In rural areas of the Mekong Countries, the problem of electricity supplying rural communities is particularly alarming. Supplying power to these areas requires facilities that are not economically viable. However, government programs are under way to provide this product that is vital to community well being. A nation priority of Mekong Countries is to provide electrical power to people in rural areas, within normal budgetary constraints. Electricity must be introduced into rural areas in such a way that maximize the technical, economic and social benefit. Another consideration is the source of electrical generation and the effects on the natural environment. The main research purpose is to implement field tests, monitoring and evaluation of the PV-Diesel Hybrid System (PVHS) at the Energy Park of School of Renewable Energy Technology (SERT) in order to test the PVSH working under the meteorological conditions of the Mekong Countries and to develop a software simulation called RES, which studies the technical and economic performance of rural electrification options. This software must be easy to use and understand for the energy planner on rural electrification projects, to evaluate the technical and economic performance of the PVHS based on the renewable energy potential for rural electrification of the Mekong Country by using RES. Finally, this project aims to give guidance for the possible use of PVHS application in this region, particularly in regard to its technical and economic sustainability. PVHS should be promoted according to the principles of proper design and adequate follow up with maintenance, so that the number of satisfied users will be achieved. PVHS is not the only possible technology for rural electrification, but for the Mekong Countries it is one of the most proper choices. Other renewable energy options such as wind, biomass and hydro power need to be studied in future.

Photovoltaic hybrid systems for rural electrification in the Mekong countries

Frugal innovation (FI) describes a phenomenon whereby solutions are developed to serve low-income customers, mainly in developing countries, with affordable products and services that help address pressing social and environmental problems. Despite a decade of academic interest in FI, we still lack an overarching understanding of the various facets of this phenomenon. Based on 48 in-depth interviews for 23 cases, we integrated and validated 10 years of FI scholarship. This study therefore set out to develop a comprehensive framework for FI, one that would identify its antecedents, mediators, and consequences. Such a framework promises a holistic perspective for FI by linking these identified factors to the concept of sustainability. The findings also reinforce the dual contribution that FI makes in terms of both business growth and inclusive growth. Finally, this study discusses the theoretical and practical implications and provides some suggestions for future research on FI. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/caim.12511

Frugal innovation: Antecedents, mediators, and consequences

This paper aims to design a controlled voltage stabilizer to protect domestic appliances from voltage dips in electrical power distribution. Voltage dips are recurrent and become a concern for distributors and consumers. Voltage dips affect the power quality and can have a negative impact on the proper functioning of domestic appliances and other sensitive electronic equipment. Today, this problem has become central and recent measurements show that voltage dips can reach 35 to 40 % in some regions of Senegal. Therefore, this work is mainly focused on the design of a single-phase CVS, using control methodologies based on PI controllers that can effectively handle large voltage dips. The proposed controlled voltage stabilizer consists of a fully controlled AC-AC power converter, based on a single-phase boost rectifier connected to a single-phase PWM inverter with control laws. The design and the control laws adopted were carried out taking into account the characteristics of the electric power distribution, as well as the domestic loads. The robustness and effectiveness of the controlled voltage stabilizer are verified by carrying out simulations in the Matlab simulink environment in various operating cases using real measurements of voltages with different types of electrical loads. Simulation results confirm the effectiveness and robustness of the proposed stabilizer. Furthermore, it enables the protection of domestic appliances by keeping the voltage level stable within a specified range around the rated value regardless of voltage dips.

Design of a Domestic Controlled Voltage Stabilizer

For the operation of the semiconductor components in the medium or high voltage converter applications, the high insulation system of their PWM control signals as well as their power transmission function is required. This paper details the design methodology to optimize a power supply function for insulated gate bipolar transistor (IGBT) gate driver with high insulated voltage capabilities by the help of a virtual prototyping tool. To achieve this, a dc-to-dc full-bridge series-series (FB-SS) resonant converter with a high air gap pot core transformer is selected (the air gap value can be selected from 1 mm to 3 mm). This high air gap transformer (or a loosely coupled transformer (k)) is used for high insulation voltage capability systems. The objective of this study is to optimize the geometric elements of the transformer and the associated electrical components in the FB-SS topology. Maximize the converter efficiency (etacon) is the main objective of the proposed optimization. Therefore, optimization results are proposed: the converter efficiency as a function of output power and insulation thickness for different pot core diameters. Finally, experimental results are compared to the simulation ones to validate this virtual prototyping tool.

