Mitigation of Negative Impedance Instabilities in DC Distribution Systems A Sliding Mode Control Approach

This book focuses on the mitigation of the destabilizing effects introduced by constant power loads (CPLs) in various non-isolated DC/DC converters and island DC microgrids using a robust non-linear sliding mode control (SMC) approach. This book validates theoretical concepts using real-time simulation studies and hardware implementations. Novel sliding mode controllers are proposed to mitigate negative impedance instabilities in DC/DC boost, buck, buck-boost, bidirectional buck-boost converters, and islanded DC microgrids. In each case, the condition for the large-signal stability of the converter feeding a CPL is established. An SMC-based nonlinear control scheme for an islanded DC microgrid feeding CPL dominated load is proposed so as to mitigate the destabilizing effect of CPL and to ensure system stability under various operating conditions. A limit on CPL power is also established to ensure system stability. For all proposed solutions, simulation studies and hardware implementations are provided to validate the effectiveness of the proposed sliding mode controllers.

Introduction.- Mitigation of Destabilizing Effects of CPL in a Boost Converter Feeding Total CPL.- Mitigation of Destabilizing Effects of CPL in a Buck Converter Feeding a Mixed Load.- Mitigation of Destabilizing Effects of CPL in a Bidirectional Buck-Boost Converter.- Mitigation of Destabilizing Effects of CPLs in an Islanded DC Microgrid.

Dr. Deepak Fulwani is working as an assistant professor in Department of Electrical Engineering at Indian Institute of Technology Jodhpur (IITJ). He also worked at IIT Guwahati and IIT Kharagpur. He obtained his Ph.D. from IIT Bombay in 2009; he was also awarded for excellence in Ph.D. thesis work in 48th convocation. His research fields include control of networked systems and DC micro-grid.

Dr. Suresh Singh is currently a Senior Project Engineer in the Department of Electrical Engineering at Indian Institute of Technology, Jodhpur, India. He has recently completed his PhD from IIT Jodhpur in 2016. Dr. Singh has over 10 years of teaching and research experience. His research interests include smart grids, AC/DC microgrids: renewable energy integration, distributed generation, DC power systems, power management in DC microgrids, sliding mode control of DC/DC power converters, constant power loads and pulse power loads in dc distribution systems, power electronic converters, solar PV and wind energy systems, power system dynamics and control, real-time simulation of renewable energy systems, hardware-in-loop (HIL) and power-hardware-in-loop (PHIL). He has got several papers published in the international journals.