Hill-climbing and P&O method can fail under rapidly changing atmospheric conditions  fig 3.2. Starting from an operating point A, if the atmospheric conditions remains approximately constant, a perturbation ∆V in the PV voltage V will bring operating point to B and perturbation will be reversed due to decrease in thepower. But, if the irradiance increases and shift the power curve from P1 to P2 within one sampling period, the operating point will move from point A to point C. This represents increase in power and perturbation is kept same. Subsequently, operating point will diverges from the MPP and will keep diverging if irradiance is steadily increases. To guarantee that the MPP is tracked even under the sudden changes in the irradiance,  uses three-point weight comparison P&O method that compares actual powerpoint to two preceding ones before a decision is made about the perturbation sign. Reference  optimizes sampling rate while  simply uses high sampling rate.
Energy Crisis and climate change threats leads the researchers to look for alternate sources of energy [1-3]. The world is virtually on the hunt of promising renewable and sustainable sources of energy. In recent years, renewable energy sources like solar, wind, tidal, have attracted the researchers, as it is limitless, non-pollutant and available free of cost. Solar energy is considered as the most reliable source among RES. Due to technological advancement in power electronics and reduction in the manufacturing cost of PV cell, solar energy is becoming more promising source of energy [4-8]. Solar PV exhibits nonlinear characteristics and its efficiency is also low. It becomes essential to extract maximumpower from solar PV under all ambient conditions. MPPT (MaximumPowerPointTracking) algorithm is used to extract maximumpower from solar PV [9-10]. The MPPT is implemented in the control circuit of Power electronics converters. A converter without MPPT system only regulates the output voltage of PV module, but it does not ensure that PVsystem is operating at the maximumpowerpoint MPP . The operation of MPPT depends on the type of converter used [12-14]. In this paper a boost dc-dc converter is used and the performance of MPPT is evaluated.
Global Energy Crisis and climate change threats leads the researchers to look for alternate sources of energy [1-2]. Solar Energy is considered as the most reliable source among all renewable energy sources (RES) [3-8]. Solar PV is used to convert solar energy into electrical energy. Solar PV exhibits nonlinear characteristics and its efficiency is also low. It becomes essential to extract maximumpower from solar PV under all ambient conditions. MPPT (MaximumPowerPointTracking) algorithm is used to extract maximumpower from solar PV [9-10]. The MPPT is implemented in the control circuit of Power electronics converters. A converter without MPPT system only regulates the output voltage of PV module, but it does not ensure that PVsystem is operating at the maximumpowerpoint MPP . The operation of MPPT depends on the type of converter used [12- 14]. In this paper a buck-boost dc-dc converter is used and the performance of MPPT is evaluated.
ABSTRACT: Photovoltaic (PV) systems generate a significant amount of electrical energy used around the world. In accordence with high cost and low effienciency, solar panels and arrays should be operated at the maximumpowerpoint (MPP). Photovoltaic cells have variable current and voltage characteristics and MPP depends on solar irradiations and ambient temperature. Obtaining maximumpower and reaching highest efficiency level in these panels is an important research topic , [ 2]. Maximumpower poin tracking (MPPT) is developed to capture maximumpower level in variable atmospherically conditions , . In this study, the behaviour of varied incremental conductance (IC) MPPT algorithm implemented to PV modules. Larger-medium-small fixedstep sizes and variable step size were applied, analyzed under various conditions. In order to compare the step size impressions, all cases were simulated on MATLAB/Simulink platform.
ABSTRACT: Photovoltaic power generation has two major problems: the conversion eﬃciency of existing PV modules is less and amount of power generated by PVsystem changes with weather conditions. Also, the PV cell I-V characteristics are non-linear due to complex relationship of voltage & current and varies with change in temperature or insolation. There is only one point on P-V or I-V curve called MaximumPowerPoint at which PVsystem operates at maximum eﬃciency and produces maximum output power. Failure to track MPP causes significant power loss. So, MaximumPowerPointTracking (MPPT) is required to operate PVsystem at MPP. The P&O algorithm and INC algorithm are commonly used methods to track MPP by adjusting duty cycle of DC-DC converter. The existing methods use microcontroller or DSP controller to implement MPPT algorithm. FPGA provides number of advantages over sequential machine microcontroller, as FPGA does concurrent operation i.e. instructions executed continuously and simultaneously. However DSP does signal processing related calculation only. Using FPGA number of components required is less and FPGA is faster than DSP. Thus, the size of components required for power converter decreases. The MPPT algorithm is implemented on FPGA which continuously track the maximumpoint under rapid environmental changes.
energy can be directly converted electricity through photovoltaic effect. Being exposed to the sunlight, photons with energy greater than the band-gap energy of the semiconductor are absorbed and create some electron-hole pairs proportional to the incident irradiation. Under the influence of the internal electric fields of the p-n junction, these carriers are swept apart and create a photocurrent which is directly proportional to solar insolation. PVsystem naturally exhibits a nonlinear I-V and P-V characteristics which vary with the radiant intensity and cell temperature.
