Optimum Permanent Magnets Configuration in Flat-Quasi Linear Permanent Magnet Generators

Flat-quasi type of linear permanent magnet generators (LPMGs) have been considered to be applied for several applications, such for wave energy conversion and free piston combustion engine. One of the important issues concerning LPMG is the permanent magnets configuration, due to its effects to the generator’s excitation performance. In this paper, a 1 kW flat-quasi LPMG would be designed and built. During the process, optimum permanent magnets configuration was required and researched. The optimum configuration considered the output power and resulted cogging force. Invetigation was then conducted by modifying several variables, including poles’ arrangement, pole length, number of pole, and pole skewing angle. The modification constraints were total permanent magnets’ volume and generator dimension. The results showed that permanent magnet configuration with halbach arrangement, pole length equals 55% of the slot pitch length, and 61.19o skewing angle produced the optimum output values

Maximum Power Point Tracking using Particle Swarm Optimization Algorithm for Hybrid Wind-Tidal Harvesting System on the South Coast of Java

This paper proposes a hybrid wind-tidal harvesting system (HWTHS). To extract maximum power from the wind and tidal, HWTHS implements particle swarm optimization (PSO) algorithm in maximum power point tracking (MPPT) method. The proposed HWTHS had been tested on the range of possible input appropriate to the characteristics of the southern coast of Java. The presented result shows that by using PSO-based MPPT algorithm, maximum power point can be achieved. Thus the efficiency of HWTHS is 92 %, 94 % in wind section and 91 % in tidal section. By using PSO-based MPPT, HWTHS can respond well to changes in wind and tidal speed, whether it's a change from low speed to a higher speed or change from high speed to lower speed wherein time to reach new steady state is ± 0.1 s. At varied wind and tidal speed, PSO algorithm can maintain Cp of the system in the range of 0.47 - 0.48 so that power can be extracted to the maximum

Optimizing Tri-Core Permanent-Magnet-Linear-Generator Direct-Drive Wave-Energy-Conversion System Design for Sea Wave Characteristics in South Coast Yogyakarta

According to statistical data, the south coast Yogyakarta has significant ocean wave height which can be used to generate electricity by using wave-energy-converter system. One of the simplest way to convert wave energy to electricity is using direct-drive wave-energy-conversion (WEC) system with permanent-magnet-linear-generator (PMLG). This method is simple because it doesn’t need to convert linear motion to rotational motion. However, PMLG has large electric power losses, has great weight in both of the stator and rotor, and expensive to make. In this paper, a tri-core PMLG was designed. The electric power losses in the winding, translator weight, and manufacturing cost were ideally minimized using multiobjective optimization combined with simulated annealing (SA) algorithm. Then, the design was verified using finite element analysis. The optimized design of this PMLG was simulated using sinusoidal ocean waves which usually occur in the south coast of Yogyakarta to analyze the performance of this linear generator. Simulation result has been shown that this generator can generate 911 watt peak output power at the rated condition and at the optimum load with 81.14% efficiency. This confirms that the optimized design of PMLG is suitable for direct-drive WEC with low power losses and manufacturing cost

Aplikasi Magnetic Energy Recovery Switch sebagai Dynamic Voltage Restorer pada motor Induksi

Renewable energy source likes solar panel and wind turbine have intermittent character from instability power source generated. The instability power source can make dip voltage in power grid which happen in half cycle until few seconds. To stabilize the voltage in power grid from dip voltage, some methods have been developed using power electronics technology like VSI inverter, STATCOM, energy storage, OLTC, and MERS. The power electronic circuits have some advantages, such as small dimensional size and lightweight to keep voltage in power grid. In this paper, the MERS circuit was applied in induction motor which has small full bridge circuit, uncomplexity computation, and low switching frequency, so it needs low end hardware requirement. This paper proposed the use of MERS dc capacitor with 50% value from induction motor resistance. The result shows that MERS has advantage and can keep the voltage in power grid when the voltage below 39% and 15% above rated voltage (220 Vrms) with the recovery time around 0.3 second and keep the dip voltage over 1 second

Quasi-flat linear PM generator optimization using simulated annealing algorithm for WEC in Indonesia

