scholarly journals Transformerless Multilevel Voltage-Source Inverter Topology Comparative Study for PV Systems

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3261 ◽  
Author(s):  
Adyr A. Estévez-Bén ◽  
Alfredo Alvarez-Diazcomas ◽  
Juvenal Rodríguez-Reséndiz
Keyword(s):  
Leakage Current ◽  
Clean Energy ◽  
Industrial Applications ◽  
Renewable Energies ◽  
International Standards ◽  
Voltage Source ◽  
Switching Frequency ◽  
Multilevel Inverters ◽  
Pv Systems ◽  
Advantages And Disadvantages

At present, renewable energies represent 25% of the global power generation capacity. The increase in clean energy facilities is mainly due to the high levels of pollution generated by the burning of fossil fuels to satisfy the growing electricity demand. The global capacity of generating electricity from solar energy has experienced a significant increase, reaching 505 GW in 2018. Today, multilevel inverters are used in PV systems to convert direct current into alternating current. However, the use of multilevel inverters in renewable energies applications presents different challenges; for example, grid-connected systems use a transformer to avoid the presence of leakage currents. The grid-connected systems must meet at least two international standards analyzed in this work: VDE 0126-1-1 and VDE-AR-N 4105, which establish a maximum leakage current of 300 mA and harmonic distortion maximum of 5%. Previously, DC/AC converters have been studied in different industrial applications. The state-of-the-art presented in the work is due to the growing need for a greater use of clean energy and the use of inverters as an interface between these technologies and the grid. Also, the paper presents a comparative analysis of the main multilevel inverter voltage-source topologies used in transformerless PV systems. In each scheme, the advantages and disadvantages are presented, as well as the main challenges. In addition, current trends in grid-connected systems using these schemes are discussed. Finally, a comparative table based on input voltage, switching frequency, output levels, control strategy used, efficiency, and leakage current is shown.

scholarly journals Feedback Loop Control Strategies of the Multi Dc Bus Link Voltages Using Adaptive Fuzzy Logic Control

2013 ◽  
Vol 64 (3) ◽  
pp. 143-151
Author(s):  
Farid Bouchafaa ◽  
Mohamed Seghir Boucherit ◽  
El Madjid Berkouk
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Control Strategies ◽  
Harmonic Distortion ◽  
Power Converter ◽  
Voltage Source ◽  
Switching Frequency ◽  
Pwm Rectifier ◽  
Loop Control ◽  
Multilevel Inverters

Voltage source multilevel inverters have become very attractive for power industries in power electronics applications during last years. The main purposes that have led to the development of the studies about multilevel inverters are the generation of output voltage signals with low harmonic distortion; the reduction of switching frequency. A serious constraint in a multilevel inverter is the capacitor voltage-balancing problem. The unbalance of different DC voltage sources of five-level neutral point clamping (NPC) voltage source inverter (VSI) constitutes the major limitation for the use of this new power converter. In order to stabilize these DC voltages, we propose in this paper to study the cascade constituted by three phases five-level PWM rectifier, a clamping bridge and five-level NPC (VSI). In the first part, we present a topology of five-level NPC VSI, and then they propose a model of this converter and an optimal PWM strategy to control it using four bipolar carriers. Then in the second part, we study a five-level PWM rectifier, which is controlled by a multiband hysteresis strategy. In the last part of this paper, the authors study shows particularly the problem of the stability of the multi DC voltages of the inverter and its consequence on the performances of the induction motors (IM). Then, we propose a solution to the problem by employed closed loop regulation using PI regulator type fuzzy logic controller (FLC). The results obtained with this solution confirm the good performances of the proposed solution, and promise to use the inverter in high voltage and great power applications as electrical traction.

scholarly journals Adaptive Phase-Shifted PWM based on Particle Swarm Optimization for Cascaded H-Bridge Inverter with Unequal Dc-link Voltages

2018 ◽  
Vol 7 (4.15) ◽  
pp. 469
Author(s):  
Pakedam Lare ◽  
Byamakesh Nayak ◽  
Srikanta Dash ◽  
Jiban Ballav Sahu
Keyword(s):  
Particle Swarm Optimization ◽  
Particle Swarm ◽  
Pso Algorithm ◽  
Industrial Applications ◽  
High Order ◽  
Control Technique ◽  
Voltage Source ◽  
Switching Frequency ◽  
Swarm Optimization ◽  
The Cost

The cascaded H-Bridge Multilevel Inverter has been found a promising technology in industrial applications because of its higher voltage with less distortion production. Various PWMs techniques have been proposed to push the harmonics frequencies higher than the switching frequency and thus reduces the THD as compared to non-carrier control technique based upon grid frequency. The Phase-Shifted PWM technique has an advantage over others PWM techniques because its harmonics orders are multiples of switching frequency and also depend on the number of levels of the inverter. The phase shifting angle is uniform when the equal voltage sources are adopted. However, in applications where sets of different voltage source levels feed the H-Bridge cells, the Phase Shifted PWM suffers its high order harmonics elimination capability. As a solution to alleviate this problem, an adaptive variable angle approach is proposed in this paper using Particle Swarm Optimization (PSO) algorithm to eliminate desired higher order harmonics. The algorithm is used to minimize the cost function based on high order sideband harmonics elimination equations. The results through MATLAB/Simulink environment shown in this paper confirm the reduction of sideband harmonics of higher orders, and the overall THD.  