A Virtual Prototyping Tool of a Power Transmission Function for IGBT Gate Drivers with High Insulated Voltage Capabilities

Le Cambodge est un pays situe en Asie du Sud-Est, avec grand potentiel de ressources en energies renouvelables. Meme fort de ce potentiel, la puissance electrique actuellement installee n'est pas suffisante pour tout le pays. Environ 80% de la population vit dans les zones rurales et 75% des menages sont sans reseau electrique. Ils utilisent une batterie, le moteur diesel, des bougies ou du kerosene pour l'eclairage, la television, les multimedia et autres appareils menagers. Une minorite des citoyens, dans la partie nord utilise des modules pico hydro electriques achete dans les pays voisins pour eclairage. Mais la tension de sortie et la frequence ne sont pas vraiment stables en cas de modification de la charge ou de la vitesse de rotation de la turbine. La duree de vie des appareils electromenagers peut ainsi etre reduite et des reparations locales sont necessaires. Des millions de Cambodgiens ne peuvent pas acceder a l'energie electrique en raison de deux facteurs principaux : les barrieres technologiques et les couts d'investissement eleves. Nos activites de recherche visent a eliminer ces barrieres technologiques en concevant des systemes de production d'energie pico-hydroelectrique avec une installation rapide et peu couteuse, simple et adaptee a une application locale tout en gardant une qualite de l'alimentation electrique satisfaisante. La premiere partie de cet ouvrage decrit la situation de l'energie dans les zones rurales du Cambodge ou les gens sont confrontes a un manque d'alimentation electrique. En consequence, ils ne peuvent ni ameliorer leur niveau de vie, ni developper leur communaute. Les villageois riches utilisent une batterie de voiture, des systemes photovoltaiques ou pico-hydroelectriques alors que les villageois pauvres utilisent des bougies ou du kerosene pour l'eclairage. Des entreprises locales fournissent des solutions electriques basees sur des energies renouvelables, mais les prix sont inabordables et loin de leurs attentes. Par consequent, une solution originale est proposee dans cette these avec la recuperation de composants electriques d'occasion en vue de la mise en œuvre d'un nouveau systeme de generation d'electricite pour les zones rurales isolees. Il s'agit ici d'innovation frugale pour le bas de la pyramide sociale. Les composants utilises sont : machine asynchrone, alimentation sans interruption (UPS), alimentation de PC et d'autres equipements electroniques, etc. Ces composants recycles peuvent etre rassembles pour former ainsi une solution technologique interessante permettant de delivrer la puissance de sortie necessaire. La deuxieme partie de ce memoire presente la modelisation de l'etage de puissance de la machine asynchrone triphasee utilisee comme un generateur asynchrone monophase avec une phase d'excitation et les deux autres phases connectees en serie pour alimenter la charge. Cette configuration est nommee 'Excited Induction Generator (EIG)'. Des condensateurs sont ajoutes aux bornes de l'EIG pour compenser la puissance reactive, leurs valeurs influencent la position des poles et des zeros du systeme qui sont decrits dans une analyse du lieu des poles en fonction des variations parametriques du systeme. La partie suivante de cette these est consacree a la modelisation sur site des pertes dans la machine asynchrone. La methode doit permettre d'obtenir des resultats simplement, rapidement, sans aucune information prealable sur la machine, afin de pouvoir integrer ulterieurement ce modele dans un algorithme d'optimisation energetique. Les plans d'experiences apportent des elements de reponse methodologiques convaincants. La modelisation des pertes totales (pertes fer et pertes Joule rotor) est realisee en mode de fonctionnement " moteur " et " generateur ", pour differentes machines de puissances differentes. Les resultats de simulations et les resultats experimentaux de l'EIG seront introduits dans le dernier chapitre. La derniere partie de ce memoire decrit la commande des tensions/courants avec des resultats de simulations et des resultats experimentaux sur plusieurs generateurs asynchrones. Les regulateurs proportionnel-integral et proportionnel-resonnant sont testes. Les controleurs en boucle fermee sont tout d'abord implantes en analogique dans le circuit de l'UPS puis dans l'environnement dSPACE/MATLAB Simulink.

