A modified particle swarm optimization based maximum power point tracking for photovoltaic converter system

This thesis presents a modified Particle Swarm Optimization based Maximum Power Point Tracking for Photovoltaic Converter system. All over the world, many governments are striving to exploit the vast potential of renewable energy to meet the growing energy requirements mainly when the price of oil is high. Maximum Power Point Tracking (MPPT) is a method that ensures power generated in Photovoltaic (PV) systems is optimized under various conditions. Due to partial shading or change in irradiance and temperature conditions in PV, the power-voltage characteristics exhibit multiple local peaks; one such phenomenon is the global peak. These conditions make it very challenging for MPPT to locate the global maximum power point. Many MPPT algorithms have been proposed for this purpose. In this thesis, a modified Particle Swarm Optimisation (PSO)-based MPPT method for PV systems is proposed. Unlike the conventional PSO-based MPPT methods, the proposed method accelerates convergence of the PSO algorithm by consistently decreasing weighting factor, cognitive and social parameters thus reducing the steps of iterations and improved the tracking response time. The advantage of the proposed method is that it requires fewer search steps (converges to the desired solution in a reasonable time) compared to other MPPT methods. It requires only the idea of series cells; thus, it is system independent. The control scheme was first created in MATLAB/Simulink and compared with other MPPT methods and then validated using hardware implementation. The TMS320F28335 eZDSP board was used for implementing the developed control algorithm. The results show good performance in terms of speed of convergence and also guaranteed convergence to global MPP with faster time response compared to the other MPPT methods under typical conditions (partial shading, change in irradiance and temperature, load profile). This demonstrates the effectiveness of the proposed method

A Review on Favourable Maximum Power Point Tracking Systems in Solar Energy Application

This paper reviews different types of maximum power point tracking (MPPT) techniques for solar photovoltaic (PV) application. Since the PV output power is known affected by sun radiation and temperature, it is necessary to search for an effective method for extracting maximum amount of power from PV cell/modules. In this study, a total of seven control algorithms were selected, comprising the most popular methods among the established techniques. A comparison in terms of convergence speed, complexity, as well as the basic concept of each method had been carried out for future reference. Based on the accessible simulation results, modified Perturb and Observe (P&O) method had shown its effectiveness for obtaining actual maximum power point while solving major drawbacks of the conventional P&O. This paper also discusses typical solar MPPT system, including the pros and cons of each part of the system

CONTROLLERS AND METHODS FOR DIFFERENT ELECTRICAL MEASUREMENTS IN SYNCHRONIZATION OF RENEWABLE ENERGY SOURCES FOR GRID CONNECTIVITY: A REVIEW

In this paper, different controllers used in synchronization of renewable energy sources are studied. A study regarding the use of artificial intelligence in synchronization of grid connected power converters, efficient method for phase angle detection, frequency variation detection and good performance during voltage depression etc  carried out here. Importance of hybrid controllers over conventional controllers is also presented. Possibility of  Z source T type inverter as an alternate solution to DC-DC converter is explored based on existing works

VHDL Based Maximum Power Point Tracking of Photovoltaic Using Fuzzy Logic Control

It is important to have an efficient maximum power point tracking (MPPT) technique to increase the photovoltaic (PV) generation system output efficiency. This paper presents a design of MPPT techniques for PV module to increase its efficiency. Perturb and Observe method (P&O), incremental conductance method (IC), and Fuzzy logic controller (FLC) techniques are designed to be used for MPPT. Also FLC is built using MATLAB/ SIMULINK and compared with the FLC toolbox existed in the MATLAB library. FLC does not need knowledge of the exact model of the system so it is easy to implement. A comparison between different techniques shows the effectiveness of the fuzzy logic controller techniques.  Finally, the proposed FLC is built in very high speed integrated circuit description language (VHDL). The simulation results obtained with ISE Design Suite 14.6 software show a satisfactory performance with a good agreement compared to obtained values from MATLAB/SIMULINK. The good tracking efficiency and rapid response to environmental parameters changes are adopted by the simulation results

