scholarly journals Performances of Photovoltaic System Using Grid Tied Transformerless Inverter

2021 ◽  
pp. 287-292
Author(s):  
Ashish Raut ◽  
Sneha Tibude
Keyword(s):  
Leakage Current ◽  
Pulse Width Modulation ◽  
Neutral Line ◽  
Photovoltaic System ◽  
Pv Systems ◽  
Double Frequency ◽  
Power Switches ◽  
Dc Bus ◽  
Bus Voltage ◽  
Inverter Topology

In order to eliminate the common-mode (CM) leakage current in the transformer less photovoltaic (PV) systems, the concept of the virtual dc bus is proposed in this paper. By connecting the grid neutral line directly to the negative pole of the dc bus, the stray capacitance between the PV panels and the ground is bypassed. As a result, the CM ground leakage current can be suppressed completely. Meanwhile, the virtual dc bus is created to provide the negative voltage level for the negative ac grid current generation. Consequently, the required dc bus voltage is still the same as that of the full-bridge inverter. Based on this concept, a novel transformer less inverter topology is derived, in which the virtual dc bus is realized with the switched capacitor technology. It consists of only five power switches, two capacitors, and a single filter inductor. Therefore, the power electronics cost can be curtailed. This advanced topology can be modulated with the unipolar sinusoidal pulse width modulation (SPWM) and the double frequency SPWM to reduce the output current ripple. As a result, a smaller filter inductor can be used to reduce the size and magnetic losses.

scholarly journals Novel Three-Port Bidirectional DC/DC Converter with Three-Winding Coupled Inductor for Photovoltaic System

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1132 ◽  
Author(s):  
Yu-En Wu ◽  
Kai-Cheng Hsu
Keyword(s):  
Photovoltaic System ◽  
Pv System ◽  
Leakage Inductance ◽  
Bidirectional Converter ◽  
Power Switches ◽  
System Output ◽  
Step Down ◽  
Dc Bus ◽  
Bus Voltage ◽  
Voltage Spike

This study proposes a novel three-port bidirectional converter with a three-winding coupled inductor and applies it to a photovoltaic (PV) system to step up the PV system output to a dc bus or dc load while charging the battery. When the PV output is insufficient, battery voltage is stepped up to the dc bus voltage, and when the dc bus has excess energy, it is stepped down to charge the battery. Thus, a three-port bidirectional high step-up/step-down converter is achieved. A three-winding common core coupled inductor is designed and implemented in the converter, and a full-wave doubler circuit is used on the high-voltage side to achieve a high step-up effect. Power switches and diodes in the circuit are shared to achieve bidirectional operation. The output capacitors recover secondary-side leakage inductance energy in the step-up mode, and the third winding can be used to recover primary-side leakage inductance energy to reduce the voltage spike on switching in order to improve the converter’s conversion efficiency. A 500-W three-port bidirectional converter is implemented to verify the feasibility and practicability of the proposed topology. According to the measurement results, the highest efficiency of the PV step-up mode is 95.3%, the highest efficiency of the battery step-up mode is 94.1%, and the highest efficiency of the step-down mode is 94.8%.

scholarly journals New Pulse Width Modulation Technique to Reduce Losses for Three-Phase Photovoltaic Inverters

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Mohannad Jabbar Mnati ◽  
Dimitar V. Bozalakov ◽  
Alex Van den Bossche
Keyword(s):  
Control Strategy ◽  
Pulse Width Modulation ◽  
Photovoltaic System ◽  
Pv System ◽  
Total Cost ◽  
Switching Losses ◽  
Three Phase ◽  
Operational Lifetime ◽  
Term Energy ◽  
Dc Bus

Nowadays, most three-phase, “off the shelf” inverters use electrolytic capacitors at the DC bus to provide short term energy storage. However, this has a direct impact on inverter lifetime and the total cost of the photovoltaic system. This article proposes a novel control strategy called a 120° bus clamped PWM (120BCM). The 120BCM modulates the DC bus and uses a smaller DC bus capacitor value, which is typical for film capacitors. Hence, the inverter lifetime can be increased up to the operational lifetime of the photovoltaic panels. Thus, the total cost of ownership of the PV system will decrease significantly. Furthermore, the proposed 120BCM control strategy modulates only one phase current at a time by using only one leg to perform the modulation. As a result, switching losses are significantly reduced. The full system setup is designed and presented in this paper with some practical results.

