30 kVA grid-forming inverter for energy storage system

Inquiry

In the microgrid, the regional load can be supported by the regional small
scale generator or renewable sources, which can be treated as a small inde
pendent control power system composed of distributed renewable sourc
e, conventional small scale generator, energy storage system (ESS), superv
isory system, and regional loads. The microgrid is connected to the main p
ower grid with static switch. Normally, the microgrid is connected to the
main power grid and controlled for supporting the stability of the power
grid. When the main power grid is abnormal, the microgrid is disconnecte
d from the main power grid by the static switch. Then the regional loads a
re powered by the regional sources and ESS.
The 30 kVA grid-forming (GFM) inverter for energy storage system is prop
osed in this research, which integrating the supervisory system and power
inverter. The supervisory system commend the power inverter for automa
tic frequency control (AFC), photovoltaic (PV) output smoothing, or load c
ompensation for contract capacity, etc. As the power inverter is connected
with the grid, the real or reactive power is provided to or received from th
e grid by the commend of the supervisory system. When the grid is off, th
e power inverter can support the regional load by forming a stand-alone v
oltage source. The 3-phase 3-level neutral-point clamped, NPC, inverter is
adopted in this research. With the multilevel structure, lower output harm
onic distortion and voltage stress reduced to only half of the input dc-link
voltage for lower switching losses are obtained. The wide-bandgap power
switch, SiC, is adopted for the superior characteristics to the conventional

Si-based power switch. Then, the switching frequency is increased for high
er power density and also power conversion efficiency.

National Cheng Kung University

Due to NCKU’s rapid development, the R&D Committee has become increasingly important. In order to meet the needs of NCKU's academic research planning, integration, industry cooperation and academic cooperation, it has become an independent operating unit for practical functions. Therefore, in the 5th University Council of the 1994 academic year, the R&D Committee was renamed the Office Of R&D(ORD) after the amendment of Article 8 of NCKU’s organizational regulations. NCKU Regulations Governing the Establishment of the Office of Research and Development were approved in the 7th University Council of the same academic year. In addition to the original three divisions, the instrumentation equipment center was established for integration and planning of NCKU’s relevant instrumentation and equipment, bringing further into play the overall function of ORD, which will be more beneficial to NCKU’s teachers and students. In June 2006, the Office of International Academic was established. The Academic Cooperation Division of ORD Department was converted into the International Cooperation Division and shifted to the Office of International Academic. Original URL: History and Vision https://en.ord.ncku.edu.tw/article-history.html The copyright belongs to the author. For commercial reprints, please contact the author for authorization, and for non-commercial reprints, please indicate the source.