A model predictive current control(MPCC)with adaptive-adjusting method of timescales for permanent magnet synchronous motors(PMSMs)is proposed in this paper to improve the dynamic response and prediction accuracy in t...A model predictive current control(MPCC)with adaptive-adjusting method of timescales for permanent magnet synchronous motors(PMSMs)is proposed in this paper to improve the dynamic response and prediction accuracy in transient-state,while lessening the computational burden and improving the control performance in steady-state.The timescale characteristics of different parts of MPCC,such as signal sampling,prediction calculation,control output,model error correction,are analyzed,and the algorithm architecture of MPCC with multi-timescale is proposed.The difference between reference and actual speed,and the change rate of actual speed are utilized to discriminate the transient state of speed change and load change,respectively.Adaptive-adjusting method of control period and prediction stepsize are illustrated in detail after operation condition discrimination.Experimental results of a PMSM are presented to validate the effectiveness of proposed MPCC.In addition,comparative evaluation of single-step MPCC with fixed timescale and proposed MPCC is conducted,which demonstrates the superiority of proposed control strategy.展开更多
A detailed analysis of benzofuranone compounds under multiple tandem mass spectrometry （ESI-MS^n） conditions is reported. Element composition data of the fragment ions were obtained with the aid of comparison of the...A detailed analysis of benzofuranone compounds under multiple tandem mass spectrometry （ESI-MS^n） conditions is reported. Element composition data of the fragment ions were obtained with the aid of comparison of the multiple tandem mass spectra of four compounds, and the structures of which are identical except for some substituted groups or epimers or cis-trans-isomers. Attempts have been made to provide rational pathways for the formation of the fragment ions from these protonated compounds. And the structure-fragmentation relationships will facilitate the characterization of the structures of other analogs.展开更多
To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its ...To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its stability is analyzed by using Lyapunov stability criterion.Secondly,according to the relationship among bus current,switching state and phase current,a single bus resistance sampling current reconstruction scheme without current sensors is adopted,which effectively reduces the cost of motor system.Finally,the feasibility and effectiveness of the proposed scheme are verified by simulation.展开更多
CONTROLLING carbon emissions to achieve green and sustainable development has become a global consensus and general trend.China established“30.60”decarbonization goal for carbon peak and carbon neutrality in 2019.As...CONTROLLING carbon emissions to achieve green and sustainable development has become a global consensus and general trend.China established“30.60”decarbonization goal for carbon peak and carbon neutrality in 2019.As electromechanical energy conversion devices,the electrical machines and systems play important roles in both renewable energy harvesting,such as wind,tidal,ocean current energy。展开更多
Traditional metal oxide semiconductor(MOS)gas sensors have limited applications in wearable devices owing to their inflexibility and high-power consumption by substantial heat loss.To overcome these limitations,we pre...Traditional metal oxide semiconductor(MOS)gas sensors have limited applications in wearable devices owing to their inflexibility and high-power consumption by substantial heat loss.To overcome these limitations,we prepared doped Si/SiO_(2)flexible fibers by a thermal drawing method as substrates to fabricate MOS gas sensors.A methane(CH_(4))gas sensor was demonstrated by subsequently in situ synthesizing Co-doped ZnO nanorods on the fiber surface.The doped Si core acted as the heating source through Joule heating,which conducted heat to the sensing material with reduced heat loss;the SiO_(2)cladding was an insulating substrate.The gas sensor was integrated into a miner cloth as a wearable device,and the concentration change of CH_(4)was monitored in real time through different colored lightemitting diodes.Our study demonstrated the feasibility of using doped Si/SiO_(2)fibers as the substrates to fabricate wearable MOS gas sensors,where the sensors have substantial advantages over tradition sensors in flexibility,heat utilization,etc.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 52077054in part by the Natural Science Foundation of Hebei Province under Grant E2019202092+2 种基金in part by the China Postdoctoral Science Foundation under Grant 2021T140077 and 2020M681446in part by the State Key Laboratory of Reliability and Intelligence of Electrical Equipment under Grant EERI_PI2020002in part by the Funds for Creative Research Groups of Hebei Province under Grant E2020202142.
文摘A model predictive current control(MPCC)with adaptive-adjusting method of timescales for permanent magnet synchronous motors(PMSMs)is proposed in this paper to improve the dynamic response and prediction accuracy in transient-state,while lessening the computational burden and improving the control performance in steady-state.The timescale characteristics of different parts of MPCC,such as signal sampling,prediction calculation,control output,model error correction,are analyzed,and the algorithm architecture of MPCC with multi-timescale is proposed.The difference between reference and actual speed,and the change rate of actual speed are utilized to discriminate the transient state of speed change and load change,respectively.Adaptive-adjusting method of control period and prediction stepsize are illustrated in detail after operation condition discrimination.Experimental results of a PMSM are presented to validate the effectiveness of proposed MPCC.In addition,comparative evaluation of single-step MPCC with fixed timescale and proposed MPCC is conducted,which demonstrates the superiority of proposed control strategy.
文摘A detailed analysis of benzofuranone compounds under multiple tandem mass spectrometry （ESI-MS^n） conditions is reported. Element composition data of the fragment ions were obtained with the aid of comparison of the multiple tandem mass spectra of four compounds, and the structures of which are identical except for some substituted groups or epimers or cis-trans-isomers. Attempts have been made to provide rational pathways for the formation of the fragment ions from these protonated compounds. And the structure-fragmentation relationships will facilitate the characterization of the structures of other analogs.
文摘To solve the chattering problem caused by discontinuous switching function in traditional sliding mode observer,a piecewise square root switching function with continuously varying characteristics is designed,and its stability is analyzed by using Lyapunov stability criterion.Secondly,according to the relationship among bus current,switching state and phase current,a single bus resistance sampling current reconstruction scheme without current sensors is adopted,which effectively reduces the cost of motor system.Finally,the feasibility and effectiveness of the proposed scheme are verified by simulation.
文摘CONTROLLING carbon emissions to achieve green and sustainable development has become a global consensus and general trend.China established“30.60”decarbonization goal for carbon peak and carbon neutrality in 2019.As electromechanical energy conversion devices,the electrical machines and systems play important roles in both renewable energy harvesting,such as wind,tidal,ocean current energy。
基金This work was supported by the Key Research and Development Program of Shanxi Province(202102030201002)the Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China(IRT_17R70)+2 种基金the State Key Program of National Natural Science of China(11434007)the 111 Project(D18001)the Fund for Shanxi“1331 Project”Key Subjects Construction.
文摘Traditional metal oxide semiconductor(MOS)gas sensors have limited applications in wearable devices owing to their inflexibility and high-power consumption by substantial heat loss.To overcome these limitations,we prepared doped Si/SiO_(2)flexible fibers by a thermal drawing method as substrates to fabricate MOS gas sensors.A methane(CH_(4))gas sensor was demonstrated by subsequently in situ synthesizing Co-doped ZnO nanorods on the fiber surface.The doped Si core acted as the heating source through Joule heating,which conducted heat to the sensing material with reduced heat loss;the SiO_(2)cladding was an insulating substrate.The gas sensor was integrated into a miner cloth as a wearable device,and the concentration change of CH_(4)was monitored in real time through different colored lightemitting diodes.Our study demonstrated the feasibility of using doped Si/SiO_(2)fibers as the substrates to fabricate wearable MOS gas sensors,where the sensors have substantial advantages over tradition sensors in flexibility,heat utilization,etc.