Synchronized Symmetrical Bus-Clamping PWM Strategies for Three Level Inverter: Applications to Low Switching Frequencies

2011 ◽  
Vol 12 (2) ◽  
Author(s):  
Sreenivasappa Bhupasandra Veeranna ◽  
Udaykumar R Yaragatti ◽  
Abdul R Beig
Keyword(s):  
Pulse Width ◽  
Output Voltage ◽  
High Performance ◽  
Pulse Width Modulation ◽  
Industrial Applications ◽  
Voltage Source ◽  
Switching Frequency ◽  
Space Vector ◽  
Digital Implementation ◽  
Switching Losses

The digital control of three-level voltage source inverter fed high power high performance ac drives has recently become a popular in industrial applications. In order to control such drives, the pulse width modulation algorithm needs to be implemented in the controller. In this paper, synchronized symmetrical bus-clamping pulse width modulation strategies are presented. These strategies have some practical advantages such as reduced average switching frequency, easy digital implementation, reduced switching losses and improved output voltage quality compared to conventional space vector pulse width modulation strategies. The operation of three level inverter in linear region is extended to overmodulation region. The performance is analyzed in terms THD and fundamental output voltage waveforms and is compared with conventional space vector PWM strategies and found that switching losses can be minimized using bus-clamping strategy compared to conventional space vector strategy. The proposed method is implemented using Motorola Power PC 8240 processor and verified on a constant v/f induction motor drive fed from IGBT based inverter.

scholarly journals A comparative study of cascade H-bridge multilevel voltage source inverter and parallel inductor multilevel current source inverter

2019 ◽  
Vol 10 (3) ◽  
pp. 1355
Author(s):  
Nik Fasdi Nik Ismail ◽  
Norazlan Hashim ◽  
Dalina Johari
Keyword(s):  
Output Voltage ◽  
Current Source ◽  
Harmonic Distortion ◽  
Voltage Source ◽  
Voltage Source Inverter ◽  
Analysis Study ◽  
Multilevel Inverters ◽  
Advantages And Disadvantages ◽  
Current Source Inverter ◽  
Current Source Inverters

This paper presents the analysis study between multilevel inverters that are often classified into multilevel voltage source and multilevel current source inverters.  For multilevel voltage source inverter (MVSI), the specific topology studied for this work is the Cascaded H-Bridge MVSI.  Whereas, the multilevel current source inverter (MCSI) is based on Paralleled Inductor Configuration MCSI.  For this study, the analysis between these converters are done with respect to the number of components, the advantages and disadvantages of each converters during performing inverter operation. In term of output voltage and current quality, the percentage of the Total Harmonic Distortion (THD) are measured and compared for both topologies.  MATLAB/Simulink software has been used in this research to design and simulate in order to study the performances of both inverters.

scholarly journals Stabilization of multi DC bus link voltages of multilevel NPC VSI. Application to double stator induction motors

2012 ◽  
Vol 22 (1) ◽  
pp. 107-120
Author(s):  
D. Beriber ◽  
A. Talha ◽  
M. Boucherit
Keyword(s):  
Stability Problem ◽  
Induction Motors ◽  
Power Converter ◽  
Neutral Point ◽  
Voltage Source ◽  
Switching Frequency ◽  
Voltage Source Inverter ◽  
Multilevel Inverters ◽  
Dc Bus ◽  
The Stability

Stabilization of multi DC bus link voltages of multilevel NPC VSI. Application to double stator induction motors Voltage source multilevel inverters have become very attractive for power industries in power electronics applications during last years. The main purposes of studying multilevel inverters are the generation of output voltage signals with low harmonic distortion and reduction of switching frequency. An important issue of the multilevel inverter is the capacitor voltage-balancing problem. The unbalance of different DC voltage sources of multilevel neutral point clamped (NPC) voltage source inverter (VSI) constitutes the major limitation for the use of this new power converter. In this paper, we present study on the stability problem of the input DC voltages of the three-level Neutral Point Clamping (NPC) voltage source inverter (VSI). This inverter is useful for application in high voltage and high power area. In the first part, we remind the model of double stator induction motors (DSIM). Then, we develop control models of this inverter using the connection functions of the semi-conductors. We propose a Pulse Width Modulation (PWM) strategy to control this converter. The inverter is fed by constant input DC voltages. In the last part, we study the stability problem of the input DC voltages of the inverter. A cascade constituted by two three-level PWM rectifiers - two three-level NPC VSI - DSIM is discussed. The results obtained show that the input DC voltages of the inverters are not stable. To solve this problem, we propose to use a half clamping bridge. This solution is very promising in order to stabilize the input DC voltages of this converters.

