scholarly journals A Switched Quasi-Z-Source Inverter with Continuous Input Currents

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1390 ◽  
Author(s):  
Jing Yuan ◽  
Yongheng Yang ◽  
Frede Blaabjerg
Keyword(s):  
Lower Cost ◽  
Renewable Energy Sources ◽  
Power Conversion ◽  
Experimental Tests ◽  
Superior Performance ◽  
Passive Components ◽  
Prior Art ◽  
Voltage Stress ◽  
Power Switches ◽  
Continuous Input

Impedance source converters as single-stage power conversion alternatives can boost and regulate the output voltages of renewable energy sources. Nevertheless, they, also known as Z-source inverters (ZSIs), still suffer from limited voltage gains and higher stresses across the components. To tackle such issues, extra diodes, passive components, and active switches can be utilized in the basic ZSIs. In this paper, a modified switched-quasi-Z-source inverter (S-qZSI) is proposed, which features continuous input currents and high boosting capability to boost output voltage by minor modifications of a prior-art topology. Furthermore, the voltage stress of the active switches is reduced, which contributes to a lower cost. The operation principles are discussed comprehensively. The performance of the proposed ZSI in terms of conversion ratio, voltage gain, and stresses on the power switches and capacitors is benchmarked with selected ZSIs. Finally, simulations and experimental tests substantiate the theoretical analysis and superior performance.

scholarly journals Design and Analysis of a High-Gain Step-Up/Down Modular DC–DC Converter with Continuous Input Current and Decreased Voltage Stress on Power Switches and Switched-Capacitors

2021 ◽  
Vol 13 (9) ◽  
pp. 5243
Author(s):  
Maysam Abbasi ◽  
Ehsan Abbasi ◽  
Li Li ◽  
Behrouz Tousi
Keyword(s):  
High Voltage ◽  
Output Voltage ◽  
Renewable Energy Sources ◽  
High Gain ◽  
Voltage Regulation ◽  
Input Current ◽  
Switched Capacitors ◽  
Voltage Stress ◽  
Power Switches ◽  
Continuous Input

Due to concerns, such as global warming and depletion of fossil fuels, countries are forced to integrate energy storage devices (ESSs) and renewable energy sources (RESs), such as photovoltaic (PV) systems, wind turbines and fuel cells, into their power networks. Here, a new high gain DC–DC converter with step-up/down ability is proposed for modern applications. Since this converter provides high variable voltage gain, it can be employed for output voltage regulation purposes in RESs such as solar panels. Additionally, this converter provides a remarkable reduction in voltage stress on the switched capacitors and power switches. Due to its modular structure obtained by employing switched-capacitors (SCs), it is possible for this topology to gain a very high voltage conversion ratio using low duty-cycles produced by a simple and straightforward control system. To be specific, the more the number of SC cells increase, the more the output voltage increases. The proposed converter has a continuous input current allowing to extract the maximum power from RESs like PV panels. It should be noted that the application of this converter is not limited to the aforementioned ones since it can be used in various applications needing high voltage gains such as generating the desired voltage level in high voltage direct current (HVDC) systems especially their transmission lines. For validating the performance of the proposed structure, comprehensive comparisons and experimental results are presented.

scholarly journals Modified Impedance-Source Inverter with Continuous Input Currents and Fault-Tolerant Operations

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3408
Author(s):  
Jing Yuan ◽  
Yongheng Yang ◽  
Ping Liu ◽  
Yanfeng Shen ◽  
Frede Blaabjerg
Keyword(s):  
Energy Supply ◽  
Fault Tolerant ◽  
Short Circuit ◽  
Experimental Tests ◽  
Open Circuit ◽  
Input Current ◽  
Prior Art ◽  
High Voltage Gain ◽  
Continuous Current ◽  
Continuous Input

Impedance-source (Z-source) inverters are increasingly adopted in practice, where a high voltage gain is required. However, issues like drawing a non-continuous current from the DC source and ceasing the energy supply under DC source faults are also observed. In this paper, an embedded enhanced-boost Z-source inverter (EEB-ZSI) is thus proposed to tackle the issues. The proposed EEB-ZSI employs two DC sources, which enable the continuous input current and fault-tolerant operations (e.g., open-circuit and short-circuit faults in the DC sources). The operational principles are presented in detail with an in-depth circuit analysis. Moreover, the proposed EEB-ZSI is benchmarked with prior-art Z-source inverters. Experimental tests further demonstrate the effectiveness of EEB-ZSI regarding the continuous input current and flexible fault tolerance.

