Inverter Topology Research Articles

A Grid-Connected PV System Based on Quasi-Z-Source Inverter With Maximum Power Extraction

This paper proposes an approach to link photovoltaic arrays with the AC grid using Z-source inverter (ZSI) and quasi-Z-source inverter (QZSI) topologies. These topologies boost the DC-link voltage and invert it to AC voltage in one stage, resulting in a reduction in the overall system size and cost. The paper presents a control technique that fixes the DC-link voltage on the inverter bridge terminals, tracks the maximum power point (MPPT), and controls the amount and quality of power injected into the grid using unity power factor. The proposed control algorithm utilizes two independent control variables, shoot-through duty cycle (ST) and modulation index, to decouple the control of the DC and AC sides. The effectiveness of the proposed control technique is verified through simulations of a grid-connected PV system. The results demonstrate that the proposed system can efficiently extract maximum power from PV arrays while regulating the DC-link voltage and ensuring unity power factor operation. Additionally, experimental testing of ZSI/QZSI further confirms the results of analysis and simulation.

A Reduced Switch Count, Self-Balanced, 13-Level Inverter Based on a Dual T-Type Configuration

A new Dual T-Type 13-Level inverter topology is presented in this paper, featuring less power switches, gate drivers, and diodes, than inverters based on traditional multilevel topologies, such as Neutral Point Clamped, Flying Capacitor, T-Type and Cascaded H-Bridge, or previously proposed reduced switch count 13-level inverter topologies. Moreover, no additional circuits are required to equalize the voltage of capacitors present in each pole, nor complex modulation strategies, leading to a reduction of cost and power losses. Exploiting a Nearest Level Modulation technique, the proposed topology performs well in terms of efficiency and total harmonic distortion, as confirmed by experimental tests.

Evaluation of CHB MLI based shunt APF using low pass filter and self-tuning filter

The increasing demand for high-rating power supply in the distribution system causes the conventional inverter topology, six step voltage source inverter (SSVSI) unsuitable for being applied as active power filter (APF). Multilevel inverter (MLI) is generally the best suitable inverter for APF, but not all types of MLI can be used for high-voltage applications. Among the MLIs topology, cascaded H-bridge (CHB) is the best choice since it can produce output voltage more than twice the amount of DC source. Moreover, CHB MLI topology uses fewer power devices and is simple in design. Low pass filter (LPF) is a common method used for harmonic extraction in this controller. However, this method faces various problems, such as an additional need for phase lock loop (PLL) algorithm and slow transient and steady-state responses. Therefore, self-tuning filter (STF) is introduced as a new filtering method to overcome this problem. This paper evaluates CHB MLI's performance for APF using STF as a harmonic extraction. The model was developed and verified in MATLAB/Simulink. The results show that harmonic extraction using STF performs better total harmonic distortion (THD) than conventional LPF. Nevertheless, both algorithms produce THD below 5%, defined as the permissible value stated in IEEE 519.

Flux-Rate Controlled Harmonic Filtering of an Integrated Magnetics-Based Isolated Single-Phase Inverter Topology

Flux-Rate Controlled Harmonic Filtering of an Integrated Magnetics-Based Isolated Single-Phase Inverter Topology

Reduction of Spurious Switching in Direct Vector Quantized Space Vector Pulse Density Modulation Scheme for Multilevel Inverters

A generalized online switching scheme for multi-level inverter based on Direct Vector Quantized Space Vector Pulse Density Modulation (DVQSVPDM) suitable for adjustable speed drive is proposed in this article. The existing DVQSVPDM schemes have spurious switching as the voronoi region is determined from integrated error vector of Sigma Delta Modulator (SDM). This results in high Total Harmonic Distortion (THD) of Common Mode Voltage (CMV) at lower modulation index. In the proposed DVQSVPDM the nearest three space vectors to the reference vector forms the triangular voronoi region. The integrated error vector of SDM is quantized to its nearest space vector in the voronoi region to generate the switching vectors. This reduces spurious switching associated with DVQSVPDM schemes and improves the performance at lower modulation index by reducing THD of CMV. The proposed scheme works for all n-level inverter topologies and the computations required remain same irrespective of level of inverter. Redundant states of switching vectors are not considered for switching which results in the discontinuous nature of proposed scheme. The performance of proposed DVQSVPDM is compared with space vector based modulation schemes and third harmonic injected sine PWM scheme and the results are presented. The proposed scheme is experimentally validated for a 3hp open end winding induction motor fed with three-level inverters on both sides.

