• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.433-434
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• 2020

본 논문은 단상 영구자석 동기 전동기의 가변속 운전을 위한 가변 비례공진 전류 제어 기법을 제안한다. 단상 영구자석 동기 전동기의 전류 제어 시 3상 교류 전동기에 널리 적용되는 벡터 제어를 적용할 경우, 필연적으로 좌표변환 및 가상의 q축 성분 생성을 위한 과정이 요구된다. 하지만, 단상 영구자석 동기 전동기의 구조적인 특징을 고려하여 비례공진 제어 기법을 적용하게 되면 3상 교류 시스템에서 필요로 하는 추가적인 좌표변환 과정이 요구되지 않는다. 이에 본 논문에서는 가변속 운전에 따른 공진 주파수 변화를 반영한 가변 비례공진 전류제어 기법을 제안하고자 한다. 제안한 전류 제어 기법의 효용성을 검증하기 위해 다수의 실험을 진행하였다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.435-436
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• 2020

본 논문에서는 단상 영구자석 동기 전동기의 센서리스 운전을 위한 회전자 자극 검출 기법을 제안한다. 제안한 회전자 초기 자극 검출 방법은 비대칭 공극을 갖는 단상 영구자석 동기 전동기에 고주파 전압 및 옵셋 전류를 인가하여 회전자 자극 위치에 따른 전류 옵셋의 크기를 검출함에 있다. 이를 위해 가상의 dq축 모델을 이용한 고정자 전류의 크기를 비교하여 회전자 자극을 검출하고자 한다. 제안된 방법은 다수의 실험 결과를 통해 타당성을 입증하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.233-236
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• 2009

In this study, the characteristic of the hybrid rocket motor with $LN_2O$(Liquid Nitrous oxide) was investigated experimentally. HDPE(High Density PolyEthlene) was used as fuel with different sized single port. When used $LN_2O$, combustion efficiency is lower than using $GN_2O$(Gas Nitrous oxide), because of completeness of vaporization of droplet and mixing. And regression rate was changed by different oxidizer phase. This behavior was considered that flame temperature and combustion of solid fuel front/end surface.

• Fire Science and Engineering
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• v.21 no.4
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• pp.59-64
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• 2007

We studied on the fires about the electrical motors in this paper. We compared and analyzed about the transformation and damage state of single-phase induction motors used in the home appliances when we applied electrical overload and exterior flame. This experiment was progressed by the electrical overload application test and the exterior flame application test through the locked rotor of motor. In case of the exterior flame application test, it is divided into the apply voltage case and not apply voltage case. The result of an experiment through the locked rotor of motor, it was able to observe the short-circuit marks between layers at the winding coil parts, and it was appeared a transformed dendritic tissue structure of winding coil by the electrical overload test. The application voltage and the application exterior flame, it was confirmed that the stator winding coil parts were remain original shapes and observed that the color of the winding coil's circumference was changed to red. The non-application voltage and the application exterior flame, it was observed that the stator winding coil parts were transformed quite from original shapes. It was observed that the color of the winding coil and circumference parts was changed to red at the same case of non-application voltage.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.5
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• pp.71-85
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• 1993

The Cycloconverter that the author is going to treat in this paper, has strong advantages over the D.C. Link Inverter in points of chattering torque problem and natural commutation. Thus, the Cycloconverter is expected to be well applied to large and low-speed machines which require better speed control at low frequency. But the control circuit of Cycloconverter has two weak points described as follows. 1) Because of its rather complicated control circuit, it is likely to be illoperating due to unexpected noise signals, thus the higher the accuracy and reliability of the circuit is required to be, the more the circuit may cost. 2) Because the load current is not purely sinusoidal, the Cycloconverter may possibly be destroyed in case of inaccurate convert switching resulted from the difficulties in detecting the load current-zero and the current direction at the moment. In this paper, the author first of all intends to design and build a modified VVVF-type Noncirculating Current Cycloconverter to which recently proposed control methods are applied for improving the circuit simplicity, the control performance, and the system reliability. And then, experiments for observing the output waveforms of the Cycloconverter which is controlled by Singled-Board Computer using 8086 16-bit microprocesser are carried out. Finally the author concludes the result of this study as follows. 1) By replacing the conventional analog control circuits such as Reference Wave Generator, Cosine Timing Wave Generator, and Comparator with softwares, a great circuit simplicity is achieved. 2) The output of the designed Cycloconverter changes its frequency very fast without showing discontinuity of its waveform, and this waveform characteristics enables the smooth speed control of Induction Motor. 3) The design control circuit of Cycloconverter can be applied to the systems of 12 or 24 pulses because of its short processing period.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.973-974
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• 2011

