A novel transformer-less eleven-level inverter with optimized Buck–Boost controller and minimal switch design for grid-connected PV systems

Power quality (PQ) issues are generally categorises under voltage sag swells interruptions and harmonics interruptions. Also low voltage ride through (LVRT) is one of the grid code requirements. Custom power devices (CPDs) like unified power quality conditioner (UPQC) is capable to mitigate the LVRT and power quality problem and reduce the supply voltage and current problem. This paper deals with MATLAB simulation work of UPQC during low voltage ride through problem of grid connected PV plant. In this article artificial neural network (ANN) based UPQC is presented to enhance the LVRT and to reduce the total harmonic distortion (THD) value in power system. It used the pulse width modulation (PWM) technique for supplying the pulses to insulated gate bipolar transistors (IGBT) device. This model also restricts current harmonics to enter in service grid. Proposed system is able to provide power factor of 0.9, reduce harmonics up to 7 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> order, provide constant power under 90% sag and supply THD 2.93%.

This study shows a novel design for a unified power quality conditioner (UPQC) to improve the power quality. The designed UPQC has two active power filters (APF) in shunt and series combinations. PWM (pulse width modulation) and hysteresis controls are the two control mechanisms used in this study. To reduce harmonics, a direct-quadrature zero (dq0) conversion is performed. In case 1, for a single-bus system, the total harmonic distortion (THD) of the source current in the system without UPQC was 22.22%. After applying the designed method, THD has been reduced significantly to 2.68%. In case 2, for multi-bus systems, the THD was 20.62% and 5.05% with and without the UPQC, respectively. Here the THD in the grid input voltage was 20.62%, whereas the output voltage was 0.80%. The IEEE 519–2014 standard for voltage and current harmonics distortion criterion for electrical system design is followed in the research.

In addition to Power Quality (PQ) problems caused by solid state devices in the distribution side of grid connected Photo Voltaic (PV) system, quality of power also suffers in the source side by the usage of converters. Generally, PQ problems mitigation strategy has turned into a critical issue in grid-connected PV systems. This paper proposes a control topology for PQ issues mitigation scheme in grid connected PV systems. The primary goal of this study is to enhance the PQ in power distribution system through eradicating the voltage interruption, voltage swell and sag as well as voltage fluctuation. To accomplish these changes, Unified Power Quality Conditioners (UPQCs) with controllers were utilized. Then the faults are mitigated by the utilization of UPQC with Tree Seeds Algorithm (TSA) — Adaptive Neuro-Fuzzy Interference System (ANFIS). At first, the normal properties of the grid-connected PV systems are dissected. From that point forward, a few interruptions are made in the system and the abnormal characteristics are analyzed. Then the abnormal characteristics of PQ problems are diminished in the utilization of UPQC and TSA–ANFIS controllers. UPQC is one of the best filters topologies which can mitigate and control all PQ problems. The combined algorithms of TSA-ANFIS are used to keep the dc-link voltage in UPQC at consistent level. The proposed hybrid approach is executed in MATLAB/Simulink platform and the performance is studied. Further, the proposed method is compared with existing Elephant Herding Optimization (EHO) technique and also with hybrid EHO-ANFIS techniques. The comparison results showed that the proposed technique is superior to the EHO and EHO-ANFIS techniques.

&lt;span lang="EN-US"&gt;In order to enhance electricity quality, a grid-connected photovoltaic (PV) system simulation is presented in this study. A 200 kW photovoltaic system is integrated to a utility grid and loads. A 25 kV 3-level insulated gate bipolar transistor (IGBT) bridge converter is used. Through this system integration of a renewable energy source with a non-renewable source is achieved. This system also wins over the intermittent nature of the renewable source (solar energy) and non-reliability of conventional sources (utility grid). Power and signal quality for various signals such as ripple factor and total harmonic distortion has improved. The suggested system is investigated using MATLAB/Simulink environment. Total harmonic distortion (THD) in voltage and current, ripple factor correction is also incorporate in the MATLAB model.&lt;/span&gt;

