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The present paper suggests a simulation study for a grid connected photovoltaic system, associated to a shunt active power filter (SAPF). On the one hand, to extract the maximum power from the PV generator a fuzzy logic Maximum power taking point (MPPT) is proposed in order to track permanently the optimum point. On the other hand, direct power control (DPC) is used to control the shunt active power filter in order to compensate the undesirable harmonic. The simulation of the system under the Matlab/SimulinkTM environment demonstrates the robustness of the proposed controls that simultaneously guarantee harmonic current compensation, unit power factor operation and injection of solar power to the power grid.

In this paper we present a new maximum power point tracking algorithm based on a modified Perturb and Observe (P&O) algorithm. The proposed algorithm is a dual mode one, the switching between the two modes is based on the value of the derivative of the power with respect to the voltage at the output of the solar panel, which must be null at the maximum power point. The first mode, a conventional P&O is active when the value of the derivative is smaller than a threshold, when its value surpasses the threshold, the second mode is activated, which prevents the voltage at the output of the solar panel to get far away from the maximum power point voltage ( V mpp ). The implementation of the proposed algorithm is very simple, similarly to the P&O, it needs just two sensors, one dedicated for the current and the second for the voltage. In comparison with the P&O, this algorithm has better performance without increasing the implementation cost. The proposed algorithm is tested by simulations using Simulink/Matlab™ to control a boost converter supplying a resistive load R. In order to further test the proposed algorithm, experimental results are presented to prove its effectiveness. The results are compared to those given by the P&O algorithm. Simulation and experimental results show that the proposed algorithm prevents the divergence of the operating point, and has a smaller response time which allows to extract more power and to decrease the losses on the adaptation stage of the solar energy system.

This paper proposes a modified perturbation and observation maximum power point tracking algorithm for small wind energy conversion systems to overcome the problems of the conventional perturbation and observation technique, namely rapidity/efficiency trade-off and the divergence from peak power under a fast variation of the wind speed. Two modes of operation are used by this algorithm, the normal perturbation and observation mode and the predictive mode. The normal perturbation and observation mode with small step-size is switched under a slow wind speed variation to track the true maximum power point with fewer fluctuations in steady state. When a rapid change of wind speed is detected, the algorithm tracks the new maximum power point in two phases: in the first stage, the algorithm switches to the predictive mode in which the step-size is auto-adjusted according to the distance between the operating point and the estimated optimum point to move the operating point near to the maximum power point rapidly, and then the normal perturbation and observation mode is used to track the true peak power in the second stage. The dc-link voltage variation is used to detect rapid wind changes. The proposed algorithm does not require either knowledge of system parameters or of mechanical sensors. The experimental results confirm that the proposed algorithm has a better performance in terms of dynamic response and efficiency compared with the conventional perturbation and observation algorithm.

SUMMARY The choice and design of a high efficient maximum power point tracking (MPPT) algorithm is a necessity in the PV system design. Many approaches have been proposed in literature, among them, the methods that are based on perturb and observe (P&O), widely used in commercial products due their simplicity and ease of implementation. In this paper, a new modified P&O (MPPT) method with adaptive duty cycle step size using fuzzy logic controller is proposed. Both, simulation and experimental design are provided in several aspects. The proposed and classical methods are developed and tested successfully using a CUKDC–DC converter, which is connected to a SunTech STP085B model. The proposed method is able to improve the dynamic response and steady-state performance of the PV systems simultaneously and effectively. In addition, analysis and comparison with the conventional fixed step size P&O have been presented. Copyright © 2015 John Wiley & Sons, Ltd.

In this paper, simulation and practical implementation of direct power control is presented for a PWM Rectifier application. The proposed DPC control has several advantages, including the grid current very close to sinusoidal waveforms (TDH < 1.2%), and good regulation of DC-bus voltage is achieved using the PI controller. The simulation and the experimental results obtained in this study, demonstrate the effectiveness of the direct power control algorithm to eliminate the harmonic currents, ameliorate the active power quality and minimize the reactive energy effect which allowed us to affirm the strength of the proposed strategy.

The real implementation of DC-DC boost converters controllers is slightly difficult due to their non minimum phase behavior and the non zero output voltage error. Integral Sliding Mode Controllers (ISMC)s have proved to be able to deal with this kind of converters and to eliminate the chattering phenomenon. In order to cancel the output voltage error, we apply in this paper, an ISMC to a detailed modelling of boost converter (by considering the associated parasites). Numerical and experimental comparative studies with the ideal case and the classical SMC verify the effectiveness and the robustness of this controller.

