Development of a microcontroller-based, photovoltaic maximum power point tracking control system
TL;DR: In this paper, a buck-type DC/DC converter is used to maximize the photovoltaic array output power, irrespective of the temperature and irradiation conditions and of the load electrical characteristics.
Abstract: Maximum power point tracking (MPPT) is used in photovoltaic (PV) systems to maximize the photovoltaic array output power, irrespective of the temperature and irradiation conditions and of the load electrical characteristics. A new MPPT system has been developed, consisting of a buck-type DC/DC converter, which is controlled by a microcontroller-based unit. The main difference between the method used in the proposed MPPT system and other techniques used in the past is that the PV array output power is used to directly control the DC/DC converter, thus reducing the complexity of the system. The resulting system has high-efficiency, lower-cost and can be easily modified to handle more energy sources (e.g., wind-generators). The experimental results show that the use of the proposed MPPT control increases the PV output power by as much as 15% compared to the case where the DC/DC converter duty cycle is set such that the PV array produces the maximum power at 1 kW/m/sup 2/ and 25/spl deg/C.
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TL;DR: The many different techniques for maximum power point tracking of photovoltaic (PV) arrays are discussed in this paper, and at least 19 distinct methods have been introduced in the literature, with many variations on implementation.
Abstract: 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.
5,022 citations
TL;DR: In this article, the perturb and observe (PO) algorithm is used in photovoltaic (PV) systems to maximize the PV array output power by tracking continuously the maximum power point (MPP) which depends on panels temperature and on irradiance conditions.
Abstract: Maximum power point tracking (MPPT) techniques are used in photovoltaic (PV) systems to maximize the PV array output power by tracking continuously the maximum power point (MPP) which depends on panels temperature and on irradiance conditions. The issue of MPPT has been addressed in different ways in the literature but, especially for low-cost implementations, the perturb and observe (PO moreover, it is well known that the P&O algorithm can be confused during those time intervals characterized by rapidly changing atmospheric conditions. In this paper it is shown that, in order to limit the negative effects associated to the above drawbacks, the P&O MPPT parameters must be customized to the dynamic behavior of the specific converter adopted. A theoretical analysis allowing the optimal choice of such parameters is also carried out. Results of experimental measurements are in agreement with the predictions of theoretical analysis.
2,696 citations
TL;DR: A modified variable step size INC MPPT algorithm is proposed, which automatically adjusts the step size to track the PV array maximum power point and can effectively improve the MPPT speed and accuracy simultaneously.
Abstract: Maximum power point tracking (MPPT) techniques are employed in photovoltaic (PV) systems to make full utilization of PV array output power which depends on solar irradiation and ambient temperature. Among all the MPPT strategies, the incremental conductance (INC) algorithm is widely used due to the high tracking accuracy at steady state and good adaptability to the rapidly changing atmospheric conditions. In this paper, a modified variable step size INC MPPT algorithm is proposed, which automatically adjusts the step size to track the PV array maximum power point. Compared with the conventional fixed step size method, the proposed approach can effectively improve the MPPT speed and accuracy simultaneously. Furthermore, it is simple and can be easily implemented in digital signal processors. A theoretical analysis and the design principle of the proposed method are provided and its feasibility is also verified by simulation and experimental results.
1,235 citations
Cites background or methods from "Development of a microcontroller-ba..."
...is more attractive due to the simplified control structure [6]....
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...The PV output power is used to directly control the power converter duty cycle to reduce well the complexity of the system [6]....
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...The MPP voltage has been reported to be nearly 78% of the open voltage [6]....
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...The PV output power is employed to directly control the converter duty cycle, contributing to a simplified control system [6]....
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TL;DR: In this paper, a MATLAB-based modeling and simulation scheme is presented for studying the I-V and P-V characteristics of a PV array under a nonuniform insolation due to partial shading.
