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This article has reported on an industrial R&D project aimed at identifying a cost-effective response to the more and more challenging high-speed motor requirements that presently come from the gas industry sector. To meet the very high efficiency, dynamic performance, and reliability standards required by cutting-edge turbomachinery drive applications, a special PM synchronous motor prototype has been developed. The identified technology includes AMBs for rotor levitation, a slotless stator design, and a Halbach-array PM rotor. Motor design optimization through genetic algorithms has been presented as a tool to search for the best tradeoff between performance targets and industrial production cost reduction. Extensive prototype testing under converter supply has been reported as a successful validation of the selected technology.

Gli attuatori oleodinamici usati per timonerie e pinne stabilizzatrici sviluppano elevate coppie a basse velocità. Viene presentato, in alternativa, un innovativo motore elettrico lineare ad elevata spinta alimentato da inverter per azionamenti diretti a bordo nave, che offre grandi vantaggi in termini di compattezza, manutenzione, efficienza, e tolleranza al guasto.

Permanent-Magnet Synchronous Linear Motors (PMSLM) are more and more frequently used as all-electric direct-drive actuators in those applications where a force needs to be developed along a fixed direction. In this paper, an accurate 3D thermal model of a PMSLM is derived through a lumped-parameter network approach which exploits all the symmetries in the actuator structure to maximize the spatial density of nodes. Numerically-efficient techniques are then proposed to solve the thermal network analytically. Some experimental validations are finally presented based on the thermal testing of a laboratory prototype.

A key factor in the design of photovoltaic fields is their yearly productivity and normally the nominal power is the only module parameter taken into account in the productivity predictions. The present paper intends to demonstrate how this approach disregards an important parameter, the nominal fill factor, that may significantly affect module efficiency when working in realistic environmental conditions. A complete calculation method is presented to compute a module productivity in any operating condition, using data sheets information. As an example two commercial module characteristics with different fill factors are compared to illustrate the concept in quantitative terms.

Apparatus to control a photovoltaic plant comprising at least a string of photovoltaic modules connected to an electric energy converter, and a switch connected in parallel to said string and to said electric energy converter.

Various analytical techniques have been proposed in the literature for cogging torque computation in Surface Permanent Magnet (SPM) machines. Among the various available methods, the ones found to be satisfactorily accurate are based on the Maxwell’s stress tensor, which involves both normal and tangential air-gap field and lead to quite involved calculation formulas. In this paper, a relatively simple alternative is proposed where permanent magnets are modeled as equivalent field circuits to which a well defined winding function can be associated. The approach leads to a plain cogging torque formulation where only the normal no-load air-gap flux density appears. The accuracy of the method is assessed by Finite Element (FE) analysis on some sample SPM machine geometries. The results are shown to match FE simulations with a satisfactory accuracy compared to Maxwell-stress-tensor-based analytical techniques available from the literature.