Hybrid and Adaptive P&O Maximum Power Point Tracking Techniques for PV Generation Systems

Abstract

Maximum power point tracking (MPPT) techniques work to track the maximum power from the PV cell. A lot of conventional MPPT techniques, such as the perturb and observe (P&O), succeed in catch the maximum power point (MPP) with a good performance. However, they suffer many problems during fast varying weather conditions, where slow time response and high oscillations are dominant. Also, it is difficult to select the right direction for new steps. This article illustrates two new P&O MPPT techniques for PV generation systems. They operate on the power-voltage (P-V) curve under different weather conditions. The first is an adaptive perturb and observe (A-PO) technique, which changes the perturbation step-size adeptly to deal with the rapidly varying weather conditions. The second is a hybrid perturb and observe technique (H-PO), which uses a variable step-size according to the location of the operating point relative to the MPP. The MATLAB/SIMULINK software is used to study the truth of the proposed techniques. The results demonstrate that both techniques attain the MPP faster than the conventional techniques and at a reduced oscillation rate. ________________________________________________________ Heading 1: Introduction Since antiquated occasions, petroleum derivatives have been the world s principle wellspring of energy, regardless of their adverse consequences, ecological contamination, and being exposed to exhaustion. In ongoing many years, the quest for lasting elective fuel sources has become an overall issue. Environmentally friendly power sources (RES) are the arrangement where they are lasting and maintainable [1]. Among RESs, the photovoltaic (PV) energy change frameworks have an observable effect because of their protected activity, being harmless to the ecosystem, and convenience [2, 3]. but , low proficiency is the fundamental disadvantage, where it is in the scope of 9–17% just [4–6]. As of late, PV innovations have continually advanced in plan and control strategies to expand effectiveness [7]. maximum power point tracking (MPPT) methods have an extraordinary importance to create power from PV system. Where PV age frameworks rely upon climatic conditions. The MPPT is capable to extract most extreme power from the PV system in various climate conditions. Annoy and notice (P&O) is perhaps the most utilized MPPT procedures [8–10]. The P&O technique relies upon annoying the progression size and noticing the difference in extricated power until it arrives at the maximum power point (MPP). The P&O technique chooses a reasonable advance size to improve the PV framework execution. Conventional P&O (CPO) strategies utilize a fixed advance size, so they have a great deal of disadvantages. In the event that a step with large size is utilized, the speed following reaction is quick, Hybrid and Adaptive P&O Maximum Power Point Tracking Techniques for PV Generation Systems ________________________________________________________________________________________________________________ ___________________________________________________________________________ 1695 yet it fuses high consistent state wavering levels, which diminishes the PV system effectiveness. At the point when a step with little size is utilized, the consistent state swaying levels are diminished, be that as it may, arriving at the MPP is slow, which increasing power losses. Additionally, CPOs lose the correct heading during the quick change in climate conditions, which expands the power losses and lessens the efficiency [11]. To dispose of the blemishes of CPO, a few P&O MPPT algorithms are proposed. Numerous specialists utilize variable advance size, while others utilize versatile advance size. An adaptive step size P&O algorithm is proposed to conquer the downsides of the CPO. The adaptive control algorithm (ACA) moves the working point nearer to the MPP by multiplying the short-circuit current with an ideal proportionality consistent [8]. The ACA is initiated just if there is an unexpected change in the irradiance or potentially the PV current. The short circuit current is assessed, which lessens the power losses and the extra expense of measuring components. Likewise, it tunes the progression size in two phases, in particular the coarse and fine-tuning. For the coarse-tuning, the perturbation size is resolved dependent on the irradiance level. In any case, for the fine-tuning, the annoyance size is resolved dependent on motions around the working point. An adaptive P&O MPPT (AD-PO) algorithm is proposed for wind generation systems and tested using realistic wind profiles [12]. The primary highlights of this algorithm are; applying an adaptive ratio to calculate the progression size, and assessing the limits for the particular working areas. The MPPT algorithm [9] is approved by building up an equipment model for unexpected changes in the irradiance. This technique comprises of two