Performance Of Converter Research Articles

Selective Harmonic Elimination Technique Improvement for Cascaded H-Bridge Multilevel Converters Under DC Sources Uncertainty

The performance of multilevel converters (MLCs) is at the risk of uncertainty of DC sources. This issue has a more negative effect on three-phase cascaded H-bridge MLCs (CHB-MLCs) due to more isolated DC sources. DC voltage variation can take place in all phases, but in this paper, the effect of DC voltage variation of one phase on line voltages is considered. This problem can lead to unbalanced line voltages and a lack of third harmonic elimination in a spontaneous way. Therefore, these problems cause to modify the formulation of quarter-wave symmetrical selective harmonic elimination (SHE) for three-phase CHB-MLCs so that the line voltages become resistant to DC voltage variations as well as mitigating third harmonic. To keep line voltages amplitude fixed under variation of DC voltages, it is necessary to take advantage of non-identical modulation indices to exploit the maximum capacity of DC voltages. Furthermore, regarding unequal DC voltages that can appear in numerous states in a phase, a new method based on the average of DC voltages (ADCV) per phase is employed in the formulation of SHE to reduce these states. Finally, both simulation and experimental results are presented to validate the performance of the proposed method.

Systematic Review of Bidirectional, Multiport Converter Structures and Their Derivatives: A Case Study of Bidirectional Dual Input Dual Output Converters

This study thoroughly compares multiple single bidirectional and multiport converters (MPCs), highlighting the significant role of MPCs in multi-input and multi-output (MIMO) systems. MPCs offer a more efficient and cost-effective solution than multiple single converters, especially in applications involving photovoltaic (PV), electric vehicles (EVs) with storage systems, and power grids. This research emphasizes the importance of multi-input converters (MICs) in integrating diverse voltage sources. It notes the rising popularity of multi-output DC-DC converters in portable electronics, owing to their reduced component count, lower costs, and compact design. This paper emphasizes comparisons based on diverse aspects and applications, shedding light on recent developments in basic bidirectional converters. Additionally, it delves into the advancements in MPC topologies, focusing on efficiency, reliability, and modularity improvements. These advancements are crucial for harnessing cost reduction, simplicity, and compactness. Furthermore, this paper introduces an innovative multiport DC-DC converter tailored for integrating and managing renewable sources. This new converter design enhances PV system and battery storage performance by reducing power conversion steps, using fewer components, and improving voltage-boosting capabilities. Its unique bidirectional buck-boost structure allows for versatile connections between sources and loads with varying voltage and power requirements. The performance of this novel converter is evaluated through MATLAB/Simulink simulations under different scenarios. Experimental studies further validate its effectiveness, marking a significant contribution to power conversion and management in integrating renewable sources such as DC microgrids.

Phase-Shifting Adaptive LLC Resonant Converter with Reduced Turn-Off Loss in Wide Voltage Application

In this paper, a hybrid control method with adaptive phase-shifting modulation (PSM) and pulse-frequency modulation (PFM) is proposed to optimize the steady-state performance of an LLC resonant converter in wide voltage-gain range application. For the primary-side switches under the hybrid control method, zero-voltage switching (ZVS) performance is maintained over wide voltage-gain range and the turn-off loss is reduced; therefore, the converter reconciles wide voltage-gain range and high efficiency. Mode characteristics under different phase-shifting-angle-θ and switching-frequency-fs combinations is analyzed, and then the soft-switching characteristic is revealed. By introducing time domain analysis, the turn-on current of the primary-side switches is calculated, and thus the ZVS boundary of different θ and fs combinations is inferred. In addition, to acquire the optimum steady-state operation of the converter, the turn-off current is calculated; by making the converter work near to the minimum turn-off current operating point, the turn-off loss can be reduced greatly. With the principles of achieving ZVS performance and minimizing turn-off current, the phase-shifting angle θ of PSM is designed to be adaptive to the reference output voltage, no additional circuits are needed, and the two control degrees (θ and fs) are simplified to one (fs). The simulation and experiment are developed to verify the feasibility and effectiveness of the hybrid control method; the results show that ZVS performance is maintained at wide voltage-gain range and the turn-off current of the hybrid control method is reduced to that of the single PFM, and thus the turn-off loss is reduced. The efficiency comparison validates the fact that the hybrid control method has less power loss than single PSM and single PFM.

