Study on Switched Equalizer and Control Method for Lithium-ion Battery Pack

In order to overcome the imbalance of cells in series lithium-ion battery pack, this paper proposes a new switched equalization and its FSM control method. N-MOSEETs and P-MOSFETs are used to build the switch array of the equalization. The Buck-Boost circuit including a super capacitor is used to achieve the energy balance in cells. The equalization strategy based on FSM describes the principle of switched equalization. And paper provides switching conditions in states of ESM. The major losses are also analyzed. Filially, with SIMULINK toolbox, a simulation model including 6 series batteries is built. And the simulation results verify the validity of the switched equalization and its FSM control strategy.