Variable DC-Link Voltage Regulation of Single-Phase MMC Battery Energy-Storage System for Reducing Additional Charge Throughput

作     者：Ma, Zhan Gao, Feng Zhang, Chenghui Li, Wei Niu, Decun 

作者机构：Shandong Univ Minist Educ Key Lab Power Syst Intelligent Dispatch & Control Jinan 250061 Peoples R China Shandong Univ Sch Control Sci & Engn Jinan 250061 Peoples R China 

出 版 物：《IEEE TRANSACTIONS ON POWER ELECTRONICS》 (动力电子学汇刊)

年 卷 期：2021年第36卷第12期

页      面：14267-14281页

核心收录：

学科分类：0808[工学-电气工程] 08[工学] 

基　　金：Foundation for Innovative Research Groups of National Natural Science Foundation of China Key Project of National Natural Science Foundation of China 

主　　题：Batteries Throughput Aging Frequency modulation Capacitors Voltage control Partial discharges Battery energy-storage system (BESS) charge throughput dc-link voltage modular multilevel converter (MMC) 

摘      要：Battery energy-storage system (BESS) based on the modular multilevel converter (MMC) can flexibly manage the battery packs integrated into submodules, where the battery pack can directly or through a small capacitor connect to the rear-end half-bridge circuit for reducing cost and volume caused by an additional dc-dc converter. But the alternating current ripples will cause substantial additional charge throughput for battery packs and, consequently, reduce the battery lifetime in theory. Therefore, this article proposes a variable dc-link voltage regulation method for a single-phase MMC-BESS. In specific, the phase disposition (PD) modulation scheme is improved to properly bypass the gating signals with unnecessary conduction during operation and the modified gating signals will be rearranged for balancing the states-of-charge and states-of-health. Doing so, the additional charge throughput could be significantly reduced compared with the traditional phase-shift modulation and PD modulation. Even comparing with the ideal dc current charging/discharging, the proposed method will only increase slight additional charge throughput and nearly negligible capacity loss. The experimental results of a 6.6 kW/6.6 kWh single-phase MMC-BESS prototype verified the performance of the proposed method.