Voitovych Y. Three-phase multi pulse rectifiers with electronic phase shifting

The thesis is devoted to the solution of an important scientific problem - the creation of three-phase semiconductor converters of alternating current to constant current with improved energy and mass characteristics. In many electrical networks and systems, semiconductor transducers are one of the main types of load. Semiconductor transducers are nonlinear for the power supply, and its operation affects the network operating modes, especially if the power of the converter and the network are dimensional. Therefore, when designing both electrical networks and semiconductor converters, it is necessary to take into account the effect of converters on the power supply. In power electronics, one of the most common converters is a three-phase rectifier. Schemes of three-phase power rectifiers mainly used for power supply to consumers of medium and high power. Improvement of electromagnetic compatibility in these systems is possible using schemes of three-phase rectifiers with increased pulsativeness. The use of phase-shift transformers or autotransformers is necessary for such rectifiers. The use of phase-shift magnetic elements, worsens the mass characteristics of the converter, and when the rectifier pulsity increases, their design becomes more complicated. Improvement of mass characteristics and electromagnetic compatibility is possible with the use of electronic phase shift in three-phase rectifiers with increased pulsatility. In the dissertation work the structure of multipulse rectifiers with electron phase shift of pulses more than 12 is proposed, which allows to improve the harmonic composition of consumed current by increasing the rectifier pulsity, obtaining a high power factor by using the "lagging" and "outgoing" angles of control. The expediency of using fully controlled semiconductor keys with reverse blocking capability in three phase rectifiers with electron phase shift is substantiated. The use of low-frequency pulse-width modulation for balancing the output voltages of three-phase rectifier modules is proposed. The proposed circuitry solutions of multi-pulse rectifiers with electron phase shift can be used in the design of advanced DC sources requiring improved mass performance, compliance with electromagnetic compatibility requirements.