Design and implementation of a dual-input single-output photovoltaic converter

In many solar inverters, a dc/dc converter is mainly located between the solar arrays and the inverter. This study presents an enhanced maximum power point tracking (MPPT) algorithm for photovoltaic (PV) systems that drives solar array voltages to track a reference value and decreases fluctuations and oscillations in PV voltage. Different from the previously presented methods, a novel MPPT method is proposed that ensures tracking accuracy by considering output voltage in addition to input voltage and currents. The proposed method detects dI/dV variations, compares the output voltage with the desired reference to shift operation mode and refreshes step size. The digital filtering, enhanced PI, and perturb-and-observe (P&O) tracking features of the proposed MPPT method make it robust to mitigate source fluctuations and sensitivity to partial shading based oscillations. In order to validate the success of the proposed method, a test rig has been installed with dual boost converters. The performance improvements have been verified by both simulation and experimental results that are compared to InCon and P&O MPPT methods. It is also confirmed by experimental results that the proposed MPPT method provides robust control capability in terms of tracking the reference voltage and rejecting the effects of various shading situations on solar arrays

Internet of Things Applications as Energy Internet in Smart Grids and Smart Environments

Energy Internet (EI) has been recently introduced as a new concept, which aims to evolve smart grids by integrating several energy forms into an extremely flexible and effective grid. In this paper, we have comprehensively analyzed Internet of Things (IoT) applications enabled for smart grids and smart environments, such as smart cities, smart homes, smart metering, and energy management infrastructures to investigate the development of the EI based IoT applications. These applications are promising key areas of the EI concept, since the IoT is considered one of the most important driving factors of the EI. Moreover, we discussed the challenges, open issues, and future research opportunities for the EI concept based on IoT applications and addressed some important research areas

Design and Implementation of Wireless Energy Monitoring System for Smart Grids

Measurement and remote monitoring process are very important processes for smart grids. In this study, design and implementation of smart metering system and remote monitoring system for smart grids are proposed. Designed smart metering system is capable of measuring quantities of DC current, DC voltage and power values. In order to convert measured quantities into suitable formats for transmitting wirelessly, a microcontroller-based signal processing system is designed and is implemented. Afterwards, measured voltage and current values are transmitted to receiver unit entitled as energy monitoring center by utilizing wireless communication methods. The communication infrastructure of the proposed system is conducted by ZigBee protocol due to its offered advantages such as being low cost, easy programming and low power consumption. Moreover, an interface is designed by C# programming language in Visual Stuio.Net to monitor received information by energy monitoring center in a real time. The conducted studies showed that the proposed smart metering and remote monitoring system could be efficiently utilized to observe current, voltage and power values of photovoltaic panels

From smart grid to internet of energy

From Smart Grid to Internet of Energy covers novel and emerging metering and monitoring technologies, communication systems, and technologies in smart grid areas to present a valuable reference for readers from various engineering backgrounds. Considering relevant topics on the essentials of smart grids and emerging wireless communication systems, such as IEEE 802.15.4 based novel technologies, cognitive radio networks and Internet of Energy, this book offers a discussion on the emerging trends and research direction for communication technologies. The book includes research concepts and visualization of smart grids and related communication technologies, making it a useful book for practicing network engineers

Design and Implementation of a Dual-Input Single-Output Photovoltaic Converter

In many solar inverters, a dc/dc converter is mainly located between the solar arrays and the inverter. This study presents an enhanced maximum power point tracking (MPPT) algorithm for photovoltaic (PV) systems that drives solar array voltages to track a reference value and decreases fluctuations and oscillations in PV voltage. Different from the previously presented methods, a novel MPPT method is proposed that ensures tracking accuracy by considering output voltage in addition to input voltage and currents. The proposed method detects d I / d V variations, compares the output voltage with the desired reference to shift operation mode and refreshes step size. The digital filtering, enhanced PI, and perturb-and-observe (P&O) tracking features of the proposed MPPT method make it robust to mitigate source fluctuations and sensitivity to partial shading based oscillations. In order to validate the success of the proposed method, a test rig has been installed with dual boost converters. The performance improvements have been verified by both simulation and experimental results that are compared to InCon and P&O MPPT methods. It is also confirmed by experimental results that the proposed MPPT method provides robust control capability in terms of tracking the reference voltage and rejecting the effects of various shading situations on solar arrays

Digital Transformation of Microgrids: A Review of Design, Operation, Optimization, and Cybersecurity

This paper provides a comprehensive review of the future digitalization of microgrids to meet the increasing energy demand. It begins with an overview of the background of microgrids, including their components and configurations, control and management strategies, and optimization techniques. It then discusses the key digital technologies that can be used to improve the performance of microgrids, including distributed energy resources management systems, the Internet of Things, big data analytics, blockchain technology, artificial intelligence, digital twin technology, cloud computing, and augmented reality. The paper also highlights the importance of cybersecurity in microgrids, identifying the potential security vulnerabilities and threats to microgrid cybersecurity, as well as strategies for addressing these challenges. Finally, the paper discusses the barriers and challenges regarding the digitalization of microgrids, including technical complexity, high implementation costs, regulatory barriers, data privacy and security concerns, lack of standardization, interoperability issues, limited technical expertise, and integration with the main grid. Overall, this paper demonstrates the significant potential for digital technologies to transform the future of microgrids. By leveraging advanced technologies and implementing effective cybersecurity measures, microgrids can become more efficient, reliable, and resilient, enabling them to meet the growing demand for energy and contribute to a sustainable energy future

