Parameterized Disturbance Observer Based Controller to Reduce Cyclic Loads of Wind Turbine

This paper is concerned with bump-less transfer of parameterized disturbance observer based controller with individual pitch control strategy to reduce cyclic loads of wind turbine in full load operation. Cyclic loads are generated due to wind shear and tower shadow effects. Multivariable disturbance observer based linear controllers are designed with objective to reduce output power fluctuation, tower oscillation and drive-train torsion using optimal control theory. Linear parameterized controllers are designed by using a smooth scheduling mechanism between the controllers. The proposed parameterized controller with individual pitch was tested on nonlinear Fatigue, Aerodynamics, Structures, and Turbulence (FAST) code model of National Renewable Energy Laboratory (NREL)’s 5 MW wind turbine. The closed-loop system performance was assessed by comparing the simulation results of proposed controller with a fixed gain and parameterized controller with collective pitch for full load operation of wind turbine. Simulations are performed with step wind to see the behavior of the system with wind shear and tower shadow effects. Then, turbulent wind is applied to see the smooth transition of the controllers. It can be concluded from the results that the proposed parameterized control shows smooth transition from one controller to another controller. Moreover, 3p and 6p harmonics are well mitigated as compared to fixed gain DOBC and parameterized DOBC with collective pitch

Optimization of Power Plant for Telecom Sector Based on Embedded System

Modern Telecom Sector is eventually facing exceptionally tough challenges because of continuous and unexpected increase in power density requirement for the communicating machinery and equipment. To fulfil the power requirements for the equipment, a significant architecture and an optimal technique must be introduced. In this paper, a microcontroller-based optimization use of power-density has been carried out. Meeting above requirements, various equipment and electronic devices are employed. We have designed a microcontroller-based system via PROTEUS Virtual System Modeling to acquire efficient and effective results. The main focus of our work is to supply the power to Telecom equipment in meantime. The power is feeding on batteries and DG (Diesel Generator) set, depending on the condition of the power requirements. The changeover operations are performed by different relays, which are dully programmed via a microcontroller in Keil software. The power capacity of Telecom ((Telecommunication) equipment is ranged from 39-48 Volts DC. The rectification process is done by switch mode rectifiers instead of linear rectifiers. Because the switch-mode rectifier technology has brought fabulous improvements in power density as compared to linear rectifiers. This is done via simulation of the smart switch in PROTEUS software. The outcomes of the proposed system are costeffective in terms of fuel consumption of DG

A new estimation of nonlinear contact forces of railway vehicle

The core part of any study of rolling stock behavior is the wheel-track interaction patch because the forces produced at the wheel-track interface govern the dynamic behavior of the whole railway vehicle. It is significant to know the nature of the contact force to design more effective vehicle dynamics control systems and condition monitoring systems. However, it is hard to find the status of this adhesion force due to its complexity, highly non-linear nature, and also affected with an unpredictable operation environment. The purpose of this paper is to develop a model-based estimation technique using the Extended Kalman Filter (EKF) with inertial sensors to estimate non-linear wheelset dynamics in variable adhesion conditions. The proposed model results show the robust performance of the EKF algorithm in dry, wet/rain, greasy, and fully contaminated track conditions in traction and braking modes of a railway vehicle. The proposed model is related to the other works in the area of wheel-rail systems and a tradeoff exists in all conditions. This model is very useful in condition monitoring systems for railway asset management to avoid accidents and derailment of a trai

Artificial neural networks to solve the singular model with Neumann–Robin, Dirichlet and Neumann boundary conditions

