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  • Author: Michal Krystkowiak x
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Michal Krystkowiak and Michal Gwóźdź

Abstract

In the paper the 3-phase power diode rectifier system with quasi-sinusoidal input (power grid) current is presented. In order to benefit from it, the current modulation in the DC circuit of a rectifier is used. The essential part of the current modulator is the wide-band power electronics controlled current source based on a multi-channel converter. The control algorithm of the current modulator respects impact of aliasing phenomena at system stability by using the method proposed by the authors. The paper includes the rectifier system description and rules of operation of the current modulator. Also, some results of research on both the rectifier simulation model and the laboratory prototype of a current modulator are presented.

Open access

M. Gwóźdź, M. Krystkowiak, C. Jędryczka, A. Gulczyński and D. Matecki

Abstract

In the paper, the concept of a permanent magnet synchronous generator (PMSG) with uniquely designed stator windings for wind turbines is presented. Two 3-phase windings in the stator are used, one of which is connected in the star, while the other in the delta configuration. Six-pulse rectifiers, mutually coupled by the pulse transformer, whose primary winding is supplied by the so-called “current modulator”, are placed at the outputs of both windings. The modulator output current should meet all the necessary and strict requirements. Both rectifiers operate on a common DC circuit. These solutions provide the sinusoidal magnetomotive force in the stator of the PMSG and the quasi-sinusoidal (taking into account the non-linearity of the magnetic circuit) magnetic flux. In light of the generator principle, it has been called the “PMSG with modulated the magnetic flux”. The slightly higher complexity in the structure of the generator, as compared to the normal three-phase construction, is compensated by the exceptional simplicity of the power electronics section of the system, which allows high efficiency to be reached. The current modulator (as well as the pulse transformer) is a power electronics converter with a relatively low output power as compared to the overall output power of the system. In comparison to other known solutions, the expected cost of the system should be lower. It is also expected that a high degree of reliability in terms of its operation will be achieved, and consequently, that the the ongoing costs of its maintenance will be reduced. In the paper, concept, theoretical basis of operation, and results of the studies of the simulation models of the generator, including the basic power electronics section, are presented.