Hybrid Ultracapacitor–Battery Energy Storage System Based on Quasi-<italic>Z</italic>-source Topology and Enhanced Frequency Dividing Coordinated Control for EV

TLDR

The buck/boost capability of the quasi‑Z‑source inverter enables integration of the hybrid energy storage system into the traction inverter. An ultracapacitor‑battery hybrid energy storage system (HESS) for an electric vehicle (EV) based on a bidirectional quasi‑Z‑source inverter (qZSI) is proposed in this paper. The steady power distribution principle is explained under various operation modes, and an enhanced frequency‑dividing coordinated control strategy is established to optimize dynamic power regulation and reduce battery current stress on short timescales. The battery converter can be eliminated and the rated voltages for the battery package and ultracapacitors are reduced, and simulation and experimental results in time and frequency domains confirm the superior performance of the proposed HESS.

Abstract

An ultracapacitor-battery hybrid energy storage system (HESS) for an electric vehicle (EV) based on a bidirectional quasi-Z-source inverter (qZSI) is proposed in this paper. The buck/boost characteristic in the qZSI enables the HESS incorporated into the traction inverter system. The battery converter can be eliminated and the rated voltages for the battery package and UCs are reduced. The steady power distribution principle is explained under various operation modes. An enhanced frequency dividing coordinated control strategy is established to optimize the dynamic power regulation and the battery current stress in short timescale. Both the simulation and experimental results in time and frequency domain validate the performance of the proposed HESS.