When large-scale distributed renewable energy power generation systems are connected to the power grid,the risk of grid voltage fluctuations and exceeding the limit increases greatly.Fortunately,the on-load tap change...When large-scale distributed renewable energy power generation systems are connected to the power grid,the risk of grid voltage fluctuations and exceeding the limit increases greatly.Fortunately,the on-load tap changer(OLTC)can adjust the transformer winding tap to maintain the secondary side voltage within the normal range.However,the inevitable delay in switching transformer taps makes it difficult to respond quickly to voltage fluctuations.Moreover,switching the transformer taps frequently will decrease the service life of OLTC.In order to solve this critical issue,a cooperative voltage regulation strategy applied between the battery energy storage systems(BESSs)and OLTSs.is proposed By adjusting the charge and discharge power of BESSs,the OLTC can frequently switch the transformer taps to achieve rapid voltage regulation.The effectiveness of the proposed coordinated regulation strategy is verified in the IEEE 33 node distribution systems.The simulation results show that the proposed coordinated regulation strategy can stabilize the voltage of the distribution network within a normal range and reduce the frequency of tap switching,as such elongating the service life of the equipment.展开更多
For starting high-voltage asynchronous motor,the voltage regulator based on current-limiting transformer is presented in the paper. Its mathematical model needs to be established analyzing and designing voltage regula...For starting high-voltage asynchronous motor,the voltage regulator based on current-limiting transformer is presented in the paper. Its mathematical model needs to be established analyzing and designing voltage regulator of high-voltage asynchronous motor. The mathematical model of the current-limiting transformer is deduced based on basic circuit theory. It can be found that a continuous variation reactance can describe the current-limiting transformer during starting process. The two variables functions of current and voltage are transformed into one-variable functions,and thus system control is greatly simplified. The voltage regulator is simulated on the basis. The simulation results show that this model has enough accuracy. Finally, the high-voltage asynchronous motor voltage regulator based on current-limiting transformer is designed and tested on this model.展开更多
Lithium-ion capacitors(LICs)are becoming important electrochemical energy storage systems due to their great potential to bridge the gap between supercapacitors and lithium-ion batteries.However,capacity lopsidedness ...Lithium-ion capacitors(LICs)are becoming important electrochemical energy storage systems due to their great potential to bridge the gap between supercapacitors and lithium-ion batteries.However,capacity lopsidedness and low output voltage greatly hinder the realization of high-energy-density LICs.Herein,a strategy of balancing capacity towards fastest dynamics is proposed to enable high-voltage LICs.Through electrochemical prelithiation of Nb_(2)C to be 1.1 V with 165 mAh g^(-1),Nb_(2)C//LiFePO_(4) LICs show a broadened potential window from 3.0 to 4.2 V and an according high energy density of 420 Wh kg^(-1).Moreover,the underlying mechanism between prelithiation and high voltage is disclosed by electrochemical dynamic analysis.Prelithiation declines the Nb_(2)C anode potential that facilitates electron transmission in the interlayer of two-dimensional Nb_(2)C MXene.This effect induces small drive force for Li^(+)ions deposition and hence weakens the repulsive force from adsorbed ions on the electrode surface.Benefiting from even more Li^(+)ions deposition,a higher voltage is eventually delivered.In addition,prelithiation significantly increases Coulomb efficiency of the 1st cycle from 74%to 90%,which is crucial to commercial application of LICs.展开更多
Control strategy affects directly the working performances of dynamic voltage regulator (DVR). One-cycle control is an effective nonlinear signal modulation control method. In this paper, a new one-cycle control sch...Control strategy affects directly the working performances of dynamic voltage regulator (DVR). One-cycle control is an effective nonlinear signal modulation control method. In this paper, a new one-cycle control scheme for DVR was proposed in single phase supply system. On the basis of principle analysis, the corresponding one-cycle control model for DVR was built up, which is characterized by simple control circuits, good control performance, and high control precision. As an example, a control model for single-phase DVR was simulated by using Matlab/Simulink and SimPowerSystem. The results show that the load voltage could be compensated quickly at the points of supply voltage stepping down and up, and the relative error was less than 4% in the whole voltage sag process. Both theory analysis and simulation results show that the new one-cycle control scheme for DVR is effective.展开更多