scholarly journals Improved Cascaded H-Bridge Multilevel Inverters with Voltage-Boosting Capability

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2801
Author(s):  
Sze Sing Lee ◽  
Yongheng Yang ◽  
Yam P. Siwakoti ◽  
Reza Barzegarkhoo
Keyword(s):  
Theoretical Analysis ◽  
Power Efficiency ◽  
Experimental Tests ◽  
Multilevel Inverter ◽  
Multilevel Inverters ◽  
Front End ◽  
Power Switch ◽  
Voltage Stress ◽  
Power Switches ◽  
Lower Voltage

This paper proposes two improved cascaded H-bridge (ICHB) multilevel inverters that feature voltage-boosting capability. The conventional H-bridge with a front-end dc–dc boost converter was restructured for single-stage operation. The developed three-level topology not only saves one power switch but also exhibits lower voltage stress across its capacitor. Extension to five-level generation was also introduced by merely adding two power switches and one capacitor. The final five-level topology outperforms the classical cascaded H-bridge (CHB) multilevel inverter with a significant reduction in the power switch count, with a 42% and 50% reduction in both the isolated dc source and inductor counts. The power efficiency was also improved without compromising the modularity feature of the classical CHB multilevel inverter. The operation and theoretical analysis of the proposed topologies were validated via simulations and experimental tests.

scholarly journals ANALISYS OF THERMAL EFFICIENCY OF A MODIFIED SOLAR COLLECTOR TYPE EVACUATED TUBE

2014 ◽  
Vol 13 (1) ◽  
pp. 03
Author(s):  
E. Avallone ◽  
A. I. Sato ◽  
V. L. Scalon ◽  
A. Padilha
Keyword(s):  
Solar Collector ◽  
Renewable Energy Sources ◽  
Experimental Tests ◽  
Clean Energy ◽  
Hot Water ◽  
Energy Sources ◽  
Transient Heat Flow ◽  
Important Approach ◽  
Experimental Problem ◽  
Evacuated Tube

The need of renewable energy sources due to climate change and thus the search for clean energy sources, justify the growing investment on new types of solar collectors. The research has contributed to this expansion in the scope of solar concentrator collectors, with the efficiency as the main goal. Many works have been developed in order to optimize the thermal stratification of the fluid inside the tubes and heat reservoirs, as well as mathematical modeling considering the problem as transient heat flow as boundary condition. In this work is studied experimentally, the heating of the water by solar collector modified from the conventional evacuated tube, focusing on efficiency. With the help of CFD software, a theoretical analysis is done to visualize the phenomenon, assuming the same boundary conditions and geometric experimental problem. An important approach concerns the physical separation of the flows of both cold and hot water inside the evacuated tube. The system performance was analyzed using experimental tests performed outdoors with sunlight.

scholarly journals High Step-up Coupled Inductor Inverters Based on qSBIs

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 3032 ◽  
Author(s):  
Hongchen Liu ◽  
Xi Su ◽  
Junxiong Wang
Keyword(s):  
Steady State ◽  
High Voltage ◽  
Low Voltage ◽  
Duty Ratio ◽  
Voltage Gain ◽  
Passive Components ◽  
Steady State Analysis ◽  
High Voltage Gain ◽  
Voltage Stress ◽  
Working Principle

In this paper, two types of high step-up coupled inductor inverters based on qSBIs (quasi- switched boost inverters) are proposed. By applying the coupled inductor to the qSBIs, the voltage gain of the proposed inverter is regulated by turn ratio and duty ratio. Thus, a high voltage gain can be achieved without the circuits operating at the extreme duty cycle by choosing a suitable turn ratio of the coupled inductor. In addition, the proposed circuits have the characteristics of continuous input current and low voltage stress across the passive components. A boost unit can be added to the proposed inverters for further improvement of the voltage gain. In this paper, the working principle, steady state analysis, and the comparisons of the proposed inverter with other impedance-source inverters are described. A 200 W prototype was created and the experimental results confirm the correctness of the analysis in this paper.

scholarly journals Modeling and analysis of the characteristics of SiC MOSFET

2021 ◽  
Vol 2125 (1) ◽  
pp. 012051
Author(s):  
Guoqing Qiu ◽  
Kedi Jiang ◽  
Shengyou Xu ◽  
Xin Yang ◽  
Wei Wang
Keyword(s):  
Simulation Model ◽  
Circuit Simulation ◽  
Power Conversion ◽  
Simulation Models ◽  
Data Sheet ◽  
Superior Performance ◽  
Power Devices ◽  
Matlab Simulink ◽  
Modeling And Analysis ◽  
Mathematical Processing

