A review of grid-tied converter topologies used in photovoltaic systems

This study provides review of grid-tied architectures used in photovoltaic power systems, classified by the granularity level at which maximum power point tracking (MPPT) is applied. Grid-tied PV power systems can be divided into two main groups, namely centralized MPPT (CMPPT) and distributed MPPT (DMPPT). The DMPPT systems are further classified according to the levels at which MPPT can be applied, i.e. string, module, submodule, and cell level. Typical topologies for each category are also introduced, explained and analyzed. The classification is intended to help readers understand the latest developments of grid-tied PV power systems and inform research directions

A Reduced Power Switches Count Multilevel Converter-Based Photovoltaic System with Integrated Energy Storage

A multilevel topology for photovoltaic (PV) systems with integrated energy storage (ES) is presented in this article. Both PV and ES power cells are connected in series to form a dc link, which is then connected to an H-bridge to convert the dc voltage to an ac one. The main advantage of the proposed converter compared to the cascaded-H-bridge (CHB) converter, as well as compared to the available multilevel topologies, is that fewer semiconductor devices are needed here. As the output voltage levels increase, more switches are saved, which results in a more efficient, cheaper, and smaller converter. So far, there is still no modulation strategy that is designed particularly for PV-fed multilevel converters with built-in ES. The standard modulations are impractical for such an application since they suffer from deficiencies, such as polluted output signals - thus, requiring larger output filter - and overmodulation. A modified modulation strategy for PV+ES multilevel inverters is, therefore, introduced in this article. The proposal has been simulated and experimentally validated to evaluate its effectiveness, where it has been shown that the proposed topology is not exclusively feasible, but also suffers from less conduction and switching loss, achieving higher efficiency with respect to its counterpart CHB. </p

MPPT oscillations minimization in PV system by controlling non-linear dynamics in SEPIC DC-DC converter

Solar PV power generation has achieved rapid growth in developing countries which has many merits such as absence of noise, longer life, no pollution, less time for installation, and ease of grid interface. A maximum power point tracking circuit (MPPT) consists of DC-DC power electronics converters that are used to improve the energy attainment from solar PV array. This paper presents a detailed analysis to control of chaos, a non-linear dynamic in SEPIC DC-DC converter interfaced solar PV system, to minimize the oscillations near to MPP. In SEPIC DC-DC converter, the input inductor current is continuous and capable of sweeping the whole I-V curve of a PV module from open circuit voltage (Voc) to short circuit current (Isc) operating points. To trace the true maximum power point and to nullify the oscillations near to MPP, the yield output voltage needs to ensure period-1 operation

Literature Survey On Standalone Pumping Station For Agriculture Purpose Using Solar PV

The concept of the project is to utilize the abundant solar energy available, harness it for effective work output. Here we are trying to use solar energy to run the centrifugal pump for lifting the water from the well. This can be utilized for different purpose like irrigation for agriculture & nurseries, etc. Here we are collecting all information about which kind of constraints required for planning of standalone pumping station for agriculture purpose. In this paper we are finding out which are power electronics applications in renewable energy sources. This document will help all researcher to start work on Solar PV’s, irrigation using renewable energy , as well as for finding the power electronics application in renewable energy sources. DOI: 10.17762/ijritcc2321-8169.15036

Discrete Model-Predictive-Control-Based Maximum Power Point Tracking for PV Systems:Overview and Evaluation

The main objective of this work is to provide an overview and evaluation of discrete model-predictive control (MPC)-based maximum power point tracking (MPPT) for photovoltaic systems. A large number of MPC-based MPPT methods have been recently introduced in the literature with very promising performance; however, an in-depth investigation and comparison of these methods has not been carried out yet. Therefore, this paper has set out to provide an in-depth analysis and evaluation of MPC-based MPPT methods applied to various common power converter topologies. The performance of MPC-based MPPT is directly linked with the converter topology, and it is also affected by the accurate determination of the converter parameters; sensitivity to converter parameter variations is also investigated. The static and dynamic performance of the trackers is assessed according to the EN 50530 standard, using detailed simulation models, and validated by experimental tests. The analysis in this work aims to present useful insight for practicing engineers and academic researchers when selecting the maximum power point tracker for their application.</p

Investigation of Photovoltaic Grid System under Non-Uniform Irradiance Conditions