This paper presents a study on different methods of modeling the network reconfiguration problem to take into account load variation during a period of time. This work aims to determine if the optimization process needs to take into account this fact in order to be used by a real distribution network operator. It presents a way to optimize an integral objective function. Two types of optimization are presented, a Mixed Integer Quadratic Constrained Program (MIQCP) and a Mixed Integer Non-Linear Program (MINLP). Three different processes of optimization on a defined period are presented, two avoiding the use of power flow calculation and one using it. Methods are computed using three different load scenarios on the well known Baran & Wu test case. Results tend to show that it is not useful to take into account load variation and worst case optimization is the best method.

This paper presents a new control strategy based on Lyapunov theory used to control a quadratic boost converter used in solar energy system. The proposed controller assures the stability of the system. To provide a maximum power extraction, a maximum power point tracking (MPPT) is included in the controller. First a simple MPPT algorithm based on the fact that the derivative of the power with respect to the voltage at the output of the solar panel is null when the operating point is the same as the maximum power point (MPP) is integrated in the controller, then we will propose a modified version of the algorithm operating in dual-mode with a variable step-size. The proposed controller is tested by simulations using Matlab/Simulink™ with both MPPT algorithms. The proposed dual-mode variable step-size algorithm has proved its advantage compared to the simple one. It gives a smoother output, therefore decreases power losses. The proposed controller is compared also to a conventional perturb and observe (P&O) controller. The comparison has proved that the proposed controller has a smaller response time, a lower steady-state error and a more stable operating point.

This paper presents a new control strategy for a quadratic boost converter used in solar energy system. The proposed control strategy is based on Lyapunov theory that provides the stability of the converter considered as a switched affine system, it also allows a maximum power extraction by fixing the operating point near of the maximum power point (MPP). The voltage is fixed at a constant value VMPP if the irradiation varies in a small interval, or the derivative of the power with respect to the voltage is fixed at zero. The system doesn't contain any maximum power point tracking (MPPT) controller, the MPPT is integrated in the control strategy. The simulation results have proved the robustness of the proposed control strategy and the comparison with a classic controller has shown its advantage, the output is smoother and the extracted power is maximum without using a MPPT controller.

In this article, a grid-connected photovoltaic system with functionality of power quality enhancement is studied. The integration of the photovoltaic generator into the grid takes place in one stage, using a three-phase voltage source inverter. A direct power control algorithm strategy with a new switching table has been proposed to decrease power losses into the voltage source inverter, to enhance power quality, to optimize the control of instantaneous active and reactive powers, and to perform as a multi-function device by incorporating shunt active power filter functionality. In addition to this control strategy, a maximum power point tracking perturb and observe algorithm is applied to the inverter to extract optimal available power from the photovoltaic array. The proposed system can provide the power factor correction, harmonic elimination, reactive power compensation, and simultaneously inject the maximum power available from the photovoltaic array to the load and/or grid. The multifunction...

This paper presents a modelling of power factor correction and digital implementation of different loops of circuit such as the PI controller for voltage loop and the hysteresis controllers for current loop. Three hysteresis control techniques: fixed band, sinusoidal band and variable band are applied and have been verified by simulation. For the experimental part, all cited controllers are applied and performance tests were used to validate the results obtained through simulations using a test bench based on dSPACE DS1104. Results show that the PI controller gives a better steady-state performance under large load disturbance and variation of reference values, whereas the variable band hysteresis control in the current loop gives a low THD of the input current compared to other hysteresis controls.

In this paper, we present a direct power control (DPC) of three-phase pulsewidth modulation rectifier with constant switching frequency using space-vector modulation (SVM). The developed DPC scheme is based on the predictive control strategy to achieve direct control of instantaneous active and reactive power of the converter. For this purpose, at the beginning of each switching period, the required rectifier average voltage vector allowing the cancellation of active and reactive power tracking errors, at the end of the switching period, is calculated by means of predictive control algorithm in the sense of deadbeat control. The main advantages of the proposed control, compared to the works published in this subject, are that no need to use predefined switching table and voltage vector or virtual flux position, PI-based active and reactive power control loops are not necessary and constant-switching frequency. The proposed predictive direct power control was tested both in simulations and experimentally and compared with DPC using switching table. Results have proved excellent performance, and verify the validity of the proposed DPC scheme, which is much better than conventional DPC using switching table.

