• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2004.05a
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• pp.163-168
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• 2004

Linear motor can directly apply to the system needed linear mot ions without rotary mot ions. To control a high-speed and high-resolution, the development of the linear motors is recently required in the high-integrated and speed process industry. This paper presents vibration analyses as well as measurement standards of the newly developed linear motors through analyzing the vibration characteristics and thermal behaviors of the advanced products. Vibration experiments are conducted for identifying the hysteresis and vibration level during operation. They are also included in the modal test to analyze the vibration. Analytic data using Finite Element Method (FEM) are compared with the results of the modal. Loss of temperature generated the linear motor leads to a serious deformation within its parts. The thermal behaviors are very important factor in linear motor. The FEM and experiments make it possible to understand these characteristics.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.205-206
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• 2011

Various studies on energy saving for construction sites have been carried out and some construction machines using motors have installed regenerative systems such as elevators and excavators. The construction lift also uses motors and generates more regenerative energy when the lifts descend because lifts convey many construction materials and workers. For this reason, it is possible to apply the regenerative system to the construction lift. However, if the system is applied without considering the lift's characteristics, the new development would fail; we therefore need to propose a performance requirement. Thus, the purpose of this study is to propose a performance requirement for the energy-regenerative lift prior to developing the energy-regenerative lift.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.2
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• pp.101-109
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• 2005

The newly developed speed sensorless control scheme is proposed to estimate both motor speed and rotor resistance simultaneously using variable rotor flux. The rotor flux is given as sinusoidal waveform with an amplitude and a frequency without affecting precise torque control. Especially the proposed method makes the simultaneous estimation of rotor resistance and speed with high precision even though at the low speed area including a few rpm. Moreover, on-line identification of rotor resistance can be performed simply without calculating troublesome trigonometric functions and complicated integral computation. Therefore, the proposed system can be accomplished by using very cheap microprocessors for several applications. The results of the numerical simulations and experiments demonstrate that this method is effective to estimate the speed and on-line identification of rotor resistance for sensorless induction motors.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.11
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• pp.476-482
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• 2006

Based on a field-oriented model of induction motor, an adaptive backstepping control approach using neural networks is proposed in this paper for the speed control of induction motors with uncertainties at a minimum of information. Neural networks are used to approximate most of uncertainties which are derived from unknown motor parameters, load torque disturbances and unknown nonlinearities and an adaptive backstepping controller is used to derive adaptive law of neural networks and control input directly. The controller is implemented by the hardware using DSP and the effectiveness of the proposed approach is verified by carrying out the experiment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.330-337
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• 2011

This paper presents a new fuzzy speed controller based on a fuzzy angular acceleration observer to realize a robust speed control of permanent magnet synchronous motors(PMSM). The proposed speed controller needs the information of the angular acceleration, thus the first-order fuzzy acceleration observer is designed. The LMI existence condition is given for the proposed fuzzy speed controller, and the gain matrices of the controller are calculated. It is verified that the augmented control system consisting of the fuzzy speed controller and the fuzzy acceleration observer is mathematically stable. To validate the effectiveness of the proposed acceleration observer-based fuzzy speed controller, the simulation and experimental results are shown under motor parameter variations. It is definitely proven that the proposed control scheme can precisely track the speed of a permanent magnet synchronous motor.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1166-1176
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• 2017

Estimation errors of the rotor speed and position in sensorless control systems of Permanent Magnet Synchronous Motors (PMSM) will lead to low efficiency and dynamic-performance degradation. In this paper, a parallel-type extended nonlinear observer incorporating the nominal parameters is constructed in the stator-fixed reference frame, with rotor position, speed, and the load torque simultaneously estimated. The stability of the extended nonlinear observer is analyzed using the indirect Lyapunov's method, and observer gains are selected according to the transfer functions of the speed and position estimators. Taking into account the parameter inaccuracies issue, explicit estimation error equations are derived based on the error dynamics of the closed-loop sensorless control system. An equivalent flux error is defined to represent the back Electromotive Force (EMF) error caused by the inaccurate motor parameters, and a compensation strategy is designed to suppress the estimation errors. The effectiveness of the proposed method has been validated through simulation and experimental results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.463-468
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• 2004

The digital motor protection, measuring and control equipment, as called "The digital motor control equipment", for applying to single/three phase motors designed an integrated one unit and manufactured a compact size which will be installed on the motor control center. It performs serveral protection functions and motor starting function, and measures and indicates a serveral measurement. This paper proposes the design concept and functionality of new digital motor control equipment to improve control performance and integrate several equipments for the control and protection of the motor.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.361-365
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• 2004

This paper describes the various characteristics of voltage sags which can affect the functions of three-phase induction motors that are mostly used in the power distribution systems. These assorted characteristics include motor speed losses, voltage recovery, motor reacceleration, and transient characteristics. An experimental study on the induction motor behaviors was also carried out to confirm these impacts. In addition sequential voltage sags with short durations were considered and investigated. The results show that the occurrence of the second voltage sag after the first one may affects the induction motor adversely.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.11
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• pp.17-22
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• 2010

This paper presents a unique method for simulating permanent magnet motors without time-consuming numerical methods used in the conventional magnetic circuit method. The conventional method gives us average values like torque and power over specified periods of time, but it is usually very difficult and time-consuming to obtain instantaneous characteristics like cogging torques and torque ripples. The convolution operations method we present, however, considers relative angle variations of stator magnetic circuits and rotor magnetic circuits. As a result, it makes uses of instantaneous values possible. The authors compare the new method with the coventional method and verify that calculating cogging torque values and back-emf values is possible with the proposed new convolution method.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.3 s.22
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• pp.18-23
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• 2005

Ships have been propelled and maneuvered by electrical drives since trle late seventies. Recently, rare earth PMs allow the design of brushless motors with very high efficiency over a wide speed range. This is the most important factor in ship propulsion technology. Several types PM motors have been developing for ship propulsion system. However these have disadvantage such as cogging torque. It causes an undesired effect that contributes to output ripple, vibration, and noise of machine. Therefore several techniques may be adopted in designing PM motor in order to reduce the cogging torque. This paper describes cogging torque receding methods such as adjusting arigap length, magnet arc, and magnet thickness. That are analysed by using the finite element method(FEM) and the maxwell stress tensor method.