scholarly journals Leakage Current Reduction in Single-Phase Grid-Connected Inverters—A Review

2020 ◽  
Vol 10 (7) ◽  
pp. 2384 ◽  
Author(s):  
Adyr A. Estévez-Bén ◽  
Alfredo Alvarez-Diazcomas ◽  
Gonzalo Macias-Bobadilla ◽  
Juvenal Rodríguez-Reséndiz
Keyword(s):  
Leakage Current ◽  
Harmonic Distortion ◽  
Clean Energy ◽  
Photovoltaic Module ◽  
Common Mode ◽  
Advantages And Disadvantages ◽  
Common Mode Voltage ◽  
The Common ◽  
Ac Converters ◽  
Current Reduction

The rise in renewable energy has increased the use of DC/AC converters, which transform the direct current to alternating current. These devices, generally called inverters, are mainly used as an interface between clean energy and the grid. It is estimated that 21% of the global electricity generation capacity from renewable sources is supplied by photovoltaic systems. In these systems, a transformer to ensure grid isolation is used. Nevertheless, the transformer makes the system expensive, heavy, bulky and reduces its efficiency. Therefore, transformerless schemes are used to eliminate the mentioned disadvantages. One of the main drawbacks of transformerless topologies is the presence of a leakage current between the physical earth of the grid and the parasitic capacitances of the photovoltaic module terminals. The leakage current depends on the value of the parasitic capacitances of the panel and the common-mode voltage. At the same time, the common-mode voltage depends on the modulation strategy used. Therefore, by the manipulation of the modulation technique, is accomplished a decrease in the leakage current. However, the connection standards for photovoltaic inverters establish a maximum total harmonic distortion of 5%. In this paper an analysis of the common-mode voltage and its influence on the value of the leakage current is described. The main topologies and strategies used to reduce the leakage current in transformerless schemes are summarized, highlighting advantages and disadvantages and establishing points of comparison with similar topologies. A comparative table with the most important aspects of each converter is shown based on number of components, modes of operation, type of modulation strategy used, and the leakage current value obtained. It is important to mention that analyzed topologies present a variation of the leakage current between 0 to 180 mA. Finally, the trends, problems, and researches on transformerless grid-connected PV systems are discussed.

scholarly journals Fundamental elements of constant volt/hertz induction motor drives based on dSPACE DS1104 controller

2020 ◽  
Vol 11 (4) ◽  
pp. 1670
Author(s):  
Siti Nursyuhada Mahsahirun ◽  
Nik Rumzi Nik Idris ◽  
Zulkifli Md. Yusof ◽  
Tole Sutikno
Keyword(s):  
Induction Motor ◽  
Industrial Applications ◽  
Open Loop ◽  
Voltage Source ◽  
Switching Frequency ◽  
Current Waveform ◽  
Simulink Model ◽  
Speed Regulation ◽  
Drive Control ◽  
Controller Board

An induction motor (IM) has been the workhorse of the industry for decades. It is due to its robustness, simple construction, requiring less maintenance and cheap. One of the most widely adopted IM drive control schemes for industrial applications is the open-loop constant V/Hz. In this paper, the important elements of an open-loop constant V/Hz drives are presented. These include the fundamental concept of a constant V/Hz scheme, the voltage source inverter (VSI) and its modulation schemes. Techniques that are commonly used to solve problems of low-speed operation and rotor speed regulation are briefly described. Simulations using MATLAB/Simulink package are used to help in illustrating these fundamental concepts. Finally, simple laboratory-scale experiments are conducted to implement the constant V/Hz control scheme on a ¼ hp induction motor. The constant V/Hz control is implemented using the DS1104 controller board with the C codes automatically generated from the Simulink model. A closer look at the current waveform when fref=25 Hz and 12 Hz and its respective Fourier analysis are presented. The results show that the high-frequency harmonic contents around the switching frequency can be observed for both cases, and the voltage waveform presents more spike noises in constrast to  current waveform.

scholarly journals Evolutionary and Metaphor-Metaheuristic MPPT Techniques for Enhancing The Operation of Solar PV Under Partial Shading Condition

