• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.1041-1046
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• 1989

In this paper, we attempt to control induction motors with high power efficiency as well as high dynamic performance by utilizing the recently developed theories: singular perturbation technique and noninteracting feedback control. Our controller does not need the transformation between a d-q synchronously rotating frame and a x-y stator-fixed frame. It is computationally quite simple. Furthermore, it does not depend on the rotor resistance. To illuminate the practical significance of our results, we present simulation and experimental results as well as mathematical performance analysis.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.11
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• pp.1102-1111
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• 2007

The theory for a fault-tolerant control of homopolar magnetic bearings is developed. New coil winding law is utilized such that control fluxes are isolated for an 8-pole homopolar magnetic bearing. Decoupling chokes are not required for the fault tolerant magnetic bearing since C-core fluxes are isolated. If some of the coils or power amplifiers suddenly fail, the remaining coil currents change via a distribution matrix such that the same magnetic forces are maintained before and after failure. Lagrange multiplier optimization with equality constraints is utilized to calculate the optimal distribution matrix that maximizes the load capacity of the failed bearing. Some numerical examples of distribution matrices are provided to illustrate the theory. Simulations show that very much the same dynamic responses (orbits or displacements) are maintained throughout failure events while currents and fluxes change significantly.

• Progress in Superconductivity and Cryogenics
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• v.15 no.4
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• pp.39-43
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• 2013

To reduce the magnetization loss of a coated conductor, the striation and the transposition have to be accomplished for magnetic decoupling. The loss reduction effect in incomplete as well as complete striated YBCO CCs was reported in previous research. At the case of the incomplete striated sample, the end region of the sample is non-striated. So, it is not jointed with each other. In power applications, the joint is needed because current leads must be connected with HTS coils. In this research, the influence of end-joint methods with copper and superconducting joint on magnetization loss in striated YBCO CC and spiral winding samples are presented and compared with non-striated measured result.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.742-747
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• 1998

In the High-Speed range for salient type synchronous reluctance motors, the effect of iron loss can not be negligible. In this paper, the SynRM without cage is analyzed mathematically to model and the speed control system is examined by simulation. In order to control the revolution speed, a closed-loop control with vector control and decoupling control are applied to the high-speed SynRM drives. The speed control system is analyzed to investigate the desired speed characteristics of high SynRM by simulation.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.1-3
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• 2006

This paper deals with a novel utilization method of the predicted current in the high performance PI current controller with a control time delay. The inevitable error of the predicted current in the linear servo drive using a permanent magnet linear synchronous motor is analyzed and a modified cross-coupling decoupling synchronous frame PI current controller is proposed in order to improve the current control response under the control time delay. Simulation and experimental results show that the proposed current controller has an improved current control performance under both the electrical uncertainties of a servo drive system and the control time delay.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.225-229
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• 1998

If there is a mismatch between the controller programmed rotor time constant and the actual time constant of motor, the decoupling between the flux and torque is lost in an indirect rotor field oriented control. This paper presents a new estimation scheme for rotor time constant using artificial neural networks. The parameters of induction motor model organize 2 layer neural to be weight between neuron, which is proposed new in this paper. This method makes networks simple, so its brings not only the improvement in speed but simplification in calculation. Furthermore, it is possible to estimated rotor time constant real time through on-line learning without using off-line learning. The digital simulation and the experimental results to verify the effectiveness of the new method are described in this paper.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.222-224
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• 2008

본 논문에서는 3상 VSI의 CVCF 제어를 위해 폐루프 비간섭 DQ 제어기 설계를 제안한다. DQ 제어기를 설계하기위해서 두 개의 간섭항을 폐루프 분리를 통하여 해석적인 PID 제어기를 설계한다. 제안한 PID 제어기는 시간응답을 만족하도록 설계하여 시뮬레이션을 통해 검증한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.322-322
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• 2008

Low-temperature co-fired ceramics (LTCC) have turned out to be very promising technology in accordance with the rapid developments in semiconductor technology. The demands for compact electrical assemblies, smaller power loss as well as high signal density can be fulfilled by LTCC. And for the multi-layered ceramic devices with embedded passive components such as high dielectric constant decoupling capacitor, LTCC materials require the several conditions to avoid delamination and internal cracks. For the present study, diopside-based glass is chosen as the LTCC substrate material in view of its high coefficient of thermal expansion (CTE). From the experimental resultsn the influence of each element on the CTE change can be revealed.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.2
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• pp.114-126
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• 2013

In this paper, we present a set of methodologies to model the electromagnetic susceptibility (EMS) testing of I/O buffers for mobile system memory based on the bulk current injection (BCI) method. An efficient equivalent circuit model is developed for the current injection probe, line impedance stabilization network (LISN), printed circuit board (PCB), and package. The simulation results show good correlation with the measurements and thus, the work presented here will enable electromagnetic susceptibility analysis at the integrated circuit (IC) design stage.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.459-460
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• 2014

여러 가지 분산 발전 시스템들은 마이크로그리드의 형태를 지니고 있다. 하나의 분산 발전 시스템과 비교하여 마이크로 그리드는 더 좋은 시스템 신뢰성과 제어 적응성을 가지고 있다. 이 마이크로그리드는 계통연계모드에서 부하의 수요를 담당하게 되고, 계통 사고가 발생할 시 단독운전모드로 동작을 해야 한다. 드룹제어방식은 이 때 각각의 분산발전시스템에서의 유효전력과 무효전력 부하 sharing을 통해 안정적으로 전력을 공급 할 수 있다. 본 논문에서는 드룹제어를 활용한 100KW급 대용량 인버터 병렬 운전 시스템을 제안하였다. 그리고 P-Q decoupling을 위한 가상 인덕터를 이용하여 개선된 전력 sharing에 대해 연구하고 PSIM을 통해 이를 검증하였다.