The paper presents new MPPT algorithm for partial shading of series con- nected PV cells/modules. In the shaded condition, there is a problem of de- crease in the total output power of the PVsystem. The proposed algorithm aims to reduce this problem by active bypassing of the shaded cells. The algo- rithm senses the irradiance of each cell and performs calculation in order to decide if to actively bypass the shaded cell or not. Extensive simulation results proved that algorithm works and increases the output power under partial shading conditions. Furthermore, the algorithm becomes more efficient when the number of cells is increased.
Effective renewable energy sources are those sources in which energy supplies that are refilled by natural processes as fast as we use them. All renewable energy comes, ultimately, from the sun. Solar energy comes directly from the sun and is used to produce electricity, heat, and light. However, there are two main disadvantages of photovoltaic (PV) system, the high installation cost and the low conversion efficiency of PV modules which is only in the range of 9-17% . The basic block diagram of solar system is shown in Fig. 1. Besides that, PV characteristics are nonlinear and it is very much weather dependent. Fig. 2 and Fig. 3 show the I-V and P-V characteristics of a typical PV module for a series of solar irradiance levels with constant temperature . It can be noticed that PV output voltage greatly governed by temperature while PV output current has approximate linear relationship with solar irradiances. It can be seen from the P-V characteristic curve that there is only one peak operating point which is named as the maximumpowerpoint (MPP). Due to the high capital cost of PV array, maximumpowerpointtracking (MPPT) control techniques are essential in order to extract the maximum available power from PV array in order to maximize the efficiency of PV array. Therefore, a DC-DC converter is inserted between PV generator and load or battery storage. MPPT algorithms are used to control the switching of DC-DC converter by applying pulse-width modulation (PWM) technique .
Where I D the diode is current, R sh is the shunt resistance, I L is the light generated current of solar array.Solar cell is basically a p-n junction fabricated in a thin wafer or layer of semiconductor. The electromagnetic radiation of solar energy can be directly converted electricity through photovoltaic effect. Being exposed to the sunlight, photons with energy greater than the band-gap energy of the semiconductor are absorbed and create some electron-hole pairs proportional to the incident irradiation. Under the influence of the internal electric fields of the p-n junction, these carriers are swept apart and create a photocurrent which is directly proportional to solar insolation. PVsystem naturally exhibits a nonlinear I-V and P-V characteristics which vary with the radiant intensity and cell temperature.
The Incremental Conductance MPTT algorithm usually uses a fixed iteration step size, which is determined by the accuracy and tracking speed requirement. Thus, the corresponding design should satisfactorily address the tradeoff between the dynamics and steady state oscillations. To solve these problems, a modified INC MPPT with variable step size is proposed in this paper. The step size is automatically tuned according to the inherent PV array characteristics. If the operating point is far from MPP, it increases the step size which enables a fast tracking ability. If the operating point is near to the MPP, the step size becomes very small that the oscillation is well reduced contributing to a higher efficiency and also it can effectively improve the dynamic performance and steady state performance simultaneously. The PV output power and slope of output power versus output voltage curves are shown in figure. 5.
FLC blocks are not accessible and can not be modified without redesigning it each time, causing the loss of considerable time to control our system. To avoid these drawbacks and to simplify both the access and the plot of all blocks, a modelisation of FLC membership’s functions has become a necessity. The simulation and experimental tests on a PVsystem show that the FLC provides a good tracking of the maximumpowerpoint (MPPT). Finally, we have evaluated the operation of the FLC on a real system consisting of a photovoltaic panel (BP580) model and have implemented the control strategy on a digital signal processor dSPACE DS1104.
Abstract- Solar energy is clean, renewable and its decentralized character is appropriate well at the scattered state of the zones with low density of population. The cost of electricity from the solar array system is more expensive than the electricity from the utility grid. So, it is necessary to operate the PVsystem at maximum efficiency by trackingmaximumpowerpoint at any environmental condition. In this work, the neural network back propagation algorithm is used to control the operation of the PV array in order to extract the maximumpower. Two error functions are used. The first, the classic error function, and the second is a modified error function which takes into consideration the derivative of the error function also. The results obtained are compared and discussed.
 It presented the first paper on fuzzy set theory in 1965. Since then, a new language was developed to describe the fuzzy properties of reality, which are very difficult and sometime even impossible to be described using conventional methods. Fuzzy set theory has been widely used in the control area with some application to dc-to-dc converter system. A simple fuzzy logic control is built up by a group of rules based on the human knowledge of system behavior. Matlab/Simulink simulation model is built to study the dynamic behavior of dc-to-dc converter and performance of proposed controllers. Furthermore, design of fuzzy logic controller can provide desirable both small signal and large signal dynamic performance at same time, which is not possible with linear control technique. Thus, fuzzy logic controller has been potential ability to improve the robustness of dc-to-dc converters. The basic scheme of a fuzzy logic controller is shown and consists of four principal components such as: a fuzzification interface, which converts input data into suitable linguistic values; a knowledge base, which consists of a data base with the necessary linguistic definitions and the control rule set; a decision-making logic which, simulating a human decision process, infer the fuzzy control action from the knowledge of the control rules and linguistic variable definitions; a de-fuzzification interface which yields non fuzzy control action from an inferred fuzzy control action .