Photovoltaic (PV) systems have recently been recognized as a leading way in the production of renewable electricity. Due to the unpredictable changes in environmental patterns, the amount of solar irradiation and cell operating temperature affect the power generated by the PV system. This paper, therefore, discusses the grid-integrated PV system to extract maximum power from the PV array to supply load requirements and the supply surplus power to the AC grid. The primary design is to have maximum power point tracking (MPPT) of the non-uniformly irradiated PV array, conversion efficiency maximization, and grid synchronization. This paper investigates various MPPT control algorithms using incremental conductance method, which effectively increased the performance and reduced error, hence helped to extract solar array’s power more efficiently. Additionally, other issues of PV grid-connected system such as network stability, power quality, and grid synchronization functions were implemented. The control of the voltage source converter is designed in such a way that PV power generated is synchronous to the grid. This paper also includes a comparative analysis of two MPPT techniques such as incremental conductance (INC) and perturb-and-observe (P&O). Extensive simulation of various controllers has been conducted to achieve enhanced efficient power extraction, grid synchronization and minimal performance loss due to dynamic tracking errors, particularly under fast-changing irradiation in Matlab/Simulink. The overall results favour INC algorithm and meet the required standards

Maximum power point tracking implementation by Dspace controller integrated through Z-Source inverter using particle swarm optimization technique for photovoltaic applications

Maximum Power Point Tracking (MPPT) technique is used to extract maximum power from the photovoltaic system. This paper involves working on an enhanced Particle Swarm Optimization (PSO) based MPPT method for the photovoltaic (PV) system integrated through Z-Source inverter. The main benefit of the proposed method is the diminishing of the steady-state oscillation when the maximum power point (MPP) is located. Additionally, during an extreme environmental condition, such as partial shading and large fluctuations of irradiance and temperature, the proposed method has the capability to track the MPP. This algorithm is implemented in dspace 1104 controller. MATLAB simulations are carried out under varying irradiance and temperature conditions to evaluate its effectiveness. Its performance is compared with a conventional method like Perturb and observe (P&amp;O) method

ANALYSIS AND SIMULATION OF PHOTOVOLTAIC SYSTEMS INCORPORATING BATTERY ENERGY STORAGE

Solar energy is an abundant renewable source, which is expected to play an increasing role in the grid\u27s future infrastructure for distributed generation. The research described in the thesis focuses on the analysis of integrating multi-megawatt photovoltaics (PV) systems with battery energy storage into the existing grid and on the theory supporting the electrical operation of components and systems. The PV system is divided into several sections, each having its own DC-DC converter for maximum power point tracking and a two-level grid connected inverter with different control strategies. The functions of the battery are explored by connecting it to the system in order to prevent possible voltage fluctuations and as a buffer storage in order to eliminate the power mismatch between PV array generation and load demand. Computer models of the system are developed and implemented using the PSCADTM/EMTDCTM software

Application of Modular Multilevel Converter for Interfacing Grid-Connected Photovoltaic Conversion Plants

This thesis investigates the applicability of the Modular Multilevel Converter (MMC) for interfacing grid connected photovoltaic conversion plants. A detailed three-phase 9-level simulation model is implemented in Simulink. Two control objectives are identified as distinctive for the MMC: Capacitor voltage balancing and suppression of circulating currents, both of which are included in the model. The MMC is controlled by a modified Level-Shifted Pulse Width Modulator. The model is verified by comparing its behaviour to that of the mathematical model of the MMC. The nature of photovoltaic power generation makes Maximum Power Point Tracking (MPPT) important to maximize the power yield from a pv module. All the pv modules connected to the same MPP tracker should have the same operating conditions. For largescale pv farms this is only feasible with multiple MPP trackers. Two pv inverter configurations are identified as suitable for grid connection of large-scale pv farms using the MMC: Cascaded dc-dc converters and multi-string inverter. With the former, the three phase legs share the same dc link voltage. With a multi-string topology, each submodule is fed by a separate pv string. Thus, power imbalance between the submodules are inevitable. This can be remedied by power imbalance compensation. For grid side control Synchronous Reference Frame Control (SRFC) and Model Predictive Control (MPC) is considered. MPC has the advantage of handling non-linear constraints on both states and variables. In addition it is reported to perform better than SRFC during dynamic conditions, which are likely to occur with power generation from pv modules. SRFC is implemented in the MMC simulation model. It synchronizes with the grid and delivers power at unity power factor