Новый бестрансформаторный многопульсный выпрямитель с электронным сдвигом фаз

Abstract

Purpose. This paper presents a novel converter which can reduce the input current harmonics like the conventional multipulse converters with input three phase transformer. To reduce input current THD and improve the weight and size converters multipulse rectifiers with an electronic phase shift is offered to use. Methodology. The mathematical models used for examination of the electromagnetic processes, are grounded on systems of differential equations. Calculation of harmonic current composition was performed using Fourier series and the vector representation of the investigated variables. At mathematical modelling are considered converter functionality and their influence to input current THD. Results. Structure of a novel multipulse rectifier is offered. The basic module of a novel rectifier with electronic phase shifting is a 6-pulse rectifier on fully controlled switches with the reverse blocking ability. Switching frequency is either coincide or twice the power frequency. The proposed solutions allow refusing the electromagnetic phase-shifting devices (power transformers or auto-transformers) and thereby significantly reduce the weight of the device. Originality. The article provides the use of multipulse rectifier, which does not require phase shifting transformer and is used to create a phase shift control means. Unlike power factor correction systems with high-frequency modulation, proposed converters significantly differ, as they have better electromagnetic compatibility and the virtual absence of dynamic switching losses of power switches. Practical value. It is shown that for the considered class of converters should be used 18- to 36-pulse rectifiers. For the minimisation of harmonic distortion in twenty four and above pulse converters may be used coordinated changes of shift angle between the voltages of bridge rectifier. If a 24-pulse rectifier is used in power networks with a short-circuit current in the 5-20 times more load, then input current filter with an installed capacity of less than 1% of the power load is needed.