A grid-connected photovoltaic (GCPV) system plays an important role in the development of green technology. However, generated photovoltaic (PV) power that is injected into the grid causes instability in the grid system. Previous studies have shown that power quality for a three-phase system is thoroughly being discussed, but not for a single-phase system. Single-phase system also contribute to instability in low-voltage grid networks during high power penetration as majority of the single-phase GCPV nowadays are installed on rooftops. Thus, in this study, the power quality of a single-phase single-stage GCPV system is investigated based on the total harmonic distortion (THD), power factor (PF), and the generated active (P) and reactive (Q) power during different solar irradiance and varying loads conditions. A model of the GCPV system was developed in MATLAB/Simulink, so that certain variables can be varied to observe their effect towards the power quality. The results show that the current and voltage of generated PV power are synchronized and having low current THD which is less than 1% for all cases. PF values are also in the acceptable range in compliance to IEC 61727 standard which is 0.9971, and the generated PQ is in accordance to the connected load.

Grid—connected Photovoltaic (PV) system is one of the smart—grid system branch which offers plenty of opportunity for further improvement. Apart from grid synchronizing procedure, pulse width modulation (PWM) technique plays huge role in constructing the grid—connected PV system to be more efficient and reliable. This paper presents the design and simulation of Sinusoidal PWM (SPWM) and Space vector PWM (SVPWM) based on two level three—phase voltage source inverter (VSI). The simulation is performed in MATLAB/Simulink platform. Comparison between both PWM techniques in terms of the utilization of DC voltage and total harmonic distortion (THD) were carried out. SVPWM demonstrates better performance as compared to SPWM hence is qualified to use for grid—connected PV system.

This research paper presents an effective transformer-less seven-level inverter with an optimized proportional-integral-derivative (PID) controller and buck-boost controller for grid-connected photovoltaic (PV) systems. The proposed model aims to achieve optimum power quality (PQ) in a hybrid power system integrating battery and PV. This is accomplished by utilizing a unified power quality conditioner (UPQC-PQ) with active and reactive power is developed, utilizing a hybrid metaheuristic algorithm named the honey badger algorithm (HBA) along with the equilibrium optimization algorithm (EOA), referred to as the honey badger equilibrium optimization (HBEO) algorithm. The PID controller in the proposed model is optimized using the HBEO algorithm, resulting in a highly efficient hybrid renewable energy system. By incorporating a 7-level multilevel inverter model with minimal switch usage (only 5 switches instead of 12), the proposed model ensures minimal switching losses. The proposed model is implemented and verified through the MATLAB/Simulink platform.

A unified power quality conditioner (UPQC) is a combination of shunt and series converter used to mitigate various power quality issues. In this work the shunt and series converters are designed with reduced number of switches. The new UPQC with reduced switches is controlled using SRF based Carrier Double Zero Sequence Signal Modulation (CDZSSM) technique to mitigate the various power quality issues like voltage sag, current ripples and Total Harmonic Distortion in voltage and current waveforms. This reduced switch UPQC with CDZSSM control inherits all the merits of the conventional UPQC system, but the proposed UPQC system has better utilization of DC link voltage and moreover the voltage stresses across the switches are reduced. The results obtained from simulation and hardware of the reduced switch UPQC are compared and presented.

