Hadeed Ahmed Sher

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.

Comparative analysis of maximum power point tracking techniques for PV applications

In the wake of the growing energy requirements the use of Photovoltaic (PV) systems is increasing around the world. PV systems are not linear in nature therefore special methods are used to extract the maximum available power. The non linear characteristic of the IV curve of PV module has a unique single point of maximum power. In order to operate at that power point power electronic converters are used. These power electronic converters are controlled with the help of algorithms known as Maximum Power Point Tracking (MPPT) techniques. Various unique algorithms are found in the literature with their specific advantages and drawbacks. Keeping in view that an efficient tracking of Maximum Power Point (MPP) can increase the usability of a PV system by many folds, in this paper we present a comparison of four widely used MPPT techniques i.e 1) Fractional Short Circuit Current (FSCC), 2) Fractional Open Circuit Voltage (FOCV), 3) Perturb & Observe (P&O) and 4) Incremental Conductance (IC) MPPTs are discussed. The comparative analysis provides the pros and cons of each MPPT with a resistive load. The analysis is about the time required for each algorithm to track the maximum power and the system efficiencies.

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]

Power storage options for hybrid electric vehicles—A survey

Hybrid electric vehicles (HEVs) are the future transportation structure as they provide better fuel economy. Energy storage devices are therefore required for the HEVs. The problem for deciding the optimum combination of power storage is still unresolved. The power storage options in this regard must have a feasible weight/energy ratio for better performance. This survey is about the comparison of different power storage options for HEV including the batteries, super-capacitors, and flywheel. The equivalent circuit for the potential storage devices given will help in establishing the optimum choice of energy storage.

Performance of inverter fed induction motor under open circuit DC link capacitor

Induction motors are widely used in industry due to their promising performance. Majority of induction motors are used in inverter based drives in industrial setups. Efforts are being put in the fault analysis of induction motors. Most of the analysis available in literature discusses the failure of electronic components like power MOSFET, optocoupler failure, failure of pulse generation card etc. This research work is a continuation of fault analysis studies of an inverter fed induction motor drives under different fault conditions. This paper presents the effect of dc link capacitor open circuit on the performance of inverter fed induction motor. Effect on stator current, inverter output, the speed and torque of the motor are particularly studied in this paper. The faults in the DC link is generally not that common but there is always a chance of capacitor failure. The simulated results presented in this paper can augment the efforts for the reliability enhancement of induction motor drives.

A two stage hybrid maximum power point tracking technique for photovoltaic applications

Photovoltaic (PV) systems are widely used now a days for coping the growing energy demands all across the globe. The non-linear behavior of the characteristic curve of solar module requires special arrangement to harvest maximum amount of power. To track the Maximum Power Point (MPP) across the non linear IV curve of PV module, techniques are used in addition to the power electronic circuit and are called Maximum Power Point Tacking (MPPT). Various methods of MPPT exists in literature, each bearing its own pros and cons. In this paper we presents a novel technique to improve the performance of conventional Perturb and Observe (P&O) algorithm of MPPT. Our technique removes the drawbacks of P&O under rapidly changing environmental conditions. It also executes less power oscillations under steady state conditions. The algorithm is a hybrid of Fractional Short Circuit current (FSCC) and P&O algorithms. The system takes the advantage of rapid tracking near to MPP using the FSCC and then carry on to track the exact MPP using the traditional P&O technique. The technique is verified through simulation using Matlab/SIMULINK.

Performance enhancement of a flyback photovoltaic inverter using hybrid maximum power point tracking

In this paper a grid connected photovoltaic (PV) flyback inverter operating in discontinuous conduction mode (DCM) is used to test a hybrid maximum power point tracking (MPPT) method. Moreover, the design procedure of a flyback inverter is also presented as part of this paper. The proposed hybrid MPPT method is a combination of fractional short circuit current(FSCC) and hill climbing (Perturb and Observe P&O) method. The proposed MPPT use current limits to detect abrupt weather changes and hence swiftly tracks the maximum power point (MPP) under dynamic weather conditions. This MPPT method is tested using co-simulation between PSIM and Simulink, where the control algorithm is implemented in Simulink and the grid connected inverter is executed in PSIM. The results shows enhanced energy harvesting compared with P&O when subjected to uniform and dynamic weather conditions.

Optimization of the perturb and observe maximum power point tracker for a distributed photovoltaic system

With everyday passing, power generation from photovoltaic (PV) systems are getting increased around the globe. One of the drawbacks of PV systems is that they exhibit non-linear I-V curves with respect to atmospheric conditions. Therefore, maximum power point tracker (MPPT) technique is installed in every PV system. One of the most popular technique is perturb & observe (P&O) but this technique has some shortcomings. In this paper, MPPT technique is proposed which will optimize the P&O with respect to distributed PV (DPV) plant. Such that the deficiencies of P&O are removed. The proposed technique is designed for DPV and is working in two modes. In mode-1, decision making of the proposed technique revolves around the mutual co-ordination between two modules/arrays. During this mode, one array will behave as leader (L) while other array as follower (F). In mode-2, proposed technique utilizes the individual P&O for both arrays. Model is the superior performance mode in which efficiency of the proposed technique is better than P&O. While, in mode-2 both techniques have same efficiency. Finally, the proposed technique is modeled in Matlab/Simulink. The proposed technique is tested under various weather conditions and superior performance of the proposed technique is proved through simulation results.

A hybrid maximum power point tracking method for photovoltaic applications with reduced offline measurements

In this paper, an improved hybrid maximum power point tracking (MPPT) method is presented. The proposed hybrid method is a hybrid version of fractional short circuit current (FSCC) and perturb and observe (P&O) MPPT method. The proposed improvement in this paper enables the hybrid MPPT method to detect the dynamic weather conditions more precisely than the previously developed methods. Moreover, under slowly varying weather condition the algorithm tracks the maximum power point (MPP) using the P&O MPPT. Thus, the proposed method experiences fewer offline (short circuit current) measurements and hence, better energy harnessing. The proposed MPPT method is validated using a buck-boost converter designed at a rated power of 125W and simulated using Simulink.

A new irradiance sensorless hybrid MPPT technique for photovoltaic power plants

A hybrid Maximum Power Point Tracking (MPPT) method without using an irradiance sensor is proposed in this paper. The hybrid MPPT method is a combination of conventional Perturb and Observe (P&O) and Fractional Short Circuit Current (FSCC) MPPT technique. The proposed hybrid MPPT decides intelligently about the initial operating point of P&O by using the FSCC MPPT method. This method requires no sensor for irradiation measurement because it detects intelligently about the change in irradiance. Therefore, under dynamic weather conditions the decision about measuring the initial operating point of P&O is intelligent. After finding the initial operating point the system shifts to the conventional P&O method and starts to perturb with a small perturbation size. The use of small perturbation steps enables the system to work with less power oscillations around the Maximum Power Point (MPP), while the use of FSCC helps in rapid tracking of MPP especially under the varying environmental conditions. Thus, the proposed method is fast in tracking the MPP with less power oscillations and hence better performance in terms of energy harvesting when compared with the conventional P&O technique. Impedance matching between solar panel and load is achieved using a DC-DC boost converter and the proposed method is simulated in MATLAB/SIMULINK environment. The system is simulated against the steady and dynamic weather conditions. The results shows that under steady weather condition the proposed method harvests 5% extra energy as compared with the conventional P&O. For dynamic weather conditions the proposed method harness an additional 3.5% energy when compared with the P&O method, which makes it very promising.