Search results for "Control theory"
showing 10 items of 1333 documents
Passive-damping design for vibration control of large structures
2013
In this work, a systematic strategy to design passive damping systems for structural vibration control is presented. The proposed design methodology is based on the equivalence between decentralized static velocity-feedback controllers and passive damping systems. By using recent developments in static output-feedback control, the design of passivedamping systems can be formulated as a single optimization problem with Linear Matrix Inequality constraints. Moreover, this optimization problem can be efficiently solved with standard numerical tools, even for large dimension systems. Due to its computational effectiveness, the proposed methodology can be applied to the design of passive damping…
Coherency identification and oscillation damping effects of PSS in interconnected power system: A comparative analysis approach
2016
This paper analyzes four different test systems for defining coherent generators in the multi machine power systems based on the Eigen properties of the linearized model of the inter connected power system. The disruption is measured to be dispersed in the network by smearing small signal disturbance in each case. For finding the coherent areas and their tolerances in the inter-connected power system, no generator buses are allocated to each cluster of coherent generator using similar coherency recognition methods. The technique is assessed with four test schemes, and coherent generators and zones are acquired for diverse functioning points to render a more precise consortium approach, whic…
Least squares and genetic algorithms for parameter identification of induction motors
2001
Abstract This paper deals with off-line parameter identification of induction motors by means of least square (LS) techniques and genetic algorithms (GA), using stator voltages, stator currents and velocity as input–output data. For analytical identification by LS algorithms, filtering of experimental data is performed by means of anticausal filters. Two models useful for identification are derived in which the products of acceleration and rotor fluxes, usually neglected, are taken into account. The GA-based identification method consists of the determination of the best parameters which match input–output behaviour of the motor. Both methods are investigated and compared by means of experi…
Application of the Morris method for screening the influential parameters of fuzzy controllers applied to wastewater treatment plants
2011
In this paper,we evaluate the application of a sensitivity analysis to help fine-tuning a fuzzy controller for a biological nitrogen and phosphorus removal (BNPR) plant. TheMorris Screeningmethod is proposed and evaluated as a prior step to obtain the parameter significance ranking. First, an iterative procedure has been performed in order to find out the proper repetition number of the elementary effects (r) of the method. The optimal repetition number found in this study (r = 60) is in direct contrast to previous applications of the Morris method, which usually use low repetition number, e.g. r = 10 ~ 20. Working with a non-proper repetition number (r) could lead to Type I error (identify…
A discussion on variants of stand-alone electric powerplant equipped with transverse flux generators
2015
The paper discussed several designed variants of TFG with different number of poles, speed and dimensional coefficients starting from two base module variants with a rated power of 8kW and 11 kW respectively. The proposed layout came from reluctance one and it is suitable to equipped stand-alone electric power plant being a proper solution for isolated farms. The influence of large number of poles on torque density values obtained at low rotational speed is discussed in paper.
Cascaded PD-PI controller for active power frequency control of two-area multi-units power system
2016
In interconnected multi-area power system; the real power generation within each area has to be managed through active power frequency control considering scheduled power exchange. In this work, two different controllers, namely cascaded PD-PI and conventional PID controller are considered for analyzing the dynamic response of the two area interconnected power system. Area-1 consists of two reheat type thermal generating power plant units and area-2 comprises of two non-reheat type thermal power plant units. The controller gains of PD-PI and PID controllers are efficiently tuned by ‘Teaching Learning based Optimization Technique’. In area-1, 1% step load disturbance is applied for analyzing…
On the design of observers robust to load variations for synchronous converters
2015
Due to the ever growing concern on energy efficiency issues, synchronous rectification gained increasing attention in recent years. In the semiconductor industry fast controllers developed for DC-DC converters are typically based on inductor current measures. In this context system costs and performances strictly depend on the current sensor and its proper design. In this paper we present a sensorless synchronous approach based on a current observer. The same observer formulation is valid for the three standard DC-DC converters, simplifying its design for different configurations. Furthermore the designed observers are proven to be robust against load variations, the most uncertain paramete…
Semiactive control for floating offshore wind turbines subject to aero-hydro dynamic loads
2011
Wind and wave dynamic loads might cause undesirable vibrations that affect the structure integrity and system performance of floating offshore wind turbines. This paper addresses the problem of dynamic load mitigation by using semiactive control techniques with the tuned liquid column dampers placed on the turbine’s tower. The control law is formulated based on the mixed H2/H∞ methods for ensuring the system stability and reliability. Furthermore, the proposed controller only uses output feedback so as to avoid the dependence on the knowledge of the states of the system. Peer Reviewed
Off-line path correction of robotic face milling using static tool force and robot stiffness
2015
In this paper the developed method for off-line compensation of tool deflections when milling aluminum with an industrial robot is presented. The efficiency of this approach is verified with high precision measurements of deflections using a laser tracker. The compensation method includes both the static milling process model which can predict the mean value components of the tool forces and a new combined local/global approach for estimating the combined stiffnesses of joints. With a process model such as the one presented in this paper and estimates of the robot's joint stiffness values, the tool path can be adjusted to counteract deflections of the tool during milling operations. The mod…
Hidden oscillations in aircraft flight control system with input saturation
2013
Abstract The presence of actuator saturation can dramatically degrade the system performance. Since the feedback loop is broken when the actuator saturates the unstable modes of the regulator may then drift to undesirable values. The consequences are that undesired nonlinear oscillations appear and that the settling time may unacceptably increase. Rigorous analysis of nonlinear aircraft models is a very difficult task, that is why a numerical simulation is often used as an analysis and design tool. In this paper difficulties of numerical analysis related to the existence of hidden oscillations in the aircraft control system are demonstrated.