algorithms, specifically the current perturbation algorithm (CPA) and the adaptive control algorithm (ACA). The ACA works on case of an unexpected change in radiation or the PV current. These two calculations are inferred dependent on the traditional P&O algorithm and the fragmentary short circuit current algorithm, respectively. The outcomes show that, the proposed calculation is quicker with low oscillation levels than the traditional algorithm. The adaptive methods proposed by [13] and [14] relies on placing the MPP in the vicinity of the 0.8×Voc. Thus, the initial search for the MPP is set to 0.65×Voc. An improved P&O MPPT method is suggested by [15]. This method is based on feeling the change in both voltage and current (ΔV and ΔI), that results from the change of voltage perturbation and irradiation at every step. A predictive P&O MPPT algorithm for fast and reliable tracking of MPP [16]. The proposed method depends on the Least Mean Square (LMS) algorithm. The LMS adaptive filters depends straight on the selection of the factor of the step-size. An improved adaptive P&O MPPT technique is suggested, the comparison of the proposed method with the traditional adaptive P&O is shown [17]. The proposed P&O method with adaptive duty-cycle perturbation speeds up the dynamic tracking performances, there is still steadystate oscillation around the MPP which may cause continuous dc ripples and affects the reliability of the system. The steady-state MPP determination algorithm is proposed to eliminate the oscillation. The core idea is to compare the difference of two calculated consecutive duty-cycles with a small constant (ε<1) to determine the current operating conditions. A fast determination of the global maximum operating point (GMOP) under partial shading conditions (PSCs) using a suggested high-speed MPPT module which operates in synchronism with the boost converter [18]. It exploits the inductor characteristic to obtain a PV voltage at maximum power, which acts as a reference for the PI controller to track the GMOP. An improved P&O methodology was discussed where the duty-cycle was adjusted by the perturbation size [18]–[20]. A variable-step perturb and observe (VS-PO) MPPT method for wind energy conversion system [21]. It is based on dividing the operating area into Multiple sectors. The step-size is depended on the operating section. the Pythagorean theorem and constant voltage CVMPPT are the base equation, which a modified P&O-MPPT based on. it is presented in [22]. The solar irradiance is divided into two types; slow change ( ∆G<10 w/m2) and fast change ( ∆G>10 w/m2 ). The proposed technique succeeded to solve drawbacks of the conventional PO (CPO-MPPT) algorithm, in addition the output power with CV-MPPT is higher than that of the CPO-MPPT algorithms. Turkish Journal of Computer and Mathematics Education ___________________________________________________________________________ 1696 Research Article Vol.12 No.6 (2021), 1694-1707 A variable and adaptive P&O algorithm with current predictive control is suggested [23]. this algorithm depends on the PV array voltage and current sensors. the change of The PV array power variation is slow, in addition remains constant throughout a sampling time to reduce the computational burden. In [24] the authors propose the variable-step perturb and observe (VS-PO) MPPT algorithm for the wind generation system. This method is based on dividing the power-speed (P-ω) curve into modular sectors each with a specific step-size. A hybrid MPPT controller is suggested, which integrates the fuzzy logic controller (FLC) and the P&O MPPT algorithm of a PV under dynamic weather conditions [25]. The FLC is used to select the zone of MPP then the P&O technique is employed to tracking the MPP accurately. substantially, the FLC was able to harvest only 85% of the available power. While the P&O algorithm can achieve high accuracy by using a small step size. A modified P&O MPPT is suggested, which integrate an Artificial Bee Colony (ABC) algorithm and a P&O algorithm [26]. ABC works in the first stage, then P&O works in the second stage. In the proposed algorithm the global MPP (GMPP) is first tracked by recalling the ABC algorithm followed by the P&O algorithm for the local MPP (LMPP). Thus, the proposed method works by combining the local search ability of P&O with global search ability of ABC to produce the duty-cycle for the boost converter. A hybrid intelligent of the optimal global maximum power point tracking (GMPPT) algorithm is proposed for a partial shading PV system [27]. It is depended on an improved particle swarm optimization (PSO) algorithm and variable step perturb and observe (P&O) algorithm. The authors of [19] and [28] suggest the use of multiple variables instead of a single one to extract more power from the photovoltaic system. It works in two stages, the original P&O technique and the multivariable P&O technique. On the other side, this method makes the PV system very complex as compared to other P&O methods. The aut