Optimal Inverter And Wire Selection For Solar Photovoltaic Fencing Applications

Despite the benefits and the economic advantages of agrivoltaics, capital costs limit deployment velocity. One recent potential solution to this challenge is to radically reduce the cost of racking materials by using existing farm fencing as vertical photovoltaic (PV) racking. This type of fenced-based PV system is inherently electrically challenging because of the relatively long distances between individual modules that are not present in more densely packed conventional solar PV farms. This study provides practical insights for inverter selection and wire sizing optimization for fence-based agrivoltaic systems. Numerical simulation sensitivities on the levelized cost of electricity (LCOE) were performed for 1) distance from the fence to the AC electrical panel, 2) inverter costs, and 3) geographic locations. The results showed that microinverters had better performance when the cross-over fence length was under 30 m or when the system was designed with less than seven solar PV modules, whereas string inverters were a better selection for longer fences. The cross-over number of modules depends significantly on the cost of the inverters, which is a parameter that influences the system\u27s design. The capital costs for a fence retrofit are far less than for any form of conventional PV racking. In addition, the LCOE of the vertical fencing solar agrivoltaic system can be competitive with conventional ground-mounted solar PV for the niche of farmers. Especially, when they are located between the latitudes of 10° and 50° in either the northern or southern hemisphere, and coupled with their ancillary benefits they represent a great alternative for conventional PV systems

Analysis and testing of the IPB pico-hydro emulation platform with grid connection

The global context in which there is a need to reduce environmental impacts intensifies the search for new technologies for renewable sources. In addition to environmental issues, access to basic rights and social inclusion are also motivation for electricity generation, in a context including distributed generation (DG). Currently, the pico hydro power plant is an attractive application because of its resource availability; also, it is an interesting solution for a microgrid (on-grid or off-grid). On the other hand, usually, the conversion system is not "plug and play". This project presents the tests of convertion system for a "plug and play" solution, using different turbines and water wheel, permanent magnet synchronous generators (PMSG) and photovoltaic (PV) inverters. In this approach, generators can work at variable speed, having an overvoltage protection circuit. The prerequisites for device integration must be considered: power compatibility, minimum and maximum limit voltage, and the maximum current of PV inverter. The tests were done in the pico-hydro emulation platform, in the Superior School of Technology and Management (ESTiG). The low head propeller, Turgo, and Pelton turbines are tested in the emulation platform; as well as the vertical axis water wheel. The turbines were connected to the grid using SOLAX inverters (up to 1650 W) and OMNIK (up to 2300 W), presenting satisfactory results in both. The water wheel tests used five microinverters (up to 300 W), showing grid connection with three: BEON, GWL, and INVOLAR.O contexto global em que há necessidade de redução dos impactos ambientais intensifica a busca por novas tecnologias para fontes renováveis. Além das questões ambientais, o acesso a direitos básicos e inclusão social também são estímulos à geração de energia elétrica em áreas remotas, incluindo o contexto de geração distribuída (GD). Atualmente, as plantas pico-hídricas têm sua aplicação interessante pela disponibilidade do recurso primário; e interessante solução para microrredes (on-grid ou off-grid). Por outro ponto de vista, geralmente o sistema de conversão não é "plug and play". Este projeto apresenta o teste dos sistemas de conversão com uma solução "plug and play", uttilizando diferentes turbinas, geradores síncronos de ímã permanente (GSIP) e inversores fotovoltaicos. Utilizou-se a abordagem em que os geradores podem trabalhar em velocidade variável, tendo um circuito de proteção contra sobre-tensão. Devem ser considerados os pré-requisitos para integração dos componentes: compatibilidade de potência, tensões limites e corrente máxima do inversor fotovoltaico. Os testes foram feitos na plataforma de emulação de sistemas pico-hídricos na Escola Superior de Tecnologia e Gestão (ESTiG). Testaram-se turbinas para baixa queda do tipo hélice, Turgo e Pelton; e também a roda d’água de eixo vertical. A conexão das turbinas com a rede foi feita com os inversores SOLAX (até 1650 W) e OMNIK (até 2300 W), apresentando resultados satisfatórios em ambos. Com a roda d’água foram testados cinco microinversores (até 300 W), apresentando conexão com três: BEON, GWL e INVOLAR

