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

Solid-state switch-mode rectification converters have reached a matured level for improving power quality in terms of power-factor correction (PFC), reduced total harmonic distortion at input AC mains and precisely regulated DC output in buck, boost, buck-boost and multilevel modes with unidirectional and bidirectional power flow. This paper deals with a comprehensive review of improved power quality converters (IPQCs) configurations, control approaches, design features, selection of components, other related considerations, and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of IPQC technology to researchers, designers and application engineers working on switched-mode AC-DC converters. A classified list of more than 450 research publications on the state of art of IPQC is also given for a quick reference.

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A review of single-phase improved power quality AC-DC converters

Wireless power transfer (WPT) using magnetic resonance is the technology which could set human free from the annoying wires. In fact, the WPT adopts the same basic theory which has already been developed for at least 30 years with the term inductive power transfer. WPT technology is developing rapidly in recent years. At kilowatts power level, the transfer distance increases from several millimeters to several hundred millimeters with a grid to load efficiency above 90%. The advances make the WPT very attractive to the electric vehicle (EV) charging applications in both stationary and dynamic charging scenarios. This paper reviewed the technologies in the WPT area applicable to EV wireless charging. By introducing WPT in EVs, the obstacles of charging time, range, and cost can be easily mitigated. Battery technology is no longer relevant in the mass market penetration of EVs. It is hoped that researchers could be encouraged by the state-of-the-art achievements, and push forward the further development of WPT as well as the expansion of EV.

Wireless Power Transfer for Electric Vehicle Applications

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

Acoustic impedance-matched surfaces do not reflect incident waves. Traditional means of acoustic absorption have so far resulted in imperfect impedance matching and bulky structures, or require costly and sophisticated electrical design. Inspired by electromagnetic metamaterials, a subwavelength acoustically reflecting surface with hybrid resonances and impedance-matched to airborne sound at tunable frequencies is now demonstrated.

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Acoustic metasurface with hybrid resonances

A family of offline bridgeless quasi-resonant LED drivers is introduced. The prominent features of the proposed drivers are the capacitive isolation feature, inherent low line-current distortion, and high power factor. The concept is validated by a 30-W prototype operated in the range of 150–200 kHz and 30-V dc output (LED string voltage).

A Family of Bridgeless Quasi-Resonant LED Drivers

This work is concerned with maximum power point tracking in photovoltaic systems. Under the suggested method, tracking of the maximum power point is accomplished partially by a linear control loop that emulates a nearly matched load line and partially by the fine tuning of this load line employing an iterative process that resembles conventional MPPT methods. This way, excellent tracking is achieved both in steady state and in transient situations.

Load line emulation based maximum power point tracking

This paper deals with the efficiency of systems consisting of multiple power sources. The operating point ensuring maximum efficiency is defined and solved analytically. Moreover, it is shown that, in the case of linear sources, the maximum efficiency is determined solely by the load power and the network's maximum power, independently of the sources' internal construction and their connectivity. The generic circuit theory treatment that is proposed applies to distributed power generation (smart grid, photovoltaic, fuel cells, etc.) and to distributed load systems (LED arrays, microprocessors).

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On the Maximum Efficiency of Systems Containing Multiple Sources

This paper presents a flexible energy harvesting system with an analog maximum power point tracking (MPPT) algorithm that operates using the output current. The proposed MPPT circuit is simplified as only one parameter needs to be measured and is implemented by fully analog design. Simulation and experiment results validate that the proposed MPPT algorithm has a tracking efficiency of 93.7% with a fast converging speed. The energy harvesting system is implemented and tested with a flexible solar panel, and thus can be used in wearable devices.

A flexible and wearable energy harvester with an efficient and fast-converging analog MPPT

Module integrated converters (MIC) enhance the energy capture of photovoltaic modules under mismatch conditions. It seems that the H-bridge based buck-boost topology is a very attractive choice for this purpose due to its high efficiency and wide gain range. This work suggests a sliding mode control scheme for this topology that exhibits fast and stable dynamic response with inherent current limiting and smooth transition between operation modes (buck, boost, or bridge). Moreover, the switching frequency reduces as the photovoltaic module voltage approaches its nominal value, which increases the power efficiency.

Doron Shmilovitz

Papers

A Family of Bridgeless Quasi-Resonant LED Drivers

Load line emulation based maximum power point tracking

On the Maximum Efficiency of Systems Containing Multiple Sources

A flexible and wearable energy harvester with an efficient and fast-converging analog MPPT

Sliding mode control of photovoltaic module integrated buck-boost converters