Yang Qi | Northwestern Polytechnical University (original) (raw)

Yang Qi received the B. Sc. degree in electrical engineering from Xi’an Jiaotong University, China, in 2016. He got the Ph. D. degree in Nanyang Technological University, Singapore in 2021. Since 2021, he is an associate professor at Northwestern Polytechnical University, China. His research interests include control and grid integration of energy storage systems, power system modelling and stability analysis.

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Papers by Yang Qi

IEEE Transactions on Sustainable Energy, 2021

Distributed generations (DGs) have been increasingly employed in AC microgrids to provide carbon-... more Distributed generations (DGs) have been increasingly employed in AC microgrids to provide carbon-free power supply. To coordinate multiple DGs, careful attention must be paid to the synchronization stability of their interfaced inverters. Otherwise, low-frequency oscillations and even loss of synchronism may occur and pose a great threat to the system. The conventional solutions towards this issue are to derive the microgrid state-space model and evaluate its stability based on the roots of the characteristic equation. However, tremendous efforts shall be spent on modeling as the number of DG increases. This paper provides an alternative way, which localizes the target of system synchronization stability into individual inverters. It is revealed and proven that microgrid synchronization stability can be guaranteed if all the inverters are designed to have passive synchronization behaviors. To fulfill this requirement and achieve a satisfactory phase margin, an auxiliary controller is designed to reshape frequency-power characteristics of inverters. Finally, case studies of a three-DG microgrid verify the theoretical findings as well as the effectiveness of the auxiliary controller.

Thesis Chapters by Yang Qi

Nanyang Technological University, 2021

Recent advances in power-electronics technologies facilitate the integration of distributed gener... more Recent advances in power-electronics technologies facilitate the integration of distributed generations (DGs), such as renewable energy resources (RESs) and distributed energy storage systems (DESSs). The “microgrid” concept is formed when a number of DGs and loads are coupled together through power electronics converters. To maintain the power balance of a microgrid and perform the grid-forming function, DESSs should be properly controlled through the interfaced power converters. This thesis aims to analyze and overcome several issues
regarding the coordination and control of DESSs, with the focus on the following aspects: fundamental power sharing among DESSs, unbalanced power sharing among DESSs, harmonic power sharing among DESSs, and the synchronization stability of Voltage source inverter (VSI) with DESSs.

IEEE Transactions on Sustainable Energy, 2021

Distributed generations (DGs) have been increasingly employed in AC microgrids to provide carbon-... more Distributed generations (DGs) have been increasingly employed in AC microgrids to provide carbon-free power supply. To coordinate multiple DGs, careful attention must be paid to the synchronization stability of their interfaced inverters. Otherwise, low-frequency oscillations and even loss of synchronism may occur and pose a great threat to the system. The conventional solutions towards this issue are to derive the microgrid state-space model and evaluate its stability based on the roots of the characteristic equation. However, tremendous efforts shall be spent on modeling as the number of DG increases. This paper provides an alternative way, which localizes the target of system synchronization stability into individual inverters. It is revealed and proven that microgrid synchronization stability can be guaranteed if all the inverters are designed to have passive synchronization behaviors. To fulfill this requirement and achieve a satisfactory phase margin, an auxiliary controller is designed to reshape frequency-power characteristics of inverters. Finally, case studies of a three-DG microgrid verify the theoretical findings as well as the effectiveness of the auxiliary controller.

Nanyang Technological University, 2021

Recent advances in power-electronics technologies facilitate the integration of distributed gener... more Recent advances in power-electronics technologies facilitate the integration of distributed generations (DGs), such as renewable energy resources (RESs) and distributed energy storage systems (DESSs). The “microgrid” concept is formed when a number of DGs and loads are coupled together through power electronics converters. To maintain the power balance of a microgrid and perform the grid-forming function, DESSs should be properly controlled through the interfaced power converters. This thesis aims to analyze and overcome several issues
regarding the coordination and control of DESSs, with the focus on the following aspects: fundamental power sharing among DESSs, unbalanced power sharing among DESSs, harmonic power sharing among DESSs, and the synchronization stability of Voltage source inverter (VSI) with DESSs.