Abstract:The traditional active equalization topologies often require a large number of switches, inductors, transformers or bidirectional switches to transfer energy, which undoubtedly increase the system size and cost significantly for electric vehicles. In view of this, this article proposes a voltage equalization topology based on voltage multiplier for a hybrid energy storage system consisted of lithium-ion batteries and supercapacitors. The battery equalization topology and the supercapacitor charger are integrated into a circuit containing only two switches, three inductors, and several capacitors and diodes by sharing a half-bridge inverter circuit, which can significantly reduce the size and cost of the system. The battery equalization topology has a self-modularization feature, leading to faster voltage equalization, while the supercapacitor charger has a constant current charging capability. In this article, the operation modes and waveforms are described in detail and the equalization characteristics of the proposed topology is verified by using PSIM simulation. Finally, a hybrid array consisted of 4 batteries and 4 supercapacitors was designed for experimental verification. The experimental results show that the voltage gap is reduced to less than 10 mV after equalization, proving the effectiveness of the proposed method.