• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.1
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• pp.16-23
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• 2018

PM synchronous motor may be rotated to an arbitrary direction and speed by outside wind under natural condition in cases where the fan is applied outside, such as in vehicle radiators and outdoor air-conditioners. Sensorless controls that cannot detect rotor position requires additional sensorless control algorithm because a rotor is rotated by an external load. In this study, the sensorless control of a PM synchronous motor under naturally rotating condition is proposed. The natural rotation conditions are classified as forward high-speed rotation, reverse high-speed rotation, and low-speed rotation. Experiment results verify the performance of the sensorless control, including the rotor speed and position detection at natural rotation mode and switch to the closed-loop sensorless control.

• Journal of Power Electronics
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• v.1 no.2
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• pp.88-98
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• 2001

An improved stationary frame-based digital current control technique for a permanent magnet(PM) synchronous motor is presented. Generally, the stationary frame current controller is known to provide the advantage of a simple implementation. However, there are some unavoidable limitations such as a steady-state error and a phase delay in the steady-state. On the other hand, in the synchronous frame current regulator the regulated currents are dc quantities and a zero steady-state error can be obtained through the integral control. However, the need to transform the signals between the stationary and synchronous frames makes the implementation of a synchronous frame regulator complex. Although the PI controller in the stationary frame gives a steady-state error and a phase delay, the control performance can be greatly improved by employing the exact decoupling control inputs for the back EMF., resulting in an ideal steady-state control characteristics irrespective of an operating condition as in the synchronous PI decoupling controller. However, its steady-state response may be degraded due to the inexact cancellation inputs under the parameter variations. To improve the control performance in the stationary frame, the disturbance is estimated using the time delay control. The proposed scheme is implemented on a PM synchronous motor using DSP TMS320C31 and the effectiveness is verified through the comparative simulations and experiments.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.116-118
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• 2001

This paper deals with characteristic analysis of a slotless PM linear motor using analytical method. In order to calculate voltage equations, back-EMF waveform and winding inductance are caculated by PM's magnetic field and winding's magnetic field respectively.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.2
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• pp.127-134
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• 2004

In this paper, human motor behaving model based sensory motor coordination(SMC) algorithm is implemented on robotic grasping task. Compare to conventional SMC models which connect sensor to motor directly, the proposed method used biologically inspired human behaving system in conjunction with SMC algorithm for fast grasping force control of robot arm. To characterize various grasping objects, pressure sensors on hand gripper were used. Measured sensory data are simultaneously transferred to perceptual mechanism(PM) and long term memory(LTM), and then the sensory information is forwarded to the fastest channel among several information-processing flows in human motor system. In this model, two motor learning routes are proposed. One of the route uses PM and the other uses short term memory(STM) and LTM structure. Through motor learning procedure, successful information is transferred from STM to LTM. Also, LTM data are used for next moor plan as reference information. STM is designed to single layered perception neural network to generate fast motor plan and receive required data which comes from LTM. Experimental results showed that proposed method can control of the grasping force adaptable to various shapes and types of greasing objects, and also it showed quicker grasping-behavior lumining time compare to simple feedback system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.2
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• pp.144-151
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• 2013

This paper presents a result of the mechanical noise and vibration analysis as well as the electrical characteristics analysis of the permanent magnet(PM) motor according to the driving method that is Brushless DC(BLDC) drive and Brushless AC(BLAC) drive. To do that, the characteristics of the PM motor, which have the same output power but different driving method, are investigated. At that time, the characteristics such as torque, torque ripple and flux density, and so on, are obtained by finite element analysis(FEA). Besides, noise and vibration are obtained by spectrum analysis. The magnetic noise is defined as noise generated from vibrations due to electromagnetic excitation force. In this paper, the electromagnetic excitation force is analyzed and design process of noise reduction is proposed. Finally, The validity of the analysis results is verified by test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.522-527
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• 2012

