The many different techniques for maximum power point tracking of photovoltaic (PV) arrays are discussed. The techniques are taken from the literature dating back to the earliest methods. It is shown that at least 19 distinct methods have been introduced in the literature, with many variations on implementation. This paper should serve as a convenient reference for future work in PV power generation.

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Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques

http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

This paper provides a comprehensive review of the maximum power point tracking (MPPT) techniques applied to photovoltaic (PV) power system available until January, 2012. A good number of publications report on different MPPT techniques for a PV system together with implementation. But, confusion lies while selecting a MPPT as every technique has its own merits and demerits. Hence, a proper review of these techniques is essential. Unfortunately, very few attempts have been made in this regard, excepting two latest reviews on MPPT [Salas, 2006], [Esram and Chapman, 2007]. Since, MPPT is an essential part of a PV system, extensive research has been revealed in recent years in this field and many new techniques have been reported to the list since then. In this paper, a detailed description and then classification of the MPPT techniques have made based on features, such as number of control variables involved, types of control strategies employed, types of circuitry used suitably for PV system and practical/commercial applications. This paper is intended to serve as a convenient reference for future MPPT users in PV systems.

A Comparative Study on Maximum Power Point Tracking Techniques for Photovoltaic Power Systems

After adequately demonstrating the ability to solve dierent two-objective optimization problems, multi-objective evolutionary algorithms (MOEAs) must now show their ecacy in handling problems having more than two objectives. In this paper, we have suggested three dierent approaches for systematically designing test problems for this purpose. The simplicity of construction, scalability to any number of decision variables and objectives, knowledge of exact shape and location of the resulting Pareto-optimal front, and introduction of controlled diculties in both converging to the true Pareto-optimal front and maintaining a widely distributed set of solutions are the main features of the suggested test problems. Because of the above features, they should be found useful in various research activities on MOEAs, such as testing the performance of a new MOEA, comparing dierent MOEAs, and better understanding of the working principles of MOEAs.

/pdf/scalable-test-problems-for-evolutionary-multiobjective-278lk39pfq.pdf

Scalable Test Problems for Evolutionary Multiobjective Optimization

This paper presents evaluations among the most usual maximum power point tracking (MPPT) techniques, doing meaningful comparisons with respect to the amount of energy extracted from the photovoltaic (PV) panel [tracking factor (TF)] in relation to the available power, PV voltage ripple, dynamic response, and use of sensors. Using MatLab/Simulink and dSPACE platforms, a digitally controlled boost dc-dc converter was implemented and connected to an Agilent Solar Array E4350B simulator in order to verify the analytical procedures. The main experimental results are presented for conventional MPPT algorithms and improved MPPT algorithms named IC based on proportional-integral (PI) and perturb and observe based on PI. Moreover, the dynamic response and the TF are also evaluated using a user-friendly interface, which is capable of online program power profiles and computes the TF. Finally, a typical daily insulation is used in order to verify the experimental results for the main PV MPPT methods.

Evaluation of the Main MPPT Techniques for Photovoltaic Applications

This paper proposes a high performance, single-stage inverter topology for grid connected PV systems. The proposed configuration can not only boost the usually low photovoltaic (PV) array voltage, but can also convert the solar dc power into high quality ac power for feeding into the grid, while tracking the maximum power from the PV array. Total harmonic distortion of the current, fed into the grid, is restricted as per the IEEE-519 standard. The proposed topology has several desirable features such as better utilization of the PV array, higher efficiency, low cost and compact size. Further, due to the very nature of the proposed topology, the PV array appears as a floating source to the grid, thereby enhancing the overall safety of the system. A survey of the existing topologies, suitable for single-stage, grid connected PV applications, is carried out and a detailed comparison with the proposed topology is presented. A complete steady-state analysis, including the design procedure and expressions for peak device stresses, is included. Necessary condition on the modulation index "M" for sinusoidal pulsewidth modulated control of the proposed inverter topology has also been derived for discontinuous conduction mode operation. All the analytical, simulation and experimental results are presented.