Coupled inductor is one appealing technology to improve transient response and reduce output decoupling significantly in interleaved multi-phase voltage regulators (VRs). One well known problem is that coupled inducto...Coupled inductor is one appealing technology to improve transient response and reduce output decoupling significantly in interleaved multi-phase voltage regulators (VRs). One well known problem is that coupled inductor winding structure causes PCB routing path longer than discrete inductor design. This paper investigates possible PCB routing schemes for coupled inductor and conducts a fair and quantitative comparison with discrete inductor in a server VR design. Simulation and measurement are also conducted to verify the analysis.展开更多
Coupled inductor is one appealing technology to improve transient response and reduce output decoupling significantly in interleaved multi-phase voltage regulators (VRs). One known problem is that there is no mature s...Coupled inductor is one appealing technology to improve transient response and reduce output decoupling significantly in interleaved multi-phase voltage regulators (VRs). One known problem is that there is no mature solution yet to sense the individual phase current accurately in a lossless way for couple inductor based VRs design. This will impact VR some normal function in one phase mode. This paper proposes a new solution to this problem and simulation is conducted to verify effectiveness of the proposal.展开更多
Background:KMT2(lysine methyltransferase)family enzymes are epigenetic regulators that activate gene transcription.KMT2C is mainly involved in enhancer-associated H3K4me1,and is also one of the top mutated genes in ca...Background:KMT2(lysine methyltransferase)family enzymes are epigenetic regulators that activate gene transcription.KMT2C is mainly involved in enhancer-associated H3K4me1,and is also one of the top mutated genes in cancer(6.6%in pan-cancer).Currently,the clinical significance of KMT2C mutations in prostate cancer is understudied.Methods:We included 221 prostate cancer patients diagnosed between 2014 and 2021 in West China Hospital of Sichuan University with cell-free DNA-based liquid biopsy test results in this study.We investigated the association between KMT2C mutations,other mutations,and pathways.Furthermore,we evaluated the prognostic value of KMT2C mutations,measured by overall survival(OS)and castration resistance-free survival(CRFS).Also,we explored the prognostic value of KMT2C mutations in different patient subgroups.Lastly,we investigated the predictive value of KMT2C mutations in individuals receiving conventional combined anti-androgen blockade(CAB)and abiraterone(ABI)as measured by PSA progression-free survival(PSA-PFS).Results:The KMT2C mutation rate in this cohort is 7.24%(16/221).KMT2C-mutated patients showed worse survival than KMT2C-wild type(WT)patients regarding both CRFS and OS(CRFS:mutated:9.9 vs.WT:22.0 months,p=0.015;OS:mutated:71.9 vs.WT 137.4 months,p=0.012).KMT2C mutations were also an independent risk factor in OS[hazard ratio:3.815(1.461,9.96),p=0.006]in multivariate analyses.Additionally,we explored the association of KMT2C mutations with other genes.This showed that KMT2C mutations were associated with Serine/Threonine-Protein Kinase 11(STK11,p=0.004)and Catenin Beta 1(CTNNB1,p=0.008)mutations.In the CAB treatment,KMT2C-mutated patients had a significantly shorter PSA-PFS compared to KMT2C-WT patients.(PSA-PFS:mutated:9.9 vs.WT:17.6 months,p=0.014).Moreover,KMT2C mutations could effectively predict shorter PSA-PFS in 10 out of 23 subgroups and exhibited a strong trend in the remaining subgroups.Conclusions:KMT2C-mutated patients showed worse survival compared to KMT2C-WT patients in terms of both CRFS and OS,and KMT2C mutations were associated with STK11 and CTNNB1 mutations.Furthermore,KMT2C mutations indicated rapid progression during CAB therapy and could serve as a potential biomarker to predict therapeutic response in prostate cancer.展开更多
A series connected power semiconductor array, with digital control capability could be used for developing single phase AC regulators or other applications such as AC electronic loads. This technique together with an ...A series connected power semiconductor array, with digital control capability could be used for developing single phase AC regulators or other applications such as AC electronic loads. This technique together with an ordinary gapless transformer could be used to develop a low cost AC voltage regulator (AVR) to provide better or comparable specifications with bulky ferro-resonant AVR types. One primary advantage of the technique is that digital control can be used to minimize harmonics. Commencing with a review of AC voltage regulator techniques for single phase power conditioning systems, an analysis and design aspects of this technique is presented with experimental results for AVRs. Guidelines on how to utilize the technique in a generalized basis is also summarized together with a summary of a technique for achieving harmonic control.展开更多