A DUAL AXIS SOLAR TRACKER WITH A HYBRID CASCADED MULTILEVEL INVERTER

Energy crisis is one of the biggest problems in developing countries. There is a big gap between generation and demand of Electric energy. Solar energy which is present in abundance can play a vital role to overcome the energy deficiency. The potential of solar voltaic energy can also be exploited for averting environmental pollution and managing atmospheric emission. This project work provides a proposal for design of an inverter using dual axis solar tracker installed on rooftop with a single phase hybrid cascaded multilevel inverter. The output of a photovoltaic panel depends on its position with respect to the sun at any instant of time. To extract the maximum power from the panel, tracking systems are generally used for positioning it at an optimal angle. . This project focuses on presenting the structure and application of a microcontroller based dual axis solar tracker which tracks the direction of the solar radiation thereby adjusting the movement of solar panel accordingly. This facilitates the sun to remain perpendicular to the PV panel throughout the day which makes the total energy received to be increased by 30-40%. The energy hence received gets stored in a chargeable battery. This battery has an inverter attached to it so that whenever there is a power-cut, the stored energy may be used to light up the appliances. This project also provides single phase hybrid cascaded modular multilevel inverter topology which is derived from a proposed modified H-bridge (MHB) module. This topology results in the reduction of number of power switches, losses, installation area, voltage stress and converter cost. For renewable energy environment such as Photovoltaic (PV) connected to the micro- grid system, it enables the transformer less operation and enhances the power quality. This multilevel inverter is an effective and efficient power electronic interface strategy for renewable energy systems. The verification of the applicability and performance of the proposed structure in PV renewable energy environment, INTERNATIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT (IJSREM) VOLUME: 07 ISSUE: 09 | SEPTEMBER - 2023 SJIF RATING: 8.176 ISSN: 2582-3930 © 2023, IJSREM | www.ijsrem.com DOI: 10.55041/IJSREM25875 | Page 2 simulation results were carried out by MATLAB/SIMULINK under both steady state and dynamic conditions was completed.

Design a 25-level inverter topology with less switching devices fed by PV systems

<span lang="EN-US">Multilevel inverter (MLI) technology has lately emerged as one of the most popular solutions for high power and medium voltage energy management. MLIs have many benefits and require more switches for higher levels, which are considered disadvantaged. This could result in large size and extremely expensive cost for the MLI. So, in order to overcome this problem, a new MLI topology is proposed with reduced number of switches. A 25‐level inverter fed by isolated unequal photovoltaic panels as DC sources is chosen in this study. The structure of DC voltages is chosen as (1:1:5:5) Vdc. The proposed approach, which is created using twelve switches, is ideally suited for a high-power application. Multi-carrier with a sinusoidal PWM technique is programmed as a controller. According to the simulation findings, a single-phase system's output voltage and current total harmonic distortion (THD) values are 1.2% and 0.462%, respectively, while a three-phase system's values are 1.07% and 0.342%. These findings prove that the power circuit and investigation were successful.</span>

A new floor function single‐carrier‐based modulated model predictive current control technique for single‐phase PUC5 inverter topology

SummaryIn this paper, a new floor function (F2) single‐carrier (SC)‐based modulated model predictive current control technique (M2PC2T) has been proposed by considering the conventional single‐phase five‐level packed U‐cell (PUC5) inverter topology. Generally, to regulate the output current, the finite control set‐based MPC technique without a modulator inherently operates with variable switching frequency, and it is unsuitable for industrial applications. To alleviate this, authors have implemented M2PC2T, which provides constant switching frequency of operation. In this technique, generally, the predictive algorithm has been integrated with any modulation stage. However, while the implementation of pulse width modulation (PWM) techniques, most authors have used conventional PWM techniques which further increases the control complexity as the level number increases. In this manuscript, a simple and generalized F2‐SC‐PWM technique has been proposed and integrated with the predictive algorithm. This PWM technique implementation process is very simple as compared with all conventional PWM techniques since even if the level number increases, the number of modulating and carrier signals is always only one. Finally, the complete closed‐loop control technique is called a generalized F2‐SC‐M2PC2T which is suitable for all stiff direct current (dc) sources and switched capacitor‐type multilevel inverter (MLI) topologies. The proposed control technique (PCT) has been experimentally verified with different transient and steady‐state case studies by considering resistive‐inductive load.