Voltage Regulation and Power Factor Enhancement for EV Charging Station by Using Optimization Algorithm

A Cuk converter-based Power Factor (PF) and voltage regulation enhancement model for an electric vehicle (EV) charging circuit is created and developed, utilizing an optimization technique. Using the Cuk converter's performance measures in Continuous Conduction Mode (CCM), the charging system may produce a steady output current with better PF. This project implements an optimization algorithm-based correction approach for power factor and voltage regulation. The Jaya optimization algorithm, which is a basic metaheuristic algorithm, uses less algorithm-specific parameters. The use of an optimization algorithm aids in the dynamic adjustment of converter operation to maintain the appropriate power factor and voltage levels under non-linear situations such as load fluctuations and input changes. The algorithm evaluates the output and modifies the system's parameters to optimize performance for real-time EV applications, taking into account factors such as changing load requirements, input supply uncertainty, and desired voltage levels. The suggested method is created and tested in MATLAB/Simulink. The suggested algorithm is then confirmed experimentally as a hardware prototype.

Standard log-capture differentials as performance metrics for deepwater wave power generation

As a support to performance assessment of deepwater wave energy converters, this work quantifies susceptibility of output power to short duration variations, independent of source wave statistics. Introduced as ς-metrics, the quantified measures may be a basis for technology comparisons, with possible convergence to a choice for implementation. The metrics further allow comparison between different versions of a specific converter technology, thereby helping in design revision and refinement.With power conversion represented in terms of a technology specific capture width function, the log-capture differential is defined relative to a hypothetical benchmark characterised by negligible power variability. Root-mean-square aggregation of the differential further leads to standard log-capture differentials as site independent ς-metrics for a capture-and-conversion mechanism.Study results are included in three phases. First, three established wave energy conversion technologies are analysed at respective power maximums, so as to illustrate applicability of log-capture differential and ς-metrics. Next, the metrics are analysed at fractional output power to realise converter performance at reduced variability. Finally for a given marine environment, ς-metrics are shown to be useful in projection of output power variability across technologies, together with the mean output power as fraction of rated maximum.

Modeling, simulation, and experimental studies of a novel battery charger for fuel cell applications based on a new high step‐up DC‐DC converter

SummaryDuring winter, the proton exchange membrane fuel cell (PEMFC) faces operational challenges, potentially leading to ice formation in membranes and gas technology. To achieve favorable operational conditions and output voltage, suitable power electronic devices are indispensable. Consequently, the fuel cell module links to the battery through a DC‐DC converter. Addressing the necessity for an efficient battery charger in fuel cell electric vehicle applications, this article introduces a new high step‐up DC‐DC converter. It employs a boosting structure, incorporating a coupled inductor to elevate voltage gain while substantially reducing voltage and current stresses on components, a fitting attribute for PEMFC electric vehicle battery chargers. Additionally, the proposed converter boasts high efficiency and a minimal component count. Moreover, the study meticulously explores various operating modes of the converter, offering comprehensive analyses and operational relationships. To evaluate dynamic behavior and ensure stability, the study employs small signal modeling and devises a controller based on the maximum power point tracking principle. MATLAB simulations validate the converter's performance, while a laboratory‐built prototype (48 V input, 220 V output, 500 W) substantiates its characteristics, aligning with theoretical projections. Finally, a comparative analysis between simulation, experimentation, and theoretical calculations validates the converter's functionality. Ultimately, this work emphasizes the critical role of a well‐designed high‐efficiency DC‐DC converter in the context of PEMFC electric vehicle battery charging during challenging winter conditions. The proposed converter's innovative design, minimal componentry, efficiency, and validated performance through simulation, experimentation, and theory underscore its potential significance in enhancing fuel cell electric vehicle technology.

Economic feasibility study for wave energy conversion device deployment in Faroese waters

As the world continues to battle with increasing energy demand along with the serious effects of climate change, there is a need for more reliable renewable energy sources. The objective of the present work is to study the economic feasibility for deployment of wave energy conversion devices in the Faroese coastal region. We analyze eight different wave energy conversion concepts under development at nine different nearshore locations in the Faroese coastal region. The nine different locations are classified into three coastal locations — three on the west coast, three on the east coast and three on the north coast. The eight wave energy conversion devices mostly rely on different working principles, though some of these are similar. Results show that there is quite a significant difference in the performance of the devices from coast to coast. There is also a difference between the different conversion devices as they rely on different principles and the suitability of each device varies from location to location. We also show that the Faroe Islands are a suitable location for wave energy converter deployment compared to other places. Furthermore, results show that the performance of wave energy converters in the Faroe Islands can prove to be a direct competitor to offshore floating wind energy.