The integration of renewable power sources with power grids presents many challenges, such as synchronization with the grid, power quality problems and so on. The shunt active power filter (SAPF) can be a solution to address the issue while suppressing the grid-end current harmonics and distortions. Nonetheless, available SAPFs work somewhat unpredictably in practice. This is attributed to the dependency of the SAPF controller on nonlinear complicated equations and two distorted variables, such as load current and voltage, to produce the current reference. This condition will worsen when the plant includes wind turbines which inherently produce 3rd, 5th, 7th and 11th voltage harmonics. Moreover, the inability of the typical phase locked loop (PLL) used to synchronize the SAPF reference with the power grid also disrupts SAPF operation. This paper proposes an improved synchronous reference frame (SRF) which is equipped with a wavelet-based PLL to control the SAPF, using one variable such as load current. Firstly the fundamental positive sequence of the source voltage, obtained using a wavelet, is used as the input signal of the PLL through an orthogonal signal generator process. Then, the generated orthogonal signals are applied through the SRF-based compensation algorithm to synchronize the SAPF’s reference with power grid. To further force the remained uncompensated grid current harmonics to pass through the SAPF, an improved series filter (SF) equipped with a current harmonic suppression loop is proposed. Concurrent operation of the improved SAPF and SF is coordinated through a unified power quality conditioner (UPQC). The DC-link capacitor of the proposed UPQC, used to interconnect a photovoltaic (PV) system to the power grid, is regulated by an adaptive controller. Matlab/Simulink results confirm that the proposed wavelet-based UPQC results in purely sinusoidal grid-end currents with total harmonic distortion (THD) = 1.29%, which leads to high electrical efficiency of a grid-connected PV system.

This paper proposes a fuzzy logic based new control scheme for the Unified Power Quality Conditioner (UPQC) for minimizing the voltage sag and total harmonic distortion in the distribution system consequently to improve the power quality. UPQC is a recent power electronic module which guarantees better power quality mitigation as it has both series-active and shunt-active power filters (APFs). The fuzzy logic controller has recently attracted a great deal of attention and possesses conceptually the quality of the simplicity by tackling complex systems with vagueness and ambiguity. In this research, the fuzzy logic controller is utilized for the generation of reference signal controlling the UPQC. To enable this, a systematic approach for creating the fuzzy membership functions is carried out by using an ant colony optimization technique for optimal fuzzy logic control. An exhaustive simulation study using the MATLAB/Simulink is carried out to investigate and demonstrate the performance of the proposed fuzzy logic controller and the simulation results are compared with the PI controller in terms of its performance in improving the power quality by minimizing the voltage sag and total harmonic distortion.

Performance analysis of hybrid metaheuristic assisted collateral FO controller for HRES system integrated UPQC

PWM methods is the most active topic for controlling the power electronic circuit. Several PWM approaches are more and more applied in various innovative applications of power electronics in industries that need greater performance of the system. These days the most relevant PWM method for 3 - phase VSI are SPWM, THIPWM and SVPWM. Out of these three methods SPWM is one of the naivest modulation schemes that can gather definitely in normally used analog circuit. Here major problem associated with SPWM is that it consists higher THD along with no capability to operate in over modulation region at lesser value of switching frequency. Better technique to control THD other than SPWM are SVPWM and THIPWM. For applications with higher frequency and during over modulation region SVPWM technique gives reduced THD in comparison of SPWM technique. The performance of above two methods are deliberated, studied and its comparison with switching frequency, modulation index is given in this paper. To obtain sine wave harmonic must be reduced. PWM methods are simulated for different loads and FFT analysis is used to detect the overall harmonic interference. In this article, the benefits of the DC bus voltage utilization are higher than the PWM technology. Keywords: Third harmonic injection pulse width modulation (THIPWM), pulse width modulation (PWM), sinusoidal pulse width modulation (SPWM), space vector pulse width modulation (SVPWM), voltage source inverter (VSI), total harmonic distortion (THD) Cite this Article Vijay Shankar, Ankur Kumar, Pankaj Kumar Singh. Simulation and Analysis of Three Phase VSI using THIPWM and SVPWM Techniques. Journal of Instrumentation Technology & Innovations . 2019; 9(3): 16–30p.

