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Introduction. This paper delves into the practical application of multilevel technology, particularly focusing on the capacitor-clamped converter as a promising solution for medium-to-high voltage power conversion, with specific emphasis on direct AC-AC switching conditions. Problem. The limitations of conventional single-cell matrix converters (MC) in efficiency and performance for medium-to-high voltage power conversion applications are well-recognized. Goal. The primary objective is to investigate the performance of the 3 phase modular multilevel matrix converter (3MC) with three flying capacitors (FCs) modeling. This investigation utilizes the Venturini method for gate pulse generation, aiming to compare the performance of the 3MC with standard converter designs. Methodology. To achieve the research goal, the Venturini method is adopted for generating gate pulses for the 3MC, representing a departure from conventional approaches. Detailed simulations employing MATLAB/Simulink are conducted to comprehensively evaluate the performance of the 3MC in comparison to conventional converter designs. Results. The simulation outcomes reveal a significant reduction of 73 % in total harmonic distortion (THD) achieved by the 3MC. This reduction in THD indicates improved robustness and suitability for medium-to-high voltage power conversion systems necessitating direct AC-AC conversion. These results highlight the efficacy of the 3MC in enhancing power conversion efficiency and overall performance. Originality. This paper contributes novel insights into the practical implementation of multilevel technology, particularly within the realm of capacitor-clamped converters. Furthermore, the utilization of the Venturini method for gate pulse generation in the 3MC represents an original approach to enhancing converter performance. Practical value. The research findings present significant advancements in multilevel transformer technology, offering valuable guidance for optimizing transformer design in various industrial and renewable energy applications. These contributions serve to enhance the development of reliable and efficient power systems, addressing critical needs in the energy sector. [ABSTRACT FROM AUTHOR]

Summary: This article presents a new wind energy system using 2 five‐phase permanent magnet synchronous generators (PMSGs) controlled by a fifteen‐switch rectifier (FSR) topology for grid‐connected system. The 2 five‐phase PMSGs are connected to the DC link through a FSR; at its turn, the DC link is connected to the grid through a classical three‐phase inverter. In order to boost the control performance of the proposed wind system, a sliding mode control is adopted to control both generators‐side and grid‐side converters. The proposed control is tested under varying wind velocity and compared with a proportional‐ and integral (PI)‐based control system. The obtained simulation results show that the controlled variables follow their references independently of the wind speed fluctuations; and there is a significant reduction in the speeds overshoots by 100% and in the DC‐link voltage ripples by more than 78%. In addition, the total harmonic distortion (THD) of the generated current and grid current are reduced to 7.19% and 47.80% compared with PI regulators, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper proposes a novel wind energy conversion system based on a Fivephase Permanent Magnetic Synchronous Generator (5-PMSG) and a Five to three Matrix Converter (5-3MC). The low cost and volume and also eliminating grid side converter controller are attractive aspects of the proposed topology compared to the conventional with back-to-back converters. The control of active and reactive power injected to the grid from the proposed system is carried out by a Direct Power Control (DPC) combined with a Space Vector Modulation (SVM). An advantage of this control, compared with the Conventional Direct Power Control (C-DPC) method, is that it eliminates the lookup table and lowers grid powers and currents harmonics through the use of a standard PI controller instead of hysteresis comparators. The efficiency of proposed whole system has been simulated by using MATLAB/Simulink environment. [ABSTRACT FROM AUTHOR]

Copyright of Electrotechnical Review / Elektrotehniski Vestnik is the property of Electrotechnical Society of Slovenia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents sliding mode control of sensor-less parallel-connected two five-phase permanent magnet synchronous machines (PMSMs) fed by a single five-leg inverter. For both machines, the rotor speeds and rotor positions as well as load torques are estimated by using Extended Kalman Filter (EKF) scheme. Fully decoupled control of both machines is possible via an appropriate phase transposition while connecting the stator windings parallel and employing proposed speed sensor-less method. In the resulting parallel-connected two-machine drive, the independent control of each machine in the group is achieved by controlling the stator currents and speed of each machine under vector control consideration. The effectiveness of the proposed Extended Kalman Filter in conjunction with the sliding mode control is confirmed through application of different load torques for wide speed range operation. Comparison between sliding mode control and PI control of the proposed two-motor drive is provided. The speed response shows a short rise time, an overshoot during reverse operation and settling times is 0.075 s when PI control is used. The speed response obtained by SMC is without overshoot and follows its reference and settling time is 0.028 s. Simulation results confirm that, in transient periods, sliding mode controller remarkably outperforms its counterpart PI controller. [ABSTRACT FROM AUTHOR]