Soft switching high step-up three-level boost DC-DC converter with Quasi Z-source for Photovoltaic application

A three-level Boost DC-DC converter is proposed in this paper. Quasi Z-source converter acts as an auxiliary circuit to create soft switching condition for all active elements. Consequently. The converter efficiency is very high. Using a three-level structure in the proposed converter causes the maximum voltage stress across the semiconductor devices is limited to half of the output voltage. The converter has a high voltage gain and a small number of elements. The converter is analyzed with details in all operating modes. Furthermore, the experimental results are obtained to prove the converter performance based on the theoretical considerations.

Study on Influence of Core Structure on Catalytic Converter Performance Using CFD

In recent years, as the automotive industry is growing, one of the major hope for future vehicles is to meet emissions regulations. Automobiles pollute the air, and clean-air laws have made Catalytic Converters a legal requirement because they convert harmful pollutants from an engine's exhaust into cleaner emissions. The device works with the principle of a catalyst, something that causes or speeds up a chemical reaction without itself being changed. But the presence of a catalytic converter increases the exhaust back pressure which has an indirect effect on the engine efficiency ie engine efficiency decreases, thus increasing fuel consumption. The performance of a catalytic converter is substantially affected by the flow distribution inside the substrate, a uniform flow distribution can increase its efficiency, lower the pressure drop and optimize engine performance. The flow distribution in a catalytic converter assembly 15 is governed by the geometry configurations of the inlet and outlet cone section, the substrate, and exhaust gas compositions, and therefore a better design of the catalytic converter is very important. This Project deals with the fundamental understanding and study of complex processes taking place involving fluid flow, pressure, and velocity profiles in the catalytic converter using ANSYS WORKBENCH 2022 R1. The main objective of our analysis is to determine the most effective and optimum design of a Catalytic Converter

An Observer-Based Multivariable Controller for Improved Performance of Voltage Source Converters With LCL Filter Connected to Unbalanced Grid

An Observer-Based Multivariable Controller for Improved Performance of Voltage Source Converters With LCL Filter Connected to Unbalanced Grid

Distributed Cooperative Control Strategy for Stable Voltage Restoration and Optimal Power Sharing in Islanded DC Microgrids

Conventionally, voltage regulation and economic dispatch in DC microgrid are performed at different time scales, which cannot keep the distributed generators (DGs) at the optimal operating point in real time. In this paper, a novel distributed cooperative control strategy is proposed to synchronously achieve stable bus voltage restoration and optimal power sharing in islanded DC microgrids. The proposed strategy breaks the constraints of hierarchical control strategies, and incorporates the objectives of voltage regulation and economic dispatch into a distributed cooperative control framework to eliminate average bus voltage deviation and minimize total power generation costs in real time. The stability of the proposed strategy is verified by eigenvalue analysis and steady-state analysis. Furthermore, the concept of “incremental cost (IC) margin” is introduced in cooperative control considering capacity constraints to avoid the converter output power violation and performance degradation. Finally, the MATLAB/Simulink simulation and StarSim HIL experimental results verify the effectiveness and robustness of the proposed strategy in an islanded DC microgrid under various testing scenarios.

Analysis of single switch step up DC-DC converter with switched inductor-switched capacitor cells for PV system

The presented work exhibits high gain and increased efficiency for DC-DC converter. Additionally, this topology significantly improves the voltage conversion ratio when compared with other DC-DC converters reported recently. The non-existence of high frequency transformer ensures compactness and low cost and henceforth, it is apt for clean energy applications. The analysis of the high gain converter in steady state is carried out in continuous conduction mode (CCM). Initially, the proposed converter performance is analyzed using MATLAB/Simulink platform and prototype of the same with a power rating of 200 V, 100 W is built and tested. The reliability and robustness of the converter is perceived from the experimental results and peak efficiency achieved is around 93%.

Investigation of the Effects of Different Operating Regions of ZVS LLC Resonant Converter on the Converter Performance

FM kontrollü ZVS LLC rezonans dönüştürücü, geniş bir giriş gerilim aralığı için yüksek anahtarlama frekanslarında düşük anahtarlama kayıpları ile çalışabilmektedir. Değişen giriş gerilimi ve yüke karşı sabit çıkış gerilimi elde etmek için dönüştürücünün DC gerilim kazancının, dolayısıyla çalışma aralıklarının değiştirilmesi gerekmektedir. Farklı çalışma aralıklarında dönüştürücünün DC gerilim kazancının yanı sıra birçok çalışma parametresi de değişmektedir. Bu çalışmada dönüştürücünün ZVS çalışma aralıkları değişen giriş gerilimine ve yüke karşı sabit çıkış gerilimi için verim, anahtar stresleri ve yumuşak anahtarlama yönünden karşılaştırılmıştır. Giriş gerilim aralığı 80-120 V, nominal giriş gerilimi 100 V ve çıkış gerilimi 8 V olan dönüştürücünün prototip devresi kurulmuştur. Birçok farklı giriş gerilim ve yük değeri için prototip devre üzerinden alınan ölçüm sonuçları karşılaştırmalı bir şekilde sunulmuştur. Farklı ZVS çalışma aralıklarının dönüştürücünün çalışma parametreleri üzerindeki etkisi birçok yönden ortaya konulmuştur. Ayrıca dönüştürücünün seri rezonans frekansı civarındaki çalışma performansının, bu frekans değerinin uzağındaki çalışma frekanslarına göre daha iyi olduğu gözlemlenmiştir.

