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Issue 04

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Fuzzy Logic Controlled DC-DC Converter Based Dynamic Voltage Restorer

This paper presents fuzzy logic controlled dc-dc boost converter based Dynamic Voltage Restorer (DVR) to compensate severe voltage sag problems in an electrical system. DVR absorbs real power from battery to compensate voltage sags in the system. This condition causes reduction in voltage magnitude of dc-link capacitor. Additionally, DVR requires large dc capacitors to compensate long and severe voltage sags in the system. In this study, dc-dc boost converter is connected to DVR for keeping dc link voltage constant. For this propose, a control algorithm based on Fuzzy Logic (FL) control is developed for dc-dc boost converter. The main contribution of this study is that Fuzzy Logic (FL) is firstly used to generate reference signal for PWM signals of dc-dc converter applied in DVR. FL is a very flexible controller which keeps
the dc link voltage constant during voltage sag. The performance results of proposed study are verified with PSCAD/EMDTC.

Robust Optimal Control of Chaos in Permanent Magnet Synchronous Motor with Unknown Parameters

This paper focuses on the problem of chaos suppression in permanent magnet synchronous motors (PMSM) with uncertain parameters. Firstly, the chaotic characterizations are analyzed, including bifurcation diagram, chaotic attractor, Lyapunov exponents, and power spectrum. Then, by using robust optimal control approach, a simple linear feedback controller is designed to make the system states stable. And the control gains can be obtained from a linear matrix inequality (LMI), which can be resolved easily via the MATLAB LMI toolbox. Based on Lyapunov stability theory, the stability of the proposed scheme is verified. Finally, numerical
simulation results are given to demonstrate the effectiveness of the presented method.

Simulation of Corona Discharge in DC Electrostatic Precipitator

The stable positive DC corona discharge in atmospheric air under a wire-to-cylinder system is analyzed in this paper. An iterative finite element technique is developed to obtain a general solution of the governing equations of the coupled space-charge and electric field problem. The technique is to use the finite-element method (FEM) to solve Poisson’s equation and the method of characteristics (MOC) to find the charge density from a current-continuity relation. Besides, the corona ionized field is successfully modeled using COMSOL MULTIPHYSICS 3.4. Two application modes are used to solve system of coupled equations with appropriate boundary conditions : PDE (General Form) mode for electric potential distribution and Convection and Diffusion mode for charge transport equation. In order to validate the presented numerical methods a comparison with analytical solution and measured data are made. The obtained results are in good agreement.

Improve Dual Axis Solar Tracker Algorithm based on Sunrise and Sunset Position

This paper presents sensorless dual axis solar trackers based on sun position using sunrise and sunset database. The database created from exact calculation of solar azimuth and elevation based on Terrestrial Dynamical Time (TDT)system with parameters input : local date, time, geographic location, altitude and timezone. By using linear interpolation the sun position in direction of a and b angles for other time can be obtained during a day. The solar panel move based on sun position in direction of a and b angles. The prototype solar tracker consists of digital electronics circuit and mechanical construction has been functioning as expected, especially for small-sized of solar panel. The measurement of the electrical power output of solar power between a flat position compared to the upright position of sunlight has resulted in a
greater power. For seven hours energy captured by flat posistion was 166.4 Watthour. However by used solar tracker increased to 225.05 Watthour. Thus the solar tracker algorithm has increased output power of Solar Power Generation and it’s efficiency 26 %. This technique independent from weather conditions, although cloudy, panel position remains consistent with the maximum illumination when the weather is sunny back later. By this way, the solar panel always absorbs maximum sunlight as well as generate maximum electricity.

Development of PEF source in Nanosecond range for Food Sterilization

Pulsed Electric Field [PEF] food processing technology becomes more attractive, alternative to thermal food processing technologies. Usually the high voltage pulses are generated using conventional pulse generators based on Marx cells, Spark gaps, Electrostatic filters to produce the necessary high electric filed intensity. The voltage and current are limited due to the classical switches used in the conventional generators. The switching speed and slow response of such devices increase the complexity of the control and driver circuits and also the space requirement of the conventional generators. The drawbacks of pulse generators are overcome by
the advanced semiconductor devices, such as power MOSFETs and are becoming most suitable for high speed switching high voltage pulse generators. The modern semiconductor devices are more reliable to handle high voltages and currents when implemented in typical circuits and reduces the bulkiness of the High Voltage Pulse Generator [HVPG]. This paper proposes the developments in HVPG using modern semiconductor devices. The energy efficiency can be improved by minimizing the losses during food process and it can be achieved by reducing the pulse width using modern semiconductors. The proposed generators are capable of producing
high voltage sub-microseconds pulses in the range of 100ns to few microseconds.

Implantation of the scalar control for theopen-end winding induction machine On FPGA Spartan 3E

In this paper, the authors propose the implantation of the scalar control for controlling the open-end winding induction machine on FPGA. The scalar control is simulated in matlab Simulink environment using a Xilinx System Generator. This control is implemented in a Xilinx Spartan 3E FPGA board. It is experimentally verified by the visualization of command signals for the switches of the inverters.

Joint Market Clearing of Energy and Demand Response Offers ConsideringVoltage Dependent Load Models

This paper presents a new multi-objective day-ahead market clearing (DAMC) mechanism with demand-side reserves/demand response offers, considering realistic voltage dependent load modeling. The paper proposes objectives such as Social Welfare Maximization (SWM) including demandside reserves, and Load Served Error (LSE) minimization. In this paper, energy and demandsidereserves are cleared simultaneously through co-optimization process. The paper clearly brings out the unsuitability of conventional SWM for DAMC in the presence of voltage
dependent loads, due to reduction of load served (LS). Under such circumstances multi-objective DAMC with demand response offers is essential. Multi-objective Strength Pareto Evolutionary Algorithm 2+ (SPEA 2+) has been used to solve the optimization problem. The effectiveness of the proposed scheme is confirmed with results obtained from IEEE 30 and IEEE 300 bus test systems.

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