이 논문은 단상 외전형 브러시리스 모터의 권선 인덕턴스를 해석적인 방법으로 산정하고 실험결과와 비교하였다. 모터의 초기 설계단계에서 사용하는 자기회로해석은 매우 유용하고, 인덕턴스는 자기회로해석에서 중요한 파라미터이다. 회전자계의 영향은 쇄교 자속으로 표현할 수 있고 자속 쇄교수는 인덕턴스에 비례하기 때문이다. 따라서 모터의 특성해석을 위해서 인덕턴스 산정은 매우 중요하다. 해석적인 방법으로 권선 인덕턴스를 산정하였고 회전자의 영향을 무시하였다. 그리고 LCR 미터와 전류 변화법으로 각각 권선 인덕턴스를 측정하였다. 해석값과 전류 변화법으로 측정한 권선 인덕턴스는 비슷하였다. 이 논문에서 제시한 권선 인덕턴스의 해석적인 산정방법은 모터의 초기 설계단계에서 자기회로해석으로 특성을 해석하는 데 도움이 될 것이다.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1868-1870
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• 2006

Neural network is used in many fields of control systems, but input-output patterns of a control system are not easy to be obtained and by using as single feedback neural network controller. And also it is difficult to get a satisfied performance when the changes of rapid load and disturbance are applied. To resolve those problems, this paper proposes a new algorithm which is the neural network controller. The new algorithm uses the neural network instead of activation function to control object at the output node. Therefore, control object is composed of neural network controller unifying activation function, and it supplies the error back propagation path to calculate the error at the output node. As a result, the input-output pattern problem of the controller which is resigned by the simple structure of neural network is solved, and real-time learning can be possible in general back propagation algorithm. Application of the new algorithm of neural network controller gives excellent performance for initial and tracking response and it shows the robust performance for rapid load change and disturbance. The proposed control algorithm is implemented on a high speed DSP, TMS320C32, for the speed of 3-phase induction motor. Enhanced performance is shown in the test of the speed control.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1851-1860
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• 2016

The traction motors in electric multiple unit (EMU) trains are powered by AC-DC-AC converters, and the DC link voltage is generated by single phase PWM converters, with a fluctuation component under twice the frequency of the input catenary AC grid, which causes fluctuations in the motor torque and current. Traditionally, heavy and low-efficiency hardware LC resonant filters parallel in the DC side are adopted to reduce the ripple effect. In this paper, an analytical model of the ripple phenomenon is derived and analyzed in the frequency domain, and a ripple control scheme compensating the slip frequency of rotor vector control systems without a hardware filter is applied to reduce the torque and current ripple amplitude. Then a relatively simple discretization method is chosen to discretize the algorithm with a high discrete accuracy. Simulation and experimental results validate the proposed ripple control strategy.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.803-804
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• 2006

우리는 이전 논문을 통해 Air blower용 모터에서 널리 사용되고 있는 단상 유도기를 기존의 분포 권선 방식에서 벗어나 집중 권선 방식을 사용하여 설계한 결과 생산 공정의 단계를 줄이고 많은 생산 비용을 줄일 수 있었다. 또한 집중 권선형에서 발생할 수 있는 고조파 문제를 로터의 skew와 overlap 권선 방식을 이용하여 해결 할 수 있음을 증명하였다. 그러나 이러한 이점에도 불구하고 시제품의 특성을 측정한 결과 집중 권선형 모터의 자계 불균형 때문에 기존 분포권 모터에 비해 소음과 진동 특성이 좋지 않은 결과를 보였다. 이에 본 논문에서는 소음과 진동 특성을 고려하여 기존의 기동 및 정격 토크 특성을 유지하면서 토크 리플을 저감할 수 있는 방법을 로터의 Skew 각도 영향, 권선 사양 및 스테이터 및 로터 형상 등을 고려하여 새롭게 설계하였고 그 결과를 제시하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.58-64
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• 2006

Homogeneous charge compression ignition(HCCI) combustion is an advanced technique for reducing the hazardous nitrogen oxide(NOx) and particulate matter(PM) in a diesel engine. NOx could be reduced by achieving lean homogeneous mixture resulting in combustion temperature. PM could be also reduced by eliminating fuel-rich zones which exist in conventional diesel combustion. However previous researches have reported that power-output of HCCI engine is limited by the high intensive knock and misfiring. In an attempt to extend the upper load limit for HCCI operation, supercharging in combination with Exhaust Gas Recirculation(EGR) has been applied: supercharging to increase the power density and EGR to control the combustion phase. The test was performed in a single cylinder engine operated at 1200 rpm. Boost pressures of 1.1 and 1.2 bar were applied. High EGR rates up to 45% were supplied. Most of fuel was injected at early timing to make homogeneous mixture. Small amount of fuel injection was followed near TDC to assist ignition. Results showed increasing boost pressure resulted in much higher power-output. Optimal EGR rate influenced by longer ignition delay and charge dilution simultaneously was observed.