For the traditional methods of rotor position estimation for permanent magnet synchronous motor(PMSM),the phase shift caused by the introduction of filter will affect the accuracy of rotor position estimation to some ...For the traditional methods of rotor position estimation for permanent magnet synchronous motor(PMSM),the phase shift caused by the introduction of filter will affect the accuracy of rotor position estimation to some extent.This paper presents an improved rotor position estimation method for high frequency square wave signal injection without filter.Firstly,the traditional method injects high-frequency pulse vibration signals into the estimated shafting,and the proposed method injects high-frequency square wave signals into the estimated shafting to avoid the introduction of filters in the process of extracting rotor position information.Then,the rotor position signal is decoupled in the stationary shafting,and the rotor position error after demodulation is processed by PLL.The system realized the signal processing of rotor position without filter,which improved the convergence speed and estimation precision of rotor position and the dynamic response performance of the system.The simulation results showed that the proposed method had fast convergence speed and small phase delay,and better improved the precision of rotor position detection.展开更多
Micro-arc oxidation （MAO） process was carried out on AZ91D alloy in alkaline borate solution using an alternative square-wave power source with different parameters. The effects of voltage, frequency and duty cycle ...Micro-arc oxidation （MAO） process was carried out on AZ91D alloy in alkaline borate solution using an alternative square-wave power source with different parameters. The effects of voltage, frequency and duty cycle on the coatings were investigated by orthogonal experiment. It is found that the thickness of coatings increases with the increase of voltage and duty cycle, but decreases with the increase of frequency. The structure and morphology of the coatings also depend on voltage, frequency and duty cycle. The coatings become more porous and crack with increasing voltage and duty cycle. The coating is thin and transparent when the voltage is lower than 120 V. The corrosion resistances of different coatings were evaluated by polarization curves and electrochemical impedance spectroscopy （EIS） in 3.5% NaCl （mass fraction） solution. When the optimized values of voltage, frequency and duty cycle are 140 V, 2 000 Hz and 0.4, respectively, the anodic coating shows the best corrosion resistance.展开更多
The degradation of acid orange II(AO II)by a nanoporous Fe-Si-B(NP-Fe Si B)electrode under the pulsed square-wave potential has been investigated in this research.Defect-enriched NP-Fe Si B electrode was fabricated th...The degradation of acid orange II(AO II)by a nanoporous Fe-Si-B(NP-Fe Si B)electrode under the pulsed square-wave potential has been investigated in this research.Defect-enriched NP-Fe Si B electrode was fabricated through dealloying of annealed Fe_(76)Si_(9)B_(15)amorphous ribbons.The results of UV-vis spectra and FTIR indicated that AO II solution was degraded efficiently into unharmful molecules H_(2)O and CO_(2)on NPFe Si B electrode within 5 mins under the square-wave potential of±1.5 V.The degradation efficiency of the NP-Fe Si B electrode remains 98.9%even after 5-time recycling.The large amount of active surface area of the nanoporous Fe Si B electrode with lattice disorders and stacking faults,and alternate electrochemical redox reactions were mainly responsible for the excellent degradation performance of the NP-Fe Si B electrode.The electrochemical pulsed square-wave process accelerated the redox of Fe element in Fe-based nanoporous electrode and promoted the generation of hydroxyl radicals(·OH)with strong oxidizability as predominant oxidants for the degradation of azo dye molecules,which was not only beneficial to improving the catalytic degradation activity,but also beneficial to enhancing the reusability of the nanoporous electrode.This work provides a highly possibility to efficiently degrade azo dyes and broadens the application fields of nanoporous metals.展开更多
The pressing environmental concerns and the depletion of fossil fuel reserves necessitate a transition toward sustainable energy sources.Ethanol,a renewable biomass-derived fuel,is a promising alternative due to its a...The pressing environmental concerns and the depletion of fossil fuel reserves necessitate a transition toward sustainable energy sources.Ethanol,a renewable biomass-derived fuel,is a promising alternative due to its availability and high energy density.This study investigates the synthesis of gold nanoparticles(Au NPs)via a square-wave pulse deposition technique,aiming to enhance catalytic activity for ethanol electrooxidation.By varying pulse durations,we were able to exert precise control over Au NP size and distribution without stabilizing agents.Characterization using field emission scanning electron microscopy and X-ray diffraction techniques confirmed the formation of clustered nanoparticles of metallic gold phase.Electrochemical characteristics analyses revealed that Au NPs synthesized with a 900 ms pulse duration exhibited the lowest charge transfer resistance and the highest electrochemically active surface area.The electrocatalytic performance test of these Au NPs demonstrated an anodic current density of 2.5 mA cm^-(2)and a Tafel slope of 78 mV dec^(-1),indicating superior catalytic performance and reaction kinetics.Additionally,the Au NPs showed high resistance to poisoning,as evidenced by a low j_(b)/j_(f)ratio of 0.28 and stable chronoamperometric response.These findings underscore the potential of this synthesis method for producing high-performance electrocatalysts utilized in exploiting ethanol's potential as an environmentally friendly energy carrier.展开更多
