Maximum power point tracking (MPPT) techniques play an essential role in efficiency improvement of photovoltaic systems. The present paper deals with the development of an enhanced MPPT algorithm in order to achieve maximum power point for any climatic conditions. The method under study is composed of two advanced approaches: a modified perturb and observe (MPO) algorithm based on a fuzzy logic controller for ensuring an optimal output of photovoltaic current and a model predictive current controller. The MPO algorithm is implemented with minimum rules to reduce the computational burden. The proposed MPPT is discussed, verified, and compared through simulations under the MATLAB/Simulink^™ environment, which presents a high dynamic performance under various conditions. Furthermore, a hardware validation using a dSPACE DS 1104 board is built in order to test and to assess, in real-time, the proposed MPPT.

Pack U‐Cell (PUC) multi‐level inverter is an attractive topology which widely investigated in the past few years for renewable energy conversion systems. This study introduces a modified five‐level packed Unit‐cell converter (MPUC5) for single‐phase double stage grid‐tied photovoltaic (PV) system with unity power factor. The proposed system operates as a single‐phase active power filter able to compensate reactive power generated by non‐linear loads connected to the point of common coupling, feeds the non‐linear load by the generated PV power, and injects the extra power into the grid. The MPUC5 inverter has a special topology with two DC‐link capacitors and six switches. One DC‐link of the inverter is connected to the PV arrays through DC/DC Cùk converter to draw the maximum power. Therefore, finite‐control‐set model predictive control (FCS‐MPC) for such configuration appears as a promising alternative for this inverter to work properly. Where the proposed FCS‐MPC algorithm is designed to ensure a high grid current quality, taking into consideration the issue of the capacitor voltages balancing and the switching frequency minimisation. Both simulation results and experimental validation through real‐time hardware in the loop system prove the validity and feasibility of the proposed control scheme, regarding PV power management and quality enhancement.

The control of multibody drill-string systems is not easy and designing such systems is considered challenging because of the difficulty in the dynamic analysis of its nonlinear characteristics and parametric uncertainties. An optimal hybrid interval Type-2 fuzzy PID+I logic controller (OH-IT2FPID+I) using a practical swarm optimization algorithm for a multi-degree-of-freedom oil well drill-string system is proposed in this paper. The suggested control concept is aimed to overcome several bit sticking troubles and stick–slip vibration by regulating the rotary velocities of drill-string components, especially rotary table velocity and drill bit velocity, to a predefined value. The drill-string system considered here has four degrees of freedom in the down-hole parts and the model takes the nonlinear interactions of the drill bit and the rocks into account, including friction torque and the mud drilling effect. Extensive simulations in Matlab/Simulink and experimental validations through a real-time hardware in the loop (HIL) system were performed to demonstrate the effectiveness of the suggested controller in comparison with sliding mode, Type 1 fuzzy logic and PID controllers. The quantitative comparison performed using simulation results proves that the proposed OH-IT2FPID+I provides higher control performance in terms of settling time and peak overshoot under variation of the weight on bit, the desired drill bit rotary speed, and handling parametric uncertainties. On the other hand, HIL results confirm the control performance provided by the proposed control under all different testing scenarios.

This contribution considers an improved control scheme for three-phase two-stage grid-tied photovoltaic (PV) power systems based on integral sliding mode control (ISMC) theory. The proposed control scheme consists of maximum power point tracking (MPPT), DC-Link voltage regulation and grid current synchronization. A modified voltage-oriented maximum power point tracking (VO-MPPT) method based on ISMC theory is proposed for design of an enhanced MPPT under irradiation changes. Moreover, a novel DC-Link voltage controller based on ISMC theory is proposed to achieve good regulation of DC-Link voltage over its reference. To inject the generated PV power into the grid with high quality, a voltage-oriented control based on space vector modulation (SVM) and ISMC (VOC-ISMC-SVM) has been developed to control the grid current synchronization. Numerical simulations are performed in a MATLAB/Simulink^TM (R2009b, MathWorks, Natick, MA, USA) environment to evaluate the proposed control strategy. In comparison with conventional control schemes, the developed control strategy provides an accurate maximum power point (MPP) tracking with less power oscillation as well as a fast and an accurate DC-Link regulation under varying irradiation conditions. Moreover, the transfer of the extracted power into the grid is achieved with high quality.