Contribution to electric energy generation for isolated-rural areas using 2nd life components and renewable energies : modelling and control of an induction generator

This paper explains the study of the control of an automatic voltage regulator (AVR) based on series voltage compensation using a transformer and an AC-AC converter. The paper explores the control of the output AVR using Linear-Quadratic Regulator (LQR) and anti-windup. Simulation results have verified the viability of using the proposed control technique for voltage regulation.

Study of the Control of an AC Voltage Stabilizer Using LQR and Anti-windup

In this article an original solution is proposed by using wasted electric and electronic equipment (second-life components) to create the new power generation systems for remote rural areas. This frugal innovation for rural electrification guarantees an important support social, educational and economic development goals especially in Southeast Asian countries.

/pdf/frugal-innovation-for-sustainable-rural-electrification-4rzp25aacb.pdf

Frugal Innovation for Sustainable Rural Electrification

Recently, the increasing of usage transportation is impacted by air pollution caused by conventional vehicles which are driven by an internal combustion engine (ICE). The novel vehicle's research is to replace that engine with an electric motor, it is called Electric Vehicle (EV). This paper demonstrated a strategy of independent speed steering control for four in-wheels direct drive using brushless DC (BLDC) motors when the EV drives on a straight or curved road. A geometry model of the vehicle named Ackermann-Jeantand steering model is introduced to extract each wheel rotating speeds to avoid the wheel slide with the road during the EV operates on a corner street. The hybrid fuzzy-PI controller is used as a speed controller for each motor in the model in this design. The results are also compared with PI and fuzzy logic controllers. The results of two different modes have been illustrated on GUI with a satisfied response; thus, the control system has functioned correctly. It is revealed that the EV is driven and steered safely on the road.

Four In-Wheel BLDC Motors Speed Control in EV Based on Hybrid Fuzzy-PI Controller Visual on GUI

This article treats the gate driver system for IGBT modules in Medium-Voltage (MV) applications. The study focuses principally on two functions of an IGBT gate driver: an impulse signal transmission and a power transmission. For each function, the suitable topology is proposed. Then, for safety and device's protection reason, all gate driver functions must sustain the high and very high galvanic insulation voltage capabilities. For low-cost design, the insulation system can be achieved with the help of the insulating material in a pot core planar transformer. Therefore, for each function, the optimized design of a pot-core transformer and its associated electronics components is performed with the help of a virtual prototyping tool (a genetic algorithm: GA code in MATLABTM). The first section focuses on optimization design of a selected topology for an impulse signal transmission function. A bi-objective (maximize the output voltage vout and minimize the input current imos) problem of this function that leads to a Pareto front is presented. Several Pareto fronts’ results are obtained assuming different insulation layers thickness. The second part focuses on optimization design of a selected topology for a power transmission function. Maximize the converter efficiency (ηcon) and minimize the output power (Pout) are considered as a bi-objective. Thus, numerous Pareto fronts’ results are achieved for a few different insulation thicknesses. Finally, the prototype of a single channel IGBT gate driver is invented to validate the proposed design.

/pdf/a-single-channel-igbt-gate-drivers-for-medium-voltage-3oaxeghwwc.pdf

A Single Channel IGBT Gate Drivers for Medium Voltage Converters

This paper explains the control of an automatic voltage regulator (AVR) based on series voltage compensation using a transformer and an AC-AC converter. The paper explores the control of the output of AVR using linear controller using reference transformation technique. Simulation and experimental test has been made to verify the viability of using the proposed control technique for voltage regulation.

Bunthern Kim

Papers

Study of the Control of an AC Voltage Stabilizer Using LQR and Anti-windup

Frugal Innovation for Sustainable Rural Electrification

Four In-Wheel BLDC Motors Speed Control in EV Based on Hybrid Fuzzy-PI Controller Visual on GUI

A Single Channel IGBT Gate Drivers for Medium Voltage Converters

Study of the Control of a New AC Voltage Stabilizer using Linear Controller with Reference Frame Transformation