TECHNICAL AND ECONOMICAL ANALYSIS OF RESIDENTIAL SOLAR PHOTOVOLTAIC SYSTEMS

Technical improvements and scaling have resulted in a significant reduction in solar photovoltaic (PV) module costs, which have resulted in PV industry growth both globally as well as in the United States. In many regions there have been favorable policies for solar energy due to the positive public response and support for growth of solar energy. As the demand for PV installations continues to increase, the costs continue to decline, feeding a virtuous cycle. This thesis is composed of a three part study directed towards technical as well as economical analysis of new technologies for residential solar photovoltaic systems for increasing in the PV penetration level as well as reducing greenhouse gas (GHG) emissions in the United States. First, a technical and economical analysis is performed of a complete off-grid hybrid system comprising a solar PV unit, battery storage unit and cogen unit for residential sector in United States. A new method of quantifying the economic viability of off-grid PV+battery+CHP systems by calculating the LCOE of the technology is compared to centralized grid electricity. A case study for residential electricity and thermal demand in an extreme worst case environment (Houghton, Michigan) is provided to demonstrate the methodology. Moreover, a sensitivity analysis was carried out for various input assumptions to provide decision makers with clear guides to the viability of such a hybrid system and to provide support through a preliminary analysis that indicated a potential increase in grid defection in the U.S. in the near future. Second, a technical evaluation is made as well as safety analysis is made for a fully inclusive, commercial, off-the-shelf PV system (normally consisting of a PV module and microinverter), which a prosumer can install by plugging it into an electric outlet and avoiding the need for significant permitting, inspection and interconnection processes. Such systems are referred to as ‘plug and play solar’ systems. The relevant codes and standards from the National Electric Code, local jurisdictions and utilities was reviewed for PV with a specific focus on plug-and-play solar. A streamlined application process is provided with only technical requirements to ease utility implementation. The results indicated that supporting the installation of plug-and-play solar PV with UL (Underwriters Laboratory) certified microinverters will improve PV system performance, will lead to faster uptake and higher PV penetration levels, will also improve prosumer economics, and more environmentally responsible electric power generation. Finally, a U.S. market analysis is performed for plug and play solar assuming the U.S. regulations modernize and permit the installation of plug and play solar for the residential sector. This study provides an estimate of this new U.S. market for plug and play PV systems if such regulations are updated by investigating personal financial decision making for Americans. The potential savings for the prosumer are mapped for the U.S. over a range of scenarios. This study shows that this system would generate approximately 108,417 thousand MWh per year and this distributed solar energy, which would provide prosumers approximately $13 billion/year in electricity cost savings

High Gain DC-DC and Active Power Decoupling Techniques for Photovoltaic Inverters

abstract: The dissertation encompasses the transformer-less single phase PV inverters for both the string and microinverter applications. Two of the major challenge with such inverters include the presence of high-frequency common mode leakage current and double line frequency power decoupling with reliable capacitors without compromising converter power density. Two solutions are presented in this dissertation: half-bridge voltage swing (HBVS) and dynamic dc link (DDCL) inverters both of which completely eliminates the ground current through topological improvement. In addition, through active power decoupling technique, the capacitance requirement is reduced for both, thus achieving an all film-capacitor based solution with higher reliability. Also both the approaches are capable of supporting a wide range of power factor. Moreover, wide band-gap devices (both SiC and GaN) are used for implementing their hardware prototypes. It enables the switching frequency to be high without compromising on the converter efficiency. Also it allows a reduced magnetic component size, further enabling a high power density solution, with power density far beyond the state-of-the art solutions. Additionally, for the transformer-less microinverter application, another challenge is to achieve a very high gain DC-DC stage with a simultaneous high conversion efficiency. An extended duty ratio (EDR) boost converter which is a hybrid of switched capacitors and interleaved inductor technique, has been implemented for this purpose. It offers higher converter efficiency as most of the switches encounter lower voltage stress directly impacting switching loss; the input current being shared among all the interleaved converters (inherent sharing only in a limited duty ratio), the inductor conduction loss is reduced by a factor of the number of phases. Further, the EDR boost converter has been studied for both discontinuous conduction mode (DCM) operations and operations with wide input/output voltage range in continuous conduction mode (CCM). A current sharing between its interleaved input phases is studied in detail to show that inherent sharing is possible for only in a limited duty ratio span, and modification of the duty ratio scheme is proposed to ensure equal current sharing over all the operating range for 3 phase EDR boost. All the analysis are validated with experimental results.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