This research deals with a new modelling of a three-phase network in association with a parallel active filter with the help of linear state representation in closed loop. Using this approach the harmonics compensation of current networks is treated like a matter of disturbances rejection with the tools of linear control theory. This reasoning is different from common methods which are usually based on reference tracking control. The proposed strategy is validated firstly using simulation then using a test bench fitted with a three-phase shunt active filter whose control law is implemented in real time.

This paper proposes a novel and simple direct power control (DPC) scheme of a three-phase pulsewidth-modulated rectifier without the use of a predefined switching table. The converter switching state selection is based on fuzzy logic rules, using the instantaneous active and reactive power tracking errors as fuzzy logic variables. The basic idea of fuzzy rules synthesis is based on the knowledge of the instantaneous variation of active and reactive power. According to the input fuzzy variables and in a specific moment, the best switching state of the converter is chosen to restrict the instantaneous active and reactive power tracking errors simultaneously, for maintaining the DC-bus voltage close to the reference value and guarantying the unity-power-factor operation. The main advantages of the proposed DPC scheme, compared to the classical one, are that it is not necessary to use hysteresis comparators, and smooth control of active and reactive power is obtained during all sectors. Finally, the developed DPC was tested both in simulations and experimentally, and illustrative results are presented here. Results have proven excellent performance, and verify the validity of the proposed DPC scheme which is much better than the classical DPC.

The aim of this work is to design a static feedback gain used to force a three-phase shunt active power filter to act as a current source capable of delivering the appropriate harmonics demanded by non-linear loads. This filter is connected in parallel to a three-phase power distribution system in order to keep the current supplied by the latter almost sinusoidal. The control design is performed using the H ∞ suboptimal control theory based on linear matrix inequalities (LMIs), with both partial and full state feedback. Numerical simulations will be presented in order to investigate the advantages of the full state feedback structure over the partial state feedback one, and to compare the performances of the corresponding H ∞ static control laws.

The simulation and experimental study of proportional integrator (PI) controlled DC bus voltage of three phase shunt active power filter (APF) to improve power quality by compensating harmonics and reactive power required by nonlinear load is proposed. The compensation process is based on sensing mains currents only, an approach different from conventional methods, which usually require harmonics or reactive volt-ampere values of the load. The non-sinusoidal mains voltage problem is resolved by using phase locked loop (PLL) system. Pulse width modulation (PWM) signal generation is based on hysteresis control comparators to obtain the switching signals.ű Various simulation and experimental results are presented under steady state and transient conditions.

This paper presents a theoretical and experimental analysis of Maximum Power Point Tracking (MPPT) method for photovoltaic (PV) systems based on Genetic Algorithms (GAs). The proposed algorithm is based on Genetic Algorithms (GAs) and it can estimate the current (Imp) and voltage (Vmp) at maximum power point by measuring the open circuit voltage (Voc) and the short circuit current (Isc) without knowing the irradiance and the cell temperature. The principle of GAs is searching for the maximum of fitness function and not for the minimum of power derivation; this gives more stability and minimize oscillation of output power around the maximum power point (MPP).We expose the method with a few tests; then a comparison with the famous Perturb and Observe (P&O) and Incremental Conductance (Inc-Cond) is given. We tested stability (power oscillation) with real panels. To compare response time (rapidity) we used a PV emulator (realized by Kadri et al.), so we can inject the same irradiance profile and see output PV power evolution. The response time of P&O and Inc-Cond, and the PV power oscillation varies with the duty cycle increment step; with a small step, we get less power oscillation but this needs an important time response, we can improve system rapidity with a bigger duty increment step but important power oscillation will result. With GAs based MPPT we can get more stability with rapid response time. The results obtained show better stability and less oscillation around the MPP with the new method.

This paper proposes a new Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) algorithm for Small Wind Energy Conversion Systems to overcome the rapidity-efficiency trade-off and wrong behavior problems of the conventional P&O technique. The proposed algorithm works in two separate modes. The first mode is activated when the wind speed changes slowly. Under a rapid change of the wind speed, the second mode is switched to avoid the divergence of the system. The proposed algorithm requires only the measurement of the dc-link voltage and the dc current to realize the MPPT control, so no rotor speed measurement is needed, reducing the complexity of the overall system. The performance and the validity of the new MPPT algorithm have been proved by both simulation and experimental results.

