Search results for "Control theory"
showing 10 items of 1333 documents
Design and Sensitivity Analysis of a Reduced-Order Rotor Flux Optimal Observer for Induction Motor Control
2007
This paper aims to give simple and effective design criteria of rotor flux reduced-order observers for motion control systems with induction motors. While the observer is optimized for rotor and stator resistance variations, a sensitivity analysis is carried out in the presence of variations of all the motor parameters by means of either transfer function from true to observed rotor flux or simulation in a MATLAB-SIMULINK environment, assuming the voltages supplying the motor to be different from those supplying the observer. The sensitivity analysis makes it possible to establish design criteria for the observer in question. The behaviour of the proposed reduced order observer is compared …
A Flux and Speed Observer for Sensorless SPIM Applications
2010
It is usual to find single-phase induction motor (SPIM) in several house, office, shopping, farm, and industry appliances, which is become more sophisticated and requires the development of high performance alternatives to drive a SPIM. All proposed strategies to improve the performance SPIM need the evaluation of the rotational speed or position information. Since the use of conventional sensors to measure the rotational speed cannot be justified for SPIM applications, the adoption of a sensorless strategy is a more reasonable option for these cases. This paper presents a flux and speed observer for sensorless applications involving SPIMs. The performance of the proposed observer is verifi…
Trajectory tracking of underactuated underwater vehicles
2003
This paper deals with a control strategies for underactuated underwater vehicles whose target is the tracking of a space trajectory. A cascade control strategy is employed which brings to a control law consisting of: 1) a kinematic control law, derived from the vehicle kinematic model, which forces this model to track the reference trajectory; and 2) a dynamic control law which forces the system to track the reference signals given by the kinematic control law. Conditions for asymptotic tracking of the trajectory are given with reference to the standard dynamical model of the above vehicle. An observer of the marine current is also added in order to process the control law. Simulation tests…
Robust output feedback &#x210C;<inf>&#x221E;</inf> control synthesis with pole placement for offshore wind turbine system: An LMI…
2012
This paper deals with output ℌ ∞ control synthesis for a linear parameter-varying model of a floating wind turbine. A nonlinear model is introduced and linearized to obtain a linear model for each desired azimuth angle using the wind turbine software FAST. The main contributions of this paper are threefold. Firstly, the family of linear models are represented based on an affine parameter-varying model structure. Secondly, the bounded parameter-varying parameters are removed using upper bounded inequalities in the control design process. Thirdly, the control problem is formulated in terms of linear matrix inequalities (LMIs). The simulation results show a comparison between a controller desi…
Performances Comparison for a Rotating Shaft Suspended by 4-Axis Radial Active Magnetic Bearings via 𝜇 -Synthesis, Loop-Shaping Design, and Sub ( 𝐻…
2011
The control systems applied on active magnetic bearing are several. A perfect levitation is characterized by maintaining the operating point condition that is characterized by the center of stator coincident with the geometric center of shaft. The first controller implemented for this purpose is PID controller that is characterized by an algorithm that leads the amplifier to produce control current until the operating point condition is not reached, this is obtained by an integration operator. The effect of an integrator is essential but not necessary for a centered levitation for example in the robust control characterized by a dynamic model depended on plant of system so that it depends o…
Linear parameter‐varying modelling and control of an offshore wind turbine with constrained information
2014
This study deals with linear parameter-varying modelling and output-feedback H ∞ control design for an offshore wind turbine. The controller is designed with consideration that not all the information in the feedback loop will be used. This constraint is incorporated into the design procedure. Constrained information means that a special zero-non-zero pattern is forced upon the gain matrix. The constrained controller is obtained based on parameter-dependent Lyapunov functions and formulated in terms of linear-matrix inequalities. Since the functions are dependent on the wind speed and accurate wind speed measurements are rarely available in practice, an extended Kalman filter is used to est…
Nonlinear droop control for minimum power losses operation in islanded microgrids
2017
In this work, a modified primary regulation technique is proposed to control one of the inverter interfaced units feeding an islanded microgrid. The proposed approach employs an off-line minimum losses Optimal Power Flow, OPF, to extract a lookup table for the composition of the droop curve. Simulations prove that generators reach an operating point that corresponds to a minimum loss operation for the relevant power flow distribution. Since OPF has been implemented with frequency and voltage dependent models, the results of the modified droop are stable and also energy efficient. Further studies will address further analysis on systems showing different R/X ratio and modeling of more genera…
A novel implicit correlation for the operative temperature of a PV panel
2012
Abstract The operating temperature of a commercial PV panel strongly affects the electric power output of the devices. The prediction of the operating temperature therefore plays a central role in the economic and energy assessment of PV systems. The authors propose a new implicit correlation that takes into account the standard weather variables but also the regimen of PV panel in terms of the proximity to the maximum power points. Data coming from an experimental setup were processed by using the least squares technique. To validate the reliability of the correlation, a comparison between expected values and data from other common correlations were done. The results show that the regimen …
Feasibility issues in static output-feedback controller design with application to structural vibration control
2014
Recent results in output-feedback controller design make possible an efficient computation of static output-feedback controllers by solving a single-step LMI optimization problem. This new design strategy is based on a simple transformation of variables, and it has been applied in the field of vibration control of large structures with positive results. There are, however, some feasibility problems that can compromise the effectiveness and applicability of the new approach. In this paper, we present some relevant properties of the variable transformations that allow devising an effective procedure to deal with these feasibility issues. The proposed procedure is applied in designing a static…
Vibration control for adjacent structures using local state information
2014
In this paper, a novel strategy for structural vibration control of multi-structure systems is presented. This strategy pays particular attention to mitigating negative interstructure interactions. Moreover, it is based on recent advances in static output–feedback control, which make possible the efficient computation of decentralized velocity-feedback controllers by solving a single-step optimization problem with Linear Matrix Inequality constraints. To illustrate the main ideas, a local velocity-feedback energy-to-peak controller is designed for the seismic protection of a two-building system. This controller is remarkably effective and extremely simple. Moreover, it can also be implement…