Double‐layer equalizer with multi‐winding transformer and resonance switched capacitor module for series‐connected batteries

Abstract

Abstract A double‐layer architecture for series‐connected modules is proposed to decrease the long battery string's equalizer circuit complexity, which is based on multi‐winding transformers and resonance switched capacitors. Cell voltages in a module are equalized by the multi‐winding transformer equalizer, while module voltages are unified by resonance switched capacitor converters. Both multi‐winding transformer and resonance switched capacitor share a half‐bridge, and all of the switches are derived by one pair of pulse‐width modulation (PWM). The theoretical and dynamic balance experiments are conducted to verify the equalizer feasibility. The results show that both layers’ system can realize the automatic balance without cell‐monitoring circuits. The efficiency of the proposed equalizer reaches 93.2%.