Dual DC-DC Converter Design for String Inverters Used in Solar Plants

4th International Conference on Renewable Energy Research and Applications (ICRERA) -- NOV 22-25, 2015 -- Palermo, ITALYWOS: 000379126300004This study deals with the design of a dual buck converter where both of them are simultaneously operated to regulate photovoltaic (PV) string inputs. The proposed control and converter structure is intended to improve the dc-bus interface for solar arrays and to control the dc bus voltage of a commercial grid-tie inverter that is generated by four PV arrays. The control algorithm is improved by including PI control to the regular perturb-and-observe algorithm. Regarding to the international standards on single-phase commercial string inverters such as AS4777-2013, IEC62109, and IEC61727, the maximum power of each solar array is allowed to be 1.2 kWp while the maximum total input power is limited to 4.8 kWp. Individual MPPT controllers that are improved in this study control each one of the dc converters handling dual solar arrays at the input connection. The dc interface voltages regulated by converters are coupled on a unique dc bus to generate the supply voltage of inverter section. The controllers perform a robust operation against the freely fluctuating irradiation values of each solar arrays

Single Phase Multilevel String Inverter for Solar Applications

4th International Conference on Renewable Energy Research and Applications (ICRERA) -- NOV 22-25, 2015 -- Palermo, ITALYWOS: 000379126300003The proposed study deals with modeling and implementation of a multilevel string inverter with non-isolated dc-dc converter design. The modeled system is intended to be used for solar applications that the photovoltaic panels are connected in string structure. However, the dc-dc converter and multilevel inverter are capable to be used in distributed energy generation applications owing to the proposed control infrastructure. The entire design includes dual buck converter at the dc coupling input where both of the converters simultaneously operate to regulate photovoltaic string voltages. Each dc converter is capable to manage a string comprised of two photovoltaic arrays at the input. The maximum power of each solar array is allowed to be 1.2 kWp while the maximum value of total input power is limited to 4.8 kWp regarding to the related international standards such as AS4777-2013, IEC62109, and IEC61727. The output voltages of dc converters are set to 120V by the proportional-integral controller and are coupled over dc busbar to supply 9-level string inverter. The multilevel string inverter is comprised of two H-bridges in symmetrical topology where it is arranged according to regular 5-level symmetrical inverter. Furthermore, the regular sinusoidal pulse width modulator is enhanced to increase voltage level of inverter to nine instead of regular 5-level output. The inverter provides unity power factor with 0.63% total harmonic distortion ratio

Highly Efficient Interleaved Solar Converter Controlled with Extended Kalman Filter MPPT

DC-DC power converters play an important role in the performance and control methods of solar power systems. Solar power converters are prone to high power losses due to intermittent irradiation and shading effects on solar photovoltaic (PV) modules. The device topology and control algorithm of a solar power converter are key factors to increase the total amount of harvested energy. In this paper, a solar power converter is proposed with a two−phase interleaved boost converter (IBC) topology and a novel maximum power point tracking (MPPT) method. The proposed MPPT controller is based on extended Kalman filtering (EKF) and it improves the tracking efficiency in both steady irradiation and partial shading conditions. The algorithm is improved with the prediction and estimation capabilities of the EKF algorithm. The proposed EKF MPPT is validated with simulations and experimentally validated by using the implemented two−phase IBC that is comprised of SiC MOSFETs. The proposed converter provides over 99% power conversion efficiency at 3 kW and over 96% MPPT tracking efficiency under partial shading conditions. The experimental studies verify that the proposed MPPT controller and two−phase IBC increase the overall efficiency both in steady-state and partial shading operations of a solar power converter

Highly Efficient Interleaved Solar Converter Controlled with Extended Kalman Filter MPPT

DC-DC power converters play an important role in the performance and control methods of solar power systems. Solar power converters are prone to high power losses due to intermittent irradiation and shading effects on solar photovoltaic (PV) modules. The device topology and control algorithm of a solar power converter are key factors to increase the total amount of harvested energy. In this paper, a solar power converter is proposed with a two−phase interleaved boost converter (IBC) topology and a novel maximum power point tracking (MPPT) method. The proposed MPPT controller is based on extended Kalman filtering (EKF) and it improves the tracking efficiency in both steady irradiation and partial shading conditions. The algorithm is improved with the prediction and estimation capabilities of the EKF algorithm. The proposed EKF MPPT is validated with simulations and experimentally validated by using the implemented two−phase IBC that is comprised of SiC MOSFETs. The proposed converter provides over 99% power conversion efficiency at 3 kW and over 96% MPPT tracking efficiency under partial shading conditions. The experimental studies verify that the proposed MPPT controller and two−phase IBC increase the overall efficiency both in steady-state and partial shading operations of a solar power converter