The goal of this research is to improve the efficiency and dependability of grid-connected solar photovoltaic (PV) systems by utilizing Artificial Neural Networks (ANN) and Space Vector Pulse Width Modulation (SVPWM). The main issues with power quality were reducing total harmonic distortion (THD) and enhancing voltage control. In the field of solar photovoltaic (PV) systems, these issues are crucial as power electronics converters and the amount of incoming solar radiation are both subject to fluctuation. An artificial neural network (ANN) technique uses the high-quality voltage waveform and real-time power regulation of the SVPWM inverter to dynamically adjust the inverter's switching patterns. We were able to conclude that the suggested method worked better than the conventional SVPWM processes after conducting simulations in a number of work situations. One noteworthy discovery was the average overall harmonic distortion, which is now being lowered to less than 5% in order to comply with IEEE 519 standards. The efficiency of the ANN-SVPWM system was 96% higher than that of the conventional one, and it maintained a steady voltage even when the sun's irradiation levels changed. Furthermore, this function demonstrated that grid-connected PV systems may respond more quickly to changes in the sun's conditions in real time, perhaps making them a more effective option. In the biological sciences, researchers discovered that combining artificial neural networks (ANN) with systematic vector pulse width modulation (SVPWM) enhanced the dependability, efficiency, and power quality of solar photovoltaic (PV) systems.

Introduction. To enhance the quality of power and ensure a consistent electricity supply, this study proposes the utilization of a unified power quality conditioner (UPQC) system integrated with solar photovoltaic (PV) technology. The innovation involves single DC-link connecting back-to-back voltage-compensating components arranged in series and shunt, forming the PV-UPQC. The shunt compensator utilizes energy from a PV array to address harmonics in the load current. The objective is to mitigate voltage dips and spikes by injecting voltage that is either in phase with or out of phase with the common coupling point through a series compensator. The method combines the benefits of generating renewable energy to enhance electrical quality. The goal of the paper is the power quality enhancement of grid-integrated solar PV system. The novelty of the proposed work consists of enhancement of grid-integrated solar PV system with UPQC. The purpose of integrating a UPQC into a grid-connected solar PV system is to enhance power quality by mitigating issues such as voltage fluctuations, harmonics and reactive power imbalance. Methods. The proposed topology is implemented in MATLAB/Simulink with grid-integrated solar PV system with UPQC. Results. Integrating UPQC with a grid-connected solar PV system yields substantial improvements in power quality. This includes effectively mitigating voltage fluctuations and harmonics, resulting in smoother operation and reduced disturbances on the grid. Practical value. The proposed topology has proven to be extremely useful for grid-integrated solar PV system with UPQC applications. References 15, table 2, figures 9.

The lack of control in voltage overshoot, transient response, and steady state error are major issues that are frequently encountered in a grid-connected photovoltaic (PV) system, resulting in poor power quality performance and damages to the overall power system. This paper presents the performance of a control strategy for an inverter in a three-phase grid-connected PV system. The system consists of a PV panel, a boost converter, a DC link, an inverter, and a resistor-inductor (RL) filter and is connected to the utility grid through a voltage source inverter. The main objective of the proposed strategy is to improve the power quality performance of the three-phase grid-connected inverter system by optimising the proportional-integral (PI) controller. Such a strategy aims to reduce the DC link input voltage fluctuation, decrease the harmonics, and stabilise the output current, voltage, frequency, and power flow. The particle swarm optimisation (PSO) technique was implemented to tune the PI controller parameters by minimising the error of the voltage regulator and current controller schemes in the inverter system. The system model and control strategies were implemented using MATLAB/Simulink environment (Version 2020A) Simscape-Power system toolbox. Results show that the proposed strategy outperformed other reported research works with total harmonic distortion (THD) at a grid voltage and current of 0.29% and 2.72%, respectively, and a transient response time of 0.1853s. Compared to conventional systems, the PI controller with PSO-based optimization provides less voltage overshoot by 11.1% while reducing the time to reach equilibrium state by 32.6%. The consideration of additional input parameters and the optimization of input parameters were identified to be the two main factors that contribute to the significant improvements in power quality control. Therefore, the proposed strategy effectively enhances the power quality of the utility grid, and such an enhancement contributes to the efficient and smooth integration of the PV system.