Short-circuit protection method for medium-voltage SiC MOSFET based on gate-source voltage detection

Wang, Zhankuo,Tong, Chaonan,Huang, Weichao The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.4

During the short-circuit fault of a two-level bridge converter based on silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs), the SiC MOSFETs may fail within a few microseconds without short-circuit protection. The short-circuit protection of SiC MOSFETs is an essential feature for improving the reliability of converters. This study proposes an improved short-circuit protection method for medium-voltage SiC MOSFETs subjected to shoot-through conditions. In the protection method, the gate-source voltage of the SiC MOSFETs in a half bridge is detected to determine whether a shoot-through short circuit occurs or not. A desaturation protection circuit based on V_DS measurement for a short circuit is also designed for overcurrent. The protection circuit's validity is verified by the experimental results. Compared with conventional commercial driver integrated circuits, the proposed method can detect and turn off SiC MOSFETs in 0.2 ㎲ under the shoot-through condition. Desaturation protection can be completed in 0.5 ㎲ when overcurrent occurs.

퍼지논리에 의한 최적 성형조건 결정 시스템에 관한 연구

강성남,허용정 한국산학기술학회 2002 한국산학기술학회논문지 Vol.3 No.1

사출성형에서 제품의 최종 품질에 영향을 미치는 중요한 인자들 중외 하나는 사출압력이다. 전통적으로 현장의 사출전문가는 오래된 현장 경험을 바탕으로 사출압력을 결정한다. 그러나 비전문가에게는 제품의 크기, 형상 그리고 사출공정의 전반적인 과정을 고려한 적절한 사출압을 결정하기가 쉽지 않다. 본 연구에서는 퍼지 논리(fuzzy logic)를 이용하여 제품도면에 나와 있는 제품두께와 유동길이를 알면 쉽게 초기 사출압을 결정할 수 있도록 전문가의 경험을 규칙베이스화 하였다. 규칙베이스를 구성하기 위해서 현장 전문가들을 인터뷰하고 설문조사를 한 후 기술적인 문서를 작성하여야 하지만 본 연구에서는 사출성형 해석 프로그램인 C-Mold를 이용하여 수 차례의 시뮬레이션을 반복 수행하여 규칙베이스를 구성하였다. A Short shot is a molded part that is incomplete because insufficient material was injected into the mold. Any factors that increase the resistance of polymer melt to now or prohibit delivery of sufficient material into the cavity can cause a short shot. Inappropriate injection pressure is one of the most common factors which cause a short shot. Conventionally, domain experts in injection molding decide and modify the pressure based on their experience. It is difficult for a non-expert to decide the pressure properly with the considerations such as a part dimension, shape, and other processing variables. In this study, fuzzy algorithm is proposed to standardize the empirical determination of the pressure so thai not only the experts but also non-experts can find the appropriate injection pressure easily. To acquire the more accurate results, domain experts should be interviewed and then technical documents which are collected from the experts should be restored in the fuzzy rule base. But in this study, simulations have been done by using C-MOLD to settle the rule base because it takes much time and also it's difficult to meet and interview the experts.

A Study on Optimal Solution of Short Shot Using Modular Fuzzy Logic Based Neural Network(MFNN)

강성남(Seong-nam Kang),허용정(Yong-jeong Huh),조현찬(Hyun-chan Cho) 한국지능시스템학회 2001 한국지능시스템학회논문지 Vol.11 No.6

