Control over geometric curvature and chirality of assemblies in pure aqueous media is key to the design of responsive materials and molecular machines.Here we show how aggregate geometric curvature and chirality of mo...Control over geometric curvature and chirality of assemblies in pure aqueous media is key to the design of responsive materials and molecular machines.Here we show how aggregate geometric curvature and chirality of motor amphiphiles could be switched from bicontinuous calabashes to nanoribbons or from vesicles to nanoribbons by modulating rotor orientation direction with dual light/heat stimuli to influence spontaneous curvature in assemblies.The photoisomerization and thermal helix inversion processes of molecular motors have been studied at the molecular level,and the transformation of supramolecular assemblies has been investigated at the microscopic level.The morphological evolution of the calabash-shaped assembly can be kinetically captured,suggesting that the bicontinuous calabash-shaped structures are different from the bowl-shaped aggregates based on solvent-driven assembly upon the addition of non-solvent or solvent.The investigation of dual optical/thermal control of rotor orientation can provide a new strategy for tuning the geometric curvature and chirality of nanoassemblies at the nanoscale,arriving ultimately the clusteroluminescence through-space electronic communication at responsive supramolecular nanosystems.展开更多
The aim of this paper is to investigate an adaptive sensorless direct voltage control(DVC)strategy for the stand-alone ship shaft brushless doubly-fed induction generators(BDFIGs).The proposed new rotor position obser...The aim of this paper is to investigate an adaptive sensorless direct voltage control(DVC)strategy for the stand-alone ship shaft brushless doubly-fed induction generators(BDFIGs).The proposed new rotor position observer using the space vector flux relations of BDFIG may achieve the desired voltage control of the power winding(PW)in terms of magnitude and frequency,without any speed/position sensors.The proposed algorithm does not require any additional observers for obtaining the generator speed.The proposed technique can directly achieve the desired DVC based on the estimated rotor position,which may reduce the overall system cost.The stability analysis of the proposed observer is investigated and confirmed with the concept of quadratic Lyapunov function and using the multi-model representation.In addition,the sensitivity analysis of the presented method is confirmed under different issues of parameter uncertainties.Comprehensive results from both simulation and experiments are realized with a prototype wound-rotor BDFIG,which demonstrate the capability and efficacy of the proposed sensorless DVC strategy with good transient behavior under different operating conditions.Furthermore,the analysis confirms the robustness of the proposed observer via the machine parameter changes.展开更多
An observing method for stator flux and rotor flux is presented. Based on the proposed flux observing method, a novel speed estimator has been designed. At last, the speed estimator combined with the flux observing is...An observing method for stator flux and rotor flux is presented. Based on the proposed flux observing method, a novel speed estimator has been designed. At last, the speed estimator combined with the flux observing is applied in the direct torque control system without speed sensor. The simulation results show that these methods can improve the accuracy of speed observing and the low speed performance of direct torque control system, and strengthen the robustness of system.展开更多
基金Science and Technology Program of Guangzhou,Grant/Award Number:201804010017National Natural Science Foundation of China,Grant/Award Number:21374137+1 种基金Natural Science Foundation of Guangdong Province,Grant/Award Number:2014A030313194Science and Technology Program of Guangdong Province,Grant/Award Number:2017A050506021。
文摘Control over geometric curvature and chirality of assemblies in pure aqueous media is key to the design of responsive materials and molecular machines.Here we show how aggregate geometric curvature and chirality of motor amphiphiles could be switched from bicontinuous calabashes to nanoribbons or from vesicles to nanoribbons by modulating rotor orientation direction with dual light/heat stimuli to influence spontaneous curvature in assemblies.The photoisomerization and thermal helix inversion processes of molecular motors have been studied at the molecular level,and the transformation of supramolecular assemblies has been investigated at the microscopic level.The morphological evolution of the calabash-shaped assembly can be kinetically captured,suggesting that the bicontinuous calabash-shaped structures are different from the bowl-shaped aggregates based on solvent-driven assembly upon the addition of non-solvent or solvent.The investigation of dual optical/thermal control of rotor orientation can provide a new strategy for tuning the geometric curvature and chirality of nanoassemblies at the nanoscale,arriving ultimately the clusteroluminescence through-space electronic communication at responsive supramolecular nanosystems.
基金This work was supported in part by the National Natural Science Foundation of China(NSFC)under Grants 51707079 and 51877093in part by the National Key Research and Development Program of China(Project ID:YS2018YFGH000200)in part by the Fundamental Research Funds for the Central Universities(Project ID:2019kfyXMBZ031).
文摘The aim of this paper is to investigate an adaptive sensorless direct voltage control(DVC)strategy for the stand-alone ship shaft brushless doubly-fed induction generators(BDFIGs).The proposed new rotor position observer using the space vector flux relations of BDFIG may achieve the desired voltage control of the power winding(PW)in terms of magnitude and frequency,without any speed/position sensors.The proposed algorithm does not require any additional observers for obtaining the generator speed.The proposed technique can directly achieve the desired DVC based on the estimated rotor position,which may reduce the overall system cost.The stability analysis of the proposed observer is investigated and confirmed with the concept of quadratic Lyapunov function and using the multi-model representation.In addition,the sensitivity analysis of the presented method is confirmed under different issues of parameter uncertainties.Comprehensive results from both simulation and experiments are realized with a prototype wound-rotor BDFIG,which demonstrate the capability and efficacy of the proposed sensorless DVC strategy with good transient behavior under different operating conditions.Furthermore,the analysis confirms the robustness of the proposed observer via the machine parameter changes.
文摘An observing method for stator flux and rotor flux is presented. Based on the proposed flux observing method, a novel speed estimator has been designed. At last, the speed estimator combined with the flux observing is applied in the direct torque control system without speed sensor. The simulation results show that these methods can improve the accuracy of speed observing and the low speed performance of direct torque control system, and strengthen the robustness of system.
