Two-Steps Slotting Method in Magnet Edge of PMG for Wind Energy Harvesting
Published at : 17 Dec 2020
Volume : IJtech
Vol 11, No 7 (2020)
DOI : https://doi.org/10.14716/ijtech.v11i7.4554
Nur, T., Siregar, M, 2020. Two-Steps Slotting Method in Magnet Edge of PMG for Wind Energy Harvesting. International Journal of Technology. Volume 11(7), pp. 1442-1450
| Tajuddin Nur | Department of Electrical Engineering Faculty of Engineering Atma Jaya Catholic University of Indonesia, Jl Sudirman No 51 Jakarta 12930, Indonesia |
| Marsul Siregar | Department of Electrical Engineering Faculty of Engineering Atma Jaya Catholic University of Indonesia, Jl Sudirman No 51 Jakarta 12930, Indonesia |
This
paper focuses on the study of how to decrease the value of the cogging torque
in an Inset
Permanen Magnet Generator. The permanent-magnet generator of an integral slot
number with 24 slots and 8 poles was selected and investigated for the purposes
of this study. The cogging torque of the permanent-magnet generator can be
minimized by combining two slottings in the magnet edge with a gradually
inclined surface end. The electromagnetic simulations and analysis of the
permanent-magnet generator studied were performed using numerical analysis by
means of FEMM 4.2. To obtain a faster computation, FEMM 4.2 was combined with
LUA 4.0 programming. Using FEMM 4.2, it was found that by applying two-step
slotting in the
magnet edge combined with a gradually inclined surface end, the cogging torque
of the permanent-magnet generator selected can effectively reduce the cogging
torque of the machine by approximately 98.14% compared against the initial
magnet model. It can be concluded that the integration of the two-step slotting
in the magnet edge and the gradually inclined surface end can effectively
reduce the cogging torque of the permanent-magnet generator machine.
Furthermore, decreases in the density of the magnetic flux in the core of the
permanent-magnet generator can also be found.
Cogging torque; Finite element; Integral slot number; Permanent-magnet generator
The application
of permanent-magnet
generators (PMGs) in our daily lives is now becoming more attractive and can be
used with robotics, electric vehicles, wind turbines, and many other
applications. Any PMG has some merit over other types of electrical machines.
Wind power generation has recently
been increasing in popularity because it is clean, has a low production cost, is
abundant, and because market volume has tended to significantly increase
compared with other energy sources. Using PMGs in renewable energy systems has benefits
including high performance and efficiency, simplicity, and reliability of
construction. However, the most important issue for PMG applications is the
presence of cogging torque (CT). The CT in any PMG is impacted by the
interaction among the magnetic
flux force from the rotor core and stator teeth or stator slot in the stator
core of the machine. The CT in electrical machines and in PMGs can produce
noise, vibration, and many other complicated conditions that might appear in
the machine application system.
Over the last
few years, much research has addressed these issues and sought to reduce
The purpose of this paper is to propose a new technique for CT reduction
in any PMG and to prove that employing the combination of TSS in the magnet edge
with GISE in the magnet edge could effectively lessen the peak CT value in any
PMG. The new technique of CT reduction can be applied to both integral slot
numbers and fractional slot numbers; however, in this work, the analysis of PMGs
focuses on the integral slot number. The authors have selected a PMG structure with
24 slots and 8 poles. Figure 1 illustrates
the magnet structure of the PMGs, which is the initial structure. Figure 3a shows
one-step slotting (OSS), and the Figure
3b presenst TSS. From Figure 1 it can be observed that the initial
magnet structure is a conventional magnet structure, which means no slotting was
applied in the magnet structure of the machine. Figure 3a demonstrates the use
of OSS on the magnet edge, while Figure 3b shows the application of TSS on the magnet edges of the
PMG. All PMG structures have been studied and contrasted in this paper. The three structures for a 24 slot/8
pole of PMG are analyzed and compared in this paper.
In general, the magnet rotor in any PMG is similar to that used in surfaced-mounted permanent-magnet rotors. The difference between the PMGs studied in this paper and a surface-mounted machine is the iron tooth or rotor teeth within the rotor core. As a surface-mounted machine, the permanent magnets in the rotor core of the machine are the main causes of the magnetix flux in a PMG. In the PMG structures studied, the magnets of the machine are buried in the rotor core, leading to a compact and strong rotor construction compared against surface PMGs. The structures of PMGs proposed in this study are shown in Figure 3b.
Figure 1 Construction of the Initial Structure (IS) of PMG
Figure 2 Classification of cogging torque (CT) reduction techniques for PMGs.
This paper recommends combining TSS with GISE to reduce CT for the
proposed PMSM. In comparison with the performance of the initial structure, the
ability of the PMG to harvest electrical energy from wind can be improved by
around 98.14%. Using the FEMM, it was found that the CT of the PMG proposed as
much as 98.14% in contrast with the PMG of the initial structure. It can be
concluded that combining TSS and GISE effectively reduces the CT of a PMG. The
combination of TSS and GISE on the magnet edge significantly decreased
tangential flux. It can be concluded that combining TSS and GISE in PMGs
enhances the energy harnessed from wind power.
Thank you to the Atma Jaya Catholic University especially the
Engineering Faculty for supporting this
research.
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