Analysis and control of single‐phase transformerless dual‐frequency grid‐connected inverter

SummaryTo simplify the inverter topology and suppress the leakage current more effectively, a novel transformerless dual‐frequency grid‐connected inverter with a common direct current (DC) bus is proposed. The proposed inverter retains the advantages of the traditional dual‐frequency inverter such as high efficiency and absence of resonance. In the novel topology, the power unit adopts the highly efficient reliable inverter concept (HERIC) topology with a unipolar modulation strategy, and the auxiliary unit adopts the H‐bridge topology with a bipolar modulation strategy. It is verified that the circulating current between the two units can be eliminated in the proposed inverter. The sensitivity of the circulating current is discussed by considering the tolerance of the filter inductances. In the leakage current equivalent circuit, the DC bus of the power unit is connected to the grid through a low‐impedance branch in parallel with the parasitic capacitance. Therefore, the leakage current is effectively suppressed. Finally, the experimental results are provided to verify the performance of the inverter.

A new single modulating and single carrier‐based predictive current control technique for single‐phase quadruple boost multilevel inverter topology

SummaryA new floor function single carrier‐based modulated model predictive current control (F2‐SCM2PC2) technique has been proposed in this paper by considering traditional single‐phase quadruple boost switched capacitor‐based multilevel inverter (QB‐SCMLI) topology. Conventionally, the implementation process of single modulating and single carrier‐based pulse width modulation (PWM) techniques are very much complex and finite control set‐based model predictive control (FCS‐MPC) technique inherently operates with variable switching frequency (VSF) operation, which is not suitable for industrial applications. To alleviate the aforementioned issues, a new generalized closed‐loop F2‐SCM2PC2 technique has been proposed. It consists of a simple PWM implementation process and can easily be integrated with a predictive algorithm, thereby providing a constant switching frequency (CSF) of operation. The particular single modulating and single carrier‐based PWM technique with floor function is also suitable for low and high switching frequency (LSF‐HSF) operations. The validation of floor function‐based PWM technique in open‐loop and closed‐loop F2‐SCM2PC2 techniques has been effectively verified through experimentation on QB‐SCMLI topology with consideration of resistive–inductive load.

Five-phase induction motor drive-A comprehensive review

Modern Electrical Vehicles (EV) and Electric Traction rely heavily on electrical drives. Every day, electric vehicles are being improved and expanded to include commercial vehicles such as passenger vehicles, goods delivery vehicles, and agricultural vehicles. Today, researchers are concentrating on multi-phase electrical drives to improve EV technology. This article provides a comprehensive analysis of the Five-Phase Induction Motor (FPIM) drive. The proposed study investigates the FPIM drive in terms of mathematical modeling and design, the different topologies of a Five-Phase Voltage Source Inverter (FPVSI) (Two-Level, Multi-Level, Matrix), the methodologies utilised to generate the pulse for FPVSI (Carrier-Based Pulse Width Modulation (CBPWM), Space Vector Pulse Width Modulation (SVPWM)), and the control of FPIM. This study evaluates the many strategies available in the literature for controlling the FPIM in order to assist researchers and industrial Research and Development (R&D) engineers in selecting the most suitable tool for their applications.

Efficiency of Series APF based on Nine-level NPC Inverter Compared to Seven-level Configuration

This article presents the performance comparison of Series Active Power Filter (Series APF) based on seven and nine multi-level Neutral Point Clamped (NPC) inverters using the same control scheme. The Series APF is one of the most efficient and effective modern custom power devices used in power distribution networks to compensate voltage harmonic and all voltage disturbances. The conventional configuration based on voltage source inverter (VSI) operated at very high switching frequency presents several drawbacks and limited for low power applications. To overcome these problems and improve the output voltage different multi-level are used in various power application in particular Flying Capacitor (FC), Cascade H-Bridge (CHB) and multi-level (NPC) inverters. In this study seven and nine-level (NPC) inverters are proposed for active power filtering system; these inverters present diverse advantages include the capability to reduce the harmonic content, decrease the voltage or current ratings of the semiconductors and mainly they can work at low switching frequency. To generate switching pulses Multi-Carrier Level-Shifted Pulse Width Modulation (MC-LSPWM) control technique is adopted with modified P-Q control strategies. To verify the accuracy and the performance of the proposed Series APF models, simulation is performed using MATLAB-Simulink platform and SimPowerSystem Toolbox. The obtained results show the superiority of series APF based on nine-level in term of THDv reduction compared to the systems with seven-level inverter topology.

Spf1 and Ste24: quality controllers of transmembrane protein topology in the eukaryotic cell.

