Full
Outline
The grid impedance exerts a serious impact on the stability of grid-tied inverters, and its accurate estimation is conducive to realizing the high-performance adaptive control of grid-tied inverters in weak grid conditions. The PQ variation method is a typical method of online grid impedance estimation. However, research shows that there exists a relationship of nonlinear function between real grid impedances and their estimation results, which may affect the estimation results. The traditional PQ variation method has shortcomings in the grid impedance estimation accuracy due to ignoring the influence of steady-state operating point fluctuations before and after the variation. Therefore, from the two aspects of error compensation with fixed phase-angle difference and estimation value correction with offline look-up table, two improved estimation schemes considering the operating point fluctuations are proposed respectively to achieve an accurate grid impedance estimation under weak grid conditions. The detailed theoretical analysis and test results show that compared with the traditional PQ variation method, the proposed grid impedance estimation method can achieve a higher degree of accuracy.
63
17
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
关闭全屏
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62662699(Operation and Technical Support)
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
