The tutorial will be held on Monday 3 July 2017 from 16:00 to 18:30 at Valletta Campus.
The tutorial will be held subject to a minimum of at least 3 participants.
Registration for the tutorial is on the same day from 15:30 to 16:00

Attendance at the tutorial needs to be booked online from here according to the following policy:

Student Fee payable until 27 June 2017 midnight CET: EUR 10.
Non-student Fee payable until 27 June 2017 midnight CET: EUR 20.

Nonlinear control of power inverters for smart grid integration

Dr George Konstantopoulos
Department of Automatic Control and Systems Engineering
The University of Sheffield
United Kingdom


Integrating renewable energy and other distributed energy sources into smart grids, which is mainly achieved using power inverters, is arguably the largest ‘new frontier’ for smart grid advancements. Inverters should be controlled properly so that their integration does not jeopardize the stability and reliability of the power network. Hence, essential requirements have been created for every inverter-interfaced unit to provide ancillary services to the grid by assisting in the regulation of the grid voltage and frequency. Since this is accomplished via adjusting the real and reactive power of every unit, which are nonlinear expressions of the system states, the control design and operation of inverter-interfaced units in modern smart grids makes nonlinear control and systems theory essential for analysing modern power networks.

This tutorial will present novel nonlinear control technologies for integrating power inverters into the smart grid in order to enhance its stability, reliability and resilience. Initially, the bounded droop control structure will be introduced for parallel-operated inverters in micro-grids to guarantee accurate power sharing and a given bound for every inverter voltage [1]. Then, based on the recently developed concept of the ‘bounded integral controller’ [2], the improved synchronverter technology that enables inverters to mimic the dynamic behaviour of synchronous generators with tight voltage and frequency bounds will be presented [3]. Finally, the current-limiting droop controller that maintains a limited current for every grid-connected inverter under both a normal and a faulty grid using nonlinear input-to-state stability theory will be developed and demonstrated [4-6].

This tutorial provides an excellent opportunity for PhD students and postdoctoral fellows that work in the area of control systems, power electronics and power systems to get familiar with the latest advancements in control design for smart grid integration. Since the above technologies will be experimentally demonstrated, the tutorial is also suitable for many practitioners in the area of advanced control in power systems in order to identify new control technologies that can enhance the dynamic performance of modern smart grids.

  1. C. Konstantopoulos, Q.-C. Zhong, B. Ren, and M. Krstic, “Bounded Droop Controller for Parallel Operation of Inverters,” Automatica, vol.53, pp. 320-328, 2015.
  2. C. Konstantopoulos, Q.-C. Zhong, B. Ren, and M. Krstic, “Bounded Integral Control of Input-to-State Practically Stable Non-linear Systems to Guarantee Closed-loop System Stability,” IEEE Trans. Autom. Control, vol. 61, no. 12, pp. 4196-4202, Dec. 2016.
  3. Q-C. Zhong, G. C. Konstantopoulos, B. Ren, and M. Krstic, “Improved Synchronverters with Bounded Voltage and Frequency for Smart Grid Integration,” IEEE Trans. Smart Grid, 2017 (to appear).
  4. C. Konstantopoulos, Q.-C. Zhong, and W.-L. Ming, “PLL-less Nonlinear Current-Limiting Controller for Grid-tied Inverters: Design, Stability Analysis and Operation Under Grid Faults,” IEEE Trans. Ind. Electron., vol. 61, no. 9, pp. 5582 – 5591, 2016.
  5. C. Konstantopoulos, and Q.-C. Zhong, “Nonlinear Control of Single-Phase PWM Rectifiers with Inherent Current-Limiting Capability,” IEEE Access, vol. 4, pp. 3578-3590, 2016.
  6. Q-C. Zhong, and G. C. Konstantopoulos, “Current-limiting Droop Control of Grid-Connected Inverters,” IEEE Trans. Ind. Electron., 2017 (to appear).

The Speaker

Dr George Konstantopoulos is a Lecturer at the Department of Automatic Control and Systems Engineering (ACSE), University of Sheffield, UK where he leads and manages the Control and Power Systems research group. He received his Dipl. Eng. and Ph.D. in Electrical and Computer Engineering from the Department of Electrical and Computer Engineering of the University of Patras, Greece, in 2008 and 2012, respectively, both with First Class honours. From 2011 to 2012, he worked as an Electrical Engineer at the Greek Public Power Corporation (PCC) in the area of renewable systems integration to the medium voltage grid. In 2013, he joined the Department of ACSE, University of Sheffield, as a Research Associate and was promoted to a Research Fellow in 2014, working in the area of control design and analysis of power converters in smart grid applications. His research interests include nonlinear modelling, control and stability analysis of power converters in micro-grid and smart grid applications, renewable energy systems and electrical drives. Dr Konstantopoulos is a member of the IEEE and a member of the National Technical Chamber of Greece.