Research on hydrodynamic performance of a two-buoy wave energy converter with built-in tanks

A sloshing tank is detrimental to the stability of ships and some floating structures but it may increase the amplitude of the motion of the wave energy converters (WECs). For raft-type WECs, liquid tanks can be used as a simple form of regulating the draft of a buoy. Yet, there is a lack of influence of this phenomenon on the hydrodynamic performance of the WEC. This paper mainly studies the effect of the sloshing tank on the motion and the response power of the two-body floating WEC by numerical simulation method. Correspondingly, a simplified experiment is designed for qualitative analysis and model verification, in which the two pontoons are injected with water. And the numerical model is in good agreement with the experimental model. The results show that the sloshing tanks decrease heaving amplitudes and increase the pitching angles of the buoys. The mechanism is to increase the natural frequency of a buoy. Therefore, this structure plays a role in increasing power when the wave period is under 3.5 s. In particular, a WEC with only one single tank in the second buoy absorbs more response power.

Smart current control of the wind energy conversion system based permanent magnet synchronous generator using predictive and hysteresis model

Introduction. Given the increasing demand for performance and efficiency of converters and power drives, the development of new control systems must take into account the real nature of these types of systems. Converters and dimmers power are nonlinear systems of a hybrid nature, including elements linear and nonlinear and a finite number of switching devices. Signals input for power converters are discrete signals that control the ‘opening and closing’ transitions of each component. Problem. In the multilevel inverters connected to grid, the switching frequency is the principal cause of harmonics and switching losses, which by nature, reduces the inverter’s efficiency. Purpose. For guarantee the satisfying quality of power transmitted to the electrical grid, while ensuring reduction of current ripples and output voltage harmonics. Novelty. This work proposes a new smart control, based on a predictive current control of the three level neutral point clamped inverter, used in Wind Energy Conversion System (WECS) connected to grid, based permanent magnet synchronous generator, powered by a hysteresis current control for the rectifier. This new formula guarantees handling with the influence of harmonics disturbances (similar current total harmonic distortion), voltage stress, switching losses, rise time, over or undershoot and settling time in WECS. Methods. The basic idea of this control is to choose the best switching state, of the power switches, which ameliorates the quality function, selected from order predictive current control of WECS. Results. Practical value. Several advantages in this intelligent method, such as the fast dynamic answer, the easy implementation of nonlinearities and it requires fewer calculations to choose the best switching state. In addition, an innovative algorithm is proposed to adjust the current ripples and output voltage harmonics of the WECS. The performances of the system were analyzed by simulation using MATLAB/Simulink.

A simulation and experimental verification of the operation of the oxidising catalytic converter in diesel engine.

This paper investigates an oxidizing catalytic converter in a diesel engine's particulate filter system, focusing on simulations and empirical studies. The converter, with a 1.4 dm3 volume and 400 cpsi channel density, features a platinum coating of 2.5 g/dm3. Scanning electron microscopy (SEM) examined its surface, revealing platinum and a highly porous structure with randomly distributed Pt crystallites. Simulations were conducted using AVL Boost, utilizing real exhaust gas concentrations to assess various converter volumes and channel densities for CO, HC, and NO2 conversion in NOX. These simulations were paralleled with empirical tests on an engine dynamometer. The comparison of simulation and experimental data showed that the simulation algorithm could accurately predict the converter's performance in reducing CO and HC levels and NO2 in NOX. This suggests that simulations can partly replace costly empirical research, offering a preliminary evaluation of the converter's future effectiveness.