This paper presents experimental analysis of Genetic Algorithms (GAs) based Maximum Power Point Tracking (MPPT) for photovoltaic (PV) systems. This method, presented by another paper [1], uses GAs to track the maximum power point (MPP) of PV panels. Comparison with the famous Perturb and Observe (PO with a small step, we get less power oscillation but this needs an important time response, we can improve system rapidity with a bigger duty increment step but important power oscillation will result. With GAs based MPPT we can get more stability with rapid response time. The results obtained show better stability and less oscillation around the MPP with the new method.

Maximum power point tracking (MPPT) is a necessary function in all photovoltaic (PV) systems. The classic incremental conductance (IC) MPPT algorithm is widely used in the literature. However, when large changes occur in the irradiance, the performance of this algorithm is degraded. To eliminate all of the disadvantages of the classic IC algorithm, we developed a new IC controller based on a fuzzy duty cycle change estimator with direct control. A fuzzy logic estimator (FLE) is used to estimate the new duty cycle used to track the PV array maximum power point. Compared with the fixed step IC MPPT method with direct control, the proposed algorithm reaches the MPP more accurately and faster during dynamic and steady-state conditions. A controlled Cuk DC–DC converter was implemented and connected to a SunTech STP085B PV panel to verify the accuracy of the proposed method. Matlab/Simulink was used for the simulation studies. Additionally, the algorithms were digitally implemented on the dSPACE ACE1104 platform. The results obtained confirm the advantages of the proposed algorithm.

this paper presents an identification method achieving estimation of induction machine electrical parameters. Originality of this work holds in the machine model used. It is a non-linear continuous time model defined in the (abc) frame, whose parameters are not dependent on rotor position. This model is well fitted for non-linear parameter identification algorithm, in order to apply a fault diagnosis method. A recursive algorithm has been derived from the off-line one, allowing to track parameter variation. Some experimental results conclude this paper

This paper proposes a voltage control of a single distributed generation (DG) unit powered local load. The DG system utilizes three phase four wire voltage source inverter VSI with split DC link as the medium interface and LC filter. A dual loop scheme is employed. Hysteresis current controller is used in the inner loop. In the outer loop, a compound control method based on deadbeat and repetitive controllers is proposed in this paper. Using repetitive controller the unwanted harmonics from the output voltage caused by nonlinear loads can be eliminated. The deadbeat regulator is adopted to increase dynamic response of the system to disturbance due to load transit.

This paper presents a new form of a non linear sliding surface with “optimal” parameters in order to have a suitable sliding mode controller for a DC-DC boost converter. A comparison between the proposed sliding surface (PSS) and the sliding surface proposed in [7] is done to test the effectiveness of the two forms.

This paper deals with a new concept and analysis of direct power control (DPC) switching table for a three phase shunt active power filter (SAPF) to improve power quality. The active power reference is obtained from the VSI dc-bus voltage controlled at the required level using an integrator proportional corrector. Compared to their references, active and reactive powers are directly controlled by selecting the optimal vector using a new switching table. From the SAPF's equivalent scheme analysis the instantaneous active and reactive powers (IARP) variations are obtained. The new predefined switching table is designed based on comparative study and voltage source inverter (VSI) switching vectors effect on the total IARP variations. The main advantages of this control technique are that it provides a sinusoidal source current and unity power factor with no need of linear current controllers and coordinates transformations or modulators. Extensive simulation and experimental results, obtained from steady and transient states, prove the excellent performance and verify the validity and effectiveness of the proposed power control for improving the power quality.

This article presents the design and the implementation of dSPACE DS1104 controller board-based PI and fuzzy logic peak current-mode controllers in the voltage loop and two controllers in the current loop based first on a standard fixed hysteresis band control, followed by a variable hysteresis band control to achieve constant switching frequency for a single-phase active power factor corrector in the continuous conduction mode. All these controllers have been verified via simulation in Simulink and a real-time implementation is performed on an experimental test bench utilising a rapid prototyping tool. The controllers are experimentally compared for steady-state performance and transient response. It is shown that the PI and fuzzy logic controllers give a superior steady-state performance, whereas the fuzzy logic inference based controller can achieve better dynamic response than its PI counterpart under large load disturbance and plant uncertainties. Furthermore, the variable hysteresis band control in ...

