Winding Configuration and Performance Investigations of a Tubular Superconducting Flux-Switching Linear Generator

Abstract

Primary permanent-magnet linear generators have an advantage of a simple secondary structure, which is suitable for the application of wave energy conversion. Based on vernier hybrid machines (VHMs), which are widely used for direct-drive wave energy converters, this paper proposes a tubular superconducting flux-switching linear generator (TSFSLG), which can effectively improve the performance of this kind of generators. Magnesium-diboride (MgB 2 )-type direct current superconducting windings are used in the generator to increase the magnetic energy and overcome the disadvantages of easily irreversible demagnetization of the VHMs and high-voltage regulation of a permanent-magnet flux-switching linear generator (PMFSLG). The alternating current superconducting windings are implemented to improve the efficiency. Based on the MgB 2 superconducting wire produced and measured in the laboratory, the superconducting windings structure used for the generator is designed. The coil-EMF vector is optimized, and the losses of superconducting windings are analyzed. In addition, by using the finite-element method, the no-load performances of the generator are analyzed and compared with the ones of a VHM and a PMFSLG. Finally, the on-load performance of the TSFSLG is obtained by finite-element analysis and compared with the VHM and the PMFSLG. The results validate that the proposed generator is more suitable for wave energy conversion than its counterparts.Index Terms-Finite-element method, linear flux-switching generator, superconducting winding, wave energy conversion.

A Survey of Power Take-off Systems of Ocean Wave Energy Converters

“…Zhang et al [88] changed the geometry parameters of the slot so that the effect of the Halbach PM array configuration on the electromagnetic properties of the generator and design guides were established for optimization of the key design parameters. There are also studies on how to avoid the irreversible demagnetization of magnets using the superconducting windings [57,89,90,91].…”

Analysis of the Oceanic Wave Dynamics for Generation of Electrical Energy Using a Linear Generator

“…The power takeoff devices play a vital role in converting the irregular wave motion to a regular motion for energy conversion. Linear generators (LGs) have directly been implemented to the direct drive wave energy conversion without using medium devices which has unique advantages over all other wave energy devices [21]. An LG has two major parts, namely, translator and stator.…”

“…Different types of permanent magnet linear generators (PMLGs) have been designed and analyzed for improved performance. The flat and tubular flux switching permanent magnet linear generators (FSPMLGs) have been proposed [21,24,25]. Different analyses have shown that the FSPMLGs made of PMs and steel cores have suffered from the problem of higher leakage flux leading to the reduction of electrical power generation.…”

“…Different analyses have shown that the FSPMLGs made of PMs and steel cores have suffered from the problem of higher leakage flux leading to the reduction of electrical power generation. Tubular PMLGs have been proposed [14,21,26,27] to reduce cogging forces and also increase efficiency. The maintenance of tubular PMLG is difficult due to the presence of the coils inside the periphery.…”

Analysis and design of a novel linear generator for harvesting oceanic wave energy

“…Because of this, there are significant challenges for power grids to manage the stability, security and reliability while smoothing the generated power and thus make the best use of renewable energy sources [4]. At present, the major linear generators used for wave energy extraction are permanent magnet (PM) linear synchronous machines that usually have PMs on the translator [5], [6]. The traditional linear generators have the disadvantages of complex translator structure and unexpected translator temperature rise, which might cause irreversible demagnetization of magnets and mechanical damage [7].…”