We present a new control topology for inverters, mainly dedicated to renewable energy applications. The originality is due to the integration in the inverter of an adaptive regulation of its output voltage controlled by a closed feedback loop allowing compensating the voltage drops induced by load variations. The feedback control is based on an adaptive pulse wave modulation (APWM) technique, that controls the power switches of the inverter to obtain the purest possible sine-wave voltage. The APWM technique straightforwardly compares the inverter output voltage with a reference signal at the grid frequency. In this contribution, this technique is applied to a single-phase push-pull inverter but could have been integrated for the control of all kinds of inverter topologies in renewable energy systems. We have shown that the APWM technique allows generating pure sine-wave voltage, with low total harmonic distortion compared with the generally obtained by classical systems and that load variations do not affect the quality of the output. An experimental prototype of a single-phase inverter with an adaptive regulation based on APWM technique was developed. The experimental characterizations of the prototype confirm the simulations. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper deals with a variable speed device to produce electrical energy on a power network, based on a doubly-fed induction generator (DFIG) supplied by a direct matrix converter used in wind energy conversion systems. In the first place, we carried out briefly a study of modelling on the whole system. In order to control the power flowing between the stator of the DFIG and the power network, a control law is synthesized using three types of controllers: PI, RST and sliding mode controllers. Their respective performances are compared in terms of power reference tracking, response to sudden speed variations, sensitivity to perturbations and robustness against machine parameters variations. [ABSTRACT FROM AUTHOR]

Multi-phase converters are required mainly for feeding variable speed multi-phase drive systems. This paper discusses one such solution by using direct ac-ac converter (matrix converter) that can be used to supply a six-phase and three-phase two-connected motor drive system. Matrix converter based two-motor drive system is presented for the first time in this paper. Two stator windings of six-phase and three-phase machines when connected in series while the rotors may be connected to different loads. Appropriate phase transposition is introduced while connecting the series stator winding to obtain decoupled control of the two machines. This paper proposes a scalar modulation scheme with three intervals technique of three-phase to six-phase matrix converter supplying series-connected six-phase and three-phase induction machine drive system. The dynamic decoupling of each machine from the group is obtained using the direct vector control algorithm. Mathematical modeling of the series-connected two-machine showed the possibility of independent control of each machine in the group. The independent control is demonstrated by analyzing the characteristics of the stator current references and speed of each machine under direct vector control scheme. The viability of the proposed control techniques is proved using analytically and simulation approach. [ABSTRACT FROM AUTHOR]

Recent research has shown that is possible to connect in series stator windings of multi-phase machines and control all the machines in the group independently, although the complete multi-drive system is supplied from a single multi-phase voltage source converter (VSI inverter or matrix converter). This paper analyzes a six-phase two-motor, consisting of a direct AC-AC six-phase matrix converter, a six-phase induction machine, and a three-phase induction machine. Stator windings of the two machines are connected in series in an appropriate manner. After a theoretical introduction of the six-phase matrix converter, a scalar modulation scheme with three intervals which ensures high performance and meets desired requirements is used for the control of matrix converter. Verification of the proposed system is provided by simulation and the results are given in the paper. [ABSTRACT FROM AUTHOR]

A model reference adaptive control (MRAC) of speed for series-connected two-motor drive is presented in this paper. The system consists of a six-phase induction machine and a three-phase induction machine. The stators windings of both machines are connected in series in appropriate manner. Modeling and vector control of a series-connected two-motor drive supplied by a single inverter are presented in the first part. Then, the dynamic decoupling of each machine from the group is obtained using the indirect vector control algorithm. Mathematical modeling of the multi-machine system showed the possibility of independent control of each machine in the group. The proposed controller uses a MRAC control to satisfy the hyperstability condition for tracking care of the load and multi-machine parameters changes of the drive. The simulation results show that the closed-loop system performances are satisfactory using the proposed adaptive controller. [ABSTRACT FROM AUTHOR]

In this paper, a novel vector controlled six- phase induction machine fed from six-phase matrix converter is proposed First, an appropriate vector control algorithm is discussed Next, an algorithm for calculating switching angles for six phase matrix converter is derived A scalar modulation scheme with three intervals which ensures high performance and meets desired requirements is used for the control of matrix converter. Simulation results obtained are very satisfactory and showed that direct vector control performance is enhanced using six-phase matrix converter. Furthermore, the results obtained are encouraging for application to higher power machines. [ABSTRACT FROM AUTHOR]