Grid-tied Photovoltaic System Research Articles

Grid-connected photovoltaic system employing a single-phase T-type cascaded H-bridge inverter

This paper presents the control and application of a single-phase T-type nine-level cascaded H-Bridge (TCHB) multilevel inverter (MLI) topology. This paper focuses on the effectiveness of the TCHB and its control by presenting the inverter operation based on a PI current controller along with a Maximum Power Point Tracking (MPPT) scheme to realize a grid-tied photovoltaic (PV) system and a novel PWM method offering self-balancing at the DC-link capacitors. In order to attain gating signals for power transistors (IGBTs), the TCHB employs a PWM with one triangular carrier signal and eight reference signals. In addition, a mathematical modelling of the PWM method, along with a theoretical explanation of the self-balancing process has also been provided. To prove the effectiveness of the proposed TCHB topological design, it has been comparatively analysed against other fundamental MLI and symmetric CHB topologies. In addition, to corroborate the working of the control and the PV system application, employing TCHB inverter offering nine output voltage levels (±2Vdc, ±2¾Vdc, ±Vdc, ±½Vdc, 0), simulation and hardware results have been presented.

Solar PV system-frequency adaptive disturbance observer control algorithm for compensating harmonics and frequency disturbances

This paper deals with the frequency disturbance observer control algorithm for a grid-tied PV system. The DSTATCOM in the PV system is used to compensate reactive power, load balancing, zero voltage regulation but suffer from frequency fluctuations and harmonic disturbances. A new control method to mitigate frequency disturbance and harmonic reduction has been derived in the proposed method. The frequency adaptive disturbance observer compensates the reactive power thereby balancing the non-linear load in the distribution network providing accurate magnitude estimation of load currents. The proposed system is designed in MATLAB/SIMULINK and proven satisfactory results under varying non-linear load conditions.

Solar photovoltaic system with self-consumption in villa

Grid-tied photovoltaic (PV) installations equipped with net metering devices become significant interests among villa owners in urban areas. Such devices can help to make sure of exporting excess power to the grid as well as to favor the self-consumption ratio. The self-consumption means that the owners directly utilize PV power production. This paper is aimed at simulating the energy and economic performances of a 3.24 kWp grid-tied PV system applied in the villa. The case study is a private villa located at Tibubeneng, Bali Province, Indonesia. The Sunny Design Web simulation tool is used for the PV system assessment. The simulation results reveal that the energy yield of the PV system is 4, 653 kWh/year, out of which 300 kWh/year is feeding to the grid. The self-consumption and self-sufficiency ratios are 93.5 percent and 35.6 percent, respectively. The PV system also delivers a performance ratio of 81.4 percent, the specific energy yield of 1, 436 kWh/kWp, and the payback period of 9.3 years.

Adaptive Damped Circular Current Limit Control for PV Grid-Tied System

This article deals with a double-stage photovoltaic (PV) grid-tied three-phase system with a higher order passive filter. It gives a solution to some real issues, such as load balancing, harmonics compensation, reduced filter size, and power loss, in the distribution network. The improved adaptive damped circular current limit (ADCCL) control -filter-based technique is used for harmonics elimination in this system. The maximum power is tracked from a PV array by an incremental conductance maximum power point tracking algorithm. However, the boost converter is used for extracting the maximum power from the PV array and feeds it to the grid and a proportional–integral controller used to maintain the dc-link voltage of the voltage-source converter. The ADCCL control is used to mitigate the power quality issues with the grid current total harmonic distortion below 5%. A feed-forward term of PV array is added with total active component, which improves the dynamic response. The power quality issues are mitigated and demonstrated by the test results. Moreover, the comparison is made with different controls under various dynamic conditions.

Single-Phase Grid-Tied Transformerless Inverter of Zero Leakage Current for PV System

Multi-level transformerless inverters are widely used in grid-tied PV systems since they characterized by higher efficiency and lower cost. In this context, new topologies, modulation, and control schemes were presented to solve problems of a common-mode voltage and leakage current. This work proposes a transformerless five-level inverter with zero leakage current and ability to reduce the harmonic output content for a grid-tied single-phase PV system. The neutral of the grid links to a common on which the negative and the positive terminals of the DC-link are connected via parasitic capacitors that can eliminate the leakage current. The proposed topology, with its inherent circuit structure, leads to boost the overall efficiency. Simulation and experimental results show almost zero leakage current and a high-quality output when maintaining balanced capacitor voltages on the DC-link input. The experimental results show 1.07% THD and 96.3 % maximum efficiency when injecting a power of 1.1 kW that verify the performance of the proposed inverter with PV sources.

