Improved Control Strategy for Microgrid Ultracapacitor Energy Storage Systems

Energies

Xiaobo Dou¹  Xiangjun Quan¹  Zaijun Wu¹  Minqiang Hu¹  Jianlong Sun²  Kang Yang²  Minhui Xu² 

[1] Department of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, China;

关键词: microgrid;    ultracapacitors;    converter modeling;    DC link voltage control;    resonant regulator;   

DOI  :  10.3390/en7128095

来源: mdpi

【 摘 要 】

Ultracapacitors (UCs), with their features of high power density and high current charge-discharge, have become the best choice for dynamic power compensation to improve the stability of microgrids and are increasingly being applied in microgrids. This paper presents the control of an energy storage system (ESS) based on ultracapacitors in the context of grid-connected microgrids. The ESS is composed of DC/AC and DC/DC converters tied by a dc link. An improved dynamic model for the ESS is proposed. Based on the proposed model a Proportional-Integral-Resonant (PIR) DC link voltage controller is proposed to maintain the DC link voltage through the charging-discharging control of ultracapacitors, capable of working properly under all operating conditions. An extra double frequency component is injected into the UC current by a R controller to dynamically compensate for DC instantaneous power and double frequency AC instantaneous power due to unbalanced grid conditions and disturbances. This feature maintains the DC link voltage constant under unbalanced conditions and increases the degrees of freedom of the DC/AC converter and thus facilitates the application of UCs in microgrids. Simulation and experimental results verify the effectiveness of the proposed control strategy.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.