimation. Background technique [0002] The battery energy storage system is the core of new energy systems such as smart grids, distributed energy sources, and electric vehicles. In order to achieve a certain voltage, power and energy level, the battery energy storage system needs to connect a large number of battery cells in series and parallel to form a group. Due to the manufacturing process of the battery and the influence of the working environment, there are certain differences between the single cells in the battery pack. This difference prevents the energy of the battery pack from being fully utilized, and with the continuous accumulation of differences between batteries, the capacity of individual cells will rapidly decay, thereby limiting the output power of t...

AI Technical Summary

Problems solved by technology

Using voltage as the control variable is easy to implement in engineering, but it is easily affected by internal resistance, polarization voltage, ambient temperature, etc., resulting in inaccurate balance; using SOC as the control variable can make each cell be at the same discharge depth, and control the battery pack. It is full and empty at the same time, but it ignores the voltage change of the battery during use, which cannot accurately reflect the real state of the battery and judge the charge and discharge capacity of the battery.

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