IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> MAXIMUM POWER POINT TRACKING <s> A new maximum power point tracker (MPPT) for a grid-connected photovoltaic system without solar array current sensor is proposed. The solar array current information is obtained from the sliding-mode observer and fed into the MPPT to generate the reference voltage. The parameter values such as capacitances can be changed up to 50% from their nominal values, and the linear observer cannot estimate the correct state values under the parameter variations and noisy environments. The structure of a sliding-mode observer is simple, but it shows the robust tracking property against modeling uncertainties and parameter variations. In this paper, the sliding-mode observer for the solar array current has been proposed to compensate for the parameter variations. The mathematical modeling and the experimental results verify the validity of the proposed method <s> BIB001 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> MAXIMUM POWER POINT TRACKING <s> The success of wireless sensor networks and their pervasive use is somehow constrained by energy supply which, generally provided by batteries, is a finite resource. Energy harvesting mechanisms must hence be taken into account to grant a long time operational life, with solar energy being the most interesting one in outdoor deployments due to its relatively high power density. In this paper we propose a low-power maximum power point tracker (MPPT) circuit specifically designed for wireless sensor nodes (hence effective, flexible, low cost and power-aware), i.e., a power transferring circuit for optimally conveying solar energy into rechargeable batteries even in not optimal weather conditions. High efficiency is granted by an ad hoc adaptive algorithm which, by keeping the MPPT electronics in its optimal working point, maximizes energy transfer from the solar cell to the batteries. The suggested implementation is particularly effective in critical weather conditions where traditional solutions do not work and is characterized by a flexible enough design for immediately hosting, in a plug in fashion, different solar panels and battery typologies. <s> BIB002 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> MAXIMUM POWER POINT TRACKING <s> Tracking the maximum power point (MPP) of a photovoltaic array is an essential part of a PV system. Maximum Peak Power Tracking (MPPT) Algorithms have reached a matured level for performance in terms of efficiency, speed, avoiding multiple maxima syndrome, dynamic behavior and implementation. As such, many maximum power point tracking methods have been developed and implemented. It has become very difficult to adequately determine which method is most appropriate for a given PV system application. This paper deals with a comprehensive review of Maximum Peak Power Tracking algorithms, control approaches, design features and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of improved MPPT approaches to researchers, designers and application engineers working on MPPT based photovoltaic systems. The paper also summarizes major <s> BIB003 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> MAXIMUM POWER POINT TRACKING <s> This paper is a simulation study of maximum power point tracking (MPPT) for photovoltaic systems using perturb and observe algorithm. Maximum power point tracking (MPPT) plays an important role in photovoltaic systems because it maximize the power output from a PV system for a given set of conditions, and therefore maximize the array efficiency and minimize the overall system cost. Since the maximum power point (MPP) varies, based on the irradiation and cell temperature, appropriate algorithems must be utilized to track the (MPP) and maintain the operation of the system in it. Matlab/Simulink is used to establish a model of photovoltaic system with (MPPT) function. This system is developed by combining the models established of solar PV module and DC-DC Boost converter. The system is simulated under different climate conditions. Simulation results show that the photovoltaic simulation system can track the maximum power point accurately. A particular typical 50W solar panel was used for model evaluation, and results of simulation were compared with points taken directly from the data sheet and curves published by the manufacturers. <s> BIB004 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> MAXIMUM POWER POINT TRACKING <s> This paper presents maximum power point tracker (MPPT) with incremental conductance (Inc.Cond) method with implantation of two different topologies of boost converter. Conventional and conventional interleaved boost converters are chosen. These two systems are compared together in the case of efficiency and speed. For both topologies MATLAB-SIMULINK is applied to model the system. Final results and discussions are represented to make the comparison much easier. © 2010 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [name organizer] <s> BIB005 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> MAXIMUM POWER POINT TRACKING <s> Abstract In this paper a novel photovoltaic (PV) emulating scheme for testing maximum power point tracking (MPPT) algorithms and PV inverters has been proposed. It is constructed by the parallel connection of conventional solar panels with a DC power supply operating in current source mode. The advantages of the proposed scheme are cost-effectiveness, relatively easy implementation and indoor testing of MPPT algorithms and power converters avoiding weather and time of day dependency on solar irradiation levels. Furthermore, the proposed PV emulator avoids the bandwidth problem associated with the dc converter based PV emulating systems. Detailed circuit