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This paper focuses on a two-dimensional (2-D) analytical model for a fast computation of magnetic losses due to eddy currents in the permanent magnets as well as iron losses in the ferromagnetic parts within coaxial magnetic gears. The magnetic field distribution is computed in yokes and permanent magnets by solving both Maxwell's equations, whereas for pole pieces, the magnetic field is computed by coupling the previous analytical model with a reluctance network model. Both the eddy current losses and iron losses are determined from this hybrid analytical model. The iron loss model takes into account the temporal and spatial variations of flux density. The eddy current loss model takes into account the magnet splitting. Results of this magnetostatic eddy current loss model are then compared to the results obtained with a 2-D magnetodynamic finite element model. A verification of validity limits is also proposed. The final function of this analytical model is to ensure integration into a set of models in the aim of a global mechatronic optimization of magnetic gears, for their insertion into multimegawatt wind turbines. A preliminary bi-objective, mass-efficiency optimization protocol is subsequently proposed along with an analysis of the computation time reduction via the presented models. [ABSTRACT FROM AUTHOR]

This paper proposes an original model for supercapacitors that takes into account both calendar aging and cycling aging. A state variable is used to quantify the state of aging. This model is based on a series of recent experiments conducted in various research laboratories on the same technology (Maxwell Technology) and serves to represent the degradation of equivalent series resistance and capacitance. This model is particularly useful in an aging-aware life-cycle cost analysis. We show that an accurate aging model is critical to the design of an energy storage system that optimizes the economic life-cycle cost. Such an optimization is particularly applicable for smoothing in offshore systems such as direct wave energy converters, which require both cost reduction and high reliability. The influence of an aging model in the sizing process is investigated toward the end of this paper. [ABSTRACT FROM AUTHOR]

This paper sets forth a sizing optimization methodology of a surface permanent magnet machine-converter system over a torque-speed operating profile. The two optimization objectives are to minimize the cost of the machine-converter system and to minimize (or maximize) electrical energy consumption (or generation). The optimization parameters serve to describe both the machine geometry and the electrical ratings of the electronic power converter. Each operating point of the profile is treated independently, and current control is optimized at every operating point to not only minimize machine drive losses but also satisfy several constraints and then implicitly considering flux-weakening possibility. This optimization methodology is generic and is applied to a particular case: a direct-drive conversion chain for a wave energy converter (WEC). We show that taking into account both the sizing parameters of the converter and the flux-weakening control, in addition to the classical sizing parameters of the machine, has a strong impact on the machine-converter system optimal results. Moreover, the strong coupling with the WEC through damping parameters plays also a crucial role on the sizing results. [ABSTRACT FROM PUBLISHER]