In order to deal with the boost converter non minimum phase property and to solve the Sliding Mode Control (SMC) major problem (the chattering phenomenon), a new backstepping Sliding Mode Controller is developed. In this paper, a comparative study between the proposed controller and the (2-SMC)super twisting and the classical SMC is provided in order to evaluate each controller. Simulations and experimental results show the effectiveness and the robustness of the proposed controller with respect to load variation.

This paper proposes a fuzzy control method for tracking maximum power point in photovoltaic (PV) power systems to solve a fast irradiation change problem. Perturb and Observe (P&O) is known as a very simple maximum power point tracking and is extensively disseminated. Fuzzy logic is also simple to investigate and provides fast dynamics. The suggested technique combines both fuzzy logic and P&O advantages. A fuzzy logic-based P&O algorithm is illustrated to identify the fault direction tracking of conventional P&O algorithm under trapezoidal irradiation change. The proposed algorithm is verified using Matlab/Simulink™ software. The robust tracking capability under rapidly increasing and decreasing irradiance is verified experimentally with a PV array emulator. Simulation and experimental results confirm that the proposed algorithm provides effective, fast, and accurate tracking compared to the conventional P&O algorithm.

As demands for high quality, reliability and usability of electrical power source are increasing and essential, many studies investigate algorithms of harmonic source detection. To evaluate the quality of electrical network, a method for fundamental frequency and harmonics characteristics with high accuracy is proposed. The interest of this work is to control the stability, safety and efficiency of an electrical network with fast and accurate estimation of the fundamental frequency and harmonic distorsion. In practical cases, the fundamental frequency is considered uncertain. Its deviation induces large perturbation on high range harmonics. To alleviate this drawback, we consider the fundamental frequency as an uncertain frequency and suggest a method to evaluate its value with high degree of accuracy. From this correct numerical value of the fundamental frequency, all magnitude and phase of harmonics are estimated with higher precision. Thus, this paper deals with the identification of fundamental frequency and selective harmonic identification. The method developed is derived with the Fourier series for fundamental frequency and on the Discrete Fourier Transform (DFT) for harmonics. Outset, we will focus just on the first coefficient of the Fourier series not to perform the magnitude and phase, but to explain a condition that allows to reach the real value of fundamental frequency. The algorithm is an iterative one. The result is presented in continuous case and in discrete case. After, the DFT method is applied to obtain magnitude and phase of fundamental and harmonics. The simulation and experimental results show the ability of the developed algorithm.

Photovoltaic (PV) power has been successfully used for over five decades. The output characteristics of a PV array vary nonlinearly when temperature or irradiance conditions change. At the beginning of this paper, the performance of PV panel is analyzed, for parallel and series connections of solar cell elements exposed to the same light conditions and temperature by using the Brune’s conditions of interconnection. Therefore the parameters of the equivalent circuits for each typical PV cell connections are characterized by a new set of matrix equations. A Lab View application is implemented to prove the theoretical models. Moreover, the grid connected PV systems have become more popular because they do not need battery back-ups to ensure maximum power point tracking (MPPT). However, partial shading is one of the main causes that reduces energy yield of PV array. In this respect, the second part of the paper refers to the influences of different irradiance conditions on the PV array performance in order to achieve MPPT under shaded array conditions. Consequently, PV array emulator is crucial for the operational evaluation of system components. The purpose of this study extension is to design and develop a new real-time emulator of PV array output characteristics based on closed-loop reference model.

In this paper, a study of an autonomous hybrid PV-Wind-battery system for a residential house of 4 persons in La Rochelle in France is presented. It includes system design optimization and performance evaluation in addition of its economic and environmental life cycle analysis. The results show a low environmental impact and a reasonable economic cost of the system.

