• Journal of Institute of Control, Robotics and Systems
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• v.3 no.3
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• pp.280-288
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• 1997

In this paper, we will show that the torque ripple in closed-loop drives of permanent magnet stepping motors is reduced as properly selected lead angle control method. We propose an instantaneous torque equation, which is the function of lead angle, to estimate the influence on torque ripple. We design a closed-loop lead angle control system based on the proposed instantaneous torque equation and measure the instantaneous torque in various excitation modes. It is shown that torque ripple is greatly reduced, as seen from the experimental results as well as from the computer simulation results. For example, torque ripple reduced from 78.25% to 46.82% in the case of 50 PPS single-phase excitation mode operation.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.955-957
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• 2000

This paper has explained a various excitation mode to analyze the torque performance of SRM. The simulation results show that 3-phase square excitation mode models have revealed high torque performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.829-835
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• 2006

Rotatory two-phase transverse flux machine(TFM) is a relatively new type of motor with high power density, high torque, and low speed in comparison to conventional electrical motors. However, it has some shortcomings,.i.e. complex construction and high possibility of the magnetically induced vibration due to its inherent structure. This paper investigates the characteristics of the magnetic force and the torque in the rotatory two-phase TFM by using the 3-D finite element method and the spectral analysis. This research shows that the average torque decreases and that the torque ripple increases as the phase delay increases. It also shows that the unbalanced magnetic force is one of the dominant excitation forces in this machine. And it proposes a new topology of rotatory two-phase TFM to eliminate the unbalanced magnetic force.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1021-1027
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• 2006

Torque fluctuation of an engine and angular velocity variation of a propeller shaft are the main excitation sources in the vehicle driveline. This paper presents brief mechanism of these excitation sources. Equivalent models of these systems are construced to simulate the excitation source. The computer simulation was carried out by ARLA Simul v 6.7 and ARLA-Simstat v 2.3. Results of the simulations show the characteristics of torsional excitation source of the driveline. Experimental setups for engine system and propeller shaft system are constructed with component of the vehicle. Torque fluctuation of the flywheel and angular velocity of the propeller shaft were measured from this experimental setups. Experimental results are compared with simulation results. The results from experimental analysis agree with those from theoretical results.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.412-417
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• 1998

This paper suggests the drive characteristics of a Switched Reluctance Motor(SRM) by 2-phase excitation method. T This scheme excites 2 phases simultaneously, which is similar to 2-phase excitation method of a step motor. In this s scheme. the torque is produced by mutual inductances as well as self inductances. The abrupt change of a phase e excitation produces mechanical stresses and it results in vibration and noise. The acoustic noise is reduced remarkably t through the sequential phase excitation in the 2-phase excitation. Operational principle and characteristic comp없1son t to that of the conventional SRM show that this excitation scheme has some advantages including torque ripple and n noise reduction.

• Journal of Power System Engineering
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• v.12 no.2
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• pp.55-61
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• 2008

This paper discusses the advantages of using Fourier-based periodic excitation and of combining internal and external models in dynamic robot parameter identification. Internal models relate the joint torques or forces with the motion of the robot; external models relate the reaction forces and torques on the bedplate with the motion data. This combined model allows to combine joint torque/force and reaction torque/force measurements in one parameter estimation scheme. This combined model estimation will yield more accurate parameter estimates, and consequently better predictions of actuator torque, which is shown by means of a simulated experiment on a CRS A465 industrial robot.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.336-339
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• 1990

The permanent magnet synchronous motor windings are energized by sinusoidal excitation current. The frequency of the winding excitation current is synchronous with motor movement and the phase is a function of the motor position with respect to the stator. The total operational speed range of the system is substantially incresed by controlling the phase of the excitation currents at a function of the desired speed. This becomes the torque angle between stator rotating field and motor position. In this paper, torque angle control method is described for surface permanent magnet synchronous motor (SPMSM). The control circuit for realizing control method is investigated and the system test is carried out.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2209-2217
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• 2014

A permanent-magnet-assisted switched reluctance motor (SRM) having small excitation poles, where phase coils are concentrically wound on the poles and thin permanent magnets are inserted inside the poles, is proposed in this paper. The insertion of permanent magnets into the stator excitation poles has a significant influence on positive torque improvement leading to a boost in efficiency. Three key design parameters such as the thickness of permanent magnets, space between two adjacent permanent magnets, and the width of stator excitation poles are determined during a design procedure in terms of the enhancement of positive torque. Step-by-step design modification and a comparison between the proposed permanent-magnet-assisted SRM and no-permanent-magnet SRM have been conducted by means of static torque comparison along with dynamic performance. The first prototype from steel laminations up to its physical assembly has been constructed.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.747-752
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• 1994

The switched reluctance motor has high efficiency over a wide range of speed and torque. However the switched reluctance motor exhibit comparatively low efficiency in the chopped excitation which produces additional inverter losses. This paper examines the optimal efficiency operation using choppingless excitation under the changed supply voltage. The excitation is designed to produce the required torque and speed satisfying the optimal efficiency in a nonlinear switched reluctance motor. The optimal algorithm is applied to 119 operation points which are chosen over the full range of driving torque and speed. The result in this paper indicate the improved efficiency comparing to the efficiency obtained by both switched and chopped excitataions under a fixed supply voltage.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1013-1015
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• 1993

The switched reluctance motor is excited and controlled by two kinds of excitation; chopped excitation and switched excitation. The former produces additional inverter losses, and onuses drive control to be complicated. The limit of chopping frequency reduces a range of operating speed and torque. This paper examines chopped excitation and switched excitation in a nonlinear switched reluctance motor. The result indicates switched excitation can be satisfactorily applied to the full operating range, and furthermore indicates the improved efficiency.