Ahmad El Khateb

Fuzzy-Logic-Controller-Based SEPIC Converter for Maximum Power Point Tracking

This paper presents a fuzzy logic controller (FLC)-based single-ended primary-inductor converter (SEPIC) for maximum power point tracking (MPPT) operation of a photovoltaic (PV) system. The FLC proposed presents that the convergent distribution of the membership function offers faster response than the symmetrically distributed membership functions. The fuzzy controller for the SEPIC MPPT scheme shows high precision in current transition and keeps the voltage without any changes, in the variable-load case, represented in small steady-state error and small overshoot. The proposed scheme ensures optimal use of PV array and proves its efficacy in variable load conditions, unity, and lagging power factor at the inverter output (load) side. The real-time implementation of the MPPT SEPIC converter is done by a digital signal processor (DSP), i.e., TMS320F28335. The performance of the converter is tested in both simulation and experiment at different operating conditions. The performance of the proposed FLC-based MPPT operation of SEPIC converter is compared to that of the conventional proportional-integral (PI)-based SEPIC converter. The results show that the proposed FLC-based MPPT scheme for SEPIC can accurately track the reference signal and transfer power around 4.8% more than the conventional PI-based system.

Fuzzy logic controller based SEPIC converter of maximum power point tracking

This paper presents a fuzzy logic controller (FLC)-based single-ended primary-inductor converter (SEPIC) for maximum power point tracking (MPPT) operation of a photovoltaic (PV) system. The FLC proposed presents that the convergent distribution of the membership function offers faster response than the symmetrically distributed membership functions. The fuzzy controller for the SEPIC MPPT scheme shows high precision in current transition and keeps the voltage without any changes, in the variable-load case, represented in small steady-state error and small overshoot. The proposed scheme ensures optimal use of PV array and proves its efficacy in variable load conditions, unity, and lagging power factor at the inverter output (load) side. The real-time implementation of the MPPT SEPIC converter is done by a digital signal processor (DSP), i.e., TMS320F28335. The performance of the converter is tested in both simulation and experiment at different operating conditions. The performance of the proposed FLC-based MPPT operation of SEPIC converter is compared to that of the conventional proportional-integral (PI)-based SEPIC converter. The results show that the proposed FLC-based MPPT scheme for SEPIC can accurately track the reference signal and transfer power around 4.8% more than the conventional PI-based system.

Control Methods and Objectives for Electronically Coupled Distributed Energy Resources in Microgrids: A Review

Increased penetration of distributed energy resources into conventional power systems increases control challenges. These can be suitably met by microgrids. This paper examines the architecture of microgrids and reviews their classifications and the literatures discussing their control objectives during islanded mode. It finds the use of microgrids enhancing the conventional power systems grid smartness. It also summarizes microgrid control objectives and their most common problems and solutions.

DC-to-DC Converter With Low Input Current Ripple for Maximum Photovoltaic Power Extraction

This paper presents a dc-to-dc converter, which offers continuous input and output energy flow and low input current ripple, applicable and mandatory for photovoltaic (PV) arrays and maximum power tracking applications. The PV array yields exponential curves for current and voltage where maximum power occurs at the curves mutual knee. Conventional dc-to-dc converters have a relatively high input current ripple which causes high power losses when connected to nonlinear sources like PV arrays. The proposed converter maximizes the power that can be sourced from the PV array, without the need of any electrolytic filtering capacitance. The effect of current ripple can be significant and decreases PV system efficiency. Converter simulations and experimental results support and extol the system concept.

