Analytical Solution of Magnetic Field in Permanent-Magnet Eddy-Current Couplings by Considering the Effects of Slots and Iron-Core Protrusions

Abstract

In this study, we propose an analytical model for studying magnetic fields in radial-flux permanent-magnet eddy-current couplings by considering the effects of slots and iron-core protrusions on the eddy currents. We focus on the analytical prediction of the air-gap field by considering the influence of eddy currents induced in conducting bars. In the proposed model, the permanent magnet region is treated as the source of a timevarying magnetic field and the moving-conductor eddy current problem is solved based on the resolution of time-harmonic Helmholtz equations. The spatial harmonics in the air gap and in slots, as well as the time harmonics are all considered in the analytical calculation. Based on the proposed field model, the electromagnetic torque is computed by using the Maxwell stress tensor method. Nonlinear finite element analysis is performed to validate the analytical model. The proposed model can be used for permanent-magnet eddy-current couplings with any slot-pole combination.

A Review of Recent Developments in Permanent Magnet Eddy Current Couplers Technology

“…Red and blue indicate PMs with different magnetization directions. References [98,100,104] also extended the study of slotted structures to radial fluxes. In addition, the authors of [120,121] studied the different grooves on the surface of the conductor, and compared the effects of the different shapes of grooves on the braking torque and the change in magnetic flux by using the method of finite element analysis (FEA).…”

“…A surface-mounted radial-flux PMECC with internal PMs and an external conductor rotor was proposed in references [89][90][91][92][93][94][95][96][97]. A radial-flux PMECC with an internal conductor rotor and an external PM structure was proposed in references [98][99][100]. The bilateral structure, as shown in Figure 8, also appears for the radial flux type since it can also effectively increase the torque [11,12,[101][102][103].…”

Electromagnetic Characterization of Permanent Magnet Eddy Current Structures Based on Backplane Distance Adjustment

“…The structure of the transverse telescopic cut-off drum and the internal piping is shown in Figure 1. Inside the speed reducer, there are two hydraulic channels: the extension channel (13) and the retraction channel (14), which make it impossible for the internal spray system, which is located under the cut-off drum teeth, to feed water from the outer drum.…”

Design of High Resolution Magnetic Probe for Magnetic Field Measurement on AES Cryptographic FPGA to Analyze the Side Channel Attack

“…The magnetic field probe is designed with magnetic field collecting coil with a plastic probe holder. To obtain the detailed information from the detected magnetic field, the detected signal is processed by using image processing [13][14][15][16].…”