This paper presents an overview of MPPT methods, and considers their suitability in systems which experience a wide range of operating conditions. From this, it is clear that each MPPT method has its own advantages and disadvantages and the choice is highly application-dependent. When using solar panels in residential locations, the objective is to reduce the payback time. To do so, it is necessary to constantly and quickly track the maxi- mum powerpoint. Furthermore, the MPPT should be capable of minimising the ripple around the MPP. There- fore, the two techniques stages—incremental conductance (IC) and perturbation and observation (P & O) algo- rithms are suitable. These two methods have been evaluated by simulating a standalone PVsystem, utilising a DC-DC boost converter to connect the PV panel to the load. In particular, the performance of each method has been considered over a wide range of different irradiation conditions. Results show that the enhance of perturb and observe algorithm exhibits faster dynamic performance and achieves steady state level better than the in- cremental conductance method over a broad range of irradiation settings and load profiles.
A solar cell is a p-n jucton semiconductor device. It recieves energy from the sun and convert it into electrical energy. The simple equivalent circuit of PV has been show in figure 1 which consists of a current source model of the luminous flux, the losses modeled by two resistor, shunt resistor R sh , a series resistor R s , and diode -.
The thesis focus is to develop MaximumPowerPointTracking (MPPT) algorithm that based on the Simplified Fuzzy Logic Controller (SFLC). It is known that the output of the PV panel is always fluctuates due to the changes in the irradiation of the sunlight and surrounding temperature. This inconsistency of the output voltage is no good to the load. To compensate the problem, a power converter is used to reduce the fluctuation. However, the efficiency of the power converter is much depends on the maximumpowerpoint tracked of the solar panel. Therefore, there is a need for a MPPT algorithm to be implemented in the power converter. In this thesis, Simplified Fuzzy Logic Controller (SFLC) is employed. The proposed of Simplified Fuzzy logic Controller (SFLC) has several advantages as compared to the conventional Fuzzy Logic Controller (CFLC), such as less number of rules and tuning parameters. To verify, full system model is developed in MATLAB-Simulink software and simulated. From the results, it was shown that the features of the proposed Simplified Fuzzy Logic Controller (SFLC) are justified.
This paper proposes a New Particle swarm algorithm for improving the Optimization and performance of MaximumPowerPointTracking in PVSystem. The PSO technique has been applied for multi-junction solar cell system. The solar panels are made up of different type materials and give constant output from Boost converter. The main aim of PSO algorithm is to find out duty cycle to the Boost converter to maintain constant output voltage irrespective of power produced by solar panels. This proposed Particle Swarm Optimization (PSO) is also used to minimizing active power loss, voltage deviation and voltage stability index. A detailed simulation of the proposed method has been simulated in Matlab/Simulink. The simulation result shows that this design can be effectively realized in practical applications.
Abstract—The output power of PV module varies with module temperature, solar insolation and loads. And in order to quickly and accurately track the sun, it is necessary to track the maximumpowerpoint (MPP) all the time. After studying various algorithms, a new algorithm was presented in this paper based on online short-circuit current,open- circuit voltage, and variable step of perturbation and observation method. This algorithm could track MPP change rapidly and accurately without the disturbance of photovoltaic system, and also can reduce the power oscillation around MPP and the light mutation of the false judgement phenomenon. A theoretical analysis and the designed principle of the proposed algorithm are described in detail. And some experiment and simulation results are made to demonstrate that the effectiveness of the proposed algorithm and also the proposed could reach MPP which is faster than traditional P&O method about 0.2s. The system has a good dynamic and steady-state performance.
The power generated by a PV array is dependent on a number of factors, and displayed by the IV curve. The point on the IV curve where the PV array is greatest is called the maximumpowerpoint. Environmental factors will influence the solar energy input on a PV array, and hence the output power. The maximumpowerpoint does not occur at a fixed position on the IV curve, therefore is unable to be determined in advance. Maximumpowerpointtracking is a function included in modern solar inverters, commonly implemented through constant adjustment of the system operating voltage. There are a number of methods which can be used to monitor and maintain operation at the maximumpowerpoint. Two methods of maintaining maximumpower are perturb and observe and incremental conductance. (National Instruments, 2009c)
ABSTRACT: This work develops a most point following (MPPT)algorithm for optimizing solar battery performance that's strongto chop-chop varied climatic conditions. above all, a novelextremum seeking (ES) controller, that utilizes the electrical converterripple, is intended and tested on a simulated array withgrid-tied electrical converter. The new algorithmic program is benchmarked againstthe perturb and observe (PO) methodology victimization irradiance informationgathered on a upside array experiment in Princeton, NJ. Theextremum seeking controller achieves associate potency of ninety nine.7%and transient rise to the MPP of .1 seconds, that is one hundred timesfaster than perturb and observe