DNA replication, transcription, and translation in eukaryotic cells occur with decreasing but still high fidelity. In contrast, for the estimated 33% of the human proteome that is inserted as transmembrane (TM) proteins, insertion with a non-functional inverted topology is frequent. Correct topology is essential for function and trafficking to appropriate cellular compartments and is controlled principally by responses to charged residues within 15 residues of the inserted TM domain (TMD); the flank with the higher positive charge remains in the cytosol (inside), following the positive inside rule (PIR). Yeast (Saccharomyces cerevisiae) mutants that increase insertion contrary to the PIR were selected. Mutants with strong phenotypes were found only in SPF1 and STE24 (human cell orthologs are ATP13A1 and ZMPSte24) with, at the time, no known relevant functions. Spf1/Atp13A1 is now known to dislocate to the cytosol TM proteins inserted contrary to the PIR, allowing energy-conserving reinsertion. We hypothesize that Spf1 and Ste24 both recognize the short, positively charged ER luminal peptides of TM proteins inserted contrary to the PIR, accepting these peptides into their large membrane-spanning, water-filled cavities through interaction with their many interior surface negative charges. While entry was demonstrated for Spf1, no published evidence directly demonstrates substrate entry to the Ste24 cavity, internal access to its zinc metalloprotease (ZMP) site, or active withdrawal of fragments, which may be essential for function. Spf1 and Ste24 comprise a PIR quality control system that is conserved in all eukaryotes and presumably evolved in prokaryotic progenitors as they gained differentiated membrane functions. About 75% of the PIR is imposed by this quality control system, which joins the UPR, ERAD, and autophagy (ER-phagy) in coordinated, overlapping quality control of ER protein function.

Comparative performance of modular with cascaded H-bridge three level inverters

<span lang="EN-US">The conventional two-level inverter becomes no longer has the ability to cope with the high-power requirement, so this paper discusses two very common topologies of multilevel inverter like modular multi-level converter (MMC) and cascaded H-bridge (CHB) multi-level inverter for induction motor drive applications. This work attempts to investigate the comparison between MMC and CHB. The comparison is done in aspects of the configuration, concept of operation, advantages and disadvantages, the comparison is also consider output voltage (line to line) waveform, total harmonic distortion (THD) of the output line voltage waveform and the current drawn by both inverters. The performance of the inverters under carrier-based pulse width modulation (PWM) technique and mainly in-phase disposition (IPD), level shifted pulse width modulation is viewed. The paper discusses the comparison between the two multilevel inverters (MLIs) with motor drive applications especially induction motor. The operation of the motor is studied under certain value of load torque. The simulation results for the induction motor with the two inverters (modular multi-level and Cascaded H-bride) for three numbers of levels using MATLAB/Simulink are provided). The obtained results are encouraging and promising especially in the improvement of the THD% results.</span>

Design and control of a novel topology for multilevel inverters using high frequency link

The requirement of more than one source in multilevel inverters is an issue to be solved for applications with a single DC source. One solution to this problem is to obtain the required voltages using High Frequency Link (HFL). With the traditional use structure of HFL, only one DC source is generated from each diode bridge unit. In this study, voltage generation is diversified as full and half by adding only one switching device and one diode to this circuit. With the proposed modified HFL circuit topology, 35 levels were obtained from 15 level generating circuits. It was compared with some recently published papers using HFL and a satisfactory result was observed in terms of total standing voltage (TSV), although the use of switching devices was reasonable. Proposed topology with different frequency and amplitude outputs has been verified both in simulation environment and experimentally using FPGA board. In terms of the economic dependability of the proposed inverter, calculations for the TSV, cost per level factor, and efficiency have been performed. According to the results obtained, it has been observed that the total harmonic distortion of the output waveform of the proposed topology is 2.5%.

PI Controlled Bridged Grid-Connected Solar PV Network for Electric Vehicle Battery Charging

The Z-source inverter (ZSI) topology replaces multiple stages into a single stage in power conversion so it is going to be an appropriate topology for 1-phase grid-connected PV system. In this paper, the various z-source topologies are discussed as available in different literature. This paper has proposed a proportional and integral (PI) Controlled bridged grid-connected solar photovoltaic (PV) network for electrical vehicle charging. The different modulation techniques applied in these topologies have been described. The bridged grid-connected network equipped with solar modules can prove effective in developing charging infrastructures for electric vehicles (EVs) at residential or commercial complexes. The different parameters of this suggested topology may vary during different time instants of a whole day at different modes of procedure i.e solar PV generation to the grid, EV to grid, and both PV and EV to grid. The simulation work has been done with the PWM technique to obtain battery voltage and grid voltage, Fast Fourier Transform, and total harmonic distortion.