Synchronous reluctance machine(SynRM)can be perceived as a special type of permanent magnet synchronous machine(PMSM),and shares similar control method,i.e.the sine-wave current drive with sinusoidal phase currents.In...Synchronous reluctance machine(SynRM)can be perceived as a special type of permanent magnet synchronous machine(PMSM),and shares similar control method,i.e.the sine-wave current drive with sinusoidal phase currents.In this paper,square-wave drive,which is employed for permanent magnet brushless(BLDC)motors,is employed for the SynRM,in order to economically reduce the cost of rotor position sensor.It is revealed that the torque density and efficiency are slightly sacrificed,whereas torque ripple is deteriorated,proving the SynRM with square-wave drive still promising for the cost-sensitive application if torque ripple is not considered as a critical issue.To further investigate the additional pulsating torque under square-wave drive,mathematical model based on a-b-c phase inductance and d-q axis inductance are established,together with the time-stepping FE calculated currents.It is concluded that the harmonics in the currents tend to cause non-sinusoidal variation of the magnetic reluctance,which can be represented as additional inductance harmonics.The harmonics of the current and inductance interact with each other,thus undesirable torque ripple components are produced.展开更多
A sensitive square-wave voltammetric method for the determination of lmidacloprid （IMD） was developed using electrochemically pretreated boron-doped diamond （BDD） electrode. Aqueous solutions were prepared with Co...A sensitive square-wave voltammetric method for the determination of lmidacloprid （IMD） was developed using electrochemically pretreated boron-doped diamond （BDD） electrode. Aqueous solutions were prepared with Confidor 200 SL as the commercial formulation of IMD. Sodium sulfate （Na2SO4） was used as supporting electrolyte. The influence of operating parameters, such as the pH of the medium, frequency, pulse amplitude, scan increment and the concentration of IMD was investigated. An irreversible cathodic peak, corresponding to the reduction oflMD is observed at 1.21 V （vs. SCE） and the electrode reaction was controlled by adsorption. Under optimized conditions, the square-wave reduction peak current was linear over the concentration range of （30-200 μmol L 1） with a detection and quantification limits of 8.60 μmol L 1 and 28.67 μmol L 1, respectively. The results were compared with spectrophotometry and HPLC methods under some conditions and found to be in good agreement. To investigate applicability to real samples, the proposed method was applied to the determination of IMD in plum juice.展开更多
基金supported by National Natural Science Foundation of China(No.61863023)Lanzhou Talent Innovation and Entrepreneurship Project Task Contract(No.2019-RC-103).
文摘For the traditional methods of rotor position estimation for permanent magnet synchronous motor(PMSM),the phase shift caused by the introduction of filter will affect the accuracy of rotor position estimation to some extent.This paper presents an improved rotor position estimation method for high frequency square wave signal injection without filter.Firstly,the traditional method injects high-frequency pulse vibration signals into the estimated shafting,and the proposed method injects high-frequency square wave signals into the estimated shafting to avoid the introduction of filters in the process of extracting rotor position information.Then,the rotor position signal is decoupled in the stationary shafting,and the rotor position error after demodulation is processed by PLL.The system realized the signal processing of rotor position without filter,which improved the convergence speed and estimation precision of rotor position and the dynamic response performance of the system.The simulation results showed that the proposed method had fast convergence speed and small phase delay,and better improved the precision of rotor position detection.
基金Project (50801056) supported by the National Natural Science Foundation of ChinaProject (2005DKA10400-Z20) supported by the National R&D Infrastructure and Facility Development Program of ChinaProject supported by the Zijin Project of Zhejiang University, China
文摘Micro-arc oxidation （MAO） process was carried out on AZ91D alloy in alkaline borate solution using an alternative square-wave power source with different parameters. The effects of voltage, frequency and duty cycle on the coatings were investigated by orthogonal experiment. It is found that the thickness of coatings increases with the increase of voltage and duty cycle, but decreases with the increase of frequency. The structure and morphology of the coatings also depend on voltage, frequency and duty cycle. The coatings become more porous and crack with increasing voltage and duty cycle. The coating is thin and transparent when the voltage is lower than 120 V. The corrosion resistances of different coatings were evaluated by polarization curves and electrochemical impedance spectroscopy （EIS） in 3.5% NaCl （mass fraction） solution. When the optimized values of voltage, frequency and duty cycle are 140 V, 2 000 Hz and 0.4, respectively, the anodic coating shows the best corrosion resistance.
