Novel converter topology and algorithm for simultaneous charging and individual cell balancing of multiple Li-ion batteries

This paper presents a novel Lithium-ion battery charger based on pulse charging technique. A central power supply acting as a controlled current source is sequentially connected in parallel with different batteries through an array of switches. A forward converter realizes the controlled current source. Magnetics are restricted to the inductor and transformer of the forward converter. Each battery contains plurality of Li-ion cells, the number being determined by the voltage level of the application. The switch array at the output provides charging and discharging pulses to individual cells. Charging algorithm expected to increase the lifetime and performance of Li-ion cells along with charge balancing for applications involving series string of Li-ion cells is presented. Simulation results to demonstrate the proposed methodology are presented.