Comparison between unipolar and bipolar single phase grid-connected inverters for PV applications

An inverter is essential for the interfacing of photovoltaic panels with the AC network. There are many possible inverter topologies and inverter switching schemes and each one will have its own relative advantages and disadvantages. Efficiency and output current distortion are two important factors governing the choice of inverter system. In this paper, it is argued that current controlled inverters offer significant advantages from the point of view of minimisation of current distortion. Two inverter switching strategies are explored in detail. These are the unipolar current controlled inverter and the bipolar current controlled inverter. With respect to low frequency distortion, previously published works provide theoretical arguments in favour of bipolar switching. On the other hand it has also been argued that the unipolar switched inverter offers reduced switching losses and generates less EMI. On efficiency grounds, it appears that the unipolar switched inverter has an advantage. However, experimental results presented in this paper show that the level of low frequency current distortion in the unipolar switched inverter is such that it can only comply with Australian Standard 4777.2 above a minimum output current. On the other hand it is shown that at the same current levels bipolar switching results in reduced low frequency harmonics

Comparison between unipolar and bipolar single phase grid-connected inverters for PV applications

An inverter is essential for the interfacing of photovoltaic panels with the AC network. There are many possible inverter topologies and inverter switching schemes and each one will have its own relative advantages and disadvantages. Efficiency and output current distortion are two important factors governing the choice of inverter system. In this paper, it is argued that current controlled inverters offer significant advantages from the point of view of minimisation of current distortion. Two inverter switching strategies are explored in detail. These are the unipolar current controlled inverter and the bipolar current controlled inverter. With respect to low frequency distortion, previously published works provide theoretical arguments in favour of bipolar switching. On the other hand it has also been argued that the unipolar switched inverter offers reduced switching losses and generates less EMI. On efficiency grounds, it appears that the unipolar switched inverter has an advantage. However, experimental results presented in this paper show that the level of low frequency current distortion in the unipolar switched inverter is such that it can only comply with Australian Standard 4777.2 above a minimum output current. On the other hand it is shown that at the same current levels bipolar switching results in reduced low frequency harmonics

Modified adaptive perturb and observe maximum power point tracking algorithm for higher effiency in photovoltaic system

Due to the continuous variation in temperature and solar irradiance, P–V characteristics curve of a photovoltaic (PV) system exhibit a non-linear, time-varying Maximum Power Point (MPP). Furthermore, the tracking becomes more complicated when the PV array is partially shaded due to the presence of multiple peaks. This work proposes a Maximum Power Point Tracking (MPPT) algorithm named Modified Adaptive Perturb and Observe (MA-P&O) to address two main limitations of the conventional Perturb and Observe (P&O), namely the steady state oscillation and the divergence from the MPP. At the same time, it locates the global peak during partial shading. The MA-P&O is equipped with an intelligent mechanism to detect the steady state oscillation, and then deploy an adaptive perturbation procedure to reduce it to the minimum. Furthermore, to avoid operating voltage from diverging from its locus, a dynamic boundary condition is imposed. For partial shading, an effective checking mechanism to precisely detect partial shading occurrence is suggested. In addition, an improved set of equation is developed to detect the exact position of local peaks under partial shading. To assess its feasibility, the proposed ideas are simulated using comprehensive PV simulator. For practical validation, the algorithm is implemented in hardware using a buck-boost converter in conjunction with dSPACE DS1104 DSP board. It is demonstrated that under the dynamic irradiance and partial shading test, the MA-P&O ensures the MPPT efficiency is 99.5%. Furthermore, when evaluated against the European Standard EN 50530 test, the MA-P&O records a 98.6% efficiency; this is up to 18% higher than the conventional and other adaptive P&O. Finally, MA-P&O is tested with a tropical daily irradiance and temperature profile. It is found that MA-P&O successfully ensures 99.2%, which is on average 3% higher than the other P&O based algorithms