Research on the Application of an SMES Based on Sliding Mode Control to Enhance the LVRT Capability of a Grid-Connected PV System

Abstract

In this paper, a superconducting magnetic energy storage (SMES) device based on sliding mode control (SMC) is proposed for grid-connected photovoltaic (PV) systems that can effectively improve the ability of a PV system to withstand low-voltage ride-through (LVRT) during faults. SMC theory is selected as a nonlinear control technique, since the SMES has the characteristics of being multivariable and nonlinear and having strong coupling in the running process. Both the voltage outer loop and the current inner loop adopt the SMC strategy based on an exponential reaching law to increase the system startup speed and effectively reduce system jitter. Next, the SMES system based on SMC is used in a 100-kW class PV system. When a symmetrical fault or asymmetrical fault occurs suddenly in the grid-connected PV system, the SMES based on SMC can more significantly improve the power and voltage of the point of common coupling (PCC) and effectively suppress the voltage fluctuations of the DC link than the case of not using auxiliary measures or the use of a PI-SMES.

Keywords:

• superconducting magnetic energy storage
• sliding mode control
• photovoltaic
• low-voltage ride-through

Additional information

Notes on contributors

Yongkai Li

Yongkai Li was born in Heze, in 1991. He received the B.S. degree in electrical engineering from Guangxi University of Science and Technology, Liuzhou, China, in 2015. He is currently pursuing the M.S. degree in electrical engineering with Sichuan University. His research interests include the superconducting magnetic energy storage systems and applied superconductivity.

Yong Lei

Yong Lei received the B.S. and M.S. degrees in electrical engineering from Southwest Jiaotong University, Chengdu, China, in 1993, and the Ph.D. degree in machinery manufacturing and automation from Sichuan University, Chengdu, China, in 2002. Since 2006, he has been an Associate Dean of the School of Electrical Engineering and Information, Sichuan University. His research interests include modern electronic technology and low-temperature superconducting techniques.

Xiaodong Lin

Xiaodong Lin was born in Chengdu, in 1993. He received the B.S. degree in electrical engineering from Sichuan University, Chengdu, China, in 2016. He is currently pursuing the M.S. degree in electrical engineering with Sichuan University. His research interests include the control and optimization of hybrid energy storage systems and applied superconductivity.

Yingwei Zhu

Yingwei Zhu received the B.S. degree in electronic science and technology in 2006 and Ph.D. degree in theory of electrical engineering and new technology from Southwest Jiaotong University in Chengdu, China, in 2011. He is currently an Associate Professor with the College of Electrical Engineering and Information Technology, Sichuan University. He is a Member of the IEEE. His major fields of research interests include power system operation and control, superconducting magnetic energy storage.