Shared-Receiver Battery Equalizer Based on Inductive Power Transfer and Bidirectional DC-DC Converter

State-of-charge (SOC) balancing is essential for safe, reliable, and long-lived operation of battery energy storage systems. Conventional wired equalizers are hampered by permanent physical connections, limited flexibility, and heightened safety hazards. To address these limitations, an inductive power transfer (IPT)-based equalizer is introduced in this article, in which the single-inductor DC-DC converter's inductor is replaced by a transmitter coil to wirelessly transfer ripple energy for SOC balancing during both charging and discharging. Additionally, a single receiver coil and switch matrix are employed, shared sequentially among all cells with adaptive connection intervals regulated by a presented efficient adaptive equalization algorithm. The equalization performance is analyzed and validated using a down-scaled proof-of-concept prototype. Furthermore, the trade-off between balancing capability and efficiency is discussed, along with the potential for cell-level fault bypass at a slight improvement in topology.