Vinnychenko I. Frequency converters based on resonant inverters with pulse-position control

Vinnychenko I.L. Frequency converters based on resonant inverters with pulse-position control. - Manuscript. Dissertation for the degree of the candidate of technical sciences (doctor of philosophy) in specialty 05.09.12 "Semiconductor power converters". – National Technical University of Ukraine "Igor Sikorsky Kyiv Ppolytechnic Institute", Kyiv, 2018. The dissertation is devoted to the development of the theory of frequency converters with an intermediate high-frequency resonant link and pulse-position control. Within the framework of the thesis, the analysis of existing circuits and methods of controlling the frequency converters output characteristics was performed. The author chose the structure of the resonant converter, which combined the advantages of pulse regulation and power transistors soft switching. The mathematical model of the converter was developed in the section of the electromagnetic processes description and the carrier pulses functional determination that allowed formulating the law of the pulse-position control, which causes the formation of the desired sinusoidal output voltage shape of the determined frequency with the low total harmonic distortion in the case of wide load variation range. The analytical dependencies were obtained as well, that made possible to calculate the converter power section elements parameters. The adaptive microprocessor control system of the frequency converter was developed and its simulation and experimental inverstigation were carried out. Keywords: additional switching block, additional resonant capacitor, total harmonic distortion, soft switching of power transistors, frequency converters, resonant inverters, calculation of circuit elements parameters, pulse-position control.