scholarly journals Analysis and Design of Coupled Inductor for Interleaved Buck-Type Voltage Balancer in Bipolar DC Microgrid

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2775
Author(s):  
Jung-min Park ◽  
Hyung-jun Byun ◽  
Bum-jun Kim ◽  
Sung-hun Kim ◽  
Chung-yuen Won
Keyword(s):  
Dynamic Response ◽  
Coupling Coefficient ◽  
Distribution System ◽  
Low Voltage ◽  
Magnetic Coupling ◽  
Two Stage ◽  
Dc Microgrid ◽  
Analysis And Design ◽  
Load Variation ◽  
Key Factor

A voltage balancer (VB) can be used to balance voltages under load unbalance in either a bipolar DC microgrid or LVDC (Low voltage DC) distribution system. An interleaved buck-type VB has advantages over other voltage balance topologies for reduction in output current ripple by an aspect of configuration of a physically symmetrical structure. Similarly, magnetic coupling such as winding two or more magnetic components into a single magnetic component can be selected to enhance the power density and dynamic response. In order to achieve these advantages in a VB, this paper proposes a VB with a coupled inductor (CI) as a substitute for inductors in a two-stage interleaved buck-type VB circuit. Based on patterns of switch poles under load variation, the variation in inductor currents under four switching patterns is induced. The proposed CI is derived from self-inductance based on the configuration structure that has a two-stage interleaved buck type and mathematical design results based on the coupling coefficient, where the coupling coefficient is a key factor in the determination of the dynamic response of the proposed VB in load variation. According to the results, a prototype scale is implemented to confirm the feasibility and effectiveness of the proposed VB.

Protection Scheme for DC Microgrid Distribution System

2012 ◽  
Vol 614-615 ◽  
pp. 1661-1665
Author(s):  
Ling Hui Deng ◽  
Zhi Xin Wang ◽  
Jian Min Duan
Keyword(s):  
Distribution System ◽  
Cost Efficiency ◽  
Power Flow ◽  
Low Voltage ◽  
Dc Microgrid ◽  
Protection Scheme ◽  
High Level ◽  
Bidirectional Power Flow ◽  
Efficiency And Reliability ◽  
Laboratory Prototype

The low voltage DC (LVDC) distribution system is a new concept and a promising technology to be used in the future smart distribution system having high level cost-efficiency and reliability. In this paper, a low-voltage (LV) DC microgrid protection system design is proposed. Usually, an LVDC microgrid must be connected to an ac grid through converters with bidirectional power flow and, therefore, a different protection scheme is needed. This paper describes practical protection solutions for the LVDC network and an LVDC system laboratory prototype is being experimentally tested by MATLAB/SIMULINK. The results show that it is possible to use available devices to protect such a system. But other problems may arise which needs further study.

scholarly journals A Soft-Switched DC/DC Converter Using Integrated Dual Half-Bridge with High Voltage Gain and Low Voltage Stress for DC Microgrid Applications

Inventions ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 63 ◽  
Author(s):  
Hadi Moradisizkoohi ◽  
Nour Elsayad ◽  
Osama Mohammed
Keyword(s):  
High Voltage ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Voltage Gain ◽  
Switching Loss ◽  
Output Stage ◽  
Dc Microgrid ◽  
Analysis And Design ◽  
High Voltage Gain ◽  
Voltage Stress

