Application of iron nitride compound as alternative permanent magnet for designing linear generators to harvest oceanic wave energy

Abstract

Most of the conventional linear generator is constructed with either Alnico (specially AlNiCo-9) or Neodymium iron boron (NdFeB) permanent magnets (PMs) for harvesting oceanic wave energy. Alnico is a composition of aluminium (Al), nickel (Ni), and cobalt (Co) added to iron, which is its major volumetric component. Alnico has a poor magnetic energy product, and NdFeB contains a rare earth element. To overcome this issue, a recently developed rare-earth free iron nitride (Fe 16 N 2) compound-based PM linear generator (PMLG) is proposed in this study as an alternative solution for avoiding rare earth material while obtaining high output power. To the best of authors' knowledge, newly invented Fe 16 N 2 is not proposed, analysed, and investigated in any electrical generator. In this context, Fe 16 N 2 is proposed in a linear generator as PM for producing adequate magnetic flux. For analysis and testing the performance of the proposed material, a PMLG is designed. The performances are compared for using Fe 16 N 2 and AlNiCo PMs in the same PMLG design for a fair comparison. It is considered that the proposed PMLG is connected to a direct drive power takeoff system. Simulation results show that the proposed PMLG having Fe 16 N 2 generates 55% more electrical power than that of using AlNiCo. The voltage, current, magnetic flux linkage, power, and magnetic flux density of the proposed PMLG are investigated extensively and compared with those of AlNiCo. The finite element method is applied in the ANSYS/Maxwell software environment for testing the PMLG with the conventional and the proposed PMs as well as results are presented. The proposed design is also validated with a small laboratory prototype.

A Review of the Linear Generator Type of Wave Energy Converters’ Power Take-Off Systems

“…The simulation results show that the output-induced voltages could be increased by using high-grade NdFeB PMs. Due to the high price of the NdFeB and the environmental aspects, the alternative has been proposed to replace the NdFeB magnets [98]. The temperature rises during the operation of the linear generator, and this rising heat can demagnetise the magnets.…”

Recent Progress in Electrical Generators for Oceanic Wave Energy Conversion

“…Moreover, the dehumidifier controls the humidity in the linear generator which would increase its lifespan. Other than these permanent magnets, the compound Fe 16 N 2 known as iron nitride is applied in [32] which exhibits the best performance among all conventional rare earth free permanent magnets. Table 2 presents outcomes of the LG for application of various high graded permanent magnets along with conventional one.…”

Potential Future Alternative Resources for Rare Earth Elements: Opportunities and Challenges

“…It is also very important to maintain a proper supply chain to meet the demand for the development of highly advanced technologies. Even the substitution of REE by other cheaper metals is difficult for most applications, though powerful permanent magnets made out of iron and nitrogen (iron nitride, Fe16N2) are helping the automotive and wind energy industries in a small way [7]. Pavel et al [8] studied the possibilities of substitution of REE in wind turbines in order to reduce the dependency on REE, but later it was found that these claims were impossible without neodymium.…”