Work

Active Suppression Method of Secondary Ripple Current for Delta-Connected Medium-Voltage Transformer-less Energy Storage System

Year: 2026

Type: conference-paper

Abstract: In medium-voltage transformer-less battery energy storage systems (MVT-BESSs), the single-phase AC/DC converter in each submodule induces secondary ripple current on the battery side, which shortens battery lifetime, degrades state-estimation accuracy, and increases system losses. To mitigate this issue, this paper proposes an active suppression strategy based on third-harmonic current injection. The mechanism of secondary ripple generation is first clarified by analyzing the AC/DC coupling behavior of the submodule. Building on the concept of suppressing DC-side ripple through AC-side third-harmonic injection, a dynamic method for computing the optimal third-harmonic current is formulated for both unity and non-unity power factor conditions. A 380-V/100-kW experimental prototype is developed, and the results show that the proposed method reduces the battery-side secondary ripple to 52.8% of its original level under both operating conditions, confirming its effectiveness.

Source: Journal of Physics Conference Series

DOI: 10.1088/1742-6596/3229/1/012085

Authors: Yunrao Guo, Xiaoping Zhou, Qingrong Lai, Yizhen Hu, Qianming Xu

Institution: Hunan University

Language: English

Topic: Multilevel Inverters and Converters

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Affordable and clean energy, Industry, innovation and infrastructure

Open Access status: diamond

Funders: National Natural Science Foundation of China, National Key Research and Development Program of China