A Zero-Sequence Steerable CBPWM Strategy for Eliminating Zero-Sequence Current of Dual-Inverter Fed Open-End Winding Transformer Based PV Grid-Tied System With Common DC Bus

Aiming at the issue of zero-sequence current (ZSC) in the dual-inverter fed open-end winding transformer (OEWT-DI) based photovoltaic (PV) grid-tied system with common DC bus, a carrier-based pulse width modulation (CBPWM) strategy with steerable zero-sequence is proposed. The modulation wave of the dual-inverter is decomposed into two modulation waves with same amplitude and 120° phase difference, and each of the modulation waves is modified through adding steerable zero-sequence component. The zero-sequence component is regulated by the ZSC control loop based on a quasi-proportional resonant regulator, which is designed to suppress the ZSC caused by the dead-time effect and other nonlinear factors. Meanwhile, the effective modulation range is also analyzed. The proposed strategy is an alternative approach to the conventional zero-sequence steerable phase shift based space vector pulse width modulation (SVPWM) strategy, but has the advantage of easy implementing and low computation cost. With the proposed strategy, both the high-frequency and low-frequency ZSC in the system can be effectively suppressed. Effectiveness of the proposed strategy is validated by experimental results on a 30-kW OEWT-DI experimental platform.

Determination of Optimum Tilt Angle for Rooftop Solar Photovoltaic System Installation for KikuKinderhaus in Kumasi

The population growth in the Ghanaian urban areas and the high energy consumption per unit area compared to the low solar energy capture by Photovoltaic (PV) systems makes solar PV energy systems investment an unattractive venture for most urban settlers. Because building architectures mostly do not incorporate solar PV systems in facility planning, most building roofs pose challenges for solar PV array installation leading to lower PV energy output. The effects of tilt angle on the output of Solar Photovoltaic Systems were analyzed in this study using RETScreen 4. The optimum tilt angle and the corresponding PV output were estimated annually for three different PV systems. It was found that, the optimum tilt angle for all the systems that would give better yield and allow self-cleaning is 10°. The information presented in this study can serve as inputs for the development of grid-tied PV system without battery storage, grid-tied PV system with battery storage and stand-alone systems in Kumasi, Ghana.

Closed-Loop Control and Performance Evaluation of Reduced Part Count Multilevel Inverter Interfacing Grid-Connected PV System

Multilevel inverters (MLIs) have drawn tremendous attention in the power sector. Application of MLI has grown extensively to improve the power quality and efficiency of the photovoltaic (PV) system. For an MLI interfacing PV system, the size, cost and voltage stress are the key constraints of the MLI that need to be minimized. This paper presents a novel reduced part count MLI interfacing single-stage grid-tied PV system along with a closed-loop control strategy. The proposed MLI consists of n repeating units and a level boosting circuit (LBC) that assists in generating 4n + 7 voltage levels instead of 2n + 3 levels. Three different algorithms are proposed for a proper selection of dc-link voltages to enhance the levels further. A comparative analysis is carried out to confirm the superiority of the developed MLI. The workability of the proposed MLI is investigated with a 1.3 kW PV system. The closed-loop control strategy ensures the maximum power tracking, dc-link voltage balancing, satisfactory operation of the MLI and injection of clean sinusoidal grid current under any dynamic changes. Comprehensive simulation analysis is carried out considering a 15-level MLI structure. Experimental tests further confirm the practicality of the topological advancement for a PV system under different dynamic conditions.

Assessment and Analysis of a Grid-Tied Photovoltaic System with Net-Metering for State University in Pampanga

The utilization of renewable and eco-friendly source of energy which is also referred as “Alternative Energy” is now being recognized around the world, particularly the Solar Energy. The study proposes a grid-tied photovoltaic system with net-metering that generates electricity that is linked in the electrical grid, where in excess power is sold to the utility company. The objective is to improve the cost of energy consumption of Don Honorio Ventura State University Main Campus by designing and assessing Electrical Power System that lessens the dependency on the Distribution Utility (DU). The design of the system used with respect to the roofing area per building is (3,464) 300 Watts polycrystalline PV panels, (2) uni-directional or (1) bi-directional meter for monitoring the import and export energy, and 30kW-100kW inverter to convert DC (direct current) to AC (alternating current).The computation of the savings was based on the total kWh used per month with the system installed and includes the excess or export energy that is generated from the PV solar panels. Through the assessment of the proposed system, it will surely help Don Honorio Ventura State University (DHVSU) Main Campus to save monthly electric bill and lessen the dependency of the University to the utility grid. Since DHVSU’s building are secondary metered by the Distribution Utility, there is a need to install separate PV System set-up tp meet the individual electrical requirement. The PV system will be installed via On-Grid Connection to the DU subject to the Net Metering rules and guidelines as stated by the Renewable Energy Act of 2008.

