In this paper, the design of a ''low cost full passive structure'' of wind turbine system without active electronic part (power and control) is investigated. The efficiency of such device can be obtained only if the design parameters are mutually adapted through an optimization design approach. For this purpose, sizing and simulating models are developed to characterize the behavior and the efficiency of the wind turbine system. A model simplification approach is presented, allowing the reduction of computational times and the investigation of multiple Pareto-optimal solutions with a multiobjective genetic algorithm. Results show that the optimized wind turbine configurations are capable of matching very closely the behavior of active wind turbine systems which operate at optimal wind powers by using a MPPT control device.

In this paper Multiobjective Genetic Algorithms (MOGAs) are used for the design of a small wind turbine generator (WTG) coupled to a DC bus through a diode bridge. The originality of the considered system resides in the suppression of the Maximum Power Point Tracker (MPPT). The poor efficiency of the corresponding passive structure is considerably improved by optimizing the generator characteristics associated with the wind turbine in relation to the wind cycle. The optimized configurations are capable of matching very closely the behavior of active wind turbine systems which operate at optimal wind powers by using a MPPT control device.

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This paper proposes a detailed numerical model of a very narrow air gap of a permanent magnet synchronous machine without an imposed axial flow. The flow structure analysis and the convective heat transfer are carefully investigated using an axisymmetric model of two concentric cylinders where the inner cylinder is rotating and the outer cylinder is stationary. For the different cases, only isothermal boundary conditions have been considered. The impact of the air gap mean temperature and of the rotation speed are thoroughly studied and all numerical findings are compared with analytical dimensionless correlations. CFD simulations show the existence of two critical Taylor numbers corresponding to the onset of further instabilities into the air gap which matches with theoretical and experimental previous results found in the literature. The Nusselt number distribution given by CFD shows a disparity with the dimensionless correlations which underestimate the effective convective heat transfer in very narrow air gaps. The numerical simulations allow the definition of a piecewise expression able to fit well the overall Nusselt number distribution over a relatively large range of Taylor numbers up to 3×10 4 . The present work shows the contribution of CFD numerical methods on the estimation of convection thermal resistances in very narrow air gaps.

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This article deals with a methodology for a computer-aided design of electromechanical actuators from the preliminary design of components to the detail design of the electrical motor. The developed library of components for the simulation takes advantage of the non-causal and object oriented characteristics of the Modelica language. The capabilities of the Modelica language and the LMS.Imagine.Lab AMESim or Dymola Platforms are strongly used in order to build a fully integrated process to design and size the different component of the final actuator. The proposed approach is illustrated with the sizing of a flight control actuator.

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