Showing papers on "Tip-speed ratio published in 2001"
TL;DR: In this paper, the three-dimensional mean velocity and turbulence fields were obtained at six axial locations within two chord lengths of the blades for three operating conditions: stalled flow over the blades, close to optimum performance, and approaching runaway.
68 citations
17 Jun 2001
TL;DR: In this paper, the design of a boost type DC/DC converter for a 20 kW wind turbine generator is described, where the generator phase inductance is big enough so no extra DC inductor is required.
Abstract: This paper describes the design of a boost type DC/DC converter for a 20 kW wind turbine generator. The generator phase inductance is big enough so no extra DC inductor is required. The electrical system is modeled using the power electronics and motor control software package PSIM, then a current controller is designed. Its steady state and transient performance shows that the generator phase inductance helps to smooth the generator phase current with a reasonable lagging angle. Furthermore, a simple current-torque model is derived for the electrical system. This model together with that of the mechanical system enables the design of the speed control loop based on the turbine tip speed ratio (TSR), the ratio of the blade tip speed to the wind speed. The simulation result based on MATLAB/SIMULINK shows the power tracking with wind variation. The whole control system is being implemented using an embedded controller.
58 citations
Proceedings Article•
01 Oct 2001
TL;DR: In this paper, the authors present an approach for combining readings from three anemometers into a composite wind speed measurement, and using this signal to control the operation of a permanent magnet generator to achieve maximum energy extraction.
Abstract: Wind speeds can vary rapidly and wind turbines cannot easily follow these variations because of their inertia and aerodynamic characteristics. For maximum energy extraction, the turbine blades should operate at their optimum tip speed ratio, but with rapid changes in wind speed, this is usually not possible. To improve the energy extraction from turbulent wind, it is necessary to establish an effective measure of the high frequency component of the wind, and then to use this measure to optimise the operation of the turbine controller for maximum energy extraction. This paper presents an approach for combining readings from three anemometers into a composite wind speed measurement, and using this signal to control the operation of a permanent magnet generator to achieve maximum energy extraction. The method combines simulation and experimental investigations into a heuristic algorithm, and demonstrates its effectiveness with field trials.
8 citations
TL;DR: In this paper, an estimation method of both torque coefficient and moment of inertia of the windmill by using genetic algorithm is proposed, where the torque coefficient is dependent on the shape of windmill and is represented as a nonlinear function of the tip speed ratio.
Abstract: In this paper, an estimation method of both torque coefficient and moment of inertia of the windmill by using genetic algorithm is proposed. Generally, the torque coefficient is dependent on the shape of the windmill and is represented as a nonlinear function of the tip speed ratio. To simulate the nonlinearity, the torque coefficient is split into the m areas with respect to the tip speed ratio and is approximated by a piecewise linear equation in each area. The gains of the piecewise linear equation in each area and the moment of inertia are regarded as the gene and adjusted by the genetic algorithm so that the estimated windmill speed and acceleration correspond to the actual values. The results demonstrate the effective of the proposed scheme for estimation of the windmill parameters.
3 citations