사출성형공정에서 나타나는 대표적인 성형불량의 하나인 미성형을 해결하기 위하여 본 논문은 퍼지의 논리 및 추론기능과 신경망의 학습 기능을 융합한 퍼지-신경망을 도입하였다. 미성형을 빠른 시간내에 해결하고 신경망의 학습속도를 높이기 위해 모듈형 두 단계의 학습 알고리즘이 본 논문에서는 제안되었다. 첫 번째 학습 모듈단계에서는 사출성형의 공정조건들이 서로 영향을 미치는 점을 고려하여 충전시간과 용융수지 온도가 결정되면 그에 상응하는 금형온도를 학습하고, 두 번째 모듈 학습단계에서는 실제로 사출성형해석을 통해 얻은 미성형 체적의 비율을 에러로 하여 에러를 줄이도록 하였다. 제안된 모듈형 퍼지-신경망을 평가하기 위해 사출성형해석이 황금분할 탐색법과 모듈형 퍼지-신경망을 이용해 각각 수행되고 그 결과를 비교하였다. In injection molding, short shot is one of the frequent and fatal defects. Experts of injection molding usually adjust process conditions such as injection time, mold temperature, and melt temperature because it is the most economic way in time and cost. However it is a difficult task to find appropriate process conditions for troubleshooting of short shot as injection molding process is a highly nonlinear system and process conditions are coupled. In this paper, a modular fuzzy neural network(MFNN) has been applied to injection molding process to shorten troubleshooting time of short shot. Based on melt temperature and fill time, a reasonable initial mold temperature is recommended by the MFNN, and then the mold temperature is inputted to injection molding process. Depending on injection molding result, specifically the insufficient quantity of an injection molded part, an appropriate mold temperature is recommend repeatedly through the MFNN

커넥터 제조를 위한 성형성 개선 기법

윤선진(S. J. Yoon),김현철(H. C. Kim),신희석(H. S. Shin) 한국소성가공학회 2012 금형가공 심포지엄 Vol.2012 No.9

As the industry demands narrow pitch connectors for the electronic devices, the moldability of small-scale connectors is a great concern for injection molding process because of their small features. The particular defects related are weld lines, black spots, and short shots. Along with these product-level defects, the durability of the machine is also a challenge for quality control purpose. In this study, we introduced some new designs to the injection mold assembly of connectors. Our new mold assembly included gas vent system, limit switch, and modified mold blocks. As a result, we successfully remove weld lines and other defects. We were also able to find out that the new system needs less maintenance cost.

A Study on Moldability by Using Fuzzy Logic Based Neural Network(FNN)

Kang, Seong Nam,Huh, Yong Jeong,Cho, Hyun Chan,Choi, Man Sung The Korean Society Of Semiconductor Display Techno 2003 한국반도체장비학회지 Vol.2 No.1

In order to predict the moldability of an injection molded part, a simulation of filling is needed. Short shot is one of the most frequent troubles encountered during injection molding process. The adjustment of process conditions is the most economic way to troubleshoot the problematic short shot in cost and time since the mold doesn't need to be modified at all. But it is difficult to adjust the process conditions appropriately in no times since it requires an empirical knowledge of injection molding. In this paper, the intelligent CAE system synergistically combines fuzzy-neural network(FNN) for heuristic knowledge with CAE programs for analytical knowledge. To evaluate the intelligent algorithms, a cellular phone flip has been chosen as a finite element model and filling analyses have been performed with a commercial CAE software. As the results, the intelligent CAE system drastically reduces the troubleshooting time of short shot in comparison with the expert's conventional way which is similar to the golden section search algorithm.

퍼지 알고리듬을 이용한 금형 온도 지적생성 시스템에 관한 연구

강성남,허용정 한국마이크로전자및패키징학회 2001 마이크로전자 및 패키징학회지 Vol.8 No.4

사출성형공정에서 미성형은 가장 빈번하게 발생하는 성형불량중의 하나이다. 이러한 미성형을 해결하기 위해 가상 경제적인 효율적인 방법은 공정조건을 개선하는 일이다. 그러나 대부분의 경우 사출 전문가의 오랜 기간 축적된 경험과 지식에 의존하기 때문에 여러 번의 시행착오을 겪어야 한다. 따라서 본 논문에서는 퍼지 알고리즘을 기반으로 하여 시스템에 적합한 공정조건을 찾는데 있어 시행착오를 줄이고, 또한 비전문가도 쉽게 적용학 수 있는 지능형 공정조건 생성 시스템을 제안하였다. A short shot is an incomplete molded part caused by insufficient material injection into the mold. Remedial actions to control the process conditions can be taken by injection molding experts based on their knowledge and experiences. However, it is very difficult for non-experts to avoid short shot by finding the proper process conditions such as mold temperature, melt temperature and filling time. In this paper, an intelligent generator of optimal process conditions based upon fully logic algorithm is proposed so that trial and error can be minimized and non-experts an well at experts can also find the optimal process conditions.

