Because typical electrical devices cannot be driven without a power converter, the use of gears is essential. Various studies have focused on magnetic gears without mechanical losses. In certain linear motion systems, such as wave energy power generators, using linear gears is inevitable. The most important aspect of gears in linear systems is manufacturing feasibility. Recently, research on linear magnetic gears has focused on tubular structures. However, tubular magnetic gears have the disadvantages of being difficult and expensive to manufacture. Alternatively, similar performance can be achieved by simplifying the tubular structure to a linear one. There are unfortunately few researches on simplified linear magnetic gears to date, and this is therefore very important.
In this paper, we performed an electromagnetic analysis of simplified linear magnetic gears (LMGs) according to the characteristics of their flux-modulation poles (FMPs). The performance of LMGs varies greatly depending on the characteristics of their FMP. Therefore, we proposed the optimal type of LMG by comparing the characteristics of the FMPs of three types of LMGs: non-laminated core, laminated core, and soft magnetic composite (SMC) core. Generally, non-laminated cores yield low efficiency because of core losses and eddy current losses, but their stiffness is vastly superior. Laminated cores have low stiffness but high efficiency because of their low electromagnetic losses. SMCs offer several advantages, including low core losses, low eddy current losses, 3-D isotropic ferromagnetic behavior, flexible machine design, and relatively good recyclability. By comparing these characteristics, we show the superiority of simplified LMG fabrication and its performance and then propose the best type of FMP by comparing their electromagnetic characteristics. The final focus of our electromagnetic analysis is determining the feasibility of constructing a simplified linear magnetic gear, along with its manufacturing cost, electromagnetic characteristics, and safety during operation. All results are validated through FE analysis and experimental results. Therefore, the final manuscript will cover more details about analysis process.