A low-dropout voltage regulator,LM2941,was irradiated by ^(60)Coγ-rays at various dose rates and biases for investigating the total dose and dose rate effects.The radiation responses show that the key electrical para...A low-dropout voltage regulator,LM2941,was irradiated by ^(60)Coγ-rays at various dose rates and biases for investigating the total dose and dose rate effects.The radiation responses show that the key electrical parameters, including its output and dropout voltage,and the maximum output current,are sensitive to total dose and dose rates, and are significantly degraded at low dose rate and zero bias.The integrated circuits damage change with the dose rates and biases,and the dose-rate effects are relative to its electric field.展开更多
The distributed AC microgrid(MG) voltage restoration problem has been extensively studied. Still, many existing secondary voltage control strategies neglect the co-regulation of the voltage at the point of common coup...The distributed AC microgrid(MG) voltage restoration problem has been extensively studied. Still, many existing secondary voltage control strategies neglect the co-regulation of the voltage at the point of common coupling(PCC) in the AC multi-MG system(MMS). When an MMS consists of sub-MGs connected in series, power flow between the sub-MGs is not possible if the PCC voltage regulation relies on traditional consensus control objectives. In addition, communication faults and sensor faults are inevitable in the MMS. Therefore, a resilient voltage regulation strategy based on containment control is proposed.First, the feedback linearization technique allows us to deal with the nonlinear distributed generation(DG) dynamics, where the PCC regulation problem of an AC MG is transformed into an output feedback tracking problem for a linear multi-agent system(MAS) containing nonlinear dynamics. This process is an indispensable pre-processing in control algorithm design. Moreover, considering the unavailability of full-state measurements and the potential faults present in the sensors, a novel follower observer is designed to handle communication faults. Based on this, a controller based on containment control is designed to achieve voltage regulation. In regulating multiple PCC voltages to a reasonable upper and lower limit, a voltage difference exists between sub-MGs to achieve power flow. In addition, the secondary control algorithm avoids using global information of directed communication network and fault boundaries for communication link and sensor faults. Finally, the simulation results verify the performance of the proposed strategy.展开更多
基金Supported by the Postdoctoral Science Foundation of China(No.2022M710039)。
文摘When large-scale distributed renewable energy power generation systems are connected to the power grid,the risk of grid voltage fluctuations and exceeding the limit increases greatly.Fortunately,the on-load tap changer(OLTC)can adjust the transformer winding tap to maintain the secondary side voltage within the normal range.However,the inevitable delay in switching transformer taps makes it difficult to respond quickly to voltage fluctuations.Moreover,switching the transformer taps frequently will decrease the service life of OLTC.In order to solve this critical issue,a cooperative voltage regulation strategy applied between the battery energy storage systems(BESSs)and OLTSs.is proposed By adjusting the charge and discharge power of BESSs,the OLTC can frequently switch the transformer taps to achieve rapid voltage regulation.The effectiveness of the proposed coordinated regulation strategy is verified in the IEEE 33 node distribution systems.The simulation results show that the proposed coordinated regulation strategy can stabilize the voltage of the distribution network within a normal range and reduce the frequency of tap switching,as such elongating the service life of the equipment.
基金Natural Science Foundation of Shanghai,China(No.14ZR1419100)Shanghai Science and Technology Commission,China(No.13160501500)+1 种基金Shanghai Maritime University Foundation,China(No.20130430)the Ministry of Transport Foundation of China(No.2013329 810350)
文摘For starting high-voltage asynchronous motor,the voltage regulator based on current-limiting transformer is presented in the paper. Its mathematical model needs to be established analyzing and designing voltage regulator of high-voltage asynchronous motor. The mathematical model of the current-limiting transformer is deduced based on basic circuit theory. It can be found that a continuous variation reactance can describe the current-limiting transformer during starting process. The two variables functions of current and voltage are transformed into one-variable functions,and thus system control is greatly simplified. The voltage regulator is simulated on the basis. The simulation results show that this model has enough accuracy. Finally, the high-voltage asynchronous motor voltage regulator based on current-limiting transformer is designed and tested on this model.
