• Energy Research

En este documento, se investiga un controlador unificado de calidad de energía (UPQC) soportado por batería para una pequeña generación de energía aislada a base de agua como controlador de voltaje y frecuencia. El generador de inducción de jaula de ardilla autoexcitado accionado por motor primario de potencia constante (pequeña turbina hidráulica) tiene una tensión, frecuencia y calidad de potencia inaceptables bajo cargas no lineales. El convertidor de fuente de voltaje controlado por voltaje basado en UPQC soportado por batería está diseñado, modelado y simulado en el entorno de MATLAB. Aquí UPQC tiene convertidores en serie y en derivación con una batería y se utiliza para alimentar las cargas locales. Este pequeño sistema de generación de energía distribuida es capaz de alimentar cargas no lineales desequilibradas porque se utiliza un convertidor de derivación para cuidar la compensación de cargas desequilibradas y siempre mantiene las corrientes de la fuente equilibradas y sinusoidales. Además, se utiliza un convertidor en serie para inyectar los voltajes en serie en los terminales del generador de inducción de la jaula de ardilla autoexcitada para regular el voltaje del punto de acoplamiento común durante cargas no lineales desequilibradas. El rendimiento de un UPQC alimentado por batería también se valida experimentalmente utilizando un prototipo de laboratorio de un generador de inducción excitado por condensador de 3,7 kW, 230 V y 50 Hz. Dans cet article, un contrôleur de qualité de l'alimentation unifié (UPQC) supporté par batterie pour une petite production d'énergie isolée à base d'hydroélectricité est étudié en tant que contrôleur de tension et de fréquence. Le générateur à induction à cage d'écureuil auto-excité entraîné par un moteur à puissance constante (petite hydroturbine) a une tension, une fréquence et une qualité de puissance inacceptables sous des charges non linéaires. Le convertisseur de source de tension contrôlée sur batterie UPQC est conçu, modélisé et simulé dans un environnement Matlab. Ici, UPQC a des convertisseurs série et shunt avec une batterie et il est utilisé pour alimenter les charges locales. Ce petit système de production d'énergie distribuée est capable d'alimenter des charges non linéaires déséquilibrées car un convertisseur en dérivation est utilisé pour s'occuper de la compensation des charges déséquilibrées et il maintient toujours les courants de source équilibrés et sinusoïdaux. De plus, un convertisseur série est utilisé pour injecter les tensions série dans les bornes du générateur à induction à cage d'écureuil auto-excité afin de réguler la tension du point de couplage commun lors de charges non linéaires déséquilibrées. Les performances d'un UPQC alimenté par batterie sont également validées expérimentalement à l'aide d'un prototype de laboratoire d'un générateur à induction excité par condensateur de 3,7 kW, 230 V, 50 Hz. In 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. في هذه الورقة، يتم التحقيق في وحدة تحكم موحدة لجودة الطاقة مدعومة بالبطارية (UPQC) لتوليد طاقة معزولة صغيرة قائمة على الماء كوحدة تحكم في الجهد والتردد. يتمتع المولد الحثي لقفص السنجاب المستثار ذاتيًا والمدفوع بمحرك رئيسي ثابت للطاقة (توربين مائي صغير) بجهد وتردد وجودة طاقة غير مقبولة تحت الأحمال غير الخطية. تم تصميم محول مصدر الجهد المضبوط القائم على UPQC المدعوم بالبطارية ونمذجته ومحاكاته في بيئة MATLAB. هنا لدى UPQC سلسلة ومحولات تحويل مع بطارية ويتم استخدامها لتغذية الأحمال المحلية. نظام توليد الطاقة الموزع الصغير هذا قادر على تغذية الأحمال غير الخطية غير المتوازنة لأنه يتم استخدام محول تحويلة لرعاية تعويض الأحمال غير المتوازنة ويحافظ دائمًا على تيارات المصدر متوازنة وجيبية. علاوة على ذلك، يتم استخدام محول متسلسل لحقن الفولتية المتسلسلة في أطراف مولد حث قفص السنجاب ذاتية الإثارة لتنظيم جهد نقطة الاقتران المشتركة أثناء الأحمال غير الخطية غير المتوازنة. يتم أيضًا التحقق من صحة أداء UPQC المدعوم بالبطارية تجريبيًا باستخدام نموذج أولي مخبري لمولد حث متحمس بمكثف 3.7 كيلو واط، 230 فولت، 50 هرتز.