Abstract: The performance of a photovoltaic (PV) array is affected by temperature, solar insolation, shading, and array configuration. Often, the PV arrays get shadowed, completely or partially, by the passing clouds, neighboring buildings and towers, trees, and utility and telephone poles. The situation is of particular interest in case of large PV installations such as those used in distributed power generation schemes. Under partially shaded conditions, the PV characteristics get more complex with multiple peaks. Yet, it is very important to understand and predict them in order to extract the maximum possible power. This paper presents a MATLAB-based modeling and simulation scheme suitable for studying the I-V and P-V characteristics of a PV array under a nonuniform insolation due to partial shading. It can also be used for developing and evaluating new maximum power point tracking techniques, especially for partially shaded conditions. The proposed models conveniently interface with the models of power electronic converters, which is a very useful feature. It can also be used as a tool to study the effects of shading patterns on PV panels having different configurations. It is observed that, for a given number of PV modules, the array configuration (how many modules in series and how many in parallel) significantly affects the maximum available power under partially shaded conditions. This is another aspect to which the developed tool can be applied. The model has been experimentally validated and the usefulness of this research is highlighted with the help of several illustrations. The MATLAB code of the developed model is freely available for download.
1,139 citations
Cites background from "Development of a microcontroller-ba..."
...The presence of multiple peaks reduces the effectiveness of the existing maximum power point tracking (MPPT) schemes [1]–[3] due to their inability to discriminate between the local and global peaks....
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TL;DR: In this article, an analytical expression for the optimal power flow from a rectified piezoelectric device is derived, and an energy harvesting circuit consisting of an AC-DC rectifier with an output capacitor, an electrochemical battery, and a switch-mode DC-DC converter that controls the energy flow into the battery.
Abstract: This paper describes an approach to harvesting electrical energy from a mechanically excited piezoelectric element. A vibrating piezoelectric device differs from a typical electrical power source in that it has a capacitive rather than inductive source impedance, and may be driven by mechanical vibrations of varying amplitude. An analytical expression for the optimal power flow from a rectified piezoelectric device is derived, and an "energy harvesting" circuit is proposed which can achieve this optimal power flow. The harvesting circuit consists of an AC-DC rectifier with an output capacitor, an electrochemical battery, and a switch-mode DC-DC converter that controls the energy flow into the battery. An adaptive control technique for the DC-DC converter is used to continuously implement the optimal power transfer theory and maximize the power stored by the battery. Experimental results reveal that use of the adaptive DC-DC converter increases power transfer by over 400% as compared to when the DC-DC converter is not used.
1,072 citations
References
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Book•
26 Jul 1989
TL;DR: In this paper, the authors present a simulation of power switch-mode converters for zero-voltage and/or zero-current switchings in power electronic converters and systems.
Abstract: Partial table of contents: Overview of Power Semiconductor Switches Computer Simulation of Power Electronic Converters and Systems GENERIC POWER ELECTRONIC CIRCUITS dc--dc Switch-Mode Converters Resonant Converters: Zero-Voltage and/or Zero-Current Switchings POWER SUPPLY APPLICATIONS Power Conditioners and Uninterruptible Power Supplies MOTOR DRIVE APPLICATIONS dc Motor Drives Induction Motor Drives Synchronous Motor Drives OTHER APPLICATIONS Residential and Industrial Applications Optimizing the Utility Interface with Power Electronic Systems SEMICONDUCTOR DEVICES Basic Semiconductor Physics Power Diodes Power MOSFETs Thyristors Emerging Devices and Circuits PRACTICAL CONVERTER DESIGN CONSIDERATIONS Snubber Circuits Gate and Base Drive Circuits Design of Magnetic Components Index
5,911 citations
"Development of a microcontroller-ba..." refers background in this paper
...inductor current at maximum output power does not exceed the power switch current rating [ 12 ]....
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...Taking into account that the ripple of the PV output current must be less than 2% of its mean value, [ 12 ], the input capacitor value is calculated to be...
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Book•
01 Jul 1991
TL;DR: In this paper, the authors present a complete instruction in one volume to design a switching power supply circuit using a tutorial, how-to approach, using higher switching frequencies, new topologies, and integrated PWM chips.
Abstract: Using this book as a guide, Pressman promises, even a novice can immediately design a complete switching power supply circuit. No other book has such complete instruction in one volume. Using a tutorial, how-to approach, Pressman covers every aspect of this new technology, including circuit and transformer design, using higher switching frequencies, new topologies, and integrated PWM chips. For this latest edition, Pressman has added in-depth discussion of power factor correction, high-frequency ballasts for fluorescent lamps, and low-input voltage power supplies for laptop computers.
