Battery Equalization Technique using a Multiport Cúk Converter

This paper investigates a battery equalization technique that employs a multiport DC-DC converter based on the Cúk topology. This approach is particularly relevant for energy storage systems coupled with low-voltage renewable sources, such as solar panels and fuel cells. A prominent challenge in these systems is imbalance between battery cells, a condition that degrades the safety and lifespan of the array. To address this issue, a Cúk equalizer topology was adopted. The methodology involved computer simulations in PSIM software to analyze the circuit behavior and validate the theoretical model. In tests with four cells initialized with different voltages, it was demonstrated that a fixed 50% duty cycle promotes natural and autonomous equalization, without the need for complex individual monitoring. The system's effectiveness was confirmed by the convergence of cell voltages and by inductor currents that reached a zero average value in steady state. The proposed solution is concluded to be a robust alternative for increasing the reliability and extending the lifespan of energy storage systems.