에어콘 팬 가이드 프레임의 블레이드 끝단 미성형 방지게이트 배치 선정 사출성형 시뮬레이션

윤태호(Tae Ho Yoon),김호윤(Hoyoon Kim),김재성(Jaesung Kim) (사)한국CDE학회 2018 한국CDE학회 논문집 Vol.23 No.3

In this study, three types of injection molding simulations, classified based on the number of gates, are conducted to reproduce the short shot displayed on the blade edges of the test injection molded fan guide frame and to solve the short shot problem. Filling analysis is used by following the trial and error method of gate sequential open time because there exists very little information about the injection conditions of the development prototype. The injection molding simulation using 6-point gate method reveals the similarity between the short shot phenomenon of the blade edge with the test product made with the same gate arrangement. Excessive filling unbalance is caused by the injection molding simulation of a 14-point gate injection that replaces the short shot produced by 6-point gate injection. The filling balance is obtained by applying 8-point gate injection to compensate the 6-point and 14-point gate method on the two blades and short shots of the blade edges can disappear. By comparing several packing times and the forces in the minimum case of the maximum injection pressure and clamping force, reduction in product deformation and proper injection molding condition by the 8-point gate are achieved.

Fuzzy Logic-Based Moldability-Conforming System in Injection Molding

Kang, Seong-Nam,Huh, Yong-Jeong,Huh, Yong-Jeong Korean Institute of Intelligent Systems 2002 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.2 No.1

Short shot is a molded part that is incomplete since insufficient material was injected into the mold. Remedial actions to solve short shot can be dune by injection molding experts based on their empirical knowledge. Modifying mold and part, changing resin to less viscous one, and adjusting process conditions are general remedies. Experts of injection molding might try to adjust process conditions such as mold temperature, melt temperature, injection time based on their empirical knowledge as the first remedy because adjustment of process conditions is the most economic way in time and cost. However it is difficult to find appropriate process conditions as they are highly coupled and there are so many elements to be considered. In this paper, a fuzzy logic algorithm has been proposed to find an appropriate mold temperature. With the percentage of the insufficient quantity of an injection molded part, an appropriate mold temperature can be obtained by the fuzzy logic algorithm.

남자프로골퍼의 30 야드 칩샷과 피치샷 동작의 운동학적 차이

편은경 ( Eun Kyung Pyun ),박영훈 ( Young Hoon Park ),염창홍 ( Chang Hong Youm ),손승 ( Sheng Sun ),서국웅 ( Kuk Woong Seo ),서국은 ( Kook Eun Seo ) 한국운동역학회 2007 한국운동역학회지 Vol.17 No.2

The influence of shot design on emotional expression in experimental films: Focused on the work If It’s Just a Dream

Chengyi Yang,Jinyoung Kim,Jaecheol Moon 중앙대학교 영상콘텐츠융합연구소 2021 TechArt :Journal of Arts and Imaging Science Vol.8 No.4

After the birth of cinema in 1895, while recording events, many creators wanted to make the shot aesthetically pleasing and have a certain social significance. For this reason, the lens began to develop more and more detailed, from changes in scene, to changes in movement, from changes in color, to changes in composition, the emergence of these changes, greatly enriching the content of the film, and improve the quality of the film. The shot as the basic unit of the film. It plays an important role in introducing and presenting the setting of the film as well as the emotions of the characters. Steven Katz believes that the shot in cinematography is not only an optical component of the camera, it is also the smallest element and unit of a complete film, the design and assembly of the shot is often a technique that reflects the professionalism and learning of the cinematographer, but also reflects the degree of aesthetics and aesthetic skills of the cinematographer. This paper will analyze the impact and role of shot design on the emotion of the film by analyzing the authors work and combining it with classic works, from Close-Up, Tracking shot, Pull-back dolly, etc.