The paper presents the advanced control system of the wind energy conversion with a variable speed wind turbine. The considered system consists of a wind turbine with the permanent magnet synchronous generator (PMSG), machine side converter (MSC), grid side converter (GSC) and control circuits. The mathematical models of a wind turbine system, the PMSG generator and converters have been described. The control algorithms of the converter systems based on the methods of vector control have been applied. In the advanced control system of the machine side converter the optimal MPPT control method has been used. Additionally the pitch control scheme is included in order to achieve the limitation of maximum power and to prevent mechanical damage of the wind turbine. In the control system of the grid side converter the control of active and reactive power has been applied with the application of Voltage Oriented Control (VOC). The performance of the considered wind energy system has been studied by digital simulation. The results of simulation studies confirmed the good effectiveness of the considered wind turbine system and very good performance of the proposed methods of vector control and control systems.

The mathematical model of the five-phase squirrel-cage induction motor and the system of the dual five-phase voltage source inverter have been presented. The control methods and control systems of the field-oriented control of the five-phase induction motor with an open-end stator winding are described. The structures of the direct fieldoriented control system (DFOC) and the Indirect Field-oriented control system (IFOC) with PI controllers in outer and inner control loops are analyzed. A method of space vector modulation used to control the system of the dual five-phase voltage source inverter has been discussed. The results of simulation studies of the field-oriented control methods are presented. Comparative analysis of the simulation results was carried out.

Massive multiple-input-multiple-output (MIMO) and beamforming are key technologies, which significantly influence on increasing effectiveness of emerging fifth-generation (5G) wireless communication systems, especially mobile-cellular networks. In this case, the increasing effectiveness is understood mainly as the growth of network capacity resulting from better diversification of radio resources due to their spatial multiplexing in macro- and micro-cells. However, using the narrow beams in lieu of the hitherto used cell-sector brings occurring interference between the neighboring beams in the massive-MIMO antenna system, especially, when they utilize the same frequency channel. An analysis of this effect is the aim of this paper. In this case, it is based on simulation studies, where a multi-elliptical propagation model and standard 3GPP model are used. We present the impact of direction and width of the neighboring beams of 5G new radio gNodeB base station equipped with the multi-beam antenna system on the interference level between these beams. The simulations are carried out for line-of-sight (LOS) and non-LOS conditions of a typical urban environment.