Classical and fuzzy controllers for a hybrid flow controller

Abstract

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.

Closed‐loop control system for an improved hybrid flow controller and its comparison with some hybrid devices

“…Therefore, PST Tap is increased (decreased) when TSSC step is negative (positive). In general, while the TSSC step is not zero or the measured power is not in the acceptable region, control strategy of IHFC is similar to [8], and α is fixed at 90°. Otherwise, TCSC is controlled only in capacitive mode to eliminate possible error.…”

“…Despite various ways to improve the HFC configuration, in the proposed method the initial firing angle of the TCSC is set to 90°(when thyristors of TCSC are not fired) to benefit current designed controllers for the HFC [7,8] (the reader is referred to [8] for a more detailed discussion of switching strategies for the HFC). In this method, the conventional HFC provides the transmitted power to a lower band of ΔP, and by controlling the TCSC in the capacitive mode (i.e.…”

“…In other words, using this method, TCSC (TSSC) plays a vital role in controlling the transmitted power when it is near to (far from) desired power. Therefore the previous closed-loop controllers [7,8] can be designed for the conventional HFC and simple controllers such as proportional-integralderivative (PID) ones are applicable to control the firing angle of the TCSC.…”

“…A multi-objective optimisation methodology to find its optimal location has been presented in [6]. Based on discrete event systems [7] and an improved strategy [8], some controllers have been designed to control the HFC. Although the difference between operating points is reduced relative to the PST alone, the results verify that accurate control of the demanded power cannot be achieved.…”

Fuzzy Modeling Development for Lettuce Plants Irrigated with Magnetically Treated Water

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