Doctoral Dissertations


"Modular multilevel converters (MMC) have gained prominence for high power applications in recent years due to their technical merits such as voltage scalability, harmonic performance, and high efficiency. Integration of renewable energy sources such as solar photovoltaic (PV) systems and energy storage systems (ESS) to the grid using power electronic (PE) resources is increasing due to the techno-economic successes achieved by such systems. Following these developments, the integration of MMCs with PV plants and ESS systems is one of the dynamic research avenues being pursued. Along these lines, an integrated development of PV plants, ESS, and alternating- and direct-current (ac/dc) power plants through Multi-port Autonomous Reconfigurable Solar (MARS) systems is proposed.

The main research focus is on the modeling, control, and benefits of MARS systems compared to the discrete development of state-of-the-art PV, ESS, and HVdc links. Ultrafast high fidelity MARS HVdc models are developed to test advanced control algorithms. The advanced control algorithms include synchronverter-based (SG-based) control and grid forming predictive control methods. The grid forming control methods are defined as the control methods that regulate converter output voltage without any phase-locked loop (PLL) mechanisms. The proposed grid forming predictive control is based on the model based predictive control (MBPC-based) for frequency support and also includes traditional voltage support control. The proposed control algorithms in the MARS control architecture are evaluated for various short circuit ratio (SCR) and inertia conditions. To illustrate the technical benefits of MARS systems, the MARS system architecture is compared with the discrete development of state-of-the-art PV plants and hybrid PV plants. In addition, the MARS system is proposed as a promising solution to the momentary cessation problem often seen in PE-based resources connected to low SCR and low inertia grids"--Abstract, page iv.


Crow, Mariesa

Committee Member(s)

Debnath, Suman
Kimball, Jonathan W.
Ferdowsi, Mehdi
Shamsi, Pourya
McMillin, Bruce M.


Electrical and Computer Engineering

Degree Name

Ph. D. in Electrical Engineering


This paper is based upon work supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under Solar Energy Technologies Office (SETO) Agreement Number 34019.


Missouri University of Science and Technology

Publication Date

Spring 2021

Journal article titles appearing in thesis/dissertation

  • Synchronverter-based control of multi-port autonomous reconfigurable solar plants (MARS)
  • Model based predictive control for frequency support in multi-port autonomous reconfigurable solar plants
  • A predictive grid forming control for multi-port autonomous reconfigurable solar plants
  • Suite of solutions for reducing momentary cessation in PV/hybrid PV plants in low SCR and low inertia grids


xvi, 110 pages

Note about bibliography

Includes bibliographic references.


© 2021 Phani Ratna Vanamali Marthi, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 11841

Electronic OCLC #