Abdullah M. Noman

A New Sensorless Hybrid MPPT Algorithm Based on Fractional Short-Circuit Current Measurement and P&O MPPT

This paper presents a new maximum power point tracking (MPPT) method for photovoltaic (PV) systems. The proposed method improves the working of the conventional perturb and observe (P&O) method in changing environmental conditions by using the fractional short-circuit current (FSCC) method. It takes the initial operating point of a PV system by using the short-circuit current method and later shifts to the conventional P&O technique. The advantage of having this two-stage algorithm is rapid tracking under changing environmental conditions. In addition, this scheme offers low-power oscillations around MPP and, therefore, more power harvesting compared with the common P&O method. The proposed MPPT decides intelligently about the moment of measuring short-circuit current and is, therefore, an irradiance sensorless scheme. The proposed method is validated with computer software simulation followed by a dSPACE DS1104-based experimental setup. A buck-boost dc-dc converter is used for simulation and experimental confirmation. Furthermore, the reliability of the proposed method is also calculated. The results show that the proposed MPPT technique works satisfactorily under given environmental scenarios.

A fuzzy logic control method for MPPT of PV systems

Maximum power point trackers are so important in photovoltaic systems to increase their efficiency. Many methods have been proposed to achieve the maximum power that the PV modules are capable of producing under different weather conditions. This paper proposed an intelligent method for maximum power point tracking based on fuzzy logic controller. The system consists of a photovoltaic solar module connected to a DC-DC Buck-boost converter. The system has been experienced under disturbance in the photovoltaic temperature and irradiation level. The simulation results show that the proposed maximum power tracker could track the maximum power accurately and successfully in all condition tested. Comparison of different performance parameters such as: tracking efficiency and response time of the system shows that the proposed method gives higher efficiency and better performance than the conventional perturbation and observation method.

An intelligent control strategy of fractional short circuit current maximum power point tracking technique for photovoltaic applications

This paper presents an improved Fractional Short Circuit Current (FSCC) Maximum Power Point Tracking (MPPT) technique in which an additional control loop is used to find the proper moment to measure the SCC. The target is to reduce the power losses in MPPT process that occur as a result of intermittent time based short circuit current measurements. The proposed modification enables the conventional FSCC MPPT to decide intelligently about the measurement of SCC thus reduces the number of times the photovoltaic (PV) module is isolated from the load. Although number of algorithms for tracking MPPT has been reported, the proposed method suits well for low cost PV applications. A Matlab/Simulink based model is employed to test the functional abilities of the proposed method. The comparison of the proposed method and conventional time based FSCC method is also presented in the simulation analysis. Finally, a 130W prototype based on the dSPACE DS1104 controller and experimental results are presented to verify the effectiveness of the proposed method. The technique is verified under uniform shading conditions. The results show satisfactory performance against test conditions. V C 2015 AIP Publishing LLC .[ http://dx.doi.org/10.1063/1.4906982]

DSPACE Real-Time Implementation of MPPT-Based FLC Method

Maximum power point trackers are so important in photovoltaic systems to improve their overall efficiency. This paper presents a photovoltaic system with maximum power point tracking facility. An intelligent fuzzy logic controller method is proposed in this paper to achieve the maximum power point tracking of PV modules. The system consists of a photovoltaic solar module connected to a DC-DC buck-boost converter. The system is modeled using MATLAB/SIMULINK. The system has been experienced under disturbance in the photovoltaic temperature and irradiation levels. The simulation results show that the proposed maximum power tracker tracks the maximum power accurately and successfully in all conditions tested. The MPPT system is then experimentally implemented. DSPACE is used in the implementation of the MPPT hardware setup for real-time control. Data acquisition and control system is implemented using dSPACE 1104 software and digital signal processor card. The simulation and practical results show that the proposed system tracked the maximum power accurately and successfully under all atmospheric conditions.

Simulation and Practical Implementation of ANFIS-Based MPPT Method for PV Applications Using Isolated Ćuk Converter

Photovoltaic (PV) module behavior is not linear in nature with respect to environmental conditions and hence exhibits nonlinear PV curves. There is only a single point in the nonlinear PV curve at which the power is maximum. Therefore, special methods have been proposed to track this maximum power point (MPP). This paper proposed an intelligent method for MPP tracking (MPPT) based on adaptive neuro-fuzzy inference system (ANFIS) controller. The proposed system consists of a PV module connected to a DC-DC isolated Cuk converter and load. A MATLAB/SIMULINK-based MPPT model is built to test the behavior of the proposed method. The proposed method is tested under different weather scenarios. Simulation results exhibit the successful tracking of the proposed method under all ambient conditions. Comparison of the tracking behavior of the proposed method with the perturb and observe method is also presented in the simulation results. In addition, a 220 W prototype with the help of dSPACE 1104 data acquisition system is built and tested under practical weather conditions on a sunny day as well as on a cloudy day. Experimental results are presented to verify the effectiveness of the proposed method. These results exhibit satisfactory performance under different practical weather conditions.