Linear permanent magnet generator (LPMG) is an essential component in recent wave energy converter (WEC) which exploits wave’s heave motion. It could be classified into tubular-type, flat-tricore type, and quasi-flat type. In previous researches, these three models have been studied and designed for pico-scale WEC. Design optimization has further been conducted for flat-tricore LPMG, by using simulated annealing (SA) algorithm. It modified some parameters to minimize the resulted copper loss. This paper aims to optimize a quasi-flat LPMG design by applying SA algorithm. The algorithm would readjust the initial LPMG parts dimension. Then, the output of the optimized design would be analyzed and compared. The results showed that the optimization could reduce the copper loss by up to 73.64 % and increase the efficiency from 83.2 % to 95.57 %. For various load resistances, the optimized design also produces larger efficiency. However, the optimized design has a larger size and produces larger cogging force than the initial design

Pengatur Cahaya (dimmer) Lampu Fluorescent Dengan Saklar Pemulih Energi Magnetik (Magnetic Energy Recovery Switch)

Until now, electrical energy consumption for lighting by around 15% of the entire world's electrical energy consumption. Lighting load includes household applications, offices, business and industry, approximately 80% of its form fluorescent lamp or tube lamps (TL). This type of lighting is more widely used because of the power used is relatively small compared with the light bulb (incandescent). Additionally TL lamps are also cooler than incandescent bulb with the same power consumption. Problem associated with this type of lamp is how to regulate the intensity of the light it produces. This study aims to regulate the intensity of TL light, so it can reduce electric power consumption in line with the electrical energy savings. Magnetic energy recovery switch (MERS) is used to control the lamp voltage in order to control the light intensity as a dimmer. The switch is mounted in series to compensate for voltage drop due to an inductive component in the form of ballast. The results showed that MERS can be used as a fluorescent lamp dimmer. Light intensity settings done by controlling the charging and discharge the capacitor of MERS

A Strategy to Balance Supply and Demand Fluctuation for RES-Based Microgrids in Isolated Area

RES-based microgrids are often threatened by critical conditions due to variations in solar radiation in PV plants or wind intensity in wind turbines. This study provides a strategic framework to balance the supply and demand fluctuation for RES-based microgrids in an isolated area. By proposing the NILM, the load can be separately monitored for load shedding later when a critical condition occurs. NILM based on Data-Flow Programming (BDT) offers an appropriate NILM method to be applied to isolated areas. The infrastructure needed to implement the proposed method is related to building a monitoring station equipped with a set of computers and sensors so that the NILM algorithm can proceed. The load shedding and load priority algorithm are also presented in this study to achieve customer satisfaction. The method was developed by considering the limitations of infrastructure in communication, transportation, and other technologies in isolated areas. Therefore, it is necessary to have good cooperation between grid operators and consumers so that the proposed method can work properly

Digital Synchronoscope Prototype Based on STM32F401 Nucleo

Nowadays, world trend in maintaining energy sustainability is connecting several small and medium scale generators from renewable energy sources to the main electricity grid through a distribution network, or popularly known as the microgrid. One of the main problems of the microgrid is the synchronization of parallel operation. Generator synchronoscope, synchronization detector, and regulator device, will certainly make the microgrid operation easier and more reliable. Digital synchronoscope, which is more thorough in the detection of synchronization parameters and equipped with automation features for the tripping process in generator synchronization, can replace analog synchronoscope which is still widely used. This study was implemented to produce a prototype of digital synchronoscope that has some advantages such as low priced, robust, and simple in electrical schematic

Performance of Linear Generator Designs for Direct Drive Wave Energy Converter under Unidirectional Long-Crested Random Waves

For generating electricity, direct-drive wave energy converters (WECs) with linear permanent magnet generators (LPMGs) have advantages in terms of efficiency, simplicity, and force-to-weight ratio over WEC with rotary generators. However, the converter’s work under approaching-real wave conditions should be investigated. This paper studies the performance of a pico-scale WEC with two different LPMGs under unidirectional long-crested random waves. Different significant wave heights (using data in the Southern Ocean of Yogyakarta, Indonesia) and peak frequencies are tested. The JONSWAP energy spectrum is used to extract the wave elevations, while the MSS toolbox in MATLAB Simulink is employed to solve the floater’s dynamic responses. Next, the translator movements are extracted and combined with the flux distribution from FEMM simulation and analytical calculation, and the output powers are obtained. An experiment is conducted to test the output under constant speed. The results show for both designs, different tested significant wave height values produce higher output powers than peak frequency variation, but there is no specific trend on them. Meanwhile, the peak frequency is inversely proportional to the output power. Elimination of the non-facing events results in increasing output power under both parameters’ variation, with higher significant wave height resulting in a bigger increase. The semi iron-cored LPMG produces lower power loss and higher efficiency