Module integrated converters focus many research because they are considered as most promising solutions for grid connection of photovoltaic power generation systems. Most of the proposed approaches relied so far on the use of series string of DC-DC converter to create a high voltage string connected to DCAC inverter. The boost converter is better in this application. However, under inhomogeneous irradiation, the power generated from each PV module and output DC voltage of each boost becomes unbalanced so that the output currents of each boost are balanced and equal to the string current. In this case the boost converter cannot always deliver all the power from a mixture of shaded panels and those delivering full power. In this paper, a centralized MPPT with string current diverter for solving the series connection problem in photovoltaic power generation system is proposed to overcome this problem. One important feature of the proposed circuit herein is the ability to effectively decouple each PV module from the rest of the string, making this insensitive to changes in the string current. Hence it is possible to obtain the maximum power from the PV generator and allow it to operate at the optimum efficiency. The simulation and experimental results verify that the proposed topology exhibits good performance anyway of inhomogeneous irradiation. On the other hand, the string current diverter circuit does not operate if irradiation is homogeneous. So, in this last condition, the topology efficiency is improved.

Module integrated converters focus many research because they are considered as most promising solutions for grid connection of photovoltaic power generation systems. Most of the proposed approaches relied so far on the use of series string of DC-DC converter to create a high voltage string connected to DC-AC inverter. The boost converter is better in this application. However, under inhomogeneous irradiation, the power generated from each PV module and output DC voltage of each boost becomes unbalanced so that the output currents of each boost are balanced and equal to the string current. In this case the boost converter cannot always deliver all the power from a mixture of shaded panels and those delivering full power. In this paper, a non-dissipative string current diverter is proposed to overcome this problem. One important feature of the proposed circuit herein is the ability to effectively decouple each converter from the rest of the string, making this insensitive to changes in the string current. Hence it is possible to obtain the maximum power from the PV module and allow it to operate at the optimum efficiency. The simulation and experimental results verify that the proposed topology exhibits good performance anyway of inhomogeneous irradiation. On the other hand, the string current diverter circuit does not operate if irradiation is homogeneous. So, in this last condition, the topology efficiency is improved.

This paper presents a novel GA (genetic algorithms) based method to carry out the maximum power point tracking (MPPT) based on the cell model. For that it is necessary to measure the open circuit voltage (Voc) and short circuit current (Isc), then the proposed algorithm gives directly and rapidly the optimal voltage (Vop) so the duty cycle is adjusted. The simulation results are obtained by changing Isc and Voc values. The proposed technique permits to verify the linearity between Vop and Voc and between optimal current (Iop) and Isc. The results are compared with the conventional Perturb and Observe (P&O) and Incremental Conductance (IncCond) algorithms.

This paper presents an analysis and a modeling approach to obtain a small-signal model design and the digital implementation of a linear control technique for single-phase boost power factor correctors (PFC). Such converters present nonlinear characteristics and approximations of them are used to drive the models. The proposed circuit significantly improves the dynamic response of the converter to load steps without the need of a high crossover frequency of the voltage loop by adding low-pass filter. So, a low distortion of the input current is easily achieved. This controller has been verified via simulation in Simulink using a continuous time plant model and a discrete time controller. Real-time implementation is performed on an experimental test bench utilizing a rapid prototyping tool. The controller is experimentally confirmed for steady-state performance and transient response.

In this paper, an improved maximum power point (MPP) tracking (MPPT) with better performance based on voltage-oriented control (VOC) is proposed to solve a fast-changing irradiation problem. In VOC, a cascaded control structure with an outer dc link voltage control loop and an inner current control loop is used. The currents are controlled in a synchronous orthogonal d,q frame using a decoupled feedback control. The reference current of proportional-integral (PI) d-axis controller is extracted from the dc-side voltage regulator by applying the energy-balancing control. Furthermore, in order to achieve a unity power factor, the q-axis reference is set to zero. The MPPT controller is applied to the reference of the outer loop control dc voltage photovoltaic (PV). Without PV array power measurement, the proposed MPPT identifies the correct direction of the MPP by processing the d-axis current reflecting the power grid side and the signal error of the PI outer loop designed to only represent the change in power due to the changing atmospheric conditions. The robust tracking capability under rapidly increasing and decreasing irradiance is verified experimentally with a PV array emulator. Simulations and experimental results demonstrate that the proposed method provides effective, fast, and perfect tracking.

This paper presents a performance analysis of transformless single switch quadratic boost converter for two stages photovoltaic grid connected system. The aim of this structure is to obtain at the same time high conversion ratio and excellent efficiency for a wide source voltage range by using quadratic boost converter. The DC voltage conversion ratios of these converters have a quadratic dependence on duty cycle providing thus a large step-up and offering the possibility of higher switching frequency. This research focuses on the development of this new structure with only one single active switch and their theoretical analysis with relevant equations and operating principle. Moreover, a complete simulation and experimental results with maximum power point tracking (MPPT) function are presented to confirm their interest in photovoltaic applications.

