This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/ACCESS.2020.2970613, IEEE Access VOLUME XX, 2017 1 Date of publication xxxx 00, 0000, date of current version xxxx 00, 0000. Digital Object Identifier 10.1109/ACCESS.2017.Doi Number Modelling and Control of Dish-Stirling Thermal Integrated with PMDC Generator Optimized by Meta-heuristic Approach Ramesh Kumar 1 , (Member, IEEE), Nidul Sinha 2 , (Senior Member, IEEE) 1 National Institute of Technology Mizoram, Aizawl, Mizoram 796012, India 2 National Institute of Technology Silchar, Silchar, Assam 788010, India Corresponding author: Ramesh Kumar (e-mail: rameshelectric@gmail.com ). ABSTRACT This paper proposes an autonomous microgrid system for the first time with solar thermal dish-Stirling engine coupled with permanent magnet direct current generator and battery energy storage system along with uncontrolled variable loads. Both proportional-integral (PI) and proportional-integral- derivative (PID) controllers are considered separately for the bidirectional charge controller and buck-boost converter controller for the dish-Stirling system. The modern meta-heuristic algorithms including recent ones like particle swarm optimization, mine blast algorithm and grey wolf optimizer (GWO), have been adopted for tuning the gain parameters of the controllers used for the direct current common bus voltage stability and power sharing. The work considers variable insolation level for somehow mimicking the natural solar variation all the day. The simulation of the proposed model is carried out in MATLAB/Simulink and the results are obtained with two types of controllers for comparison. The results demonstrate the superior performance of the PID controllers optimized with GWO algorithm in terms of faster convergence rate, DC voltage profile, and maintenance of SOC of battery and energy efficiency as compared to the other two algorithms. It is also to be noted that the use of a permanent magnet DC generator coupled to the solar dish-Stirling engine improves the electric conversion efficiency and reduces cost effectively as compared to AC generators. INDEX TERMS DC-DC converter, grey wolf optimizer, microgrid, PI/PID controller, solar dish-Stirling, voltage stability. I. INTRODUCTION An increase in population and technology developments demand more and more energy to fulfill their energy requirements. The conventional energy sources like thermal power station and hydropower plants are not sufficient to meet the total energy requirement. The large hydropower plants affect the environment and ecosystem whereas thermal power plants emit pollutants (like CO 2 , SO 2 , etc.) into the air and cause the environment temperature to increase. Due to global warming, there is international pressure to reduce the CO 2 emission by shutting down the sources of these types of harmful gases. Non-conventional distributed energy sources are the solution to these problems. India has initiated to form an international solar alliance of those countries who receive sufficient solar irradiance to generate electric power to curtail carbon emission. Dish-Stirling (DS) solar-thermal system is a prominent source of renewable energy and having recent technology for electrical power generation. Dish-Stirling solar-thermal system (DSTS) has the highest efficiency (around 30%) among all other solar-thermal power generation systems by converting direct solar irradiance into electricity considering losses [1]. Fig. 1 shows the mechanical design of DSTS in which the Stirling engine is placed at the focal point of the parabolic concave mirror or dish collector. Stirling engines are mechanical devices working on the principle of the Stirling cycle; solar receivers are so designed to transfer the received solar energy to the compressible working fluid like air, hydrogen, helium, nitrogen or even vapor [2]. The Stirling engines convert solar heat energy into mechanical power by compression and expansion of working fluid during cooling and heating of it respectively. The compression and expansion of working fluid produce linear motion which is to be converted into rotary motion and acts as a prime mover for the generator connected to it for the generation of electrical power [3], [4]. Review of the literature shows that most of the researchers have used