• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.3
• /
• pp.375-383
• /
• 2008

This paper deals with reduction and analysis of cogging torque for permanent magnet synchronous generators with multi-pole rotor for wind power applications. Open-circuit field solutions are derived using a magnetic vector potential and a two-dimensional (2-d) polar coordinate systems. On the basis of derived open-circuit field solutions and 2-d permeance functions, we also derive open-circuit field solutions considering stator slotting effects. By using open-circuit field solutions considering stator slotting effects and energy variation methods, this paper analytically predicts the cogging torque considering skew effects. All analytical results are shown in good agreement with those obtained from finite element (FE) analyses. In order to reduce the cogging torque, by predicting the variation of the cogging torque according to pole arc/pitch ratio using analytical and FE methods, pole arc/pitch ratio which makes the cogging torque minimum are determined. However, we confirm that measured value for cogging torque of the PMG with determined pole arc/pitch ratio is twice higher than predicted value. Therefore, the reason for an error between measured and predicted cogging torque is discussed in terms of a shape of PMs and is proved experimentally.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.9
• /
• pp.938-948
• /
• 2009

In this paper, permanent magnets were used to remove magnetic sludge in the condenser of the power plant. To obtain the flow characteristics and magnetic information that are needed for determining a proper design of the magnetics sludge removal apparatus, numerical simulations were performed through the use of two commercial codes, ANSYS Workbench-Emag and CFX. Experiments were also performed on various kinds and sizes of magnets to obtain the magnetic information through a gauss meter. By analyzing the results of simulations and experiments, the minimum magnetic force that is able to remove the any size of the magnetic sludge in the condenser was calculated, and the design of the removal apparatus was confirmed. The test model which was confirmed by simulations and experiments was made. After testing, the test results were compared with those of numerical simulations and have good agreements.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.18 no.1
• /
• pp.18-25
• /
• 2013

In this paper, a nonlinear controller based on adaptive back-stepping method is proposed for high performance operation of Interior Permanent Magnet Synchronous Motor (IPMSM). First, in order to improve the performance of speed tracking, a nonlinear back-stepping controller is designed. In addition, since it is difficult to achieve the high quality control performance without considering parameter variation, a parameter estimator is included to adapt to the variation of load torque in real time. Finally, for the efficiency of power consumption of the motor, controller is designed to operate motor with the minimum current for the required maximum torque. The proposed controller is tested through experiment with a 1-hp Interior Permanent Magnet Synchronous Motor (IPMSM) for the angular velocity reference tracking performance and load torque volatility estimation, and to test the Maximum Torque per Ampere (MTPA) operation. The result verifies the efficacy of the proposed controller.

• Proceedings of the KIEE Conference
• /
• 1999.11a
• /
• pp.24-27
• /
• 1999

This paper proposed a method to reduce torque ripple of double-layer axial flux permanent magnet motor. Torque is generated by interacting between current of stator winding and airgap flux. In the case of slotless axial flux permanent magnet motor, only commutation torque component is significant. Hence, cogging and reluctance torque will not be considered. For this propose, we were supplied differential phase current in each winding and shifted rotor magnet. According to shifted rotor magnet and flux and phase of current were shifted, phase of developed torque in each side is difference. As a result, we could reduce the total torque ripple in motor and obtain minimum torque ripple in the case of 7.5 degree shifting angle between two rotors.

• Proceedings of the KIEE Conference
• /
• 2001.04a
• /
• pp.314-316
• /
• 2001

This paper present the position control method for the application of permanent magnet linear synchronous motor. Controller is designed as a conventional P-PI controller, but the extra information is used such as velocity and acceleration from motion profiles. The profiles comes from S-Curve which is an optimized point-to-point motion profiles to achieve fast motions with minimum vibration[2]. In this application, the targets of the position control are maximum 10um position error within 10msec after respective ending point of position profiles. The implementation of the controller has been done in full digital way. All the controller is designed on the DSP TMS320VC33 control board. To prove performance of the controller, the experiment was performed with a servo linear motor.

• Proceedings of the KIEE Conference
• /
• 2005.04a
• /
• pp.37-39
• /
• 2005

This paper is proposed maximum thrust design of slotted Permanent Magnet Linear Synchrous Motor (PMLSM) using surface harmonic method considering slot effect. The genetic algorithm is used for optimization. The objective functions are the maximum thrust and the minimum detent force. This time, design parameters are set as PM width, PM height and slot width.

• Transactions on Electrical and Electronic Materials
• /
• v.6 no.2
• /
• pp.67-69
• /
• 2005

Magnetic properties of a field cooled YBaCuO superconductor beneath the toroidal permanent magnet was examined by means of improved magneto-balancing method at 77 K. Magnetic flux measurements of a toroidal magnet revealed a concave shaped field distribution with a single minimum and a null field along the axis of the torus at the point where the field reversed. The observed values of both the suspension position and the force exerted upon the superconductor specimen were in good agreement with those calculated from the magnetization curve of the specimen and the intensity of the magnetic field of the used permanent magnet.

• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.968-970
• /
• 1993

In this paper, the loss components of IPMSM(Inteiror Permanent Magnet Synchronous Motor) is derived. To maximize the efficiency of the motor, a design method that optimizes the design variables is proposed Objective function consists of stator winding loss, core loss, and mechanical loss. Simulated annealing is used as the optimization method which is appropriate for finding the global minimum of nonlinear function with many local minima. Through the simulation of the motor characteristics, the prominence of the proposed design method is verified.

• Journal of the Korean Society of Industry Convergence
• /
• v.22 no.1
• /
• pp.29-37
• /
• 2019

A new permanent magnet biased hybrid maglev actuator is developed. Compared to the classical hybrid maglev actuators, the new maglev has unique flux paths such that bias fluxes are separated with control flux paths. The control flux paths have minimum reluctances only developed by air gaps, so the currents to produce control fluxes can be minimized. The consumed power to operate this maglev system can also be minimized. The gravity load can be compensated with the static magnetic forces developed by the permanent magnet bias fluxes while external disturbances are controlled with the bidirectional AC magnetic forces developed by control fluxes by currents. 1-D circuit model is developed for this model such that the flux densities and magnetic forces are extensively analyzed. 3-D finite element model is also developed to analyze the performances of the maglev actuator.

• International journal of advanced smart convergence
• /
• v.10 no.2
• /
• pp.175-186
• /
• 2021

We have studied the speed regulation of the permanent magnet synchronous motor (PMSM) servo system in this paper. To optimize the PMSM servo system's speed-control performance with disturbances, a non-linear speed-control technique using a back-propagation neural network (BP-NN) algorithm forthe controller design of the PMSM speed loop is introduced. To solve the slow convergence speed and easy to fall into the local minimum problem of BP-NN, we develope an improved BP-NN control algorithm by limiting the range of neural network outputs of the proportional coefficient Kp, integral coefficient Ki of the controller, and add adaptive gain factor β, that is the internal gain correction ratio. Compared with the conventional PI control method, our improved BP-NN control algorithm makes the settling time faster without static error, overshoot or oscillation. Simulation comparisons have been made for our improved BP-NN control method and the conventional PI control method to verify the proposed method's effectiveness.