The aim of this work is to solve the case study singular model involving the Neumann–Robin, Dirichlet, and Neumann boundary conditions using a novel computing framework that is based on the artificial neural network (ANN), global search genetic algorithm (GA), and local search sequential quadratic programming method (SQPM), i.e., ANN-GA-SQPM. The inspiration to present this numerical framework comes through the objective of introducing a reliable structure that associates the operative ANNs features using the optimization procedures of soft computing to deal with such stimulating systems. Four different problems that are based on the singular equations involving Neumann–Robin, Dirichlet, and Neumann boundary conditions have been occupied to scrutinize the robustness, stability, and proficiency of the designed ANN-GA-SQPM. The proposed results through ANN-GA-SQPM have been compared with the exact results to check the efficiency of the scheme through the statistical performances for taking fifty independent trials. Moreover, the study of the neuron analysis based on three and 15 neurons is also performed to check the authenticity of the proposed ANN-GA-SQPM

On-line measurement of dielectric relaxation : use of unorthodox stimuli

This thesis describes a method, improved in speed and accuracy, for low frequency dielectric relaxation measurement and the design of an instrument incorporating this. The method implemented is based on the application of a perfectly low-pass filtered step (the Si function) as the stimulus, the current response being captured by an on-line computer. A discrete Fourier transform can then be performed on the acquired data, leading to the direct computation of the dielectric constant and loss. The generation of unorthodox stimuli (e.g. Si and sinc functions) which were not available by continuous linear systems, is discussed. A novel data storage technique is introduced for such slowly converging `non-causal' waveforms. As it stands the resulting instrument gives sufficient bandwidth (up to 120Hz) to allow cross-calibration with bridge methods, but is also valid down to 0.01Hz. The whole system was initially tested on a lumped circuit - a known RC-series model. The experimental results obtained were found to be in good agreement with those predicted theoretically. The system was also tested with a real polymer dielectric sample, and the results obtained correlated in form with those obtained using other methods, confirming the success of the technique. In addition, a unique form of potential error has been identified and corrected. Finally, the equipment needed was reduced to a personal computer with a data acquisition card and the function generator. As a simple computer-aided measurement method it should prove useful in the laboratory, particularly in the study of polymers.</p

LED Based Optical Wireless Communication System for WBAN

In this paper the O-WBANs (Optical Wireless Body Area Networks) is presented as an alternative to the radio and microwave BANs which are plagued with issues like interference, power hungry, hazardous and costly spectrum. Various experiments performed in this work demonstrate the feasibility of LED (Light-Emitting Diode) based optical systems to be used for BANs. The system cost is kept as low as possible. Mainly the effects on the optical link are observed under ambient light and with different modulation schemes by varying link distance and line of sight in this paper. Experimental results reveal the satisfactory link availability up to the distance of 7 feet (around 2m, the optimum range of WBAN) and within the field of view of 30-60º. The low cost solution presented in this paper meets the WBANs data rate requirement for physiological data (i.e. 10-100 kbps). As IR (Infra-Red) signals do not provide any interference with the signals generated by the medical equipment of hospitals which is the problem in case of RF or microwave signals, additionally the IR signals are confined within a room hence IR signaling can prove to be potential candidate for WBAN fulfilling its security and limited access requirement

Identification of Wheel-Rail Contact Condition Using Multi- Kalman Filtering Approach

Condition changes at the rail surface due to the fallen tree leaves and/or other contaminations can cause the low adhesion levels which present a serious challenge for the traction/braking control systems to avoid the problem of wheel slip/slide. This paper presents a multiple model based method for the identification of the adhesion limit to overcome the problem of the wheel slip/slide in poor contact conditions. The proposed scheme is an indirect method that exploits the dynamic properties of the conventional solid axle wheelset in response to changes in contact condition at the wheel-rail interface avoiding difficult and expensive measurement requirements. A nonlinear model of lateral and yaw dynamics of a conventional solid axle wheelset is used for the study. The non-linearity and changes in the interaction with the rail are modelled by using a set of non-linear creep/slip curves. The scheme consists of a bank of Kalman filters based on the linearized wheelset models. Each Kalman filter in the filter bank is optimally tuned to operate in a specific contact condition. Normalized root mean square values from the residual of each filter calculated using time moving windows are assessed to identify the operating condition of the wheelset