Discrete-Time Modeling and Control for LFC Based on Fuzzy Tuned Fractional-Order PD<sup>μ</sup> Controller in a Sustainable Hybrid Power System
Muhammad Majid Gulzar, Sumbal Gardezi, Daud Sibtain, Muhammad Khalid
Abstract
A power system that comprises a photovoltaic (PV), wind energy system (WES), and fuel cell (FC) with a battery energy storage system (BESS), is collectively called a hybrid power system. The research shows discrete-time modeling of fuzzy tuned fractional-order proportional derivative (F-FOPD <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</sup> ) Controller for load frequency control (LFC) of this hybrid power system. Under varying load conditions, the gains of the fuzzy tuned fractional-order proportional-derivative (F-FOPD <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</sup> ) will be tuned automatically by a fuzzy logic controller. A diesel generator (DG) with zero-input power, is running as a synchronous condenser to provide the reactive power balance and voltage stability to the WES for automatic generation control (AGC). The hybrid scheme is tested under changing system parameters, load fluctuations, and a worst-case scenario which is the occurrence of three-phase symmetrical faults with the opening of circuit breaker (CB) with a delay of 5 cycles. The proposed controller enhances the optimization of the power system as well as decreases the transients. In case of surplus power availability, the secondary load (SL) absorbs the additional power. The control strategy ensures that the error in frequencies remains zero. The proposed scheme of control not only minimizes the frequency oscillation but also attains the minimum steady-state error in case of dynamic load conditions.