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Generating electrical power from solar energy is very popular. There are many studies aiming at increasing the efficiency and designing simpler systems. Electrical power generated by PV cells depends on solar irradiances, ambient temperatures and electrical loads. To transfer maximum available power from PV cells to the grid, Maximum Power Point Tracker (MPPT) algorithms have been developed and implemented. In this study, a simpler single-phase single-stage grid connected system has been designed and analysed. The proposed circuit does not require complex circuitries and modulation techniques. A 175 Watt prototype system is implemented. Under different environmental conditions, the control unit forces the system to operate at the maximum available power.

Improving power efficiency for a Photovoltaic (PV) system becomes important issue for researchers. To achieve maximum power extraction from PV panels, different kinds of Maximum Power Point Tracking (MPPT) methods have been investigating in the literature. In all techniques, direct and indirect mode approaches can be implemented. Based on the physical application of the PV system under different condition, the efficiency and convergence speed become important. In this paper, a grid connected simple single stage PV system by using different MPPT methods in direct and indirect modes has been analysed to find out the best mode and technique for a specific PV system application. Three of the most preferred MPPT algorithms: the perturb & observe (P&O), incremental conductance (Inc. Cond.) and fuzzy logic control (FLC) have been performed in MATLAB Simulink and compared their performance in direct and indirect modes in terms of convergence speed and tracking accuracy by the proposed single stage PV system. The results show that direct mode MPPTs have better tracking accuracy but less convergence speed than indirect MPPTs. Therefore, indirect mode MPPTs present better performance for the rapid atmospheric changing applications. Additionally, FLC based MPPT exhibits almost best tracking performance for direct and indirect modes.

The power generation from photovoltaic (PV) system is not constant and it varies based on solar irradiance and temperature. For any environmental condition, to convert maximum available solar energy, PV systems must be operated at maximum power point. To accomplish that two different maximum power point tracking (MPPT) methods have been presented in this study. The first method can determine MPP point by measuring the derivative of PV cell power (dP) and PV cell voltage (dV) which is called Perturb & Observe (P&O) method. The second method uses fuzzy-logic-control (FLC) based MPPT method to determine MPP point for actual environment conditions. In this paper, 3kW PV system model is studied in MATLAB. According to the simulated results, FLC based MPPT method has better performance than P&O method. Compared to the P&O method, FLC-based MPPT can increase tracking accuracy and efficiency performance 0.13% under standard test conditions (STC).

Multiple local maximum power points occur in the power–voltage characteristic curve of the photovoltaic (PV) systems due to use of bypass diodes under partial shading conditions, and this also leads to decrease the maximum power level of the PV system. This paper proposes an energy recovery‐based PV system to enhance maximum power level and working efficiency under partial shading conditions. In this study, a 350‐W PV system design and application, which can operate at maximum power point under partial shading condition, is made using two 175‐W PV panels. The main purpose of the system is to maintain power generation from the shaded PV panel by energy recovery circuit without any damage on the PV panels and also connect PV panels to the grid by single power circuit. To perform the maximum power point tracking (MPPT) task for the PV system, a single input variable used fuzzy logic control (FLC)‐based MPPT method is developed. Therefore, this study investigates and analyzes energy recovery connected and fuzzy logic control‐based MPPT controlled PV system under partial shading conditions. Effectiveness of the proposed system has been verified through simulation and experimental results.

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Events and transients are becoming more and more crucial in modern astronomy such as supernovae, gammaray bursts and so on. VOEvent messages have all information to make the follow-up observations for transients and events which forces the scientists to make robotic observations. Robotic autonomous telescopes usually run under the control of a scheduler, which provides high-level control by selecting astronomical targets for observation. TUY 40 is a new robotic autonomous telescope control system designed by TÜBİTAK National Observatory (TUG). TUY 40 is based on 16 inch Meade LX-200 telescope mount and optical tube without any Meade electronic components and drive motors. The telescope control software developed on open-source Talon software and LabVIEW is presented. The algorithm for telescope control (slewing, tracking, homing etc.) was implemented in National Instruments PXI chassis written in LabVIEW real-time software from scratch. Talon is open-source software based on the GNU/C UNIX platform. A new TCP/IP library was implemented within Talon software to communicate with hard real-time telescope control software in LabVIEW PXI chassis. Initial setup without any permanent pier and polar alignment showed that the pointing error of the telescope has been obtained as 2.22 arcmin (132 arcsec) in RA axis (horizontal axis of the image) and 25 arcsec in Dec axis (vertical axis of the image), and tracking error has been observed as ≈4.8 arcsec per second.

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