In this paper, a soft-switched boost converter including an integrated dual half-bridge circuit with high voltage gain and continuous input current is introduced that can be suitable for the applications requiring a wide voltage gain range, such as for the front-end of the inverter in a DC microgrid to integrate renewable energy sources (RES). In the proposed converter, two half-bridge converters are connected in series at the output stage to enhance the voltage gain. Additionally, the balanced voltage multiplier stage is employed at the output to increase the voltage conversion ratio, as well as distribute the voltage stress across semiconductors; hence, switches with smaller on-resistance RDS(on) can be adopted resulting in an improvement in the efficiency. The converter takes advantage of the clamp circuit not only to confine the voltage stress of switches, but also to achieve the soft-switching, which leads to a reduction in the switching loss as well as the cost. The mentioned features make the proposed converter a proper choice for interfacing RES to the DC-link bus of the inverter. The operation modes, steady-state analysis, and design consideration of the proposed topology have been demonstrated in the paper. A 1-kW laboratory prototype was built using gallium nitride (GaN) transistors and silicon carbide (SiC) diodes to confirm the effectiveness of the proposed topology.

scholarly journals Analysis of a Series‑Parallel Resonant Converter for DC Microgrid Applications

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 542
Author(s):  
Bor-Ren Lin
Keyword(s):  
Low Voltage ◽  
Magnetic Coupling ◽  
Input Voltage ◽  
Soft Switching ◽  
Parallel Structure ◽  
Resonant Circuit ◽  
Resonant Converter ◽  
Dc Microgrid ◽  
Power Semiconductors ◽  
Power Diodes

An input-series output-parallel soft switching resonant circuit with balance input voltage and primary-side current is studied and implemented for direct current (DC) microgrid system applications. Two resonant circuits are connected with input-series and output-parallel structure to have the advantages of low voltage stresses on active devices and low current stresses on power diodes. A balance capacitor is adopted on high voltage side to balance two input capacitor voltages. The LLC (inductor–inductor–capacitor) resonant circuit cells are employed in the converter to have soft switching operation for power semiconductors. The magnetic coupling component is adopted on the primary-side to automatically realize current balance of the two resonant circuits. In the end, a laboratory hardware circuit is built and tested. Experiments demonstrate and prove the validity of the resonant converter.

Design of a low voltage DC microgrid system for rural electrification in South Africa

2014 ◽  
Vol 25 (2) ◽  
pp. 9-14 ◽  
Author(s):  
Gilbert M. Bokanga ◽  
Atanda Raji ◽  
Mohammed T.E. Kahn
Keyword(s):  
South Africa ◽  
Distribution System ◽  
Low Voltage ◽  
Power Delivery ◽  
Rural Electrification ◽  
Local Power ◽  
Solar Panels ◽  
Dc Microgrid ◽  
Photovoltaic Panel ◽  
Solar Systems

This project entails the design of a low voltage DC microgrid system for rural electrification in South Africa. Solar energy is freely available, environmental friendly and it is considered as a promising power generating source due to its availability and topological advantages for local power generation. Off-grid solar systems are perceived to be a viable means of power delivery to households in rural outlying areas in South Africa as solar panels can be used almost anywhere in the country. The design presented in this paper is based on the power demand estimation, photovoltaic panel selection, battery sizing and wire selection for the distribution system.

Scaling Law of Coupling Coefficient and Coil Size in Wireless Power Transfer Design via Magnetic Coupling

2017 ◽  
Vol 137 (4) ◽  
pp. 326-333
Author(s):  
Chiaki Nagai ◽  
Kenji Inukai ◽  
Masato Kobayashi ◽  
Tatsuya Tanaka ◽  
Kensho Abumi ◽  
...  
Keyword(s):  
Coupling Coefficient ◽  
Scaling Law ◽  
Magnetic Coupling ◽  
Wireless Power Transfer ◽  
Power Transfer ◽  
Wireless Power ◽  
Coil Size

Development and Evaluation of a Fast Voltage Calculation Method for Low-Voltage Distribution System

2013 ◽  
Vol 133 (4) ◽  
pp. 343-349
Author(s):  
Shunsuke Kawano ◽  
Yasuhiro Hayashi ◽  
Nobuhiko Itaya ◽  
Tomihiro Takano ◽  
Tetsufumi Ono
Keyword(s):  
Calculation Method ◽  
Distribution System ◽  
Low Voltage ◽  
Voltage Distribution
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