• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.53-54
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• 2016

본 논문은 전동기 구동용 SiC MOSFET 인버터의 NEMA(National equipment manufacturer's association) 규격 만족을 위한 출력 필터 구조에 따른 영향을 분석한다. 구조와 목적에 따라 정현파 필터와 dv/dt 필터를 적용하여 380V, 60Hz, 3.7kW급 유도 전동기를 대상으로 실험을 수행하여 설계한 필터가 NEMA 규격을 만족시킬 수 있을 뿐만 아니라 전동기 누설전류를 감소시켜 효율까지 향상시킬 수 있음을 확인하였다.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.294-295
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• 2010

DC 모터의 전류 제어는 회전에 의해 발생하는 역기전력을 외란으로 취급하여 역기전력을 보상하는 방법이 많이 사용된다. 본 논문에서는 속도 센서를 사용할 수 없는 모터 응용 분야에서 상태 관측기를 사용하여 전류 제어기를 구성하는 문제를 다룬다. 제안된 관측기는 간단한 1차 모델에 대한 PI 관측기로 설계되며 역기전력을 추정하는 형태로 구성된다. 실험을 통해 제안한 관측기가 1차 모델만을 고려하여 설계되었음에도 DC 모터의 불확실성에 강인한 성능을 보임을 확인한다.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.331-332
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• 2010

본 논문에서는 24V급 저가형 팬 모터 드라이버를 설계하기 위해 단상 인버터 회로를 제시 하였고, 제시한 회로의 동작특성 확인을 위해 단상 BLDC 모터의 모델링 및 회로설계를 PSIM 시뮬레이션 툴을 통해 수행 하였다. 제시한 회로가 저가격으로 구현 가능함을 검토하였고 실제 적응 가능함을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1320-1321
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• 2015

무인항공기(Unmanned Aerial Vehicle, UAV)를 활용하여 넓은 범위를 감시하기 위해서 조종자가 반복적으로 같은 경로를 따라서 UAV를 비행시키는 것은 관리 및 운영에 필요한 비용과 시간 문제가 발생한다. UAV로 넓은 지역을 감시하기 위해서는 UAV의 자율 비행 연구가 필요하다. 전통적인 접근 방법은 GPS를 기반으로 이동할 위치를 연속적으로 설정해서 비행 경로를 설정한다. GPS 기반의 경로 설정은 비행 경로에 장애물이 없을 때 적합하다. 장애물을 고려한 비행을 위해서는 모터프리미티브 기반의 비행 기법이 필요하다. 이 논문에서는 UAV를 자율 비행시키기 위한 모터프리미티브의 구조를 제안한다. UAV의 비행 경로를 설정할 때 비행할 위치를 직접 설정하지 않고 감시할 위치를 설정해서 모터프리미티브를 정의하는 기법을 소개한다. 이와 같은 방법은 UAV가 감시할 위치가 사전에 정의될 때 조종사가 UAV의 경로를 쉽게 설정할 수 있다.

• Journal of Power Electronics
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• v.17 no.4
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• pp.1071-1087
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• 2017

This paper introduces a DC/AC converter, which can be connected in parallel with a diode rectifier for regenerative applications. The DC/AC converter is supposed to transmit regenerative energy to the power grid when a motor is braking. Isolation transformers are not needed in the topology, which can reduce the size and cost. An analysis of the zero-order current existing in the system is carried out. In addition, algorithms to minimize the zero-order current, control the power factor and keep the DC bus voltage stable are discussed. A 55kW industrial prototype is built to verify the proposed analysis and control strategies.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.442-447
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• 2008

A numerical analysis has been conducted to investigate and characterize the unsteadiness of flow structure and oscillatory vacuum pressure inside of a supersonic diffuser equipped to simulate the high-altitude rocket test on the ground. A physical model of concern includes a rocket motor, a vacuum chamber, and a diffuser, which have axisymmetric configurations, using nitrogen gas as a driving fluid. Emphasis is placed on investigating physical phenomena of very complex and oscillatory flow evolutions in the diffuser operating at very close to the starting condition, i.e. minimum starting condition, which is one of major important parameters in diffuser design points of view.

• Journal of Wellbeing Management and Applied Psychology
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• v.4 no.4
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• pp.31-34
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• 2021

Purpose: The purpose of this study is to review health-care program using the recent robotic horse-riding technology and its clinical effects for chronic low back pain. Research design, data and methodology: Recent clinical articles were determined under three inclusion criteria for in-depth review: 1) article that is published within 1 year, 2) article that includes the detailed explanation of health-care program using robotic horse-riding, 3) the article that deals with chronic low back pain during more than 6 months. Results: As a result, the finally-determined two articles demonstrated the clinical effects of robotic horse-riding statistically on pain intensity, low back muscle strength, spinal alignment, and fear-avoidance belief. Conclusions: After in-depth review, I concluded that health-care program using robotic horse-riding for chronic low back pain needs to be provided at low-intensity (e.g. less than 6km/h horse walking program) in the beginning of health-care for improving their motor control ability, then, at the increased intensity for strengthening core muscles.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.6
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• pp.439-444
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• 2018

The performance improvement in the high speed region for the sensorless based synchronous machine drive is discussed in the paper. Conventional dynamic overmodulation method in the vector controlled AC driver requires some calculation of maximum amplitude of the applying voltage vector to limit its amplitude, which leads to increase the calculation time of microprocessor. For low performance microprocessor, this might be impossible to complete the control loop within limited control time. Thus, to reduce the calculation time, the constantly limited amplitude for applying voltage vector is tried in this paper to drive sensorless based synchronous motor. Certainly, there exists some errors in amplitude and phase angle between inverter voltage and calculating voltage in the sensorless algorithm. But, this errors are too small to prevent the high speed sensorless operation within overmodulation region. The validities of the proposed method is proved by the experimental results.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.25-30
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• 2017

Arago's disk system consists of a speed controller of the DC motor (inner loop controller) and a position controller of the magnetic bar angle (main controller), which are implemented by the design of the PI and PID controller, respectively. First, we analyzed the nonlinear characteristics of the Arago disk system and found the operating point range of three locations as a result. In this paper, a gain scheduler method was applied to guarantee a constant control performance in the range of $0{\sim}130^{\circ}C$, and a structure to change the controller according to the control reference value based on the previously obtained operating points was experimentally implemented. The Distributed Control Systems (DCS) configuration using the Controller Area Network (CAN) was used to verify the proposed method by improving the operational efficiency of the entire experimental system. So, simplicity of the circuit and easy diagnosis were achieved through a single CAN bus communication.

• PNF and Movement
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• v.11 no.2
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• pp.119-126
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• 2013

Purpose : The neurologically impaired patients have sensory, motor, cognition, perception problems which cause reduction of body schema, balance control and postural control provoke disfunction. The purpose of this case report was to evaluate effects on gait&balance upon improvement of postural control for left hemiplegia. Methods : This study has performed single subject design from March to April 2013 for 6 weeks. The subject of this study was a 67years old female patient with left hemiplegia. Timed Up and Go (TUG) test and Functional Reach (FR) test were used as evaluation tool. The subject was treated 5 times a week for 30 minutes each. Results : The result is that the walking velocity was decreased, the ability of gait was improved than before the training. The length of FR was increased from 8.33cm to 22.67cm. Conclusion : According to the results, the treatment improves subject's ability of walking in this study.