Two-Way Coupling Simulation of Fluid-Multibody Dynamics for Estimating Power Generation Performance of Point Absorber Wave Energy Converters

The objective of the present study is to develop and validate a two-way coupling simulation method between viscous fluid and multibody dynamics to estimate the power generation performance of point absorber wave energy converters. For numerical analysis of fluid dynamics, an enhanced density correction model was proposed to improve the accuracy and stability of the pressure calculation in DualSPHysics, an open-source code based on smoothed particle hydrodynamics (SPH). Through 2D hydrostatic and wave generation simulations, it was seen that the relative error in the average pressure was reduced from 11.81% to 1.64%. In addition, an interaction interface was developed to enable coupling simulation with RecurDyn, a commercial software for the simulation of multibody dynamics. Simulations were performed for a 3D single-body cylinder with a simple shape and a two-body floating wave energy converter (WEC) in regular waves, varying the linear damping coefficient of the power take-off (PTO) system to verify the proposed coupling simulation method for fluid-multibody dynamics. The results were benchmarked against experimental data, revealing a relative error of 1.05% with the experimental results when employing a high damping coefficient for the PTO system. Furthermore, to improve the efficiency of the two-body WEC, two design modifications were suggested; their impact on power generation performance improvement was examined. The developed method is anticipated to contribute to research aiming to enhance the power generation efficiency of various wave power devices with multiple elements and joints, pending further validation and refinement of the simulation approach.

A Numerical Investigation of the Hydrodynamic Performance of a Pitch-Type Wave Energy Converter Using Weakly and Fully Nonlinear Models

In this study, the performance of a wave energy converter (WEC) rotor under regular and irregular wave conditions was investigated using 3D nonlinear numerical models. Factors such as the power take-off (PTO) load torque, wave periods, spacing of multiple WEC rotors, and wave steepness were analyzed. Two models were employed: a weakly nonlinear model formulated by incorporating the nonlinear restoring moment and Coulomb-type PTO load torque based on the potential flow theory, and a fully nonlinear model based on computational fluid dynamics. The results show that the average power estimated by both numerical models is consistent, with a wave steepness of 0.03 for the range of one-way and two-way PTO load torques, except for the deviations observed in the long range of the one-way PTO load torque. Furthermore, the average power of the WEC rotor under the applied PTO load torque exhibits a quadratic dependency, regardless of the wave steepness. In addition, adopting a one-way PTO load torque was more efficient than adopting a two-way PTO load torque. Therefore, the fully nonlinear model demonstrated its ability to handle a high degree of nonlinearity, surpassing the limitations of the weakly nonlinear model, which was limited to moderate wave steepness.

A single switch high gain multilevel boost converter with switched inductor topology for photovoltaic applications

This paper proposes a new transformer-less single-switch high-gain dc-dc converter for solar power systems. The suggested converter is created by supplementing the conventional boost converter with a switched inductor cell plus a voltage multiplier stage. The converter has several benefits, including a high voltage conversion ratio, reduced voltage stress on semiconducting switches and diodes, a reduction in the need for gate drivers because only one switch is used, as well as constant input current to prolong the lifespan of the photovoltaic cell. The analytical waveforms of the recommended converter can be seen in the continuous conduction mode (CCM). The analysis of voltage stress is done. In the presence of parasitic components, increased voltage gain and efficiency were also obtained.The proposed high-gain converter topology is compared to recently published high-gain converter topologies in terms of performance. Using PSIM, a high-gain dc-dc converter's performance is studied and analysed with regard to its low switching voltage stress. The suggested converter is successful in stepping up 20V to 400V at 160W power capacity, while offering a continuous input source current at 95% efficiency.

Phase shift control of dual active bridge DC‐DC converter based on feedforward compensation and transient optimization strategy

SummaryIn the context of the dual active bridge (DAB) bidirectional DC‐DC converter using the traditional dual‐phase‐shift (DPS) control method, a transient DC bias occurs during power co‐direction and commutation conversion. This bias negatively impacts the converter's transient performance and can lead to harsh effects, such as hard switching problems, resulting in power loss and excessive current stress. In a closed‐loop control system, poor transient response may destroy the stability of the converter. In this paper, the transient‐optimized‐dual‐phase‐shift (TODPS) control strategy is proposed to eliminate the transient DC bias and to maintain soft switching during transient states. It reduces power loss, eliminates excessive current stress, and allows for smooth transitions between single‐phase‐shift (SPS) and DPS control strategies without introducing DC bias. A closed‐loop control system based on TODPS control is established with feed‐forward compensation to adjust the primary‐side current and modify transmission power. This adjustment enhances the transient performance of the DAB converter. The proposed strategy is versatile and applicable to various power conversion scenarios involving DAB converters. It enables quick switching of the magnitude and direction of the primary‐side current during transient states, resulting in a smooth transient effect without noticeable overshoot or oscillation. The experiment results verify the effectiveness of the proposed transient optimization strategy.