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The article presents various concepts of three-phase power rectifiers with improved quality of converted electric power. This effect is obtained by modulating the currents in the DC output circuits of the rectifiers by means of power electronics controlled voltage or current sources, working as a so-called voltage or current modulators. For further quality improvement of the grid currents of the analyzed systems, it was proposed to use an additional controlled current source connected in parallel to the DC load, hereinafter referred to as a supporting system. The original elaborated method of controlling this source (supporting system) was presented. The main goal of the work was to propose a solution for an effective method of improving the quality of energy conversion in rectifier systems, especially high power ones, by using controlled current sources in DC circuits, operating as the power electronics current modulator and the supporting system.

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 threephase 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.

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