Optimized PID controller for both single phase inverter and MPPT SEPIC DC/DC converter of PV module

Introduced here is an implementation of an optimized Proportional, Integral, and Derivative (PID) controller that controls single-phase inverter and single-ended primary-inductor DC/DC converter (SEPIC). The main improvement is the endowment of classical PID controller with gradient-descent optimization method, which generates exact values for PID-controller parameters Kp, Ki, and Kd, which in turns track the maximum power. The method was applied post-use of Ziegler-Nichols method, reducing optimization time. SEPIC maximum-power-point tracker (MPPT) ensures optimal utilization of PV cells. The method further proves its efficacy in variable-load conditions. TMS320F28335 DSP has been used to implement the controlled pulse width modulation (PWM). The controlled system has been verified by simulation and implemented in a prototype. Then, experimental results have been compared with those for conventional single-phase inverter.

Fuzzy Logic Controller for MPPT SEPIC converter and PV single-phase inverter

This paper introduces an implementation of Fuzzy Logic Controller (FLC) for the single-ended primary-inductor converter (SEPIC) that control the maximum power point tracking (MPPT) signal together with the cascaded single-phase inverter. The extracting of the maximum power through using the SEPIC fuzzy controller is considered the main improvement here. Fuzzy-controlling in duty cycle increases/decreases the voltage level for the SEPIC according to the maximum power. SEPIC MPPT ensures optimal utilization for the PV array. The controller further proves its accuracy in variable-load conditions. TMS320F28335 DSP has been used to implement the controlled pulse width modulation (PWM). The controlled system has been verified by simulation and implemented in a prototype. Then, experimental results have been compared with those for conventional single-phase inverter.

Hybrid Takagi‐Sugeno Fuzzy FED PID Control of Nonlinear Systems

The new method of proportional‐integral‐derivative (PID) controller is proposed in this paper for a hybrid fuzzy PID controller for nonlinear system. The important feature of the proposed approach is that it combines the fuzzy gain scheduling method and a fuzzy fed PID controller to solve the nonlinear control problem. The resultant fuzzy rule base of the proposed controller contains one part. This single part of the rules uses the Takagi–Sugeno method for solving the nonlinear problem. The simulation results of a nonlinear system show that the performance of a fed PID Hybrid Takagi‐Sugeno fuzzy controller is better than that of the conventional fuzzy PID controller or Hybrid Mamdani fuzzy FED PID controller.

The effect of input current ripple on the photovoltaic panel efficiency

This paper presents the effect of the input current ripple on the photovoltaic source efficiency. The input and output current can be either continuous or discrete, with or without ripple, giving either continuous or discrete energy flow hence affecting the input source efficiency or the output load application. This paper considers the influences of the converter input current ripple on the photovoltaic module and the loss of power extracted, in conjunction with converter efficiency, thus losses in the overall system efficiency. With input current (or voltage) ripple, there is no maximum power point; instead, there is maximum power track or locus curve. When the input current ripple reduces to zero, the maximum power curve becomes a point, specifically the DC maximum power point.

Ćuk-Buck Converter for Standalone Photovoltaic System

This paper presents MPPT converter for battery charger. The converter combines both ćuk and buck converters to extract the maximum power from the sun while supplying a controlled constant current/voltage to the battery. The topology uses two control signals instead of one control signal; one for tracking the maximum power point, another for charging the battery providing constant current/voltage to the battery. The advantage of this converter is to exploit the maximum power of the PV array avoiding battery damage caused by variable MPPT voltage. The effectiveness of the proposed converter was tested in simulation in various operating conditions.

Type-2 Fuzzy Logic Approach of a Maximum Power Point Tracking Employing SEPIC Converter for Photovoltaic System

This paper introduces a type-2 fuzzy logic controller (FLC) as a maximum power point tracker (MPPT), which can handle the uncertainties of the rules under high variations in weather conditions. The MPPT employed single-ended primary-inductor (SEPIC) converter. The new controller improves maximum power tracker search method by rules fuzzifying. An accurate and fast converging to maximum power point is offered by type-2 fuzzy tracker during both steady-state and varying weather conditions compared to conventional fuzzy MPPT methods. The performance of the proposed maximum power point tracker is demonstrated in MATLAB simulation at different operating conditions.