scholarly journals A Topology Synthetization Method for Single-Phase, Full-Bridge, Transformerless Inverter with Leakage Current Suppression Part I

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 434 ◽  
Author(s):  
Xiumei Yue ◽  
Hongliang Wang ◽  
Xiaonan Zhu ◽  
Xinwei Wei ◽  
Yan-Fei Liu
Keyword(s):  
Leakage Current ◽  
Pulse Width ◽  
Single Phase ◽  
Pulse Width Modulation ◽  
Circuit Model ◽  
Double Frequency ◽  
Highly Efficient ◽  
Sinusoidal Pulse Width Modulation ◽  
Derivation Procedure ◽  
Bridge Topologies

Single-phase full-bridge transformerless topologies, such as the H5, H6, or the highly efficient and reliable inverter concept (HERIC) topologies, are commonly used for leakage current suppression for photovoltaic (PV) applications. The main derivation methodology of full-bridge topologies has been used based on both a DC-based decoupling model and an AC-based decoupling model. However, this methodology is not suited to the search for all possible topologies, and cannot verify whether they are inclusive. Part I of this paper will propose a new topology derivation methodology based on unipolar sinusoidal pulse width modulation (USPWM) to search all possible full-bridge topologies for leakage current suppression. First of all, a unified circuit model is proposed, instead of the DC- and AC-based models. Secondly, a mathematic method called the MN principle is then proposed to search for all possible topologies, and a derivation procedure is provided. It was verified that all existing topologies could be found using the proposed method; furthermore, seven new topologies were derived. The proposed topology derivation methodology is extended to search topologies under Double-Frequency USPWM (DFUSPWM). Twenty topologies under USPWM and four topologies under DFUSPWM have been derived.

scholarly journals Novel approach for SVPWM of two-level inverter fed induction motor drive

2020 ◽  
Vol 11 (4) ◽  
pp. 1750
Author(s):  
Olwi A. Elkholi ◽  
Mohamed A. Enany ◽  
Ahmed F. Abdo ◽  
Mahmoud Eid
Keyword(s):  
Induction Motor ◽  
Pulse Width Modulation ◽  
Frequency Converter ◽  
Harmonic Distortion ◽  
Motor Drives ◽  
New Approaches ◽  
Novel Approach ◽  
Three Phase ◽  
Dc Bus ◽  
Bus Voltage

<p class="Abstract">Due to their better DC bus utilization and easier digital realization, Space Vector Pulse Width Modulation (SVPWM) scheme is the most widely used PWM scheme. Also two level inverter is the traditional frequency converter because it has fewer components and is lower complex to control, but on the other hand it generates higher harmonic distortion. This paper presents the realization of novel SVPWM approaches applied to the three phase induction motor drives. Specifically various schemes are based on using more combinations of step operation in each cycle to approximate the reference vector, such as 24 and 48 step operations in each cycle. The basic principle of conventional SVPWM with different modulation index M is presented. The switching sequences of new approaches are described. The modulation signals waveforms, DC bus voltage utilization, De-rated motor torque, standard error of average torque, voltage and current harmonic of new approaches are analyzed by the MATLAB/SIMULINK software. The results confirms that 48 step SVPWM approach is the best compared to other approaches.</p>

scholarly journals Performance Improvement of a Grid-Tied Neutral-Point-Clamped 3-φ Transformerless Inverter Using Model Predictive Control

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 856 ◽  
Author(s):  
Hani Albalawi ◽  
Sherif A. Zaid
Keyword(s):  
Model Predictive Control ◽  
Leakage Current ◽  
Predictive Control ◽  
Pulse Width Modulation ◽  
Harmonic Distortion ◽  
Neutral Point ◽  
Pv Systems ◽  
Pv Panel ◽  
Current Controller ◽  
Lc Filter

