Mathematical analysis of the turbine coefficient of performance for tidal stream turbines

Unregulated water currents such as tides and ocean currents include energy that could be utilized for electricity production. These currents can be seen as dead bodies of water with potential energy, driven by gravity or alive moving with a kinetic energy (KE). Tidal stream turbines are a relatively new technology for extracting KE from tidal currents, which is currently in progress from development stage to industrial execution. One of the most important factors in tidal power analysis is the rotor efficiency coefficient or turbine coefficient of performance (λ). It depends on the rotor blade geometry and water velocity. This article presents a mathematical description of good interpolating functions which describe this coefficient analytically, for tidal stream turbines. Nonlinear curve-fitting solver in least-squares sense has been used in this study. Various interpolation functions have been proposed. The proposed mathematical descriptions can be very helpful for tidal power analysis and output power estimation

LC compensators for power factor correction of nonlinear loads

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEA method is presented for finding the optimum fixed LC compensator for power factor correction of nonlinear loads where both source voltage and load current harmonics are present. The LC combination is selected because pure capacitive capacitors alone would not sufficiently correct the power factor. Optimization minimizes the transmission loss, maximizes the power factor, and maximizes the efficiency. The performance of the obtained compensator is discussed by means of numerical examples

Practical considerations regarding power factor for nonlinear loads

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2004 IEEEThe choice of LC compensator may be constrained by the availability of manufacturers units. To account for this, the capacitor values are chosen from among standard values and for each value the transmission losses is minimized, or power factor is maximized, or transmission efficiency is maximized. The global minimum or maximum is obtained by scanning all local minims or maxims. The performance of the obtained compensator is discussed by means of numerical examples

Harmonic current extraction of shunt active power filter based on prediction current technique - Hysteresis PWM

Due to the wide spread of power electronics equipment in modern electrical systems, the increase of the harmonics disturbance in the ac mains currents has became a major concern due to the adverse effects on all analysis and simulation using MATLAB-SIMULINK of a three-phase shunt active equipment. This paper presents the Shunt Active Power Filter (SAPF) to compensate the generated harmonics by 3-phase Rectifier Bridge fed R-L load. The harmonic current extraction is based on prediction current extraction technique -hysteresis PWM generation pattern

Comparative analysis of optimal damped and undamped passive filters using MIDACO-solver

Copyright © 2022 The Authors. Harmonic pollution is one of the challenging problems facing power networks recently due to the widespread non-linear loads and inverter-based renewables. In this regard, this work presents the optimal design of damped and undamped passive filters using a solver called Mixed-Integer Distributed Ant Colony Optimisation (MIDACO). This solver is employed to obtain an optimal design strategy for single-tuned passive power filters by investigating three primary criteria – minimisation of active power losses of the Thevenin’s resistor, maximisation of the true power factor, and maximisation of the transmission efficiency. Several constrictions associated with the designed filters have been considered, in which the global maximum or minimum criterion was attained by retaining the quality factors of the designed filters within a particular range, damping harmonic resonance, achieving a permissible range of the power factor, limiting voltage harmonic distortion by complying with IEEE Std. 519–2014 restrictions. Besides, the performance limits of capacitors operating in distorted systems have been met while complying with IEEE Std. 18–2012. Further, the results obtained using the MIDACO solver in four different case studies are compared to those obtained using particle swarm optimisation and genetic algorithm. In addition, this work depicts the damping resistor of the inductance in the single-tuned filters. The benefits and drawbacks of damping over an undamped filter are discussed. Finally, the results validate the effectiveness of the MIDACO solver employed in this paper.The authors did not receive support from any organisation for the submitted work

Harmonics mitigation of industrial power system using harmonic blocking compensators

This paper presents a passive harmonic blocking compensator (PHBC) for harmonic suppression and reactive power compensation in distribution systems. PHBC composed of a line series filter tuned to the fundamental frequency and a shunt passive filter. FORTRAN Feasible Sequential Quadratic Programming (FFSQP) is used as an optimization tool to find the proper sizing of parameters of the suggested filter for minimizing the supply current total demand distortion (TDD), where maintaining a given power factor at a specified range is desired. The optimal design of the PHBC, the contribution of the newly developed method and its feasibility are presented in two study cases

Electric and Hybrid Vehicle Drives and Smart Grid Interfacing

Over the few last decades, the demand for electrical energy is rising remarkably. As a result, the usage of environmentally friendly and renewable energy sources has been increased. Parallel to these developments, the number of the gasoline-powered vehicle has been increased and therefore the energy shortages and environmental concerns increased as well. From this perspective, research into the usage of renewable energy sources instead of fossil fuels in the automotive industry is proceeding fast. One of the most important issues, which play a significant role in overcoming the problem mentioned above, is the implementation of modern electrical networks including Electric Vehicle (EVs). In this chapter, the standard EVs applications in smart grids are presented and discussed. Besides, two novel low-impacts efficient Vehicle to Hybrid (V2H) battery and Hybrid Vehicle to Grid (V2G) smart grid battery are presented. The new schemes utilized switched filter-capacitive compensation to ensure fast multi-mode charging with enhanced power quality and power factor in addition to minimal inrush currents and improved energy utilization