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In this study, a Z-source alternating current-to-alternating current (AC-AC) converter with a specific topology, which can provide both buck and boost modes, is investigated. This converter, which can be implemented easily, utilizes only two switches with complemented commands. A comparison between the Z-source AC-AC converter and a conventional thyristor voltage controlled one is presented here, and it shows that in the most areas, the Z-source converter provides a faster response and lower total harmonic distortion of the output currents than the conventional one. Moreover, the Z-source converter is also extended to the multiphase systems. In addition, a new arrangement of this converter is proposed here to remove the isolated single-phase sources. Furthermore, an open-loop method is proposed for soft-starting applications. Finally, a closed-loop control system is also suggested for a three-phase Z-source converter to soft start and control the speed of an induction motor. Computer simulations show the validity and effectiveness of the proposed schemes. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY This paper proposes a modified switching strategy for hybrid flow controller (HFC) as a power flow controller. The current strategies for HFC are suitable only for specific situations and generally are not applicable. The modified strategy is implemented by using the logical operators as a classical controller. Simulation results on two situations, representing all the possible states of the HFC, verify its performance. The fluctuations of the transferred active power caused by switching the HFC might have an adverse effect on the decision of the controller as well as the stability of the system. To mitigate the fluctuations, a fuzzy logic controller is designed, and also a comparison with the classical controller is provided. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]