In this paper, we estimate renewable energy from wind and solar for different sites. Two methods are applied in case of wind energy: Weibull distribution and direct integration methodology. In additional, influence of the data sampling interval is studied. Results show that the computational method based on the integration of the power is more accurate. Also, it is shown that the hourly time resolution provides satisfactory accuracy in wind and solar resource estimation, in comparison with one minute's resolution. Results allow better design for hybrid systems (wind and photovoltaic energy). Moreover, Data acquisitions are minimized. A shorter time of treatment and less expensive measurement equipments are required.

The utilization of voltage source inverter (VSI) connected to the grid in photovoltaic systems requires application of control systems capable of regulating the active and reactive output current, ensuring high power quality levels and achieving relative immunity to grid perturbations. In the single phase system the LCL filter is adopted, which can reduce the required filtered inductance and the cost. However, the performance of the power flow depends largely on the quality of the applied current control strategy. In this paper an optimized control scheme for the VSI is proposed to improve the current regulation capability based on the digital deadbeat control using a minimum number of sensors. Detailed discussions about the design of the controller are given out. Finally simulation and experimental results verify the correctness of the analysis and availability of the control strategy.

This paper presents a new control method entitled direct power control (DPC) for shunt active power filter (APF), which is applied to eliminate line current harmonics and compensate reactive power. Its main goal is to rebuild active and reactive source powers to be compared to references values using hysteresis control. The active power reference is issue of DC-side of inverter and reactive power reference is set to zero for unity power factor. The outputs of hysteresis controllers associated with a switching table, control the instantaneous active and reactive power by selecting the optimum switching state of the voltage source inverter (VSI). A theoretical analysis with a complete simulation of the system and experimental results are presented to prove the excellent performance of the proposed technique.

This paper is concerned with the design and implementation of current control of three-phase PWM rectifier based on predictive control strategy. The proposed predictive current control technique operates with constant switching frequency, using space-vector modulation (SVM). The main goal of the designed current control scheme is to maintain the dc-bus voltage at the required level and to achieve the unity power factor (UPF) operation of the converter. For this purpose, two predictive current control algorithms, in the sense of deadbeat control, are developed for direct controlling input current vector of the converter in the stationary α – β and rotating d – q reference frame, respectively. For both predictive current control algorithms, at the beginning of each switching period, the required rectifier average voltage vector allowing the cancellation of both tracking errors of current vector components at the end of the switching period, is computed and applied during a predefined switching period by means of SVM. The main advantages of the proposed predictive current control are that no need to use hysteresis comparators or PI controllers in current control loops, and constant switching frequency. Finally, the developed predictive current control algorithms were tested both in simulations and experimentally, and illustrative results are presented here. Results have proven excellent performance in steady and transient states, and verify the validity of the proposed predictive current control which is compared to other control strategies.

This paper proposes direct power control (DPC) for three-phase PWM rectifiers using a new switching table, without line voltage sensors. The instantaneous active and reactive powers, directly controlled by selecting the optimum state of the converter, are used as the PWM control variables instead of the phase line currents being used. The main goal of the control system is to maintain the dc-bus voltage at the required level, while input currents drawn from the power supply should be sinusoidal and in phase with respective phase voltages to satisfy the unity power factor (UPF) operation. Conventional PI and a designed fuzzy logic-based controller, in the dc-bus voltage control loop, have been used to provide active power command. A dSPACE based experimental system was developed to verify the validity of the proposed DPC. The steady-state, and dynamic results illustrating the operation and performance of the proposed control scheme are presented. As a result, it was confirmed that the novel DPC is much better than the classical one. Line currents very close to sinusoidal waveforms (THD < 2%) and good regulation of dc-bus voltage are achieved using PI or fuzzy controller. Moreover, fuzzy logic controller gives excellent performance in transient state, a good rejection of impact load disturbance, and a good robustness.

This paper presents a new control method entitled direct power control (DPC) for shunt active power filtering (5th, 7th, 11th, …) (SAPF), which is applied to eliminate line current harmonics and compensate reactive power. Its main goal is to rebuild active and reactive powers to be compared to references values using hysteresis control. The outputs of hysteresis controllers associated with a switching table, control the instantaneous active and reactive power by selecting the optimum switching state of the voltage source inverter (VSI). A theoretical analysis with a complete simulation of the system and experimental results are presented to prove the excellent performance of the proposed control technique.