基金financial supported from the National Natural Science Foundation of China (Nos. 51977185 and 51972277)the financial supported from Southwest Jiaotong University Science and Technology Rising Star Program (No. 2682021CG021)
文摘Lithium-ion capacitors(LICs)are becoming important electrochemical energy storage systems due to their great potential to bridge the gap between supercapacitors and lithium-ion batteries.However,capacity lopsidedness and low output voltage greatly hinder the realization of high-energy-density LICs.Herein,a strategy of balancing capacity towards fastest dynamics is proposed to enable high-voltage LICs.Through electrochemical prelithiation of Nb_(2)C to be 1.1 V with 165 mAh g^(-1),Nb_(2)C//LiFePO_(4) LICs show a broadened potential window from 3.0 to 4.2 V and an according high energy density of 420 Wh kg^(-1).Moreover,the underlying mechanism between prelithiation and high voltage is disclosed by electrochemical dynamic analysis.Prelithiation declines the Nb_(2)C anode potential that facilitates electron transmission in the interlayer of two-dimensional Nb_(2)C MXene.This effect induces small drive force for Li^(+)ions deposition and hence weakens the repulsive force from adsorbed ions on the electrode surface.Benefiting from even more Li^(+)ions deposition,a higher voltage is eventually delivered.In addition,prelithiation significantly increases Coulomb efficiency of the 1st cycle from 74%to 90%,which is crucial to commercial application of LICs.
基金The National Science and Technology Sup-port Project (No.2007BAA12B03)
文摘Control strategy affects directly the working performances of dynamic voltage regulator (DVR). One-cycle control is an effective nonlinear signal modulation control method. In this paper, a new one-cycle control scheme for DVR was proposed in single phase supply system. On the basis of principle analysis, the corresponding one-cycle control model for DVR was built up, which is characterized by simple control circuits, good control performance, and high control precision. As an example, a control model for single-phase DVR was simulated by using Matlab/Simulink and SimPowerSystem. The results show that the load voltage could be compensated quickly at the points of supply voltage stepping down and up, and the relative error was less than 4% in the whole voltage sag process. Both theory analysis and simulation results show that the new one-cycle control scheme for DVR is effective.
文摘Coupled inductor is one appealing technology to improve transient response and reduce output decoupling significantly in interleaved multi-phase voltage regulators (VRs). One well known problem is that coupled inductor winding structure causes PCB routing path longer than discrete inductor design. This paper investigates possible PCB routing schemes for coupled inductor and conducts a fair and quantitative comparison with discrete inductor in a server VR design. Simulation and measurement are also conducted to verify the analysis.
文摘Coupled inductor is one appealing technology to improve transient response and reduce output decoupling significantly in interleaved multi-phase voltage regulators (VRs). One known problem is that there is no mature solution yet to sense the individual phase current accurately in a lossless way for couple inductor based VRs design. This will impact VR some normal function in one phase mode. This paper proposes a new solution to this problem and simulation is conducted to verify effectiveness of the proposal.
基金This work was supported by the Natural Science Foundation of China(NSFC 81902577)the Research Foundation for the Postdoctoral Program of Sichuan University(2021SCU12014).
