• Energy Research

AbstractThis study deals with a new control for a double‐stage grid‐integrated solar photovoltaic array (SPVA)‐based energy generation system, which is based on adjoint least mean square (ALMS) control. This ALMS control algorithm has some new features: (1) it provides a fast rate of convergence, (2) harmonics mitigation ability, and (3) ease of implementation. The solar PV energy generating system includes a DC–DC boost converter, a voltage source converter (VSC), a ripple filter, a three‐phase grid, and local non‐linear loads. The VSC is controlled for feeding the active power from the solar array to the grid and three‐phase non‐linear loads. Moreover, VSC control is used to improve the grid current quality. A DC–DC boost converter is coupled between the photovoltaic array and the DC‐link capacitor, which tracks the maximum SPVA power from the SPV array by using perturb & observe algorithm. Here, the main goals of SPVA generating system are to eradicate power quality problems caused by unbalanced and non‐linear loads and to provide sinusoidal grid currents at solar PV array irradiance variation. Moreover, a comparison of ALMS control is made with other control algorithms. Performance of this ALMS control is studied at varying non‐linear loads and under different environmental conditions on a developed prototype in the laboratory. The simulated results of the system are validated with test results. Detailed behaviour of the grid‐integrated SPV system and harmonics spectrum of grid currents are given here while meeting the IEEE 519 Standard.

Este documento presenta una estrategia de control robusta para un sistema de generación distribuida (DGS)basado en energía solar fotovoltaica (PV) con capacidades de transición sin interrupciones desde el modo aislado hasta el modo conectado a la red y viceversa. El DGS propuesto consiste en una matriz solar fotovoltaica, un convertidor elevador de CC-CC, un convertidor de fuente de tensión (VSC) y cargas no lineales locales. En el modo conectado a la red, el VSC regula la tensión del enlace de CC y el convertidor elevador opera la matriz solar fotovoltaica en el punto de máxima potencia. Además, la compensación de potencia reactiva de carga y la eliminación de armónicos con la operación del factor de potencia unitario se logran utilizando el algoritmo de control basado en el signo normalizado de contracción robusta avanzado (ARSNS). Por lo tanto, la distorsión de la corriente de la red se mantiene dentro del estándar IEEE-519 y el estándar IEEE-1547. Bajo la condición de falla de la red, el DGS propuesto opera en un modo aislado sin ninguna unidad de almacenamiento. Las operaciones de sincronización y resincronización de la red se ejecutan a través del algoritmo de control de sincronización inteligente (SYC) con bucle de bloqueo de fase de la transformada de Fourier rápida (FFT-PLL). Los mejores resultados demostraron las capacidades del sistema bajo las condiciones de carga no lineal anormales y desequilibradas de la red. Ce document présente une stratégie de contrôle robuste pour un système de production distribuée (DGS) solaire photovoltaïque (PV) avec des capacités de transition sans couture du mode îloté au mode connecté au réseau et vice versa. Le DGS proposé se compose d'un réseau photovoltaïque solaire, d'un convertisseur d'amplification CC-CC, d'un convertisseur de source de tension (VSC) et de charges non linéaires locales. En mode connecté au réseau, le VSC régule la tension de liaison CC et le convertisseur d'amplification fait fonctionner le réseau photovoltaïque solaire au point de puissance maximale. De plus, la compensation de puissance réactive de charge et l'élimination des harmoniques avec un fonctionnement de facteur de puissance unitaire sont réalisées à l'aide de l'algorithme de contrôle avancé basé sur le signe normalisé de rétrécissement robuste (ARSNS). Par conséquent, la distorsion du courant du réseau est maintenue dans la norme IEEE-519 et la norme IEEE-1547. Sous la condition de défaut du réseau, le DGS proposé fonctionne dans un mode îloté sans unité de stockage. Les opérations de synchronisation et de resynchronisation du réseau sont exécutées par l'algorithme de contrôle de synchronisation intelligent (SYC) avec une boucle à verrouillage de phase à transformée de Fourier rapide (FFT-PLL). Les résultats du test démontrent les capacités du système dans des conditions de charge anormales et non équilibrées. This paper presents a robust control strategy for a solar photovoltaic (PV)-based distributed generation system (DGS) with seamless transition capabilities from islanded to the grid-connected mode and vice versa.The proposed DGS consists of a solar PV array, a dc-dc boost converter, voltage source converter (VSC), and local nonlinear loads.In grid-connected mode, VSC regulates the dc-link voltage and the boost converter operates the solar PV array at the maximum power point.Moreover, the load reactive power compensation and harmonics elimination with unity power factor operation are achieved using the advanced robust shrinkage normalized sign (ARSNS)-based control algorithm.Therefore, the grid current distortion is maintained within the IEEE-519 standard and the IEEE-1547 standard.Under the grid fault condition, the proposed DGS operates in an islanded mode without any storage unit.The grid synchronization and resynchronization operations are executed through the intelligent synchronization control (SYC) algorithm with fast Fourier transform phase-locked loop (FFT-PLL).Test results demonstrate the system capabilities under the abnormal grid and unbalanced nonlinear load conditions. تقدم هذه الورقة استراتيجية تحكم قوية لنظام توليد موزع للطاقة الشمسية الكهروضوئية (الكهروضوئية) مع قدرات انتقال سلسة من الجزيرة إلى الوضع المتصل بالشبكة والعكس بالعكس. تتكون DGS المقترحة من مصفوفة الكهروضوئية الشمسية، ومحول تعزيز DC - DC، ومحول مصدر الجهد (VSC)، والأحمال غير الخطية المحلية. في الوضع المتصل بالشبكة، ينظم VSC جهد وصلة DC ويقوم محول التعزيز بتشغيل مصفوفة الكهروضوئية الشمسية عند أقصى نقطة طاقة. علاوة على ذلك، يتم تحقيق تعويض القدرة التفاعلية للحمل والقضاء على التوافقيات مع تشغيل عامل طاقة الوحدة باستخدام علامة الانكماش القوية القياسية المتقدمة (ARSNS). لذلك، يتم الحفاظ على تشوه تيار الشبكة ضمن معيار IEEE -519 ومعيار IEEE -1547. في ظل حالة عطل الشبكة، تعمل DGS المقترحة في وضع الجزيرة دون أي وحدة تخزين. يتم تنفيذ عمليات مزامنة الشبكة وإعادة المزامنة من خلال التحكم الذكي في المزامنة (خوارزمية YY) بسرعة مع نتائج تحويل القفل السريع (FEEEE -1547).

