A Stator-PM Transverse Flux Permanent Magnet Linear Generator for Direct Drive Wave Energy Converter

Abstract

Transverse flux permanent magnet linear generator (TF-PMLG) is widely used in direct drive wave energy converter (DD-WEC) because of its high power density. Traditional transverse flux machine (TFM) is designed and built in form of translator-PM. But translator-PM configuration needs a large amount of PM and the cost is high in long stroke application, like DD-WEC. Recently, the stator-PM linear machines have gained more attention for reducing the PM volume and improving the generator performances under low-speed conditions. In this paper, a novel stator-PM TF-PMLG for DD-WEC has been proposed. The fundamental configuration and operation principle of the generator are illustrated. Then, the expressions of the back EMF and the electromagnetic thrust are derived by magnetic circuit analysis. Main dimension parameters, such as PM thickness, central angle of the outer stator shoe and pole pitch are determined and optimized based on finite element analysis (FEA). This topology has advantages of low PM consumption and high power density, and is a suitable candidate for long stroke applications, like DD-WEC, in which a high power per PM volume is usually needed to reduce the amount of permanent magnet and ensure high power density.

A Review of Transverse Flux Machines Topologies and Design

“…The operation, design and modeling of rotating, linear and tubular machines is quite similar (e.g., torque ripple in rotating machines versus force ripple in the linear case), that is why this review is mainly focused on rotating machines. Nevertheless, linear [4,9,10,21,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] and tubular [11][12][13]33,[42][43][44][45][46][47][48][49][50][51][52][53][54] TFMs have specific applications that are presented at the end of this section. In any case, commercial exploitation of TFMs is currently limited to very few manufacturers [55][56][57].…”

“…Linear and tubular TF generators for wave energy have been proposed in [33,52] and TF tubular machines have been presented for use with a free-piston engine in [44,45,48,49].…”

Investigation of the Effects of the Pole Shoe Geometry on the IPM T-LSM Features: Application to Free Piston Engines

“…L INEAR machines have been and continue to be viable candidates in several industrial fields where they exhibit higher performance than their rotating counterparts. They are integrated in wave energy conversion systems [1]- [4], Maglev trains [5]- [7], ropeless elevators [8], [9], electromagnetic suspensions [10], [11], and free piston engines [12]- [15].…”

Dimensioning Optimization of the Permanent Magnet Synchronous Generator for Direct Drive Wind Turbines

“…The reduction of the PMSG weight is also an optimization criterion for its application on wind turbines to minimize the fixed and variable losses and to maximize the PMSG efficiency [21][22][23][24]; Chen et al, 2021 [24] simulated a cross-flow PMSG to reduce the volume of the magnetic poles using the finite element method and the magnetic equivalent circuit. In this work, they reported the yield improvement of the machine with a low volume of the magnetic poles and high-power density.…”

“…Generally, the research works related to the PMSG optimization for wind turbines have obtained only a design as the result of the criteria used for the optimization [14,24,25,29,30]. This contribution aims to develop an optimization methodology for the PMSG dimensioning to be coupled to wind turbines regarding the wind resource, the turbine rotor, and the power converter; also the PMSG dimensioning involves two optimization criteria where for each radius of the magnet base (R bi ), the generator was optimized based on maximum efficiency and later the obtained optimal generator for maximum efficiency that had the minimum weight was searched but the optimization process based on minimum weight was not carried out.…”