In this paper, a new switching table is presented for direct power control (DPC) of three-phase PWM rectifiers. The proposed switching table is synthesized by analyzing the instantaneous active and reactive power correction. For this reason, and based on the sign and magnitude of the change in instantaneous active and reactive power, the best converter switching state allowing smooth control of active and reactive power simultaneously during each sector is selected. The dc-bus voltage is maintained at the required level by controlling active power to be constant and equal to its reference value. The unity power factor (UPF) operation of the converter is achieved by maintaining the reactive power zero during all sectors. Simulation and experimental results have proven that the proposed DPC is much better than the classical one and verify the validity and performance of the presented DPC.

Several schemes and control techniques have been proposed in active power filtering these last years, often assuming that all the components are well sized, or at least they do not affect the control algorithm performance. The first step in designing an active filter is to select suitable values. This allows to reduce costs and avoids a lot of control problems. This paper deals with design, simulation and experimentation of a Shunt Active Power Filter (SAPF) to improve power quality. After recalling and comparing some methods already published in this area, a design procedure of a 20 KVA SAPF is presented. Afterwards, the study of the impact of parameters on signals quality is discussed. In order to control capacitor DC voltage and mains current with fixed carrier PWM in d-q frame, simulated and experimental results are provided to prove parameters choice and demonstrate the effectiveness of the proposed approach.

A three-phase shunt active power filter is generally used to compensate current harmonics demanded by non-linear loads, so that the source current remains quasi-sinusoidal and therefore the level of harmonic pollution in an electrical network is decreased. Most of the existing classical control methods for a three-phase shunt active filter usually lead to a non-linear control problem due to the non-linearity of the Park transformation. In a previous work, a compensated three-phase power distribution system has been successfully represented by a dasiasimplepsila linear state space model. Its state matrix contains a fundamental parameter used to extract the desired frequency component of any electrical signal. The linearity of the model enables one to use the control theory in a linear context in order to build a control system. In this paper, a three-phase shunt active filter is driven using output feedback control with Hinfin performance in order to reduce the number of measured outputs. The control method is mainly based on Linear Matrix Inequalities which are considered as a powerful tool for numerically solving control problems. The ability of the synthesized controller to provide an acceptable harmonic compensation is investigated through both numerical simulations on a prototype built in Simulink and experimental results.

In this paper, direct power control (DPC) of three-phase PWM rectifiers based on fuzzy logic controller is presented, without line voltage sensors. The instantaneous active and reactive powers, directly controlled by selecting the optimum state of the converter, are used as the PWM control variables instead of the phase line currents being used. The proposed fuzzy logic controller presents the advantage that is based on linguistic description and does not require a mathematical model of the system. The controller ensures a good regulation of the output voltage, and guarantees the power factor close to one. The simulation and experimental results show that the designed fuzzy controller has a good dynamic behavior, a good rejection of impact load disturbance, and is very robust.

This paper deals with the synthesis of a static output feedback control law with Hinfin performance for a three- phase shunt active power filter used to compensate current harmonics so that the network current remains quasi-sinusoidal and therefore electric power quality is improved. In a previous work, this system has been successfully driven by a state feedback controller. However, the main goal is to reduce the number of measured outputs. The objective of this work is the design of an output feedback Hinfin controller by non-iterative means. This can be easily achieved by imposing a block diagonal structure on the Lyapunov matrix in order to transform bilinear matrix inequalities into a convex optimization problem. The validity of the synthesized static gain is investigated through numerical simulations.

In this paper, the validity of a linear complex-valued model proposed for describing a three-phase shunt active filter used to improve the quality of the electrical energy, and the ability of the Hinfin control design tool to provide a robust controller capable of compensating current harmonics demanded by switching loads are confirmed through numerical simulations. At a first time, ideal ones are performed by considering the pulse-width modulated voltage source inverter of the active filter as a simple gain. Then, a prototype of an active filtered three-phase power distribution network is built in Simulink in order to reveal difficulties that may be encountered in a real implementation and how one can overcome them. After taking into consideration the modifications required to avoid these difficulties, experimental results based on a laboratory prototype are provided to verify the effectiveness of the control algorithm.