Simulation and dSPACE hardware implementation of the MPPT techniques using buck boost converter

Maximum power point trackers are so important in photovoltaic systems to increase their efficiency. This paper presents a photovoltaic system with maximum power point tracking facility. The system consists of a photovoltaic solar module connected to a DC-DC buck boost converter and load. The system is modeled using MATLAB/SIMULINK. Maximum power point tracking is achieved using perturbation and observation method and incremental conductance method. The MPPT system is simulated and experimentally implemented. The implementation of the MPPT hardware setup is done using dSPACE real time control. Data acquisition and the control system is implemented using dSPACE 1104. The simulation and the practical results show that the proposed system tracked the maximum power accurately and successfully under different conditions tested.

Analytical Approach to Circulating Current Mitigation in Hexagram Converter-Based Grid-Connected Photovoltaic Systems Using Multiwinding Coupled Inductors

The hexagram multilevel converter (HMC) is composed of six conventional two-level voltage source converters (VSCs), where each VSC module is connected to a string of PV arrays. The VSC modules are connected through inductors, which are essential to minimize the circulating current. Selecting inductors with suitable inductance is no simple process, where the inductance value should be large to minimize the circulating current as well as small to reduce an extra voltage drop. This paper analyzes the utilization of a multiwinding (e.g., two, three, and six windings) coupled inductor to interconnect the six VSC modules instead of six single inductors, to minimize the circulating current inside the HMC. Then, a theoretical relationship between the total impedance to the circulating current, the number of coupled inductor windings, and the magnetizing inductance is derived. Owing to the coupled inductors, the impedance on the circulating current path is a multiple of six times the magnetizing inductance, whereas the terminal voltage is slightly affected by the leakage inductance. The HMC is controlled to work under variable solar radiation, providing active power to the grid. Additional functions such as DSTATCOM, during daytime, are also demonstrated. The controller performance is found to be satisfactory for both active and reactive power supplies.

Cascaded multilevel inverter topology with high frequency galvanic isolation for grid connected PV system

Cascaded H-bridge MLI is an attractive solution for grid connected PV system. DC sources can be replaced by PV module/panel and due to the separated DC link feature and the voltage control becomes possible. Thus, individual maximum power point tracking (MPPT) control in each PV module can be achieved, and the total power extracted from PV panels will be maximized and hence the efficiency improves In this paper, a single phase cascaded H-bridge multilevel inverter topology is proposed for grid connected PV system. The proposed multilevel inverter configuration consists of PV modules, each is connected to one DC-DC flyback converter to achieve best MPPT as well as used for galvanic isolation in order to improve system efficiency. The DC-DC flyback converters are cascaded to amplify the DC voltage in order to be used for medium and high voltage systems and the result output voltage is used as an input to one H-bridge inverter. H-bridge inverters are then cascaded to generate multilevel output voltage. On the other hand, the operation of H-bridge MOSFETS is that the two upper MOSFETS are operating at line frequency while the two lower MOSFETS are operating at switching frequency. This will reduce switching losses and hence extra improving system efficiency can be achieved. Finally, the proposed configuration improves the system efficiency due to the multilevel inverter, obtain the best MPPT, achieve isolation at high frequency, eliminating the leakage current due to parasitic capacitances between PV module and ground, decupling the second harmonic voltage ripple and reducing the switching losses in the inverters.

An intelligent FLC method for tracking the maximum power of photovoltaic systems

Maximum power point trackers are so important in photovoltaic systems since they become an efficient solution to improve the overall system efficiency. This paper presents a photovoltaic system with maximum power point tracking facility. An intelligent fuzzy logic controller method is proposed in this paper to achieve the maximum power point tracking of PV modules. The system consists of a photovoltaic solar module connected to a DC-DC Buck-boost converter. The proposed input variables are the change in the voltage and the change in the power of the PV module which the output variable is the reference voltage which is then accumulated every certain time. The system is modeled using MATLAB/SIMULINK. The system has been experienced under disturbance in the photovoltaic temperature and irradiation levels. The simulation results show that the proposed maximum power tracker tracks the maximum power accurately and successfully in all condition tested. Comparison of different performance parameters such as: tracking efficiency and response time of the system shows that the proposed method gives higher efficiency and better performance than the conventional perturbation and observation method.