An Improved Quadruple-Boost Switched-Capacitor-Based Nine-Level Inverter

This letter proposes an improved quadruple boosting nine-level (IQB9L) inverter with a reduced component count requiring ten switches, three diodes, and two capacitors for 9 L operation. The capacitors are self-voltage balanced using the series-parallel technique, ensuring sensorless operation. The devised structure exhibits the least conducting devices at each level resulting in reduced conduction losses. In addition, fewer devices transit at any level than similar state-of-the-art topologies, thus, reducing switching losses. A detailed comparison of the proposed IQB9L inverter demonstrates its improved performance. The experimental results are presented to validate the feasibility of the proposed inverter topology.

Grid Harmonics Suppression for Three Phase Dual-Frequency Grid-Connected Inverter Based on Feedforward Compensation

Using a low pulse ratio, the electromagnetic interference and switching loss of an inverter can be effectively reduced, particularly in high-power applications. However, due to variations in grid impedance, it is a challenging task to achieve stable operation of an LCL-type grid-connected inverter (GCI) using the active damping method with low pulse ratio. Thus, a novel three-phase dual-frequency GCI is presented to ensure the symmetry of the output power and the stable operation of the system address stability issues. The proposed inverter topology in this article is composed of two inverters in parallel, which are, respectively, a power inverter unit (PIU) and an auxiliary harmonic elimination unit (AHEU). To reduce the switching loss and improve the inverter efficiency, the switching frequency of the PIU is relatively low, injecting current into the grid. Moreover, the feedforward compensation method is used in AHEU. AHEU operates at high switching frequency to generate a current component that is symmetrical with the ripple com-ponent, improving the power quality, without extracting the current harmonic as the current reference. The operating principle of feedforward compensation is explained, and a proper parameter design procedure is presented in this paper. Since L filters are used for the proposed inverter, the system can operate stably where the ratio of switching frequency to fundamental frequency is low. A 10 kW laboratory prototype was built. The experimental results showed that the grid current ripple could be effectively eliminated and the THD of the grid current was 3.01%. The proposed inverter has good stability in a weak grid, and the efficiency of the proposed inverter is 95.98% at rated current, which is 0.81% higher than the traditional GCI, effectively increasing the efficiency of the system.

Simulation of Asymmetrical Seven Level Multi Level Inverter using MATLAB Simulink

Abstract: Multi-Level Inverter (MLI) has gained significant significance in medium power and medium voltage AC drive applications. Various topologies have been developed in the design of MLIs. Hybrid topologies are emerging to minimize component requirements and reduce switching losses. This paper introduces a comprehensive analysis and functioning of the asymmetrical seven level multi-level inverter topology. The modeling process is executed using the MATLAB Simulink environment.

VSG Control for Cascaded Three-Phase Bridge Based Battery Inverter

With the increasing number of new energy sources connected to the grid, the unbalanced output of three-phase grid-connected inverters and the lack of no inertia and damping characteristics in the traditional microgrid control system will seriously affect the stability of voltage, frequency, and power angle for microgrids. This paper proposes a novel cascaded three-phase bridge inverter topology for the battery system used for the electric vehicle. Compared with traditional cascaded H-bridge inverters, the proposed multilevel inverter can achieve self-adaptive balance for three phases. The mathematical model of a cascaded three-phase bridge inverter is established in this paper. Based on the voltage and current equations of a multilevel inverter, a new modulation strategy named carrier phase-shifted-distributed pulse width modulation (CPSD-PWM) was developed, which is more suitable for cascaded three-phase bridge inverters. The harmonic analytic equations of carrier phase-shifted pulse width modulation (CPS-PWM) and CPSD-PWM are constructed by the double Fourier analysis method. Compared with the traditional PWM modulation strategy, the CPSD-PWM can reduce the output harmonics and improve the balance of the three-phase output, which can realize the three-phase adaptive balance in the cascaded three-phase bridge inverter. This paper develops a cascaded three-phase bridge multilevel power converter system based on the virtual synchronous generator (VSG) control strategy. The voltage and frequency of inverter output can be accurately controlled in both island mode and grid-connected mode through active power-frequency regulation and reactive power–voltage regulation, and the stability of primary frequency regulation for the multilevel microgrid inverter can be improved by collaborative optimization of virtual inertia and virtual damping. The CPSD-PWM modulation strategy and VSG control strategy are verified by the simulation results and experimental data for the cascaded three-phase bridge inverter.