scholarly journals Modal Analysis and Rotor-Dynamics of an Interior Permanent Magnet Synchronous Motor: An Experimental and Theoretical Study

2020 ◽  
Vol 10 (17) ◽  
pp. 5881
Author(s):  
Selma Čorović ◽  
Damijan Miljavec

This paper investigates mechanical vibrations of an interior permanent magnet (IPM) synchronous electrical motor designed for a wide range of speeds by virtue of the modal and rotordynamic theory. Mechanical vibrations of the case study IPM motor components were detected and analyzed via numerical, analytical and experimental investigation. First, a finite element-based model of the stator assembly including windings was set up and validated with experimental and analytical results. Second, the influence of the presence of the motor housing on the natural frequencies of the stator and windings was investigated by virtue of numerical modal analysis. The experimental and numerical modal analyses were further carried out on the IPM rotor configuration. The results show that the natural frequencies of the IPM rotor increase due to the presence of the magnets. Finally, detailed numerical rotordynamic analysis was performed in order to investigate the most critical speeds of the IPM rotor with bearings. Based on the obtained results, the key parameters related to mechanical vibrations response phenomena, which are important when designing electrical motors with interior permanent magnets, are provided. The main findings reported here can be used for experimental and theoretical mechanical vibration analysis of other types of rotating electrical machines.

Author(s):  
Ho-Joon Lee Et.al

Approximately 2.5 billion won can be saved every year by replacing existing induction motors, which are traction motors for urban railway vehicles, with permanent magnet motors. This paper presents a study on the structural design of a completely enclosed motor to commercialize an interior permanent-magnet synchronous motor (IPMSM) for the traction of urban railway vehicles. The proposed solution provides protection from an inflow of dust and magnetic powder into the rotor that can deteriorate the motor performance and cause burnout. In addition, unless it is a water-cooled or oil-cooled structure, cooling of an electric motor used in medium and large-sized equipment is not easily accomplished. However, completely enclosed motors are vulnerable to overheating; therefore, research into housing design is required to provide cooling. Additionally, the permissible current density through the stator winding must be considered in the design to prevent the occurrence of thermal demagnetization of permanent magnets. Furthermore, IPMSMs require a separate driver for operation and speed controls for a wide range of operating conditions such as rail traction. Thus, a study has been conducted on IPMSMs and other related driver and control technologies, and their suitability has been validated through performance tests.


Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5082
Author(s):  
Jae-Woo Jung ◽  
Byeong-Hwa Lee ◽  
Kyu-Seob Kim ◽  
Sung-Il Kim

We designed and analyzed an interior permanent magnet synchronous motor (IPMSM) to prevent irreversible demagnetization of the permanent magnets (PMs). Irreversible demagnetization of NdFeB PMs mainly occurs due to high temperature, which should thus be minimized. Therefore, it is necessary to reduce the eddy current loss in the PM through optimal design. The shape of the rotor core was optimized using finite element analysis (FEA) and response surface methodology. Three-dimensional (3-D) FEA is required for accurate computation of the eddy current loss, but there is huge time, effort, and cost consumption. Therefore, a method is proposed for indirectly calculating the eddy current loss of PMs using 2-D FEA. A thermal equivalent circuit analysis was used to calculate the PM temperature of the optimized model. For the thermal analysis, the copper loss, core loss, and eddy current loss in PMs were estimated and applied as a heat source. Based on the results, we confirmed the stability of the optimum model in terms of the PM demagnetization.


Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2406 ◽  
Author(s):  
Cezary Jędryczka ◽  
Dawid Danielczyk ◽  
Wojciech Szeląg

This paper deals with the torque ripple minimization method based on the modulation of the phase currents of the permanent-magnet synchronous motor (PMSM) drive. The shape of the supply current waveforms reducing the torque ripple of the machine considered was determined on the basis of finite element analysis (FEA). In the proposed approach, the machine is supplied by a six-leg inverter in order to allow for the injection of zero sequence current harmonics. Two test PMSMs with fractional-slot concentrated windings (FSCW) and surface-mounted permanent magnets (SPMs) have been examined as a case study problem. Wide-range fractional analyses were performed using developed numerical models of the electromagnetic field distribution in the considered machines. The results obtained show that the level of torque ripple in FSCW PMSMs can be effectively reduced by the modulation of the phase currents under the six-leg inverter supply.


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