• Title/Summary/Keyword: criteria for commutation

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Optimized PWM Switching Strategy for an Induction Motor Voltage Control

  • Lee, Hae-Hyung;Hwang, Seuk-Yung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.06a
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    • pp.527-533
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    • 1998
  • An optimized PWM switching strategy for an induction motor voltage control is developed and demonstrated. Space vector modulation in voltage source inverter offers improved DC-bus utilization and reduced commutation losses, and has been therefor recognizedas the perfered PWM method, especially in the case of digital implementation. Three-phase invertor voltage control by space vector modulation consists of switching between the two active and one zero voltage vector by using the proposed optimal PWM algorithm. The prefered switching sequence is defined as a function of the modulation index and period of a carrier wave. The sequence is selected by suing the inverter switching losses and the current ripple as the criteria. For low and medium power application, the experimental results indicate that good dynamic response and reduced harmonic distortion can be achieved by increasing switching frequency.

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An Optimized PWM Switching Strategy for an Induction Motor Voltage Control (전압제어 유도 전동기를 위한 최적 PWM 스위칭 방법)

  • Han, Sang-Soo;Chu, Soon-Nam
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.5
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    • pp.922-930
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    • 2009
  • An optimized PWM switching strategy for an induction motor voltage control is developed and demonstrated. Space vector modulation in voltage source inverter offers improved DC-bus utilization and reduced commutation losses and has been therefor recognized the preferred PWM method especially in case of digital implementation. An optimized PWM switching strategy for an induction motor voltage control consists of switching between the two active and one zero voltage vector by using the proposed optimal PWM algorithm. The preferred switching sequence is defined as a function of the modulation index and period of a carrier wave. The sequence is selected by using the inverter switching losses and the current ripple as the criteria. For low and medium power application, the experimental results indicate that good dynamic response and reduced harmonic distortion can be achieved by increasing switching frequency.

Examining the Disparity between Court's Assessment of Cognitive Impairment and Online Public Perception through Natural Language Processing (NLP): An Empirical Investigation (Natural Language Processing(NLP)를 활용한 법원의 판결과 온라인상 대중 인식간 괴리에 관한 실증 연구)

  • Seungkook Roh
    • The Journal of Bigdata
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    • v.8 no.1
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    • pp.11-22
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    • 2023
  • This research aimed to examine the public's perception of the "rate of sentence reduction for reasons of mental and physical weakness" and investigate if it aligns with the actual practice. Various sources, such as the Supreme Court's Courtnet search system, the number of mental evaluation requests, and the number of articles and comments related to "mental weakness" on Naver News were utilized for the analysis. The findings indicate that the public has a negative opinion on reducing sentences due to mental and physical weakness, and they are dissatisfied with the vagueness of the standards. However, this study also confirms that the court strictly applies the reduction of responsibility for individuals with mental disabilities specified in Article 10 of the Criminal Act based on the analysis of actual judgments and the number of requests for psychiatric evaluation. In other words, even though the recognition of perpetrators' mental disorders is declining, the public does not seem to recognize this trend. This creates a negative impact on the public's trust in state institutions. Therefore, law enforcement agencies, such as the police and prosecutors, need to enforce the law according to clear standards to gain public trust. The judiciary also needs to make a firm decision on commuting sentences for mentally and physically infirm individuals and inform the public of the outcomes of its application.