Evaluation of Photovoltaic Inverters According to Output Current Distortion in a Steady-State and Maximum Power Point Tracking Marko Dimitrijević, Milutin Petronijević, Dardan Klimenta Applied Sciences Switzerland, 2025 The limits of direct current (DC) injection and output current distortion of grid-connected photovoltaic (PV) inverters are specified in the IEEE 1547-2018 standard. The standard prescribes limits of output current harmonics, but the input voltage and power at which output current distortion is measured are not specified. This manuscript presents the results of DC injection and output current distortion measurements for three commercial single-phase PV inverters, with 3 kVA, 3.3 kVA, and 6 kVA rated power. During the measurements, the inverters are powered by a programmable DC source that emulates the power voltage characteristic of a PV array, providing different input conditions. In addition to steady-state measurements at constant input voltage and power, the change in the output current spectrum over time during the maximum power point tracking (MPPT) is also measured. The results show that the output current distortion depends on the input voltage and power. Moreover, the current distortion of some of the tested inverters exceeds the limits specified by the standard in some cases. The presented results suggest that further research on the dependence of the output current distortion from PV inverters on their input power and voltage is needed.
Emulation of photovoltaic arrays under non-uniform environmental conditions Marko A. Dimitrijević, Milutin Petronijević, Ivana Radonjić COMPEL the International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 2025 Purpose The purpose of this manuscript is to present a method for emulating photovoltaic (PV) arrays under non-uniform environmental conditions such as illumination, temperature and soiling using a programmable power supply. Design/methodology/approach A key element of the emulation method is generating the characteristics of the PV arrays, which is enabled by the software tool developed for this purpose. The software tool inputs are the connected PV modules’ current-voltage (I-V) characteristics, obtained through simulation or measurement and the connection topology. The outputs are a PV array’s I-V and corresponding power-voltage (P-V) characteristics. Findings The P-V characteristics of PV arrays under non-uniform environmental conditions have multiple local maxima. The operation and performance of maximum power point tracking (MPPT) algorithms are evaluated using such characteristics generated with the software tool, showing that multiple local maxima can mislead the MPPT algorithm. Output current distortion during the MPPT process is also measured, revealing changes in the output current spectrum. Practical implications Experimental evaluation of the performance of PV systems under non-uniform conditions is very difficult. Climatic conditions cannot be directly influenced, and creating an artificial environment that mimics certain conditions is complicated and expensive. Moreover, changing the array configuration for each experiment is time-consuming. The described method for emulating the PV array significantly facilitates the testing of PV systems and allows experiments in different scenarios that are not feasible in real conditions. Originality/value This manuscript describes a unique software tool for generating I-V characteristics for emulating PV arrays. The manuscript’s value is reflected in the method’s applicability and versatility.
Experimental Verification of Grid Inverter Operation in Urban Environment Milutin Petronijević, Ivana Radonjić, Boban Veselić, Marko Dimitrijević, Čedomir Milosavljević, et al. Proceedings 2024 11th International Conference on Electrical Electronic and Computing Engineering Icetran 2024, 2024 This study offers experimental testing of commercial and laboratory inverters, utilized in a laboratory prototype of an urban microgrid. Operation of grid inverters supplied by PV arrays in urban environments, encounters challenges such as partial shading and soiling. Emulation of the current-voltage characteristics of PV arrays enables repeated and reliable testing of inverter operation under irregular supply conditions. It has been shown that finding the maximum power point can be challenging under conditions of partial shading and soiling. Additionally, meeting the grid quality standards for the delivered power represents a challenge. Satisfying these requirements can be achieved through careful design of LCL filters at inverter output terminals, but further improvement can be achieved only through an adequate selection of the primary controller. To further improve the quality of grid currents, the possibility of applying innovative control algorithms has been demonstrated for laboratory inverters. Application of sliding mode controllers, besides ensuring system robustness, can prevent overshoots and fault responses from the current protection circuit by introducing a specific anti-windup structure.