基金financially supported by Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,the National Natural Science Foundation of China(51790484,51671106)Chinese Academy of Sciences(ZDBSLY-JSC023)Fundamental Research Funds for the Central Universities(30919011404)。
文摘The degradation of acid orange II(AO II)by a nanoporous Fe-Si-B(NP-Fe Si B)electrode under the pulsed square-wave potential has been investigated in this research.Defect-enriched NP-Fe Si B electrode was fabricated through dealloying of annealed Fe_(76)Si_(9)B_(15)amorphous ribbons.The results of UV-vis spectra and FTIR indicated that AO II solution was degraded efficiently into unharmful molecules H_(2)O and CO_(2)on NPFe Si B electrode within 5 mins under the square-wave potential of±1.5 V.The degradation efficiency of the NP-Fe Si B electrode remains 98.9%even after 5-time recycling.The large amount of active surface area of the nanoporous Fe Si B electrode with lattice disorders and stacking faults,and alternate electrochemical redox reactions were mainly responsible for the excellent degradation performance of the NP-Fe Si B electrode.The electrochemical pulsed square-wave process accelerated the redox of Fe element in Fe-based nanoporous electrode and promoted the generation of hydroxyl radicals(·OH)with strong oxidizability as predominant oxidants for the degradation of azo dye molecules,which was not only beneficial to improving the catalytic degradation activity,but also beneficial to enhancing the reusability of the nanoporous electrode.This work provides a highly possibility to efficiently degrade azo dyes and broadens the application fields of nanoporous metals.
基金supported by the National Research and Innovation Agency(BRIN)and Lembaga Pengelola Dana Pendidikan(LPDP)Ministry of Finance,Republic of Indonesia through Riset dan Inovasi Untuk Indonesia Maju(RIIM)scheme batch 2 with contract number 1/PG.02.00.PT/LPPM/IV/2024(110/IV/KS/11/2022).
文摘The pressing environmental concerns and the depletion of fossil fuel reserves necessitate a transition toward sustainable energy sources.Ethanol,a renewable biomass-derived fuel,is a promising alternative due to its availability and high energy density.This study investigates the synthesis of gold nanoparticles(Au NPs)via a square-wave pulse deposition technique,aiming to enhance catalytic activity for ethanol electrooxidation.By varying pulse durations,we were able to exert precise control over Au NP size and distribution without stabilizing agents.Characterization using field emission scanning electron microscopy and X-ray diffraction techniques confirmed the formation of clustered nanoparticles of metallic gold phase.Electrochemical characteristics analyses revealed that Au NPs synthesized with a 900 ms pulse duration exhibited the lowest charge transfer resistance and the highest electrochemically active surface area.The electrocatalytic performance test of these Au NPs demonstrated an anodic current density of 2.5 mA cm^-(2)and a Tafel slope of 78 mV dec^(-1),indicating superior catalytic performance and reaction kinetics.Additionally,the Au NPs showed high resistance to poisoning,as evidenced by a low j_(b)/j_(f)ratio of 0.28 and stable chronoamperometric response.These findings underscore the potential of this synthesis method for producing high-performance electrocatalysts utilized in exploiting ethanol's potential as an environmentally friendly energy carrier.
基金supported in part by the National Natural Science Foundation of China under Grant 52007161.
文摘Synchronous reluctance machine(SynRM)can be perceived as a special type of permanent magnet synchronous machine(PMSM),and shares similar control method,i.e.the sine-wave current drive with sinusoidal phase currents.In this paper,square-wave drive,which is employed for permanent magnet brushless(BLDC)motors,is employed for the SynRM,in order to economically reduce the cost of rotor position sensor.It is revealed that the torque density and efficiency are slightly sacrificed,whereas torque ripple is deteriorated,proving the SynRM with square-wave drive still promising for the cost-sensitive application if torque ripple is not considered as a critical issue.To further investigate the additional pulsating torque under square-wave drive,mathematical model based on a-b-c phase inductance and d-q axis inductance are established,together with the time-stepping FE calculated currents.It is concluded that the harmonics in the currents tend to cause non-sinusoidal variation of the magnetic reluctance,which can be represented as additional inductance harmonics.The harmonics of the current and inductance interact with each other,thus undesirable torque ripple components are produced.
基金financially supported by the Tunisian Ministry of Higher Education and Scientific Research
文摘A sensitive square-wave voltammetric method for the determination of lmidacloprid （IMD） was developed using electrochemically pretreated boron-doped diamond （BDD） electrode. Aqueous solutions were prepared with Confidor 200 SL as the commercial formulation of IMD. Sodium sulfate （Na2SO4） was used as supporting electrolyte. The influence of operating parameters, such as the pH of the medium, frequency, pulse amplitude, scan increment and the concentration of IMD was investigated. An irreversible cathodic peak, corresponding to the reduction oflMD is observed at 1.21 V （vs. SCE） and the electrode reaction was controlled by adsorption. Under optimized conditions, the square-wave reduction peak current was linear over the concentration range of （30-200 μmol L 1） with a detection and quantification limits of 8.60 μmol L 1 and 28.67 μmol L 1, respectively. The results were compared with spectrophotometry and HPLC methods under some conditions and found to be in good agreement. To investigate applicability to real samples, the proposed method was applied to the determination of IMD in plum juice.