Abstract Although the superior performance of SiC MOSFET devices has beenvalidated by many studies, it is necessary to overcome many technical bottlenecks to make SiC MOSFET gradually replace Si-based power devices into the mainstream. In view of the current situation where the performance of SiC MOSFETs in power conversion devices cannot be evaluated well at this stage, it is necessary to carry out fine modeling of SiC MOSFETs and establish accurate simulation models. In this paper, the powerful mathematical processing capability and rich modules of Matlab/Simulink are used to build a SiC MOSFET model, and then the product data sheet is compared with the fitted data. The results show that the switching simulation waveforms are in general agreement with the data sheet waveforms, and the error is less than 7%. Verifing the accuracy of the model and reducing the difficulty of modeling, it provides a new idea for establishing the circuit simulation model of SiC MOSFET in Matlab/Simulink.

Analysis of High-Speed Electrical Generators for Utility Applications

2013 ◽  
Author(s):  
Miroslav P. Petrov
Keyword(s):  
Electricity Generation ◽  
High Speed ◽  
Renewable Energy Sources ◽  
Scale Up ◽  
Energy Utilization ◽  
Superior Performance ◽  
Electricity Production ◽  
Small Scale ◽  
Technical Challenges ◽  
Compact Design

High-speed alternators are believed to be well developed nowadays, following the improvement in performance and decrease of costs for electronic power converters and permanent magnet materials. Their compact design and their ability to vary the rotational speed in off-design conditions promise superior performance when compared to conventional generators. High-speed alternators are only available in limited sizes for small-scale applications, whereas improvements in efficiency and optimized part-load behavior are particularly important especially for small-scale electricity generation. Enhanced energy utilization for electricity production by small utility plants or by distributed units located at private homes or commercial buildings, based on thermodynamic cycles powered by natural gas or various renewable energy sources, is possible to be achieved through a wider application of grid-integrated high-speed technology. This study presents a critical review of previous research and demonstration work on high-speed electrical machines and a summary of the technical challenges limiting their performance and their expansion into larger sizes. Conclusions are drawn for finding appropriate solutions for practical high-speed electricity generation units and their readiness for a much wider deployment. Closer analysis is attempted on the thermal and mechanical integrity of high-speed alternators and the technical challenges that slow down their scale-up to MW-size units for utility applications. The necessary research and development work that needs to be done in the near future is outlined and discussed herein.

Switched capacitor based single DC source boost multilevel inverter (S2-MLI) featuring isolation based soft charging with minimum device count

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tamiru Debela ◽  
Jiwanjot Singh
Keyword(s):  
Pulse Width Modulation ◽  
Multilevel Inverter ◽  
Superior Performance ◽  
Inrush Current ◽  
Switched Capacitor ◽  
Multilevel Inverters ◽  
Current Voltage ◽  
Power Switches ◽  
Input Source ◽  
Interest In Research

Abstract Multilevel inverters (MLIs) have formed a new wave of interest in research and industry. Switched capacitor-based multilevel inverters are used to avoid the need for multiple separated DC sources compared to cascaded MLIs. However, the inclusion of several capacitors creates problems such as high inrush current, voltage imbalance. To avoid these drawbacks, this paper proposes an isolation-based scheme by using a flyback converter in the switched capacitor multilevel inverter. Further, the overall topology provides step-up AC voltage across the load from a single DC source with fewer power switches. To generate a step-up five-level voltage across the load, switched capacitor-based multilevel inverter needs six power switches and only one capacitor. To get the appropriate switching operation to generate the NL-levels, phase disposition pulse width modulation (PD-PWM) has been developed. The extended nine-level S 2 -MLI is also discussed in this paper under different conditions as change in input source voltage and dynamic load change. Moreover, to prove the superior performance of switched-capacitor single DC source multilevel inverter (S2-MLI), comparative analysis with existing single DC source MLI has been performed. The effectiveness and feasibility of the proposed topology are tested with varieties of loads by simulation using Matlab/Simulink. To validate the simulation results, hardware implementation has been done of five-level S2-MLI considering resistive and motor load by using DSpace 1103 controller.

scholarly journals Novel non‐isolated high step‐up converter with fewer passive devices and low voltage stress of power switches

2020 ◽  
Vol 13 (11) ◽  
pp. 2302-2311
Author(s):  
Ningrui Yang ◽  
Jun Zeng ◽  
Renjun Hu ◽  
Junfeng Liu
Keyword(s):  
Low Voltage ◽  
Passive Devices ◽  
Voltage Stress ◽  
Power Switches
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