• Title/Summary/Keyword: start current

Search Result 584, Processing Time 0.034 seconds

An Off-line Maximum Torque Control Strategy of Wound Rotor Synchronous Machine with Nonlinear Parameters

  • Wang, Qi;Lee, Heon-Hyeong;Park, Hong-Joo;Kim, Sung-Il;Lee, Geun-Ho
    • Journal of Electrical Engineering and Technology
    • /
    • v.11 no.3
    • /
    • pp.609-617
    • /
    • 2016
  • Belt-driven Starter Generator (BSG) differs from other mild hybrid systems as the crankshaft of vehicle are not run off. Motor permits a low-cost method of adding mild hybrid capabilities such as start-stop, power assist, and mild levels of regenerative braking. Wound rotor synchronous motor (WRSM) could be adopted in BSG system for HEV e-Assisted application instead of the interior permanent magnet synchronous motor (IPMSM). In practice, adequate torque is indispensable for starter assist system, and energy conversion should be taken into account for the HEV or EV as well. Particularly, flux weakening control is possible to realize by adjusting both direct axis components of current and field current in WRSM. Accordingly, this paper present an off-line current acquisition algorithm that can reasonably combine the stator and field current to acquire the maximum torque, meanwhile the energy conversion is taken into consideration by losses. Besides, on account of inductance influence by non-uniform air gap around rotor, nonlinear inductances and armature flux linkage against current variation are proposed to guarantee the results closer to reality. A computer-aided method for proposed algorithm are present and results are given in form of the Look-up table (LUT). The experiment shows the validity of algorithm.

An Exploratory Study on Fintech Regulations and Start-ups: Focusing on the US, China, and Korea Cases (핀테크 산업 규제와 스타트업 활성화 방안에 대한 탐색적 연구: 미국, 중국, 한국 사례를 중심으로)

  • Jeon, Seongmin;Pak, Do Hyun
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.15 no.1
    • /
    • pp.45-57
    • /
    • 2020
  • Among the fintech businesses that are actively developing around the world, payment and settlement are the most prominent. Korea has a well-developed IT industry and a good existing card payment environment, however, its innovative movement is overwhelmingly slower than that of other countries in the fintech. In this study, we try to assess the regulations on fintech and their impacts on the startup ecosystem by comparing the cases of U.S., China, and Korea. We have found that both the United States and China have lowered barriers to entry for the newly launched fintech industry, allowing startups and IT companies to start fintech businesses at the existing financial sector. Particularly the implementation of predictable regulations in U.S., and the failure to apply the financial regulations in China, help start-up companies' growth in the fintech industry. This finding provides us with a lesson that current positive regulations in Korea should gradually change into negative regulations, and predictable regulations that strictly enforce post-management except major items rather than pre-approval. The policy implications are discussed with the perspective of start-ups in fintech industry.

Youth Startup Firms: A Case Study on the Survival Strategy for Creating Business Performance (청년창업기업의 창업초기 생존전략 : 중진공 청년전용자금 활용기업 사례)

  • Lee, Seung-Chang;Lim, Won-Ho;Suh, Eung-Kyo
    • Journal of Distribution Science
    • /
    • v.12 no.6
    • /
    • pp.81-88
    • /
    • 2014
  • Purpose - Entrepreneurship promotion is emerging as an important economic growth agenda. However, in Korea, entrepreneurship has weakened because of the collapse of the venture bubbles of the 2000s and the global economic recession in 2008, which have induced the business community to choose stability over risk. The Korean government has been implementing several support projects to inspire and promote youth entrepreneurship through various means including financial assistance; however, the perpetuation rate of young entrepreneurship is still low as compared to advanced economies such as the US and EU. This case study focuses on the Youth Start-Up Business Support Program of the Small & Medium Business Corporation, and explores practical alternatives. Further, it aims to suggest managerial factors and a conceptual model for change management factors affecting the business performance creation of a startup company, based on the Small and medium Business Corporation's young venture startup fund. Research design, data, and methodology - Many studies examine the current progress and issues of startup firms, for example, a lack of systematic cultivation of entrepreneurship and startup business training, lack of commercialization funding for youth startup businesses, lack of mentoring, and inadequate infrastructure. From prior research, we address four factors, namely, personal managerial capabilities, innovative business model, sufficient cash flow, and social network, affecting startup companies' business performance. This study involved a sample survey of 200 young entrepreneurs to investigate casual relations between the four factors and business performance. A regression analysis was used to verify the hypotheses. Results - First, in relation to differences in the founder's personal characteristics, age, sales amount, and number of employees significantly impact business performance. Second, regarding the causal relation between the four factors for creating business performance, an innovative business model and social networking have supported the hypotheses, revealing that the more that a start-up founder has an innovative business model and social networking, the more the start-up firms are likely to have better performance (e.g., sales volume, employment, ROE, ROI, etc.). Although the founder's competency and sufficient cash flow have no significant relationship with business performance, the mean value was higher performance for high founder's competency and sufficient cash flow. Conclusions - This study provides basic data on policy support strategies of the Small and Medium Business Corporation, to help young entrepreneurs achieve their start-up business goals. It shows that young entrepreneurship startup firms should strive to explore ideas to satisfy customers' needs, and that changes in customer value and the continuous innovation of business model differentiation are required to actively respond to change management. Moreover, at the infant startup stage, they should activate social network programs to share information, thereby offsetting resource scarcity and managing business risk. Further, the establishment of a long-term vision and the implementation of training programs in related specific fields should be supported to strengthen founders' personal capabilities.