Table of contents
Part I:Fundamental Switching Regulators Buck, Boost, and Investor Topologies.Push-Pull and Forward Converter Topologies.Half- and Full-Bridge Converter Topologies.Flyback Converter Topologies.Current-Mode and Current-Fed Topologies.Miscellaneous Topologies.Part II: Magnetics and Circuits Designs.Transformer and Magnetic Design.Bipolar Power Translator Base Drives.MOSFET Power Transistors and Input Drive Circuits.Magnetic-Amplifier Postregulators.Turnon, Turnoff Switching Losses and Snubbers.Feedback-Loop Stabilization.Resonant Converters.Part III: Typical Switching Power Supply Warehouse.Part IV: Newer Applications for Switching Power Supply Technique.Power Factor, Power Factor Correction.High-Frequency Power Sources for Fluorescent Lamps.Low-Input-Voltage Regulators for Laptop Computers and Portable Electronics.
1,015 citations
"Development of a microcontroller-ba..." refers background in this paper
...pacitance of the MOSFET source and the output inductor [13], but it does not affect the MPPT operation....
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TL;DR: A simple method of tracking the maximum power points (MPPs) and forcing the system to operate close to these points is presented, and the principle of energy conservation is used to derive the large- and small-signal model and transfer function.
Abstract: Photovoltaic systems normally use a maximum power point tracking (MPPT) technique to continuously deliver the highest possible power to the load when variations in the insulation and temperature occur. It overcomes the problem of mismatch between the solar arrays and the given load. A simple method of tracking the maximum power points (MPPs) and forcing the system to operate close to these points is presented. The principle of energy conservation is used to derive the large- and small-signal model and transfer function. By using the proposed model, the drawbacks of the state-space-averaging method can be overcome. The TI320C25 digital signal processor (DSP) was used to implement the proposed MPPT controller, which controls the DC/DC converter in the photovoltaic system. Simulations and experimental results show excellent performance.
746 citations
"Development of a microcontroller-ba..." refers methods in this paper
...In the method described in [7], the power converter is controlled using the PV array output power [Fig....
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TL;DR: A high-performance discrete MPPT controller that tracks the maximum power point with zero-slope regulation and current-mode control is presented and the DC-DC power converter is capable of combining with the BESS for performing the functions of power conditioning and active power filtering.
Abstract: This paper introduces a residential photovoltaic (PV) energy storage system, in which the PV power is controlled by a DC-DC power converter and transferred to a small battery energy storage system (BESS). For managing the power, a pattern of daily operation considering the load characteristic of the homeowner, the generation characteristic of the PV power, and the power-leveling demand of the electric utility is prescribed. The system looks up the pattern to select the operation mode, so that powers from the PV array, the batteries and the utility are utilized in a cost-effective manner. As for the control of the system, a novel control technique for the maximum power-point tracking (MPPT) of the PV array is proposed, in which the state-averaged model of the DC-DC power converter, including the dynamic model of the PV array, is derived. Accordingly, a high-performance discrete MPPT controller that tracks the maximum power point with zero-slope regulation and current-mode control is presented. With proposed arrangements on the control of the BESS and the current-to-power scaling factor setting, the DC-DC power converter is capable of combining with the BESS for performing the functions of power conditioning and active power filtering. An experimental 600 W system is implemented, and some simulation and experimental results are provided to demonstrate the effectiveness of the proposed system.
421 citations
TL;DR: In this paper, a microcomputer-based control of a residential photovoltaic power conditioning system is described, which is responsible for array current feedback control, maximum power tracking control, array safe zone steering control, phase-locked reference wave synthesis, sequencing control, and some diagnostics.
Abstract: Microcomputer-based control of a residential photovoltaic power conditioning system is described. The microcomputer is responsible for array current feedback control, maximum power tracking control, array safe zone steering control, phase-locked reference wave synthesis, sequencing control, and some diagnostics. The control functions are implemented using Intel 8751 single-chip microcomputer-based hardware and software. The controller has been tested in the laboratory with the prototype power conditioner and shows excellent performance.
339 citations