STI-2062-1

This project investigated solar variability, power conversion and electric power grid response aspects of high penetration solar PV. These are the primary determining factors for acceptable penetration levels. Therefore, the study not only focused on the power system interactions, but also on the design of advanced power conditioners to explore more efficient design options and to look into advanced control impacts to the higher penetration PV deployment systems. Through extensive laboratory and field testing, the team gathered the essential information to better understand grid characteristics, PV systems configuration and power conditioning systems

Quasi-switched inverter using space vector pulse width modulation with triangular comparison for photovoltaic applications

Este trabajo analiza un prototipo para un inversor elevador cuasi-conmutado (qSBI) alimentando una carga resistiva aislada desde una fuente de CC. Se propone el uso de una modulación de ancho de pulso de vectores espaciales (SPWM) con comparación triangular que genera un incremento en el factor de ganancia del qSBI, y se contrasta su desempeño con otro tipo de modulaciones de vectores espaciales, tales como las modulaciones discontinuas. Para verificar la validez de la extensión de rango de tensión en el convertidor qSBI, se desarrolló una plataforma de pruebas semi-personalizada. Esta plataforma utiliza una tarjeta DSP de punto flotante (Analog Devices ADSP-21369) para el procesamiento de las estrategias de control, y una tarjeta de interfaz que incluye un arreglo lógico programable (FPGA) de Xilinx (Spartan-3), que permite desarrollar la modulación sincronizada que el qSBI necesita. Los resultados experimentales demuestran mejoras en el desempeño del convertidor qSBI en cuanto al factor de ganancia, reducción del estrés de voltaje en el capacitor y los perfiles de corriente de entrada. Las estrategias discontinuas de modulación del vector espacial no presentan un buen desempeño cuando se compara con las modulaciones continuas SVPWM o SPWM, ya que los niveles de rizado en las corrientes tomadas del módulo PV son de aproximadamente el doble que en el caso de las técnicas de modulación continuas. Finalmente, el uso del convertidor qSBI como microinversor es puesto en evidencia por dos casos experimentales prácticos de un sistema fotovoltaico PV con un algoritmo de ajuste del máximo punto de potencia (MPPT).This work analyzes a prototype of a quasi-switched boost inverter (qSBI) feeding an isolated resistive load from a DC source. The use of spatial vector pulse width modulation (SPWM) with triangular comparison is proposed to increase the qSBI gain factor, and its performance is contrasted with other types of spatial vector modulations, such as discontinuous modulations. To verify the validity of the method for voltage range extension in the qSBI converter, a semi-customized test platform was developed. This platform uses a DSP floating point card (Analog Devices ADSP-21369) for processing and control strategies and an interface card that includes a programmable logic array (FPGA) from Xilinx (Spartan-3), which allows to develop the synchronized modulation qSBI needs. The experimental results show improvements in the performance of the qSBI converter in terms of gain factor, voltage reduction in the capacitor, and input current profiles. Discontinuous space vector modulation strategies do not perform well when compared to continuous SVPWM or SPWM modulations, because the ripple levels in the currents taken from the PV module are approximately twice as great as in continuous modulation techniques. Finally, the usefulness of a qSBI as PV microinverter is confirmed by two practical experimental cases of a PV photovoltaic system with a maximum power point adjustment algorithm (MPPT)