There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

In this study, a cascade two-loop non-linear controller is developed for single-phase shunt active power filters which is robust and stable in a wide range of output current and DC-link voltage changes. A variable structure proportional-integral controller is designed to regulate DC-link voltage in the outer loop. Also filter output current is controlled in the inner loop using adaptive backstepping approach. All of the model uncertain parameters are estimated using designed estimation rules. By introduction of suitable Lyapunov functions, proposed controller stability is investigated using Barbalat lemma. Grid reference current is calculated indirectly using a phase-locked loop circuit according to DC-link voltage error. Designed active power filter has been implemented using TMS320F28335 digital signal processor and practical response of the developed controller is studied in some tests. It is shown that the proposed controller is able to eliminate harmonic components of the local load current with a fast dynamic response. Also, compensation capability of the designed non-linear approach is compared with sliding mode controller in similar conditions.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-pel.2016.0366

Experimental design of the adaptive backstepping control technique for single-phase shunt active power filters

Multi-objective voltage and frequency regulation in autonomous microgrids using Pareto-based Big Bang-Big Crunch algorithm

A Lyapunov function based model predictive control for three phase grid connected photovoltaic converters

Nonlinear adaptive control design with average performance analysis for photovoltaic system based on half bridge shunt active power filter

Cascade nonlinear control of shunt active power filters with average performance analysis

This paper is aimed at harvesting the photovoltaic systems extracting power under difficult irradiance and load conditions, by proposing a novel maximum power point tracking (MPPT). This proposed MPPT tactic has been examined under various climatic and load conditions using two powerful and accurate simulation environments for PV systems, MATLAB/Simulink and Proteus. The first implementation using the MATLAB/Simulink software was carried out to examine the performance of the novel MPPT tactic under sudden insolation and load change, where the second implementation using the Proteus software was carried out in order to prove that the novel MPPT tactic can be easily implemented using low-cost components, Arduino board, and LCD display. The simulation results prove that the novel MPPT tactic has a high convergence speed to locate the MPP, especially at fast solar irradiation and load variation with zero oscillation under steady-state operation, which takes less than 9.6 milliseconds (ms) under the MATLAB/Simulink software and 0.24 microseconds (μs) under Proteus environment. That means it is about six times faster than P&O and five times faster than INC MPPT methods, and its tracking efficiency is between 99.40% and 99.86%. Furthermore, the novel MPPT tactic shows the best tracking accuracy and better ability to mitigate power losses under overall simulation scenarios compared with other traditional MPPT methods.

/pdf/implementation-of-a-novel-mppt-tactic-for-pv-system-18grbwt7i0.pdf

Implementation of a Novel MPPT Tactic for PV System Applications on MATLAB/Simulink and Proteus-Based Arduino Board Environments

ABSTRACT This paper offers an innovative maximum power point tracking (MPPT) approach for photovoltaic system under temperature varying. Basically, the innovative approach is introduced to improve tracking performance under difficult scenarios of temperature change. By far, it can be used to avoid the main shortcomings of the conventional MPPT strategies, e.g., ripple around the MPP at steady-state regime, sluggishness velocity converging, and loss of tracking direction under fast change of temperature. Also, it can be used to improve the tracking performance under low irradiance level and rapid load change. With respect to its direct control strategy based on the photovoltaic current control, it provides a quick tracking of the real MPP without steady-state fluctuations. To show the advantages and accuracy of the innovative MPPT approach, a comparison with other traditional strategies, e.g., P&O and INC techniques is investigated using simulation in MATLAB/Simulink® software under different scenarios of temperature, load, and insolation levels. In the light of the results collected, the innovative MPPT approach minimized the convergence time by five times, reduced the steady-state fluctuations to zero and improved the average tracking efficiency by 8.51% and 9.04% compared to the P&O and INC MPPT schemes, respectively.

An innovative Fast-Converging speed MPPT approach without oscillation for temperature varying in photovoltaic systems applications

This paper develops and discusses an improved MPPT approach for temperature variation with fast-tracking speed and reduced steady-state oscillation. This MPPT approach can be added to numerous existing MPPT algorithms in order to enhance their tracking accuracy and response time and to reduce the power loss. The improved MPPT method is fast and accurate to follow the maximum power point under critical temperature conditions without increasing the implementation complexity. The simulation results under different scenarios of temperature and insolation were presented to validate the advantages of the proposed method in terms of tracking efficiency and reduction of power loss at dynamic and steady-state conditions. The simulation results obtained when the proposed MPPT technique was added to different MPPT techniques, namely, perturb and observe (PO besides, the steady-state power oscillations of the conventional P&O, INC, and modified MPP-Locus MPPT methods are 2, 1, and 0.6 watts, but it is neglected in the case of using the improved approaches. In this study, the MATLAB/Simulink software package was selected for the implementation of the whole PV system.

/pdf/an-improved-maximum-power-point-approach-for-temperature-16ua9takui.pdf

An Improved Maximum Power Point Approach for Temperature Variation in PV System Applications

The problem of controlling reduced-part three-phase shunt active power filters is addressed in the presence of nonlinear loads. The control objective is twofold: (i) compensation of the current harmonics and the reactive power absorbed by the nonlinear load in order to ensure a satisfactory power factor correction (PFC) at the grid-filter connection point; (2) regulation of the DC bus voltage at the inverter input. The considered control problem entails several difficulties including: (1) the high dimension and strong nonlinearity of the system; (ii) the numerous state variables that are inaccessible to measurements; (iii) the system parameter uncertainty. The problem is dealt with by designing a nonlinear adaptive controller with cascade structure including two control loops. The inner-loop regulator is designed using the Lyapunov technique to ensure the PFC objective, while the outer-loop involves a linear PI type control law for DC bus voltage regulation. The controller also includes an adaptive observer estimating the grid voltages and impedances parameters. The resulting control performances are formally analyzed using the averaging theory. Simulation results are presented illustrating the performances and the strong robustness of the proposed control strategy.

Younes Abouelmahjoub

Papers

Cascade nonlinear control of shunt active power filters with average performance analysis

Implementation of a Novel MPPT Tactic for PV System Applications on MATLAB/Simulink and Proteus-Based Arduino Board Environments

An innovative Fast-Converging speed MPPT approach without oscillation for temperature varying in photovoltaic systems applications

An Improved Maximum Power Point Approach for Temperature Variation in PV System Applications

Adaptive Nonlinear Control of Reduced‐Part three‐Phase Shunt Active Power Filters