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Electronic phase shifting in multipulse rectifier
(Sciendo, 2017) Sokol, Yevgen I.; Zamaruiev, Volodymyr V.; Ivakhno, Volodymyr V.; Voitovych, Yurii
This paper presents a novel converter which can reduce the harmonics like the conventional multipulse converters with input three phase transformer. To reduce total harmonic distortion of input current and improve the weight and size of converters, it is suggested to use multi-pulse rectifiers with an electronic phase shift. The basic module is a 6-pulse rectifier on fully controlled switches with the reverse blocking ability. Switching frequency either coincides or is twice the power frequency. The proposed solutions allow refusing from the electromagnetic phase-shifting devices (power transformers or auto-transformers) and thereby significantly reduce the weight of the device. Unlike power factor correction systems with high-frequency modulation, the proposed converters are significantly different, as they have better electromagnetic compatibility and the virtual absence of dynamic switching losses of power switches.
AC/DC converter for DC traction power supply system with high-speed train operation
(2019) Sokol, Yevgen I. ; Sychenko, Viktor; Voitovych, Yurii; Kosariev, Yevhen; Styslo, Bohdan; Hubskyi, Petro
Purpose of the work is improved approaches to ensure the required quality parameters of voltage in the traction network based on modern technologies and equipment. The pulsating mode of the power consumption in the railroad power supply network is the cause of the occurrence of voltage pulsations in the contact network. The use of active rectifiers in the electric power supply system of the railroad is proposed. The control system is developed by the converter, which allows to stabilize the output voltage in the DC link and also provides the unit power factor consumed by the converter and the THD consumption current at the level of 8%. A mathematical model of the converter was developed and a study of its main modes of operation was performed.
18-pulse rectifier with electronic phase shifting with autotrans-former in inverter and rectifier mode
(2018) Voitovych, Yurii; Makarov, Vadym; Pichkalov, Ievgen
To reduce harmonic distortion of the input current, multipulse rectifiers are used. They require the presence of phase-shifting transformers or autotransformers. Elimination of electromagnetic phase-shifting devices while maintaining small harmonic distortion of the input current and obtaining a power factor close to unity is possible with the use of electronic phase shift. The electronic phase shift is realized by means of the rectifier itself: the introduction of positive and negative control angles in the pairs of rectifiers’ modules. At present, 12-pulse rectifiers with electronic phase shift are known. Unlike classic rectifiers, they do not use phase-shifting transformers and have a unit power factor. Increasing of the rectifier’s pulse makes it possible to improve the harmonic composition of the input current. The use of the principle of electronic phase shift in 18-pulse rectifier leads to different levels of constant voltage at the output of the rectifiers. In this case, to equalize the currents of rectifiers’ modules, one can use both an increase the voltage at the input of rectifiers operating with large control angles and a decrease the input voltage of the rectifiers operating with smaller control angles. The principles of constructing of matching autotransformers for the 18-pulse rectifier with an electronic phase shift are considered in the article. Comparison of 18-pulse rectifiers with use of step-up and step-down autotransformers is made. Data on the installed capacity of autotransformers, power losses are obtained. The results of thermophysical modeling are presented. When comparing the parameters of the matching magnetic elements, it can be concluded that it is more appropriate to use a step-down autotransformer.

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