文摘Background:KMT2(lysine methyltransferase)family enzymes are epigenetic regulators that activate gene transcription.KMT2C is mainly involved in enhancer-associated H3K4me1,and is also one of the top mutated genes in cancer(6.6%in pan-cancer).Currently,the clinical significance of KMT2C mutations in prostate cancer is understudied.Methods:We included 221 prostate cancer patients diagnosed between 2014 and 2021 in West China Hospital of Sichuan University with cell-free DNA-based liquid biopsy test results in this study.We investigated the association between KMT2C mutations,other mutations,and pathways.Furthermore,we evaluated the prognostic value of KMT2C mutations,measured by overall survival(OS)and castration resistance-free survival(CRFS).Also,we explored the prognostic value of KMT2C mutations in different patient subgroups.Lastly,we investigated the predictive value of KMT2C mutations in individuals receiving conventional combined anti-androgen blockade(CAB)and abiraterone(ABI)as measured by PSA progression-free survival(PSA-PFS).Results:The KMT2C mutation rate in this cohort is 7.24%(16/221).KMT2C-mutated patients showed worse survival than KMT2C-wild type(WT)patients regarding both CRFS and OS(CRFS:mutated:9.9 vs.WT:22.0 months,p=0.015;OS:mutated:71.9 vs.WT 137.4 months,p=0.012).KMT2C mutations were also an independent risk factor in OS[hazard ratio:3.815(1.461,9.96),p=0.006]in multivariate analyses.Additionally,we explored the association of KMT2C mutations with other genes.This showed that KMT2C mutations were associated with Serine/Threonine-Protein Kinase 11(STK11,p=0.004)and Catenin Beta 1(CTNNB1,p=0.008)mutations.In the CAB treatment,KMT2C-mutated patients had a significantly shorter PSA-PFS compared to KMT2C-WT patients.(PSA-PFS:mutated:9.9 vs.WT:17.6 months,p=0.014).Moreover,KMT2C mutations could effectively predict shorter PSA-PFS in 10 out of 23 subgroups and exhibited a strong trend in the remaining subgroups.Conclusions:KMT2C-mutated patients showed worse survival compared to KMT2C-WT patients in terms of both CRFS and OS,and KMT2C mutations were associated with STK11 and CTNNB1 mutations.Furthermore,KMT2C mutations indicated rapid progression during CAB therapy and could serve as a potential biomarker to predict therapeutic response in prostate cancer.
文摘A series connected power semiconductor array, with digital control capability could be used for developing single phase AC regulators or other applications such as AC electronic loads. This technique together with an ordinary gapless transformer could be used to develop a low cost AC voltage regulator (AVR) to provide better or comparable specifications with bulky ferro-resonant AVR types. One primary advantage of the technique is that digital control can be used to minimize harmonics. Commencing with a review of AC voltage regulator techniques for single phase power conditioning systems, an analysis and design aspects of this technique is presented with experimental results for AVRs. Guidelines on how to utilize the technique in a generalized basis is also summarized together with a summary of a technique for achieving harmonic control.
文摘A low-dropout voltage regulator,LM2941,was irradiated by ^(60)Coγ-rays at various dose rates and biases for investigating the total dose and dose rate effects.The radiation responses show that the key electrical parameters, including its output and dropout voltage,and the maximum output current,are sensitive to total dose and dose rates, and are significantly degraded at low dose rate and zero bias.The integrated circuits damage change with the dose rates and biases,and the dose-rate effects are relative to its electric field.
基金supported in part by the National Key R&D Program of China(2018YFA0702200)the National Natural Science Foundation of China(62073065,U20A20190)。
文摘The distributed AC microgrid(MG) voltage restoration problem has been extensively studied. Still, many existing secondary voltage control strategies neglect the co-regulation of the voltage at the point of common coupling(PCC) in the AC multi-MG system(MMS). When an MMS consists of sub-MGs connected in series, power flow between the sub-MGs is not possible if the PCC voltage regulation relies on traditional consensus control objectives. In addition, communication faults and sensor faults are inevitable in the MMS. Therefore, a resilient voltage regulation strategy based on containment control is proposed.First, the feedback linearization technique allows us to deal with the nonlinear distributed generation(DG) dynamics, where the PCC regulation problem of an AC MG is transformed into an output feedback tracking problem for a linear multi-agent system(MAS) containing nonlinear dynamics. This process is an indispensable pre-processing in control algorithm design. Moreover, considering the unavailability of full-state measurements and the potential faults present in the sensors, a novel follower observer is designed to handle communication faults. Based on this, a controller based on containment control is designed to achieve voltage regulation. In regulating multiple PCC voltages to a reasonable upper and lower limit, a voltage difference exists between sub-MGs to achieve power flow. In addition, the secondary control algorithm avoids using global information of directed communication network and fault boundaries for communication link and sensor faults. Finally, the simulation results verify the performance of the proposed strategy.