Implementation of Three Phase UPS system using Multi-Loop Fuzzy Logic Controller for Linear and Non-Linear Loads

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Multilevel Converters: An Enabling Technology for High-Power Applications

| Multilevel converters are considered today as the state-of-the-art power-conversion systems for high-power and power-quality demanding applications. This paper presents a tutorial on this technology, covering the operating principle and the different power circuit topologies, modulation methods, technical issues and industry applications. Special attention is given to established technology already found in industry with more in-depth and self-contained information, while recent advances and state-of-the-art contributions are addressed with useful references. This paper serves as an introduction to the subject for the not-familiarized reader, as well as an update or reference for academics and practicing engineers working in the field of industrial and power electronics.Ministerio de Ciencia y Tecnología DPI2001-3089Ministerio de Eduación y Ciencia d TEC2006-0386

Coconut dehusker machine

Generally, coconut is dehusked manually using either a machete or a spike. These methods required skill labor and tiring to use. Attempts made so far in development of dehusking tools have been only partially successful and not effective in replacing manual methods. The reasons quoted for the failure of these tools include unsatisfactory and incomplete dehusking, breakage of the coconut shell while dehusking, spoilage of useful coir, greater effort needed than manual methods, etc

A Review on Control Strategies and Topologies of Multi Level Converter System

In recent decades, high-performance and medium voltage energy management for academia and industry have been attracted by multi-level converter topologies. In addition, the multi-level principle is used without decreasing the inverter power output to synthesise the harmonic distortion on the output waveform. For the reduction of harmonic distortion in the output waveform, the multi-level principle is used. The following topologies are presented: diode clamped inverters (neutral point clamped), condenser clamped (flying condenser), multi-level cascading (dc source, etc.) and the most effective modulation methods built for this converter category: multi-level, selective harmonic removal and space m vectors. A series of different topologies are given in this paper. Multi-level inverters have been gaining popularity in research teams and in the production of industrial applications for high and medium voltage applications for 20 years. Moreover, compared to a conventional converter, multi-level inverters can generate switched waveforms with reduced harmonic slopes. Recently, multi-level inverters have increased interest in their ability to generate high-quality wave forms at lower frequencies; the multi-level topology used in dynamic restaurant voltages reduces the harmonic distortion of the inverter output waveform without inverter output losses. By integrating control techniques for multi-level inverters, this paper discusses the most common topologies, making their implementations flexible in some power applications in many industrial areas

Cooperation of voltage controlled active power filter with grid-connected DGs in microgrid

Due to the excessive use of nonlinear loads and inverter interfaced distributed generators, harmonic issues have been regarded as a major concern in power distribution systems. Therefore, harmonic compensation in microgrids is a subject of current interest. Consequently, a novel direct harmonic voltage-controlled mode (VCM) active power filter (APF) is proposed to mitigate the harmonics in a cooperative manner and provide a better harmonic compensation performance of less than 5%. Due to the dispersive characteristics of renewable energy resources, voltage feedback based on a harmonic compensation control loop is implemented for the first time. This system can be smoothly combined with the current control loop. Our method proposes a better performance while mitigating the harmonics in comparison with conventional resistive active power filters (R-APF). Based on direct voltage detection at the point of common coupling (PCC), the proposed VCM-APF can therefore be seamlessly incorporated with multiple grid-connected generators (DGs) to enhance their harmonic compensation capabilities. The advantage of this scheme is that it avoids the need for designing and tuning the resistance, which was required in earlier conventional control schemes of R-APF for voltage unbalance compensation. Additionally, our scheme does not require the grid and load current measurements since these can be carried out at the PCC voltage, which further reduces the implementation cost of the system. Furthermore, the simulation results show the significance of proposed method