A static exciter with interleaved buck converter for synchronous generators M. Baha Bayram a , Ibrahim Sefa b,* , Selami Balci c a Gazi University, Graduate School of Natural and Applied Sciences, Ankara, Turkey b Gazi University, Technology Faculty, Department of Electrical and Electronics Engineering, Ankara, Turkey c Ministry of National Education, Ankara, Turkey article info Article history: Received 15 November 2016 Received in revised form 2 March 2017 Accepted 10 March 2017 Available online xxx Keywords: Interleaved buck converter Static excitation Co-simulation Synchronous generator LabVIEW CompactRIO abstract In this study, an interleaved buck converter based static excitation system is proposed for large-scale synchronous generators where thyristor controlled systems are widely used. The proposed system removes the slow response drawback of the thyristor controlled systems even for dynamic load conditions. The finite element analysis based model of the synchronous generator's electromagnetic system is obtained and co-simulations of the modeled generator and proposed interleaved buck converter are performed. Results ob- tained from simulation results show that, the proposed system offers better performance in terms of step response and inductor current ripple. The simulation results are validated with experimental studies. All measurement, monitoring and control processes have been performed with field programmable gate array called NI CompactRIO platform and Lab- VIEW software. © 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Introduction Synchronous generators (SG) in different structures and in different power levels from several kVA to hundreds MVA are used in electrical energy generation. Generally, excited syn- chronous generators are used in thermal, hydraulic, diesel or gas engine electric generation plants. In recent years, multi- pole excited synchronous generators are being used in high power wind turbines, which are also known as direct drive. The common feature of these generators, which are in different structures, is the necessity of controlling the exci- tation current for protection and regulation purposes. All the power plants in the electric power systems are connected parallel with each other with the common voltage and frequency values through national or international power transmission lines and power transformers. The load level in the power system, which is also called as demand factor, can be different at every seconds of the day. Thus, it can be said that the terminal voltage of the generator in any electric plant varies at every moment. Therefore, in order to keep the ter- minal voltage of the generator constant momentarily, the excitation current has to be controlled by the closed loop control system. This task is carried out by the excitation control systems called Automatic Voltage Regulator (AVR) systems. The AVR uses the terminal voltage error as a control input in the excitation control loop. The excitation current and so the generator output voltage are adjusted continuously until this error becomes zero [1e3]. * Corresponding author. E-mail addresses: bahabayram@gazi.edu.tr (M.B. Bayram), isefa@gazi.edu.tr (I. Sefa), selamibalci@gmail.com (S. Balci). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy xxx (2017) 1 e11 http://dx.doi.org/10.1016/j.ijhydene.2017.03.062 0360-3199/© 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Bayram MB, et al., A static exciter with interleaved buck converter for synchronous generators, In- ternational Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/j.ijhydene.2017.03.062