The maximum power transfer capability(MPTC)of phase-locked loop(PLL)-based grid-following inverters is often limited under weak-grid conditions due to passivity violations caused by operating-point-dependent control l...The maximum power transfer capability(MPTC)of phase-locked loop(PLL)-based grid-following inverters is often limited under weak-grid conditions due to passivity violations caused by operating-point-dependent control loops.This paper reveals and compares the mechanisms of these violations across different control strategies.Using admittance decomposition and full-order state-space models for eigenvalue analysis,MPTC limitations from control loops and their interactions are identified.The small-signal stabilities of different control loops are compared under varying grid strength,and both static and dynamic MPTCs for each control mode are examined.This paper also explores how control loop interactions impact the MPTC,offering insights for tuning control loops to enhance stability in weak grids.For example,fast power control improves the MPTC when paired with a slow PLL,while power control has minimal effect when the PLL is sufficiently fast.The findings are validated through frequency scanning,eigenvalue analysis,simulations,and experiments.展开更多
A four-level atomic system with a closed interaction loop connected by two coherent driving fields and a microwave field is investigated. The results show that inversionless gain can be achieved on a higher frequency ...A four-level atomic system with a closed interaction loop connected by two coherent driving fields and a microwave field is investigated. The results show that inversionless gain can be achieved on a higher frequency transition outside the closed interaction loop, and the gain behaviour can be modulated by the phase of the closed loop as well as the amplitude of the microwave field. The phase sensitivity property in such a scheme is similar to that in an analogous configuration with spontaneously generated coherence, but it is beyond the rigorous condition of near-degenerate levels with non-orthogonal dipole moments. Therefore this scheme is much more convenient in experimental realization.展开更多
Standard genetic algorithms （SGAs） are investigated to optimise discrete-time proportional-integral-derivative （PID） con- troller parameters, by three tuning approaches, for a multivariable glass furnace process w...Standard genetic algorithms （SGAs） are investigated to optimise discrete-time proportional-integral-derivative （PID） con- troller parameters, by three tuning approaches, for a multivariable glass furnace process with loop interaction. Initially, standard genetic algorithms （SGAs） are used to identify control oriented models of the plant which are subsequently used for controller optimisa- tion. An individual tuning approach without loop interaction is considered first to categorise the genetic operators, cost functions and improve searching boundaries to attain the desired performance criteria. The second tuning approach considers controller parameters optimisation with loop interaction and individual cost functions. While, the third tuning approach utilises a modified cost function which includes the total effect of both controlled variables, glass temperature and excess oxygen. This modified cost function is shown to exhibit improved control robustness and disturbance rejection under loop interaction.展开更多
Macrophages are typically identified as classically activated(M1) macrophages and alternatively activated(M2) macrophages,which respectively exhibit pro-and anti-inflammatory phenotypes,and the balance between these t...Macrophages are typically identified as classically activated(M1) macrophages and alternatively activated(M2) macrophages,which respectively exhibit pro-and anti-inflammatory phenotypes,and the balance between these two subtypes plays a critical role in the regulation of tissue inflammation,injury,and repair processes.Recent studies indicate that tissue cells and macrophages interact via the release of small extracellular vesicles(EVs) in processes where EVs released by stressed tissue cells can promote the activation and polarization of adjacent macrophages which can in turn release EVs and factors that can promote cell stress and tissue inflammation and injury and vice versa.This review discusses the roles of such EVs in resulating such interactions to influence tissue inflammation and injury in a number of acute and chronic inflammatory disease conditions,and the potential applications,advantage and concerns for using EV-based therapeutic approaches to treat such conditions,including their potential role of drug carriers for the treatment of infectious diseases.展开更多
基金funded by the Australian Renewable Energy Agency(No.2023/ARP010).
文摘The maximum power transfer capability(MPTC)of phase-locked loop(PLL)-based grid-following inverters is often limited under weak-grid conditions due to passivity violations caused by operating-point-dependent control loops.This paper reveals and compares the mechanisms of these violations across different control strategies.Using admittance decomposition and full-order state-space models for eigenvalue analysis,MPTC limitations from control loops and their interactions are identified.The small-signal stabilities of different control loops are compared under varying grid strength,and both static and dynamic MPTCs for each control mode are examined.This paper also explores how control loop interactions impact the MPTC,offering insights for tuning control loops to enhance stability in weak grids.For example,fast power control improves the MPTC when paired with a slow PLL,while power control has minimal effect when the PLL is sufficiently fast.The findings are validated through frequency scanning,eigenvalue analysis,simulations,and experiments.
基金Project supported by the Natural Science Foundation of Guangdong Province （Grant No 05301018）, the Research and Development Fund of Shenzhen University, China （Grant No 200549）, and the National Natural Science Foundation of China （Grant Nos 10334010 and 10404009）.
文摘A four-level atomic system with a closed interaction loop connected by two coherent driving fields and a microwave field is investigated. The results show that inversionless gain can be achieved on a higher frequency transition outside the closed interaction loop, and the gain behaviour can be modulated by the phase of the closed loop as well as the amplitude of the microwave field. The phase sensitivity property in such a scheme is similar to that in an analogous configuration with spontaneously generated coherence, but it is beyond the rigorous condition of near-degenerate levels with non-orthogonal dipole moments. Therefore this scheme is much more convenient in experimental realization.
文摘Standard genetic algorithms （SGAs） are investigated to optimise discrete-time proportional-integral-derivative （PID） con- troller parameters, by three tuning approaches, for a multivariable glass furnace process with loop interaction. Initially, standard genetic algorithms （SGAs） are used to identify control oriented models of the plant which are subsequently used for controller optimisa- tion. An individual tuning approach without loop interaction is considered first to categorise the genetic operators, cost functions and improve searching boundaries to attain the desired performance criteria. The second tuning approach considers controller parameters optimisation with loop interaction and individual cost functions. While, the third tuning approach utilises a modified cost function which includes the total effect of both controlled variables, glass temperature and excess oxygen. This modified cost function is shown to exhibit improved control robustness and disturbance rejection under loop interaction.
基金the support from Weatherhead Presidential Endowment Fund (USA)。
文摘Macrophages are typically identified as classically activated(M1) macrophages and alternatively activated(M2) macrophages,which respectively exhibit pro-and anti-inflammatory phenotypes,and the balance between these two subtypes plays a critical role in the regulation of tissue inflammation,injury,and repair processes.Recent studies indicate that tissue cells and macrophages interact via the release of small extracellular vesicles(EVs) in processes where EVs released by stressed tissue cells can promote the activation and polarization of adjacent macrophages which can in turn release EVs and factors that can promote cell stress and tissue inflammation and injury and vice versa.This review discusses the roles of such EVs in resulating such interactions to influence tissue inflammation and injury in a number of acute and chronic inflammatory disease conditions,and the potential applications,advantage and concerns for using EV-based therapeutic approaches to treat such conditions,including their potential role of drug carriers for the treatment of infectious diseases.