Design of Multi-loop Current Control Strategies for LCL Filtered Grid-connected PV System

This paper presents numerous feedback current controller methods for the grid-connected PV systems incorporating with third order LCL filter. The various potential dual-loop feedback current controller schemes for a grid-tied electrical converter and a comparison among these controllers are made based on their performance. The effectiveness of these current controllers are based on various views like performance under polluted grid condition and also the dynamic performance of two control schemes under different transient conditions. A commonly used PI controller are employed in all cases of multi-loop controllers and also the electrical converter used here is operated in voltage control mode. In this work, a third-order low-pass LCL filter is employed to minimize the high order harmonics which are created due to the switching of the converter. The LCL filter is incorporated among the dc-ac converter and the utility grid. Two current regulation techniques are focused here. The design, analysis and the performance of these controllers are briefly discussed in this paper. By comparing their performance, anyone can suggest their applications in the grid-tied PV systems. All the current control schemes are incorporated with a grid-connected system of 2-KVA voltage source inverter. Simulation results are produced to validate the performances of two current control schemes. The output ohmic resistance of VSI is taken into account here for their performance analysis.

Decoupled Control of Three Phase Grid Connected Solar PV System

A reliable grid connected Photovoltaic (PV) system require effective control schemes for efficient use of solar energy. This paper presents a three-phase grid tied PV system with decoupled real and reactive power control to achieve desired power factor with Maximum Power Point Tracking (MPPT) controller to get maximum solar energy. The synchronous reference frame (dq) control along with decoupling concept is used to control the DC-AC inverter output, while the Phase Locked Loop (PLL) synchronization technique is used to monitor and synchronize the voltage and current at the grid side. The DC-DC converter with Incremental Conductance (InC) based MPPT model is also designed in this paper due to better accuracy compared to Perturb & Observe (P&O) algorithm. The simulation is performed in MATLAB/SIMULINK and a 31.5 kW PV system is modelled to get 30 kW power with the help of MPPT at Standard Test Conditions (STC). Any power factor value between 0.85 lagging to 0.9 leading can be obtained by changingreference q current in this inverter control strategy. The simulation results show that the change of reactive powerdoes not affecttheactive power values of the system, which verifies the effectiveness of the decoupled control strategy of the inverter.

Automatic Voltage Regulation of Grid Connected Photovoltaic System Using Lyapunov Based Sliding Mode Controller: A Finite — Time Approach

Importance of PV based energy systems cannot be denied with quickly increase in renewable energy demand. Due to inherent uncertainties and non-linear behaviour of grid tied PV system, conventional control strategies are unable to provide satisfactory performance. Therefore, key purpose of this paper is to design non linear controller for the control of grid tied PV system. A novel control strategy is devised by utilizing Lyapunov base finite time non-linear reactive power and dc link voltage control. This strategy employes Lyapunov approach to ensure stability and guarantees robustness. With this control strategy, better and superior performance is observed in comparison to proportional integral controller. Furthermore, simulation results are provided to illustrate the effectiveness of proposed algorithm. Various disturbances of system such as change in solar insolation level, change in reference parameters, faults on buses are considered. With this control strategy, settling time and oscillations are found significantly less than PI controller.

PSO based Grid Tied PV System with Three Phase Dual Buck Inverter

PSO based Grid Tied PV System with Three Phase Dual Buck Inverter

Improvement of Dynamic Performance using the Grid-Tied Photovoltaic (PV) System with Nonlinear Controller

Improvement of Dynamic Performance using the Grid-Tied Photovoltaic (PV) System with Nonlinear Controller

Power Quality Improvement of Grid Connected Photovoltaic Solar Systems using 3 level Inverter

This paper demonstrate simulation modeling of gridtied SPV systems with a 3 level inverter for power quality improvement using SVPWM. To extract maximum power MPPT is used. Three level inverters are used in high power and high voltage application with reduced harmonic contents. The grid tied PV system using three levels inverter has less harmonic contents as comparison of the conventional system or without a three level inverter. The simulation study reveals that the system with three-level inverter using the SVPWM technique generates less THD compared to the conventional system.

