• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2040-2045
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• 2015

This paper deals with the electromagnetic and thermal analysis of high speed induction motor. The induction motor is analyzed by time-varying magnetic finite element method and its thermal analysis is carried out by using analytical lumped-circuit method. Analysis results are compared with the experiment of 29kW high speed motor prototype at 12,000rpm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1584-1590
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• 2017

This paper presents a implementation method of reliable speed limitation controller considering motor parameter variation in high speed operation. In spinning process of drum washing machine, speed increase has to be limited when unallowable imbalance mass is detected. Otherwise, severe noise and vibration can happen because noise and vibration are proportional to imbalance mass. To detect imbalance mass, d-axis current magnitude is used. However, we have to compensate for back-emf and power supply variation by means of detecting them because d-axis current is affected by both of them. On the other hand, we have to carefully estimate back-emf because back-emf is affected by stator resistance variation and inverter voltage error. Stator resistance variation can happen by manufacturing process for mass production or temperature variation in running. And there are inverter voltage errors between command voltage from micro-computer to inverter and real voltage from inverter to motor because of rising and falling time delay and turn-on resistance of power semiconductor switch. To solve this problem, we propose 2-step align current injection method which is to inject step-wise current right before starting. By this method, we can simply obtain stator resistance by ratio of voltage without inverter voltage error and current, and we can measure inverter voltage error. So we can obtain more exact model current, and then by simple calculation with compensation gain, we can estimate more accurate motor back-emf. We show that this method works well. It is verified through experiments.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.559-563
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• 1991

Permanent magnet synchronous motor (PMSM) is receiving increased attention for servo drive applications in recent years because of its high torque to inertia ratio, superior power density and high efficiency. Vector-controlled PMSM has the same operating characteristics as separately excited dc motor. The drive system of servo motor is requested to have an accurate response for the speed reference and a quick recovery for the disturbance such as load torque. However the dynamics of PMSM drive change greately by parameter variations. Morever, when the unkown and inaccessible disturbances are imposed on PMSM, the drive system is given a significant effect by them. As a result, the drive system with both a fast drive performance and a reduced sensitivity to parameter variations is requested. In this paper, the robust control system of PMSM with torque feedforward using load torque observer is presented. In the proposed system, load torque is estimated by the reduced order observer, and the robust control system against load torque variation is realized using the torque feedforward. Moreover, the design of speed controller with the torque observer is discussed. Simulation results show that the proposed method is effective for suppression of parameter variations and load disturbance.

• Journal of the Korean Society of Safety
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• v.17 no.2
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• pp.92-99
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• 2002

Safety-related motor operated valve(MOV) safety significance for Ulchin Unit 3 was categorized. The safety evaluation of MOV of domestic nuclear power plants affects the generic data used for the quantification of MOV common cause failure(CCF) events in Ulchin Units 3&4 PSA. Therefore, in this paper, MGL(multiple greek letter)parameter ${\beta}$, used for the evaluation of MOV CCF probabilities in Ulchin Units 3&4 probabilistic safety assessment(PSA), was re-estimated and the MOV safety significance was categorized. The re-estimation results of MGL parameter show that the value of(is decreased by 30% compared with the current value used in Ulchin Unit 3&4 PSA. The categorization results of MOV safety significance using the changed value of MGL parameter(show that the number of HSSCs(high safety significant components) is decreased by 54.5% compared with those using the current value of it used in Ulchin Units 3&4 PSA.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1679-1680
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• 2008

DC motor has been widely used in industrial applications, because the performance is excellent on the speed and position system. However, when a system has parameter uncertainty, it is very difficult to guarantee its performance. Sliding mode control is robust for parameter uncertainty. However conventional sliding mode control can not have the properties of PID controller because its sliding surface has lower order dynamics than the original system. In this paper the sliding surface design method is proposed by using virtual state for DC motor speed control. Its design is based on the augmented system whose dynamics have one higher order than that of the original system. As a result, in spite of the parameter uncertainty, the proposed sliding surface can have the same dynamic of nominal system controlled by PID controller. And the reaching phase is removed by setting an initial state which makes the initial sliding surface equal to zero.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.6
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• pp.96-103
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• 2006

An MRAC-based adaptive current control scheme of an AC servo motor is presented for the performance improvement of a servo drive. Although the predictive current control is known to give ideal transient and steady-state responses, its steady-state response my be degraded under motor parameter variations. To overcome such a limitation, the disturbances caused by the parameter variations will be estimated by using an MRAC technique and compensated by a feedforward control. The proposed scheme does not require the measurement of the phase voltage unlike the conventional disturbance estimation scheme using observer. The asymptotic stability is proved. The proposed scheme is implemented using DSP TMS320C31 and the effectiveness is verified through the comparative simulations and experiments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.3
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• pp.238-244
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• 2004

To monitor the torque of an induction motor using current, the accurate identification of the motor parameters is very important. In this study, the motor parameters such as rotor resistance, stator and rotor leakage inductance, mutual inductance are estimated for torque monitoring and indirect vector control. Estimated parameters are used to monitor the torque of vector controlled induction motor without any speed measuring sensor. Stator current is measured to estimate the magnetizing current which is used to calculate flux linkage, rotor velocity and motor torque. From the experiments, the proposed method shows a good estimation of the motor parameters and torque under the normal rotational speed.

• International Journal of Korean Welding Society
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• v.3 no.1
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• pp.2-7
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• 2003

Laser welding application for car body manufacturing has many advantages in the stiffness and the lightness of vehicle, the productivity of assembly line, and the degree of freedom in design. This presentation will express the innovation of car body manufacturing including parameter optimization, process modeling, and system integration. In this application the investment for systems was cut down dramatically by real time switching over the laser path between two welding stations. Points of technical discussion are as follows; optimization of parameters such as laser power, robot speed and trajectory, compact and useful design of jig & fixture to assure welding quality for 3 sheet-layer zinc-coated steel, system integration between 4㎾ Nd:YAG laser device and the other systems, on-line real time welding quality monitoring system, perfect safety standards for high power laser, minimization of consumption costs such as arc lamp, protective glass for optic, etc. This application was successfully launched mass production line in 2001. The laser-welded line of side panel consists of 122 stitches totally. And the length is about 2.4m.

• Journal of information and communication convergence engineering
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• v.6 no.4
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• pp.421-424
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• 2008

In torque transmission system, we must suppressed vibration for Accuracy characteristic response of motor, Therefore, vibration suppression factor is very important motor control. To suppress vibration, a various control method has been proposed. Specially, one method of vibration suppression used disturbance observer filter. This method is torsion torque passing disturbance observer filter. By the estimated torsion torque feedback, vibration can be suppressed. The CDM(coefficient diagram method) is used to design the filter and Proportional controller. But using coefficient diagram method, not adapted controller parameter in disturbance. For this solution, we used fuzzy controller for auto tuning controller parameter. We proved this approach is confirmed by simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.2
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• pp.159-163
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• 2006

In order to tune the speed controller in the linear servo applications an accurate information of a mover mass including a load mass is always required. This paper suggests the mass estimation method of a permanent magnet linear synchronous motor(PMLSM) 4y using the parameter estimation method of Least-Squares algorithm. First, the deterministic autoregressive moving average(DARMA) model of the mechanical dynamic system is derived. Then the application of the Least-Squares algorithm shows that the mass can be accurately estimated both in the simulation results and in the experimental results.