connection, parameters, electrical characteristics and mathematical model of the PV emulator are presented and discussed. Proposed PV emulating system has been used to test a boost DC/DC converter controlled by Perturb & Observe (P&O) MPPT algorithm. Test results confirmed the effectiveness of the proposed PV emulation system and all achieved results correspond well to the original designed values. <s> BIB006 </s> IMPROVING THE EFFICIENCY OF A PHOTOVOLTAIC SYSTEM BY INCORPORATING TRACKING SYSTEM AND MPPT: A REVIEW <s> MAXIMUM POWER POINT TRACKING <s> Abstract This paper presents simulation of incremental conductance (IncCond) maximum power point tracking (MPPT) algorithm used in solar array power systems with direct control method. The main difference between the proposed system to that of the existing MPPT systems includes the elimination of the proportional–integral control loop and investigation of the effect of simplifying the control circuit. Contributions are made in several aspects of the whole system, including converter design, system simulation and controller programming. The resultant system is capable of tracking MPPs accurately and rapidly without steady-state oscillation, and also, its dynamic performance is satisfactory. The IncCond algorithm is used to track MPPs because it performs precise control under rapidly changing atmospheric conditions. MATLAB and Simulink were employed for simulation studies. <s> BIB007
The output from the photovoltaic cell is affected by the changes in solar irradiance and cell temperature. In order to extract maximum power from the cell under varying loads and atmospheric conditions, Maximum Power Point Tracking (MPPT) controllers are to be provided. The incorporation of MPPT in the photovoltaic conversion circuit reduces the number of solar panels required to extract the desired output power. The electrical characteristics of a solar cell are nonlinear which lowers the effectiveness of extracting energy in non-stationary environments. The photovoltaic module is to operate at peak power for improved efficiency. When the photovoltaic array is directly connected to a load, the operating point of the system will be at the intersection of the current-voltage curve of the array and the load line BIB003 . At most times, this operating point is not the module's maximum power point. Thus an oversized array must be used to obtain the required power from the module. In order to obtain the maximum power from the system irrespective of the disturbances, MPPT system is used. The photovoltaic source terminal voltage is effectively controlled such that the product of voltage and current achieves a maximum value. This maximum value is called maximum power point and the point at which it is attained is known as the knee of the PV diode normal current-voltage curve BIB006 . Goudar, Patil and Kumar BIB003 reviewed the algorithms available to track the maximum point of a photovoltaic module. The various algorithms for tracking the maximum power point are open-circuit voltage method, perturb and observe algorithm (P&O), Optimized P&O algorithm, variable step incremental conductance algorithm, parasitic capacitance algorithm, fuzzy logic control, neural network. Mohapatra et al  studied a number of maximum power point tracking algorithms that would prove effective for solar panels under partial shading conditions. The solar panels that do not have a tracker are not normal to the solar incidence radiation throughout the day. Thus during the course of the day, the panel is subjected to varying degrees of irradiance due to the movement of the earth and shading conditions due to the placement of solar panels. Hybrid algorithms, new modelling approach and converter topologies have been introduced to track the maximum power point. Alsadi and Alsayid BIB004 proposed a system to simulate the maximum power point tracking using the perturb and observe algorithm for photovoltaic systems. Matlab/Simulink was used for establishing a model of the photovoltaic system with MPPT function. This model was combined with the solar PV module and the DC-DC Boost converter models. Different climatic conditions were simulated and evaluated. It was found that the system tracked the maximum power point accurately. Alippi and Galperti BIB002 proposed a low-power MPPT circuit for wireless sensorless nodes. The system was found to be effective in critical weather conditions such as when the cell was in shadow or when the weather was cloudy. Mirbagheri, Mekhilef and Mirhassani BIB005 introduced maximum power point tracker with incremental conductance method in a one-diode model. Two topologies were selected for testing and were compared. The conventional interleaved boost converter proved to be more efficient and faster than the conventional boost converter. Kumar, Bhaskar and Koti BIB007 compared the incremental conductance maximum power point tracking algorithm used in solar array power systems with the existing direct control method. The proposed method eliminated the use of proportional integral control loop method and proved to be more efficient and accurate than the short circuit current MPPT method especially at varying temperature. Kim, Kin and Youn BIB001 proposed a maximum power point tracker for a photovoltaic system without the use of a solar array current sensor. The information on solar array current was obtained from a sliding-mode observer. As the estimated solar array current had some chattering ripples, it was averaged over a half cycle of the alternating current utility grid frequency with the measured solar array voltage. Through simulation and experiments, it was observed that the system provided a superior performance compared to the conventional system and eliminated the use of an expensive current sensor.