Financial Ecosystem Development for Venture Capital Activation in Daejeon, Korea (대전지역 벤처창업 활성화를 위한 벤처 자금생태계 개선방안)

  • Choi, Jong-In;Bae, Kang
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.13 no.6
    • /
    • pp.39-48
    • /
    • 2018
  • Despite the fact that Daejeon has excellent technology infrastructures such as government-funded research institutes, Daedeok Innopolis, and KAIST, the infrastructure for initial investment and growth support for technological start-ups is not sufficient. In particular, the amount of venture capital supply in Daejeon is relatively low compared to other innovation infrastructures. The purpose of this study is to suggest the implications of the venture capital ecosystem in Daejeon area through the analysis of what evolution process has been undergoing and what improvements and complementary points are needed in the future. First, the role of public finance system should be strengthened in order to stimulate angel investment and private capital inflows to start-up companies. Second, in order to cultivate investment professionals in the region, it is necessary to grant local funds to local institutions, and to run investment expert training courses in universities. Third, cooperation between related agencies is needed to add accelerator functions to existing incubators and to foster new accelerators. Fourth, in order to expand the role of local governments, it is necessary to establish funds, to open innovation mindset of public officials, and to communicate effectively with the central government. Fifth, basic venture ecosystem infrastructures such as inflow of excellent manpower, prevention of technology deception, improvement of rechallenge environment should be expanded. Sixth, it is necessary to reorganize the step-by-step start-up financing policy of 'Establishment - Growth - Exit - Rechallenge'. This study is meaningful in that it has grasped the current status of venture start-up financial ecosystem in Daejeon, which is changing rapidly. In particular, it is different in that it identifies financial difficulties venture companies in Daejeon and finds ways to utilize existing financial ecosystem efficiently.

A Study on the Critical Factors Affecting Investment Decision on TIPS (민간주도형 기술창업지원 팁스(TIPS) 투자의사 결정요인에 관한 연구)

  • Goh, Byeong Ki;Park, Sol Ip;Kim, Da Hye;Sung, Chang Soo
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.17 no.5
    • /
    • pp.31-47
    • /
    • 2022
  • The TIPS, a representative public-private cooperative project to revitalize the start-up ecosystem, is a government supported policy that promotes successful commercialization through various start-up support for technology-based startups. The purpose of this study is to analyze the investment decision factors of the TIPS program and to derive priorities. In order to achieve the research purpose, first, the investment decision factors were derived through literature analysis, a Delphi surveys were conducted on investors and experts participating in the evaluation of the TIPS program, and an AHP analysis was conducted on 20 VCs to empirically analyze the priority of factors on investment decisions. As a result of the analysis, the importance of critical factors was confirmed in the order of entrepreneurs(team) > market > product/service > finance > network. The importance of detailed factors was found in the order of entrepreneur's reliability and authenticity > market growth and scalability > team members' expertise and capabilities > adequacy of current market size > new market creation. This study presented the capabilities of technology-based startups preparing to participate in the TIPS program by deriving factors that influence investment decisions from an investor's perspective and comparing and analyzing the importance. It is also meaningful that basic data on determinants of private-led investment decision-making were presented to stake-holders such as venture capital, accelerator, and start-up support institutions.

Current Status and Success Strategies of Crowdfunding for Start-up in Korea (국내 창업분야 크라우드펀딩(Crowdfunding) 현황과 성공전략)

  • Yoo, Younggeul;Jang, Ikhoon;Choe, Youngchan
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.9 no.4
    • /
    • pp.1-12
    • /
    • 2014
  • It is essential factor for business operation to raise funds effectively. However, in Korea, many start-ups and small businesses have difficulties in fund-raising. In recent years, crowdfunding, a new method for funding a project of individuals or organizations by raising monetary contributions from a large number of people, has been growing up simultaneously with diffusion of social media. Crowdfunding is on early stage in Korea, and the majority of projects are focused on cultural or art categories. There is high proportion of projects that have social value in start-up sector. Crowdfunding in Korea has great potential because success rate of it is much higher than its of advanced countries, although market size is much smaller than them. The purpose of this paper is to propose success strategies of crowdfunding for start-up through case study. 5 crowdfunding platforms of Korea and Kickstarter, the platform of United States were investigated. Then we checked the figures related to the operation of the whole Korean projects on start-up. Finally, we made comparison between the cases of success and failure by analyzing 8 project characteristics. The study shows that it were the differences in trustworthiness and activeness of project creator, value of reward and efforts for interactivity that have great effects on success of the project. Whereas there was no significant influence of societal contribution and sponsor engagement. The thesis provides success strategies of crowdfunding for start-up as follows. Firstly, creator of the project should make support base by enthusiastic activites before launching funding project. Secondly, there should be contents that can easily show the process of business development in the project information. Thirdly, there must be appropriate design of rewards for each amounts of support money. Finally, efforts for interactivity, such as frequent updates, response for comments and SNS posting, should be followed after the launch of the project.