Net-zero energy building design and life-cycle cost analysis with air-source variable refrigerant flow and distributed photovoltaic systems

Net-zero energy building (NZEB) design has been gaining widespread acceptance as a major driver to reach feasible long-term goals of energy reductions in a building sector for the coming decades. Accordingly, net-zero energy targets for commercial buildings have been specified by federal and/or local government agencies in U.S. Although moving toward NZEB goals has technically feasible long-term advantages, economic issues are one of primarily concerns by building owners and designers for the application of advanced building technologies in NZEB design of their retrofit or new building construction. However, the lack of life cycle cost (LCC) data has still hindered reliable understanding of adopting NZEB design by building owners in a cost-effective manner. In response to this gap, this study conducts life-cycle cost analysis (LCCA) of NZEB design with an energy-efficient heating, ventilation, and air conditioning (HVAC) system and a solar power generation system. To enable NZEB design, an air-source VRF heat pump (HP) type system is considered for energy-efficient HVAC equipment in an office building model with a grid-tied photovoltaic (PV) system. Results reveal that the LCC of NZEBs varies primarily due to a combined effect of annual site EUIs, on-site power generation, and cost-items of each location in U.S. climates. Some hot and mild climate zones in the U.S. represent that LCC values of NZEBs are considerably lower. In contrast, some other cold zones result in unattractive LCC values for NZEBs, caused by a combined effect of relatively lower potential of on-site PV electricity generation and city cost indices. Yet, with subsidized financing by the federal government for PV installation costs, LCC values of NZEBs become significantly attractive in most climate locations.

Design of a Grid-Tie Photovoltaic System With a Controlled Total Harmonic Distortion and Tri Maximum Power Point Tracking

This article proposes an adaptive grid-tie photovoltaic system that maximizes the power injected to the grid while maintaining a predetermined power quality level. The proposed algorithm tracks the maximum power generated by the photovoltaic source, the maximum efficiency of the dc-dc converter, and the maximum efficiency of the inverter operating within a predefined total harmonic distortion limit. The tracked parameters that comprise the operating voltage of the photovoltaic source, the switching frequency of the dc-dc converter, and the switching frequency of the sinusoidal pulsewidth modulation inverter are updated, continuously, according to the generated photovoltaic power. The proposed method is fully adaptive, fast, and has a 100% convergence rate. Derivation of the proposed technique followed by the experimental verification and discussion are presented.

Variable Parameter Resized Zero Attracting Least Mean Fourth Control for Grid-Tied PV System

This paper presents the variable parameter resized zero attracting least mean fourth (VP-RZA-LMF) control algorithm for grid-tied photovoltaic (PV) system. The proposed control algorithm is superior over the conventional control algorithms in terms of swift response and handling the irregular nature of solar irradiations. The DC bus voltage control is incorporated in voltage source converter (VSC) control. The boost converter utilizes the maximum power point tracking (MPPT) algorithm for producing its gating sequence to keep PV array voltage constant.

Design and Performance Analysis of 250 kW Grid-Connected Photovoltaic System in Iraqi Environment Using PVsyst Software

A 250 kW grid-connected photovoltaic (PV) plant systems have been installed at the Ministry of Electricity in Baghdad and penetrated to the Iraqi national grid since November 2017. This is the first high power grid-connected PV system that has been installed in Iraq and it’s one of the four parts 1MW large-scale PV systems that should be completed in early of 2019. This paper presents the design and performance analysis of this system using a PVsyst software package. The performance ratio and different losses that occurred in the system are also calculated. The results show that the performance ratio is 75% using 1428 photovoltaic panels type (Sharp 175Wp) spread over an area of 1858 m². The total energy injected into the grid is (346692 kWh/year) .Based on the simulation results that developed in this paper, the practical PV grid-tied system has been implemented in Baghdad site.

Design and Performance Analysis of 250 kW Grid-Connected Photovoltaic System in Iraqi Environment Using PVsyst Software

A 250 kW grid-connected photovoltaic (PV) plant systems have been installed at the Ministry of Electricity in Baghdad and penetrated to the Iraqi national grid since November 2017. This is the first high power grid-connected PV system that has been installed in Iraq and it’s one of the four parts 1MW large-scale PV systems that should be completed in early of 2019. This paper presents the design and performance analysis of this system using a PVsyst software package. The performance ratio and different losses that occurred in the system are also calculated. The results show that the performance ratio is 75% using 1428 photovoltaic panels type (Sharp 175Wp) spread over an area of 1858 m². The total energy injected into the grid is (346692 kWh/year) .Based on the simulation results that developed in this paper, the practical PV grid-tied system has been implemented in Baghdad site.