A Single-Stage Grid Connected Inverter Topology for Solar PV Systems With Maximum Power Point Tracking

This work presents a comparison of various maximum power point tracking (MPPT) techniques applied to 1-Phi, single-stage, grid-connected photovoltaic (PV) systems. A representative single-stage grid-connected PV system, based on buck-boost converter topology operating in discontinuous current mode (DCM) with sine-triangle pulse width modulation (SPWM) and feeding sinusoidal power into the grid, is considered for this study. MPPT techniques are compared on the basis of the time taken to reach (track) the MPP, operating point oscillations in the vicinity of MPP and the dependence of the algorithms, if any, on array configuration and parameters. Comparison is also made on the basis of the energy extracted from the PV source during the transient tracking phase. In this context, an energy tracking factor term (E
 TF
) is introduced and defined. It is observed that all the MPPT schemes studied have their own merits and demerits. The ripple correlation and beta methods offer an overall good combination of desirable features. All the results of this study are presented.

Comparison of the performance of maximum power point tracking schemes applied to single-stage grid-connected photovoltaic systems

This paper presents a new algorithm for tracking maximum power point in photovoltaic systems. This is a fast tracking algorithm, where an initial approximation of maximum power point is (MPP) quickly achieved using a variable step-size. Subsequently, the exact maximum power point can be targeted using any conventional method like the hill-climbing or incremental conductance method. Thus, the drawback of a fixed small step-size over the entire tracking range is removed, resulting in reduced number of iterations and much faster tracking compared to conventional methods. The strength of the algorithm comes from the fact that instead of tracking power, which does not have a one-to-one relationship with duty cycle, it tracks an intermediate variable /spl beta/, which has a monotonically increasing, one-to-one relationship. The algorithm has been verified on a photovoltaic system modeled in Matlab-Simulink software. The algorithm significantly improves the efficiency during the tracking phase as compared to a conventional algorithm. It is especially suitable for fast changing environmental conditions. The proposed algorithm can be implemented on any fast controller such as the digital signal processor. All the details of this study are presented.

A new algorithm for rapid tracking of approximate maximum power point in photovoltaic systems

A new, hybrid integrated topology, fed by photovoltaic (PV) and fuel cell (FC) sources and suitable for distributed generation applications, is proposed. It works as an uninterruptible power source that is able to feed a certain minimum amount of power into the grid under all conditions. PV is used as the primary source of power operating near maximum power point (MPP), with the FC section (block), acting as a current source, feeding only the deficit power. The unique "integrated" approach obviates the need for dedicated communication between the two sources for coordination and eliminates the use of a separate, conventional dc/dc boost converter stage required for PV power processing, resulting in a reduction of the number of devices, components, and sensors. Presence of the FC source in parallel (with the PV source) improves the quality of power fed into the grid by minimizing the voltage dips in the PV output. Another desirable feature is that even a small amount of PV power (e.g., during low insolation), can be fed into the grid. On the other hand, excess power is diverted for auxiliary functions like electrolysis, resulting in an optimal use of the energy sources. The other advantages of the proposed system include low cost, compact structure, and high reliability, which render the system suitable for modular assemblies and "plug-n-play" type applications. All the analytical, simulation, and experimental results of this research are presented.

An Integrated Hybrid Power Supply for Distributed Generation Applications Fed by Nonconventional Energy Sources

A new single-stage grid-connected inverter, suitable for distributed generation applications, is proposed. The inverter is universal in the sense that it can be switched between buck, boost, and buck--boost configurations by appropriately altering the pulse width modular (PWM) control. Discontinuous current mode (DCM) operation is implemented to facilitate shuffling between configurations during the converter operation. Such flexibility ensures maximum benefit of the buck, boost, and the buck--boost operations (e.g., low device stresses, higher efficiency, higher boosting capability, etc.). The PWM is achieved by comparing a high frequency carrier (triangular) waveform with a suitable reference waveform, which is not necessarily sinusoidal, but has a shape specific to the individual configuration and is derived by equating the power fed into the grid with that extracted from the source during each switching cycle. The values of the components (inductors and capacitors) need to be optimized so that DCM is maintained and the required amount of energy is transferred to the grid in all the three configurations during their respective operation. All the design expressions have been derived. A salient feature of this inverter is its compatibility with various types of sources (PV array, fuel cell, etc.) with varying voltage levels and control requirements. Being single-stage, the proposed topology offers additional advantages like modularity, compactness, and low cost. All the details of simulation and experimental work are presented.

Sachin Jain

Papers

A Single-Stage Grid Connected Inverter Topology for Solar PV Systems With Maximum Power Point Tracking

Comparison of the performance of maximum power point tracking schemes applied to single-stage grid-connected photovoltaic systems

A new algorithm for rapid tracking of approximate maximum power point in photovoltaic systems

An Integrated Hybrid Power Supply for Distributed Generation Applications Fed by Nonconventional Energy Sources

Universal Single-Stage Grid-Connected Inverter