Sahin Gullu

Dr. Sahin Gullu

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Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 July 2024 in Electronics
Verified
Journal Article
Open access
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Sahin GulluSahin Gullu
Sahin Gullu
ADAmour-che Djaho
Amour-che Djaho
AMAdje Mensah
Adje Mensah
IBIssa Batarseh
Issa Batarseh
This research focused on the implementation of state-of-the-art system integration, involving a three-phase 540 KVA bidirectional inverter and a lithium-ion battery energy storage system with a capacity of 1.86 MWh, at the Florida Solar Energy Center (FSEC). The system was firstly put into use at the FSEC for load shifting. The second step was to add photovoltaic (PV) panels for peak shaving. The third step was to take the FSEC completely off-grid. The goal of this research was to provide a case study by implementing a power management algorithm, estimating the PV panel size, and presenting the test results and an analysis. Based on the power management algorithm, load shifting was achieved by using 180 kWh energy storage. To acquire peak shaving and the uniformity of power consumption, an 80 kW PV farm was sufficient. The optimal PV panel size was 500 kW for the off-grid scenario.

22 March 2024 in International Journal of Energy Studies
Verified
Journal Article
Closed access
Sahin GulluSahin Gullu
Sahin Gullu
IBIssa Batarseh
Issa Batarseh
FAFahad Alaql
Fahad Alaql
The utilization of renewable energy sources has increased due to concerns about climate change. However, injecting the power from renewable energy sources into grid-tied systems is challenging. The techno-economic analysis a photovoltaic (PV) energy systems is investigated. As a result, this paper presents AC-PV module for Grid-Tied and Off-Grid Scenarios via optimization, modeling, and test results. Even though the output of a PV panel is DC voltage, a three-port inverter and a lithium-ion battery pack are integrated with the back of the PV panel. They are packaged as a PV system module that makes the module output have AC voltage. Therefore, an optimized AC-PV module can be a solution for residential and commercial use, which are grid-tied systems; it can be very efficient for those without access to electricity, which is an off-grid system. An integrated battery and thermal management strategy is crucial for this AC-PV module. In the article, the battery capacity optimization, the electrical and the thermal model of the battery pack, battery heat generation model are discussed by using stochastic analysis techniques; the battery test results are also obtained to identify the models’ parameters and a control algorithm is proposed to extract the battery information such as temperature, current, voltage, SoC and SoH of the battery pack.

25 December 2024 in International Journal of Energy Studies
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Journal Article
Open access
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Sahin GulluSahin Gullu
Sahin Gullu
MNMohammad Nilian
Mohammad Nilian
IBIssa Batarseh
Issa Batarseh
The control methods of Grid-forming (GFM) inverters are discussed and reviewed. Then, the droop control method’s weak points are modified to have better load sharing performance and improving the lifetime of the inverters when the system has light load situations. Also, the effects of the coupling reactance on stability and reliability are investigated. This control method is applied to three different scenarios in order to see frequency and voltage stability and load sharing between three Inverter Based Resources (IBRs) and the grid. The first case is that the voltage and frequency regulation control algorithm is presented when the IBRs have equal power ratings during the off-grid. Then, the second case is also performed in islanding mode where the load sharing control algorithm is determined based on the different power ratings of the IBRs. Lastly, this setup examined the load sharing status during the grid-tied scenario when the IBRs are not capable of supplying enough power to the load. In all cases, loads are added to and removed from the system to ensure that the frequency and voltages are in the range of continuous operation.

22 January 2026 in Electronics
Verified
Journal Article
Open access
PDF file
Sahin GulluSahin Gullu
Sahin Gullu
MKMehmet Onur Kok
Mehmet Onur Kok
KAKhalil Alluhaybi
Khalil Alluhaybi
This study conducts both experimental and statistical analyses of microinverter performance within a compact AC-PV module that integrates a PV panel and a microinverter without battery integration. Using measurement data in combination with correlation analysis, derived thermal indicators, and quadratic regression modeling, the research provides a comprehensive quantitative assessment of microinverter behavior under practical operating conditions. A central finding is that the PV module’s temperature rise above ambient, ΔTmodule, serves as the most reliable single predictor of output power with a coefficient of determination of R2 = 0.85. The coefficient determination of ΔTmodule surpasses even solar irradiance and the microinverter temperature rise, ΔTmicro, with R2 = 0.80 and R2 = 0.75, respectively. This underscores the excess thermal loading of the module, rather than the absolute temperature alone. In contrast, ambient temperature (R2 = 0.04) proves to be a negligible variable for output power prediction. Also, comparing experimental temperatures with semi-empirical models showed that the PV temperature formula captures key thermal behavior, and the difference between theoretical and measured values is around 12%. From a design standpoint, these results highlight that enhancing thermal management at the module–inverter interface can directly improve output stability and ensure battery integration in the long-term reliability of an AC-PV module in future studies.

29 January 2026 in Electronics
Verified
Journal Article
Open access
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MKMehmet Onur Kok
Mehmet Onur Kok
Sahin GulluSahin Gullu
Sahin Gullu
This work describes the design and experimental testing of a low-noise amplifier (LNA) fabricated on a printed circuit board (PCB) and operating near 2 GHz. The amplifier uses a discrete bipolar junction transistor (BJT) together with fully distributed microstrip matching networks without relying on lumped matching components. The main design goal is to obtain stable operation with low noise figure and moderate gain over a wide frequency range while keeping the circuit tolerant to layout parasitics and fabrication variations. Circuit-level simulations are performed using AWR Microwave Office and are followed by full-wave electromagnetic simulations in Sonnet Software to account for layout-dependent effects. A prototype is fabricated on a 60-mil Rogers RO4003C substrate and characterized through S-parameter, noise-figure, and linearity measurements. Measured results show a gain of approximately 13.84 ± 1 dB over the 1.75–2.25 GHz frequency range, with a minimum noise figure of 1.615 dB at 2 GHz. Stable operation is maintained across the entire band, and the measured 1 dB gain compression point is approximately 0.5 dBm. The results demonstrate that a fully distributed microstrip matching approach provides a practical and reproducible PCB-based LNA solution for sub-6-GHz receiver front-end applications.