Grid-connected photovoltaic (PV) systems are now a common part of the modern power network. A recent development in the topology of these systems is the use of transformerless inverters. Although they are compact, cheap, and efficient, transformerless inverters suffer from chronic leakage current. Various researches have been directed toward evolving their performance and diminishing leakage current. This paper introduces the application of a model predictive control (MPC) algorithm to govern and improve the performance of a grid-tied neutral-point-clamped (NPC) 3-φ transformerless inverter powered by a PV panel. The transformerless inverter was linked to the grid via an inductor/capacitor (LC) filter. The filter elements, as well as the internal impedance of the grid, were considered in the system model. The discrete model of the proposed system was determined, and the algorithm of the MPC controller was established. Matlab’s simulations for the proposed system, controlled by the MPC and the ordinary proportional–integral (PI) current controller with sinusoidal pulse width modulation (SPWM), were carried out. The simulation results showed that the MPC controller had the best performance for earth leakage current, total harmonic distortion (THD), and the grid current spectrum. Also, the efficiency of the system using the MPC was improved compared to that using a PI current controller with SPW modulation.

Photovoltaic System with SEPIC Converter Controlled by the Fuzzy Logic

2016 ◽  
Vol 7 (4) ◽  
pp. 1283 ◽  
Author(s):  
Meryem Oudda ◽  
Abdeldjebar Hazzab
Keyword(s):  
Fuzzy Logic ◽  
Duty Cycle ◽  
Output Voltage ◽  
Fuzzy Logic Controller ◽  
Photovoltaic System ◽  
Utilization Efficiency ◽  
Solar Pv ◽  
Solar Panels ◽  
Dc Bus ◽  
Bus Voltage

<span lang="EN-US">In this work, a fuzzy logic controller is used to control the output voltage of a photovoltaic system with a DC-DC converter; type Single Ended Primary Inductor Converter (SEPIC). The system is designed for 210 W solar PV (SCHOTT 210) panel and to feed an average demand of 78 W. This system includes solar panels, SEPIC converter and fuzzy logic controller. The SEPIC converter provides a constant DC bus voltage and its duty cycle controlled by the fuzzy logic controller which is needed to improve PV panel’s utilization efficiency. A fuzzy logic controller (FLC) is also used to generate the PWM signal for the SEPIC converter. </span>

Single-Phase Single Stage String Inverter for Grid Connected Photovoltaic System

2015 ◽  
Vol 785 ◽  
pp. 177-181
Author(s):  
Siti Zaliha Mohammad Noor ◽  
Ahmad Maliki Omar ◽  
M.A.M. Radzi
Keyword(s):  
Simulation Model ◽  
Single Phase ◽  
Pulse Width Modulation ◽  
Single Stage ◽  
Maximum Power ◽  
Photovoltaic System ◽  
Prototype System ◽  
Point Tracking ◽  
Power Switches ◽  
Power Point

This paper presents the development of single-phase single stage string inverters for grid connected photovoltaic system. The inverter is designed to generate an AC current in phase with the grid voltage and to extract the maximum power from the PV array. The maximum power point tracking (MPPT) is achieved by adjusting the modulation index and phase angle of the inverter’s voltage accordingly using fuzzy logic control algorithm. The prototype system is tested using 2 series of STP170s-24/Ac PV modules. Insulated Gate Bipolar Transistors (IGBTs) are used as power switches while the Sinusoidal Pulse Width Modulation (SPWM) scheme is used as the switching technique to synthesize the output waveform. Simulation model was developed in MATLAB/Simulink environment to study and evaluate behavior of the proposed converter. The results of the prototype system show good agreement with the simulation model.

