access icon free Magnetic field-modulated linear permanent-magnet generator for direct-drive wave energy conversion

© The Institution of Engineering and Technology
Received 06/06/2019, Accepted 05/02/2020, Revised 28/10/2019, Published 12/02/2020

The linear permanent-magnet synchronous generator (LPMSG) for direct-drive wave energy conversion (WEC) suffers from many drawbacks that have not yet been overcome, such as a low power density and a bulky system volume. Therefore, a magnetic field-modulated linear permanent-magnet generator (FMLPMG) with a simple structure has been designed and manufactured. First, the operating principle of the FMLPMG is demonstrated by the equivalent magnetic circuit method, which explains the high power density of the FMLPMG. Second, at a constant speed and a sinusoidal speed, the electromagnetic characteristics of the FMLPMG under the no-load and load conditions are analysed by the finite-element method. Finally, a direct-drive WEC test platform is built to simulate the process of wave action on the FMLPMG. No-load and load experiments of the FMLPMG are conducted on the test platform, and the results are compared with those of an LPMSG with the same volume and operating conditions. The results show that the FMLPMG with a high power density converts wave energy effectively and solves the problem of low power density faced by the LPMSG in direct-drive WEC.

Inspec keywords: sensorless machine control; permanent magnet generators; direct energy conversion; linear machines; magnetic circuits; synchronous generators; wave power generation; power convertors; finite element analysis

Other keywords: permanent-magnet generator; direct-drive wave energy conversion; load conditions; high power density; operating conditions; magnetic field-modulated linear; wave action; LPMSG; FMLPMG; bulky system volume; low power density; direct-drive WEC test platform; equivalent magnetic circuit method; linear permanent-magnet synchronous generator; load experiments; no-load

Subjects: Numerical analysis; Wave power; Control of electric power systems; Finite element analysis; Linear machines; Synchronous machines

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