AbstractIn this paper, a battery‐supported unified power quality controller (UPQC) for a small hydro‐based isolated power generation is investigated as a voltage and frequency controller. The self‐excited squirrel cage induction generator driven by constant power prime mover (small hydro turbine) has unacceptable voltage, frequency and power quality under non‐linear loads. The battery‐supported UPQC‐based voltage controlled‐voltage source converter is designed, modelled and simulated in MATLAB environment. Here UPQC has series and shunt converters with a battery and it is used to feed the local loads. This small distributed power generation system is capable to feed unbalanced non‐linear loads because a shunt converter is used to take care the compensation of unbalanced loads and it always maintains the source currents balanced and sinusoidal. Moreover, a series converter is used to inject the series voltages in the self‐excited squirrel cage induction generator terminals to regulate the common coupling point voltage during unbalanced non‐linear loads. Performance of a battery‐supported UPQC is also validated experimentally using a laboratory prototype of a 3.7 kW, 230 V, 50 Hz capacitor excited induction generator.

This study investigates the temporal and spatio-temporal correlations of solar power generation among different prosumers of Uppsala and Halmstad, Sweden. Using solar power generation data from seven prosumer in Uppsala and five in Halmstad, we evaluate the correlation of solar power production generation at specific locations correlates with itself over different time lags (autocorrelation). In addition, we examine the spatiotemporal correlations of solar power production at various locations over a range of lags using time shifted cross correlation. These spatio-temporal correlations can facilitate the development of synchronized demand response strategies and dynamic energy pricing. Moreover, the timeshifted cross-correlation analysis assists in improving forecasting models for solar power generation. By identifying significant correlations between solar generation data from different locations and applying time shifts to account for variations in weather and sunlight exposure, operators can enhance the accuracy of their predictions. This methodology enables them to fill in missing data points by leveraging correlated information from neighboring regions. Consequently, more robust forecasting models can be developed, leading to better resource allocation, improved energy management, and reduced operational uncertainties in the grid. This research highlights the evaluation and potential of utilizing spatio-temporal and temporal correlations in solar power data to enhance energy management and planning.