Design of a bus-based battery equalization with zero-current switching

A novel any cell to any cell equalization circuit topology with small column, low weight, low cost, and high efficiency is proposed for serial-connected batteries, especially suitable for unmanned aerial vehicles, satellites, and other fields with strict requirements on size, weight, reliability, and safety. To solve the problems of high switching losses in equalization circuits and low reliability of complex control schemes. A half-bridge circuit to convert the DC voltage of the battery into AC voltage is employed, and the energy is exchanged autonomously via the bus. At the same time, LC resonant circuit is used to achieve zero-current switching of the MOSFET, thus reduces greatly the switching losses. The working principle is analyzed by theoretical derivation, and the parameters of the circuit are optimized through circuit simulation. Furthermore, experiments which support six cells equalization are carried out to verify the feasibility and advantage of this topology. This equalization uses a bus-type architecture to improve equalization efficiency and topological flexibility making it even more valuable in the industrial and aerospace fields.