firstly a novel dynamic series equalization structure of the battery pack is proposed
which integrates a converter and equalizer. Secondly
based on this topology
an improved low switching frequency nearest level control strategy is proposed. By sorting the state of charge of the sub-module battery units
the multi-level step wave is output. The voltage harmonic distortion rate of the final output waveform is 13.02% lower than that of the traditional method
and the state switching step is added to avoid the frequent switching of the sub-modules caused by the slow change of the state of charge. At the same time
the equalization control method of mixed variables is introduced
and the equalization parameters such as inductance and duty cycle are analyzed and designed to ensure that the battery unit meets the voltage level requirements before it is put into use
and the difference in state of charge between the battery units is reduced. Through structural integration and control strategy optimization
the efficiency and performance of the battery energy storage system are improved. Finally
the effectiveness of the proposed topology and control strategy is verified in MATLAB.
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Wu T Z, Wang Y, Zhang J.Research on multilayer fast equalization strategy of Li-ion battery based on adaptive neural fuzzy inference system[J]. Journal of Energy Storage, 2023, 67: 107574.