This paper presents a result of the mechanical noise and vibration analysis as well as the electrical characteristics analysis of the permanent magnet (PM) motor according to the driving method that is Brushless DC (BLDC) drive and Brushless AC (BLAC) drive. To do that, the characteristics of the PM motor, which have the same output power but different driving method, are investigated. At that time, the characteristics such as torque, torque ripple and flux density, and so on, are obtained by finite element analysis (FEA). Besides, noise and vibration are obtained by spectrum analysis. The magnetic noise is defined as noise generated from vibrations due to electromagnetic excitation force. In this paper, the electromagnetic excitation force is analyzed and design process of noise reduction is proposed. Finally, The validity of the analysis results is verified by test.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1005-1006
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• 2007

This paper analyzed the characteristics of the claw pole permanent magnet(PM) stepping motor by using 3D Finite element method(FEM). In this motor, magnetization is occurred along the z-axis, therefore it is necessary to apply 3D FEM for analysis of the claw pole motor. A phase difference of the two stacks's detent torque is 180 degrees. When the center of a permanent magnet is identical with the middle of a pole, small detent torque is produced in order to cancel each of detent torques. However, there are construction errors which are a discrepancy between one and the other phase section in the manufacturing process, thus the detent torque is increased. Moreover, it is confirmed that the proportion of the detent torque is considerably arisen according to the error. Analysis of the construction error is studied by changing the error $0^{\circ}$ to $3^{\circ}$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.8-15
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• 2019

The PM synchronous motor drives with vector control have been applied to wide fields of industry applications due to its high efficiency. The rotor position information for vector control of a PM synchronous motor is detected from the rotor position sensors or rotor position estimators. The sensorless control based on the mathematical model of PM synchronous motor is generally used and it can be classified into back EMF -based sensorless control and magnet flux-based sensorless control. The rotor position estimating performance of the back EMF-based sensorless control is deteriorated at low speeds since the magnitude of back EMF is proportional to the motor speed. The magnitude of the magnet flux for estimating rotor position in the flux-based sensorless control is independent on the motor speed so that the estimating performance is excellent for wide speed ranges. However, the estimation performance of the model-based sensorless control may be influenced by the motor parameter variation since the rotor position estimator uses the mathematical model of the PM synchronous motor. In this paper, the rotor position estimation performance for the back EMF based- and flux-based sensorless controls is analyzed theoretically and is compared through the simulation and experiment when the motor parameters including stator resistance and inductance are varied.

• Journal of Yeungnam Medical Science
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• v.11 no.2
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• pp.248-261
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• 1994

This study was undertaken to evaluate the clinical usefulness of magnetic motor evoked potential (MEP) in the diagnosis of stroke and predicting the motor improvement following stroke. The cortical, cervical and lumbar stimulations were performed in the case of 24 healthy controls and 24 ischemic stroke patients. The central motor conduction time (CMCT) was represented by the difference of latency to a target muscle between after transcranial stimulation and after cervical or lumbar stimulation. There was no case showing no response in controls. But in 11 out of 24 ischemic patients, we could not get cortical MEP. Mean CMCT of abductor pollicis brevis muscle was not significantly different in controls and stroke patients in whom MEPs were recorded. There were significant differences between mean CMCT of normal controls and that of stroke patients showing MEPs in AH Muscle. MEP Results from testing the stroke patients were correlated with site of lesion, degree of motor weakness and motor improvement after 1 to 2 months. These results suggest that magnetic MEP is easy and useful in electrophysiological test of central motor pathway and is useful indicator for representing the motor weakness and predicting the motor outcome in acute ischemic stroke patients.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.51-54
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• 1991

The effect of inductance for optimal design of Hybrid permanent magnet step motor is presented on this paper. A pull-out torque of Hybrid permanent magnet step motor is measured and calculated by varying stator coil inductances, and power consumption of the step motor also is calculated and compared to the measured value. The relation of developed torque to parer consumption by the changing of magnetomotive force magnitude in a rotor permanent magnet is studied, which is the essence of the step motor design.