  • PDF

Design of PFM Boost Converter with Dual Pulse Width Control (이중 펄스 폭을 적용한 PFM 부스트 변환기 설계)

  • Choi, Ji-San;Jo, Yong-Min;Lee, Tae-Heon;Yoon, Kwang-Sub
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.40 no.9
    • /
    • pp.1693-1698
    • /
    • 2015
  • This paper proposed a PFM(pulse-frequency modulator) boost converter which has dual pulse-width. The PFM boost converter is composed of BGR(band gap voltage reference generating circuit), voltage reference generating circuit, soft-start circuit, error amplifier, high-speed comparator, inductor current sensing circuit and pulse-width generator. Converter has different inductor peak current so it has wider load current range and smaller output voltage ripple. Proposed PFM boost converter generates 18V output voltage with input voltage of 3.7V and it has load current range of 0.1~300mA. Simulation results show 0.43% output voltage ripple at ligh load mode and 0.79% output voltage ripple at heavy load mode. Converter has efficiency 85% at light lode mode and it has maximum 86.4% at 20mA load current.

Research on the Current Science Teaching Evaluation System and Directions for Improving Teaching Evaluation (과학과 수업평가 실태 및 개선 방안 연구)

  • Kwak, Young-Sun
    • Journal of The Korean Association For Science Education
    • /
    • v.25 no.4
    • /
    • pp.494-502
    • /
    • 2005
  • This study investigated the current science teaching evaluation system implemented in schools and directions for improving teaching evaluation using literature review, survey, and teacher interview. The first part of this paper analyzed the types, roles, and major issues of the current science teaching evaluation. In-service teachers argued that the current teaching evaluation system was discredited because of the bureaucratic procedures of teacher performance review, showcase classrooms, teachers' views on classroom as their own personal space, low ratio of teaching component in the current teacher evaluation, untrained evaluators, and the absence of professional teaching standards. The second part of the paper investigated the need for a formative teaching assessment, an ideal type of teaching assessment, and the role of participants in the teaching evaluation processes. The way forward, therefore, is to start not at the level of the administrative superstructure but at the level of teachers who will assume responsibility for developing standards of practice as the basis for evaluating their own work and improving their own professional learning to provide quality assurance.

A Study on the Application of Micro Hydro Power Generator at the Water Treatment Plant (정수장 마이크로 소수력 발전기 적용에 대한 연구)

  • Kim, Jong-Gyeum;Park, Young-Jeen;Kim, Il-Jung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.28 no.9
    • /
    • pp.67-72
    • /
    • 2014
  • Inflow or outflow from the water treatment plant and the sewage water has potential energy. If this potential energy can be converted into electrical energy by water turbine generator, it can help to save energy because of the high capacity utilization. So recently, micro hydro power plant is reviewed in the water treatment facility. If generation capacity is low, induction generator is primarily used. If output capacity is low, generated power is supplied to the inside load. Induction generator can cause voltage drop by the inrush current at a start-up and requires reactive power for magnetization. In this study, we analyzed the flow of power and voltage variation against inrush current that occurs when the induction generator starts under the terms that loads of linear and non-linear of the water purification plant are used. Analysis results are that the voltage drop is within an allowable range and the power factor is slightly reduced by the need of reactive power.

A Study on Performance Improvement of Hybrid Energy Storage System for Mild HEV (마일드 하이브리드 차량용 복합형 에너지 저장장치의 성능개선에 관한 연구)

  • Lee, Back-Haeng;Shin, Dong-Hyun;Kim, Hee-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.56 no.10
    • /
    • pp.1763-1769
    • /
    • 2007
  • To improve the cycle-life and efficiency of an energy storage system for HEV, a dynamic control system consisted of a switch between a battery and an ultracapacitor module is proposed, which is appropriate for mild hybrid vehicle with 42V power net. The switch can be controlled based on the status of the battery and the ultracapacitor module, and a control algorithm that could largely decrease the number of high charging current peak is also implemented. Therefore the cycle life of the battery can be improved such that it is suitable for a mild hybrid vehicle with frequent engine start-stop and regenerative-braking. Also, by maximizing the use of the ultracapacitor, the system efficiency during high current charging and discharging operation is improved. Finally, this system has the effects that improves the efficiency of energy storage system and reduces the fuel consumption of a vehicle. To verify the validity of the proposed system, this paper presented cycles test results of different energy storage systems: a simple VRLA battery, hybrid energy Pack (HEP, a VRLA battery in Parallel with Ultracapacitor) and a HEP with a switch that controlled by energy management system (EMS). From the experimental result, it was proved the effectiveness of the algorithm.