2019 ◽  
Vol 8 (12) ◽  
pp. 2206-2216 ◽  
Keyword(s):  
Local Maximum ◽  
Industrial Applications ◽  
Maximum Power ◽  
Operating Point ◽  
Solar Pv ◽  
Partial Shading ◽  
Pv Systems ◽  
Advantages And Disadvantages ◽  
Point Tracking ◽  
Power Point

Photovoltaic (PV) systems are the most popular electric power generation systems for domestic as well as industrial applications because of its sustainability and excess availability in nature. Under Partial Shading Condition (PSC), the nonlinear characteristics of solar PV consist of multiple local Maximum Power Points (MPPs) and one global MPP. Hence, it is difficult to operate the operating point of the solar PV closer to true MPP. There are different tracking methods available for MPP Tracking in the literature. The classical Maximum Power Point Tracking (MPPT) methods are not suitable under partial shading conditions because the operating point of PV may settle down to any one of the local MPP. Also, these methods failed to mitigate the oscillations across the operating point of solar PV. The recently developed evolutionary based MPPT techniques are becoming more prominent in order to avoid the drawbacks of classical MPP techniques. In this article, different types of MPPT techniques such as evolutionary, metaphor-metaheuristic and hybrid MPPT techniques are discussed in detail along with their advantages and disadvantages. The comparative analysis is carried out by considering the parameters such as tracking speed, oscillation across MPP, settling time, implementation complexity and efficiency

scholarly journals Multivariable Deadbeat Control of Power Electronics Converters with Fast Dynamic Response and Fixed Switching Frequency

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 313
Author(s):  
Jaime A. Rohten ◽  
David N. Dewar ◽  
Pericle Zanchetta ◽  
Andrea Formentini ◽  
Javier A. Muñoz ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Power Systems ◽  
Power Converter ◽  
Current Control ◽  
Renewable Energies ◽  
Voltage Source ◽  
Switching Frequency ◽  
Control Loop ◽  
Voltage Source Inverters ◽  
Power Electronics Converters

Power converters have turned into a critical and every-day solution for electric power systems. In fact, the incorporation of renewable energies has led towards the constant improvement of power converter topologies and their controls. In this context, over the last 10 years, model predictive control (MPC) is positioned as one the most studied and promising alternatives for power converter control. In voltage source inverters (VSI), MPC has only been applied in the inner current control loop, accelerating and improving its dynamic response, but as mentioned, has been limited only to the current control loop. The fastest of the MPC techniques is the Deadbeat (DB) control, and in this paper, it is proposed to employ DB control on the entire system, therefore accelerating the time response not only for the current loops, but also for voltage loops. At the same time, this avoids overshoots and overpower in order to protect the power converter, leading to the fastest dynamic response according to VSI capabilities. For renewable energies, fast-dynamics entails fast maximum power tracking and therefore, maximizes energy harvesting, or in other words, reduces the losses due to the control dynamics. Thus, this paper gives a clear procedure and key points for designing a DB control for all the variables based on a mathematical model, which is corroborated by simulations and the experimental results.

scholarly journals Common-Ground Photovoltaic Inverters for Leakage Current Mitigation: Comparative Review

2021 ◽  
Vol 11 (23) ◽  
pp. 11266
Author(s):  
Mahmoud A. Gaafar ◽  
Mohamed Orabi ◽  
Ahmed Ibrahim ◽  
Ralph Kennel ◽  
Mohamed Abdelrahem
Keyword(s):  
Leakage Current ◽  
Performance Indicators ◽  
High Frequency ◽  
Common Ground ◽  
Parasitic Capacitance ◽  
Pv Systems ◽  
Advantages And Disadvantages ◽  
Comparative Review ◽  
Grid Side ◽  
The Cost

In photovoltaic systems, parasitic capacitance is often formed between PV panels and the ground. Because of the switching nature of PV converters, a high-frequency voltage is usually generated over these parasitic capacitances; this, in turn, can result in a common-mode current known as leakage current. This current can badly reach a high value if a resonance circuit is excited through the PV’s parasitic capacitance and the converter’s inductive components. Transformers are usually used for leakage current mitigation. However, this decreases the efficiency and increases the cost, size, and weight of the PV systems. Number of strategies have been introduced to mitigate the leakage current in transformer-less converters. Among these strategies, using common-ground converters is considered the most effective solution as it offers a solid connection between the negative terminal of PV modules and the neutral of the grid side; thus, complete mitigation of the leakage current is achieved. Number of common-ground inverters have been recently presented. These inverters are different in their size, cost, boosting capability, the possibility of producing DC currents, and their capability to offer multilevel shaping of output voltage. This work introduces a comprehensive review and classification for various common-ground PV inverters. Therefore, a clear picture of the advantages and disadvantages of these inverters is clarified. This provides a useful indication for a trade-off between gaining some of the advantages and losing others in PV systems. In addition, the potentials for optimization based on different performance indicators are identified.

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