Microcontroller-based inverter topology integrated in PV systems

2015 ◽  
Vol 34 (1) ◽  
pp. 132-150 ◽  
Author(s):  
Mounir Bouzguenda ◽  
Tarek Selmi ◽  
Adel Gastli ◽  
Ahmed Masmoudi
Keyword(s):  
Leakage Current ◽  
Control Strategy ◽  
Design Methodology ◽  
Leakage Currents ◽  
Zero Crossing ◽  
Content Type ◽  
Pv Systems ◽  
High Conversion Ratio ◽  
Inverter Topology ◽  
Practical Implications

Purpose – The purpose of this paper is to study the problem of the leakage currents in transformerless inverter topologies. It proposes a novel topology and how important the adopted control strategy on the power quality produced by the inverter. Design/methodology/approach – The paper presents an investigation of a novel transformerless inverter topology. It adopted a control strategy in which the DC source is disconnected from the inverter when the zero vectors of the control are applied. By using such control strategy, the electrical efficiency of the whole system was improved and the leakage current was significantly reduced. Findings – The paper provides a solution to minimize the leakage current in transformerless inverter topologies. Besides, the problem of zero-crossing distortions was totally eliminated. Research limitations/implications – Because of the high conversion ratio of the boost converter, the efficiency of the whole system needs to be enhanced. Practical implications – The paper includes the experimental results of the proposed topology which are in good match with the simulation results. Originality/value – This paper identifies a need to study the leakage current phenomena in transformerless inverter topologies.

scholarly journals Circuit Parameter Range of Photovoltaic System to Correctly Use the MPP Linear Model of Photovoltaic Cell

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3997
Author(s):  
Shaowu Li
Keyword(s):  
Linear Models ◽  
Cell Model ◽  
Photovoltaic System ◽  
Parameter Range ◽  
Model Parameters ◽  
Circuit Parameter ◽  
Pv System ◽  
Pv Systems ◽  
Linear Control Theory ◽  
Bus Voltage

The real-time linearization of a photovoltaic (PV) cell has been implemented well by the proposition of two maximum power point (MPP) linear models (MPP Thevenin cell model and MPP Norton cell model). However, there is no work to specially analyze the circuit parameter range (CPR) to correctly use them, which seriously impedes the development of the linear control theory involving them. To deal with this problem, in this paper, PV systems with three usual outputs are analyzed and the expressions of their CPR are proposed under ideal conditions. Meanwhile, these expressions are improved to match the practical application. They disclose the relationships between load (or bus voltage) and model parameters of the MPP Thevenin cell model (MPP-TCM) when the MPP of PV system always exists. They also reveal the constraints of load (or bus voltage) when the MPP-TCM is always available. Finally, by some simulation experiments, the accuracy of the expressions of the CPR is verified, the regular patterns of the CPR changing with weather are disclosed, and the comparison of the CPR for different PV systems are made. In this work, the relationships between MPP-TCM and circuit parameters are successfully found, disclosing the constraints among parameters when the MPP-TCM is used to implement the overall linearization of a PV system.

scholarly journals Transformer less 1Φ Inverter for Grid-Connected PV Systems with an Optimized Control

2018 ◽  
Vol 7 (3.34) ◽  
pp. 217 ◽  
Author(s):  
T Baldwin Immanuel ◽  
P Muthukumar ◽  
C Gnanavel ◽  
M Rajavelan ◽  
M Marimuthu
Keyword(s):  
Pulse Width Modulation ◽  
Photovoltaic System ◽  
Solar Pv ◽  
Pv System ◽  
Performance Simulation ◽  
Grid Voltage ◽  
Pv Systems ◽  
One Stage ◽  
Single Phase Inverter ◽  
Sinusoidal Pulse Width Modulation

This paper investigates the transformerless single-phase inverter incorporates with the photovoltaic system along with the support of grid voltage. Solar Energy is a Non-Conventional Energy source which is mandatory for power generation due to their immeasurable parade and green pleasant nature. One-cycle control (OCC), Ruggedness and consistency which makes the interfacing with the grid easily. For grid interfacing, the inverter circuit does not need phase locked loop facility and are gradually being working for such solicitations. The strategy of the OCC inverter of one stage for solar PV applications is supported by means of a Sinusoidal Pulse Width Modulation to enhance inverter enactment at both low and high insolation levels. These factors allows the plan of a MPPT along P&O controller that pointedly progresses inverter playacting. Though, the OCC-based structures testified previous sensing of the grid voltage which slightly equalizers the strength of its characteristics, In order to dazed the restriction of prior researches, an One Cycle Control based grid-connected one-stage PV system is suggested. The sustainability of the suggested scheme is inveterate by performance simulation justification.

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