Electrical engineering & Electromechanics (Aug 2018)

DETERMINATION OF PULSATION FACTORS OF THE SYSTEM OF SUPPRESSION OF INTERFERING HARMONICS OF A SEMICONDUCTOR CONVERTER

  • V. V. Panchenko,
  • A. S. Maslii,
  • D. P. Pomazan,
  • S. G. Buriakovskyi

DOI
https://doi.org/10.20998/2074-272X.2018.4.04
Journal volume & issue
no. 4
pp. 24 – 28

Abstract

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Purpose. The purpose of the paper is to define the pulsation factors of a closed-loop automatic control system (ACS) of interfering harmonics containing a semiconductor converter with double-sided pulse-width modulation (PWM), as well as confirmation of theoretical assumptions about possibilities of self-compensation of pulsation factors’ influence in the system with double-sided PWM. Methodology. The research was conducted with the usage of classic electric circuit theory, frequency analysis methods, generalized function theory. Results. The obtained expressions mathematically relate pulsation factors, value of the damping coefficient and manipulative variable for different frequencies of interfering harmonics in the system with double-sided PWM. The research concerned harmonics with frequencies 100, 300, 600, 900 and 1200 Hz as the most significant constituents of the output voltage of a 12-pulse semiconductor converter. The obtained expressions allow taking into account settings of the selective link and its approximation on the level of supreme frequencies with aperiodic link. Originality. The research has experimentally proved theoretical assumptions about self-compensation of pulsation factors in the system with double-sided PWM. It has been shown that the damping coefficient has a low-impact influence on the values of pulsation factors. It is caused by the pass band of the selective link, which is included in the closed-loop control system of harmonics regulation. Practical value. Application of the research results can contribute to the development of the closed-loop control system for effective attenuation of interfering harmonics in direct current contact wire without interfering in the power part of the semiconductor converter. Besides the possibility to regulate output voltage, it will also help to solve the problem of electromagnetic compatibility of a traction substation semiconductor converter with contact wire. The application of the developed closed-loop control system will as well provide for decreasing the size of the filter in the direct current traction substation unit.

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