A Modular Approach to Electrical Storage & Conversion Angel V. - PowerPoint PPT Presentation

A Modular Approach to Electrical Storage & Conversion Angel V. Peterchev, Ph.D. Department of Psychiatry & Behavioral Sciences Department of Biomedical Engineering Department of Electrical & Computer Engineering Duke University

Battery Electrical Energy Storage: State-of-Art Battery Cell Controller Ctrl Grid Ctrl Micro-Grid Home DC Battery Man- AC … … age- ment Inverter Storage Battery Array • Expensive transformers & filters • Expensive high-voltage components • Weakest link determines performance • Suboptimial efficiency Angel V. Peterchev, Duke University

Novel Modular “AC Battery” Novel Low-Voltage Module Battery Cell Low- Battery Voltage Cell Switch Grid Micro-Grid Ctrl Home … • No expensive transformers & filters • Cheap, low-voltage components Controller • Optimial efficiency • Easy battery cell balancing • Fault tolerant/swappable modules • Easy system scalability Angel V. Peterchev, Duke University

Modular AC Battery Operation Dynamic transition Battery Cap Cell Voltage Time Angel V. Peterchev, Duke University

AC Battery Prototype  8 module system  Storage per module ˃ lead-acid battery (12 V, 7 Ah) ˃ aluminum electrolytic capacitor (1 mF) ˃ low-impedance ceramic capacitor (200 µF)  Switch update rate = 30 kHz; average module switching frequency = 3.75 kHz Angel V. Peterchev, Duke University [Goetz et al, Proc Appl Power Electron Conf & Expo 2016]

[Goetz et al, Proc Appl Power Electron Conf & Expo 2016] Output Quality & Balancing  High-quality output Voltage (V), Current (A)  Total harmonic distortion < 5%  – 86 dB spurious-free dynamic range Time (ms)  Excellent long-term balancing RMS load current (A) Battery voltages (V)  Tested 5 hour operation with variable load  Module voltage std. dev. < 77 mV (median = 22 mV) Time (min) Angel V. Peterchev, Duke University

Acknowledgements Duke NC State University Stefan Goetz Srdjan Lukic Zhongxi Li Xinyu Liang Chuang Wang Chengduo Zhang Chris Dougher Jeff Glass Jie Liu Charles Parker Seed funding by Duke University Energy Initiative