Abstract This paper deals with the analysis and development of a permanent magnet brushless DC (PMBLDC) motor drive coupled to a pump load powered by solar photovoltaic (PV) array for water pumping system. A simple low-cost prototype controller has been designed and developed without current and position sensors which reduces drastically the overall cost of the drive system. This controller is used to test the dynamic behavior of the PMBLDC motor drive system. The mathematical model of the system is developed with a view to carry out a comparison between experimental and simulated response of the drive system. A simple filter circuit incorporated in between PV-array and an inverter to reduce ripples and to improve the performance of the PV-array. The necessary computer algorithm is developed to analyze the performance under different conditions of varying solar insolation for a pump load.

This paper presents the different methods for compensating single phase load fed from neutral grounded star connected three phase ac system. In fact, there are three possible options for compensation in a three phase ac system depending on the phases selected for adding lossless compensating elements. In this paper, several algorithms have been developed to neutralize the neutral current and to compute the values of compensating elements for all the three schemes. Simulated results reveal that after compensation, all three supply currents are in phase with their respective phase voltages and are equal in magnitude. This procedure provides the facility to find the best option for optimum compensation of unbalanced loads.

Abstract A large number of single-phase linear and non-linear loads may be supplied from three phase ac mains with neutral conductor. They cause excessive neutral current, harmonics and reactive power burden and unbalance. A four wire DSTATCOM (distribution static compensator) is used for neutral current compensation along with reactive power compensation, harmonics elimination and load balancing. A novel control approach is proposed for the control of four wire DSTATCOM under non-ideal supply voltage conditions. A four-leg voltage–source converter (VSC) with a dc capacitor is used as a four wire DSTATCOM. The proposed control approach is based on synchronous reference frame (SRF) theory and an indirect current control technique. The switching signals for the voltage–source converter (VSC) of the DSTATCOM are derived from the estimated reference supply currents. The load balancing, harmonics elimination and the neutral current compensation are demonstrated along with unity power factor (UPF) and zero voltage regulation (ZVR) modes of operation. Simulation results based on MATLAB software with its Simulink and power system blockset (PSB) toolboxes are presented to validate the control strategy. The DSTATCOM is able to maintain the self-supported dc bus under various disturbances.

This paper deals with the analysis and design of voltage and frequency controllers for asynchronous generators to be used in isolated constant power applications such as pico and micro hydro sites. These controllers are basically load controllers which maintain the load power constant at generator terminals which in turns maintain the system frequency constant. A set of load controllers are designed, modeled and simulated in Matlab using Simulink and PSB (Power System Block-set) toolboxes to demonstrate their performance.

Li-ion batteries are playing a crucial role in the fields of renewable energy systems and electric vehicles. The reliability of these systems depends on a battery management system (BMS) which monitors the state of charge (SoC) and state of health (SoH) effectively. Knowing the SoH of a battery in advance enhances the system reliability. This article proposes an accurate online estimation of SoH of a Li-ion battery integrated in solar photovoltaic system (SPV) applications. The proposed method uses the modified coulomb counting method to estimate the SoH of a battery. The proposed SoH estimation method is simulated in MATLAB/Simulink by considering the aging factors such as temperature, charge/discharge rates and depth of discharge. Moreover, the proposed method is validated using an experimental prototype and the results are found to be satisfactory.

This paper is an attempt of detail the comparative study of the analysis of thermoelectric module (TEM) for static and dynamic modeling with temperature dependent parametric variations. This study provides an insight on computation of various parameters of TEM used for modeling power generators. Initially a brief analysis is carried out for estimation of efficiency, power, voltage and current assuming a static model. Later dynamic model has been developed under MATLAB/Simulink environment with a consideration of its dependence with temperature and results of simulation are compared. Such comparative study not only validates the efficacy of the developed model with dynamic operating conditions but also pave the way for designing the balance of system more accurately. This paper presents a near accurate model of thermoelectric generator (TEG) with realistic conditions with a user-friendly approach. The inputs of the considered model are temperature dependent parameters, temperature of hot source and ambient temperature to which cold junction is exposed. The results are computed to evaluate the performance of TEM for generated voltage, power and efficiency.

A microgrid (MG) having a wind generator and solar photovoltaic (SPV) array, which functions seamlessly from standalone to grid connected mode. The microgrid has an ability to fulfill the demand of the loads in both the modes. A third order selective tuning filter (TOSTF) based control is used for grid connected mode. This control successfully controls active power flow and mitigates of harmonics. The control approach based on proportional resonant (PR) is used in astandalone mode. Moreover, a dual TOSTF with phase locked loop (PLL) is used for effortless synchronization of the grid. This improves the seamless mode switching by effectively estimating phase angles and frequency during grid voltages unbalance. The microgrid performance and robustness of controls are validated through test results.