The system for distributed energy resources testing according to the IEEE 1547-2018 standard Marko A. Dimitrijević, Milutin Petronijević COMPEL the International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 2023 Purpose This paper aims to propose a new approach to testing distributed energy resources (DERs) in compliance with the IEEE 1547-2018 standard and describes a new, integrated testing and validation system. Design/methodology/approach The system is built on the virtual instrumentation paradigm, using acquisition modules to measure physical quantities, while signal processing, including intensive calculations of required parameters, data processing, manipulation and reporting are performed on a computing device. Findings Intensive laboratory measurements were performed on a laboratory prototype of a microgrid that emulates DERs. The results obtained using the system described were compared with the measurements obtained by the reference instruments. As all the results match, the usability of the system was verified. Practical implications This approach to the realization of the testing and validation system has obvious advantages compared to the classical instruments and provides significant flexibility in multiple aspects. First, the system described integrates all the functions of different instruments into one measuring system, making the entire testing and validation process significantly cheaper and faster. Second, the implementation of the system is possible on different computing platforms depending on specific needs. Third, the software implementation of the system functions enables simple upgrading and the introduction of new functions or changes to existing ones according to changes in the standard. Finally, the system described is designed to automatically provide reports on compliance with the standard. Originality/value This paper emphasizes the advantages of the proposed approach over classical testing. The value of the paper is reflected in the applicability and practical implications of the proposed and described hardware and software technical solutions.
Non-linear load characterisation using orthogonal apparent power decompositions Marko A. Dimitrijevic, Dejan Stevanovic, Vanco B. Litovski Elektronika Ir Elektrotechnika, 2021 There is no generally accepted definition for apparent power components in circuits with non-sinusoidal conditions. The decomposition of apparent power has been the subject of many discussions and is still an open topic. Over the years, a number of apparent power decompositions have been proposed and analysed, usually in the context of compensation. These analyses were performed by means of simulations or by calculating quantities using measurements on a simple test circuit. Here, we present a unique system capable of simultaneous apparent power decompositions for non-sinusoidal conditions in real-time. The system can calculate power components related to various power decompositions. The system’s capabilities are demonstrated on non-linear load characterization.
Improving the system for registration of electric energy consumption Dejan Stevanovic, Miona Andrejevic Stosovic, Marko Dimitrijevic 2020 International Symposium on Industrial Electronics and Applications Indel 2020 Proceedings, 2020 Existing system for registration of electric energy consumption is based on the application of commercial power meters and/or measuring groups at each load/consumer. National standards stipulate that the power meters register active, and measuring groups register both active and reactive energy. These requirements give a correct picture of consumption in systems where linear loads dominate. Unfortunately, the needs of electric energy consumers have significantly changed in recent years, so the number of nonlinear loads has increased remarkably. Non--registration of distortion component of power causes losses in power system that are proportional to power and number of nonlinear loads. Measurement results of the consumption of different types of modern loads have confirmed our presumptions. Modification of built-in power meters and measuring groups is proposed, so that it easily fits into the existing system.
On tachyonic inflaton with constraints Dragoljub D. Dimitrijevic, Marko A. Dimitrijevic, Goran S. Djordjevic, Milan Milosevic Aip Conference Proceedings, 2019
MPPT controller design for a standalone PV system Miona Andrejevic Stosovic, Marko Dimitrijevic, Vanco Litovski 2013 11th International Conference on Telecommunications in Modern Satellite Cable and Broadcasting Services Telsiks 2013, 2013
ICT and power: New challenges and solutions Marko Dimitrijević, Jelena Milojković, Slobodan Bojanić, Octavio Nieto Taladriz, Vančo Litovski International Journal of Reasoning Based Intelligent Systems, 2013
ICT and power: Synergy and hostility M. Dimitrijevic, J. Milojkovic, S. Bojanic, V. Litovski 2011 10th International Conference on Telecommunications in Modern Satellite Cable and Broadcasting Services Telsiks 2011 Proceedings of Papers, 2011
