Grid-Forming(GFM)converters are prone to fault-induced overcurrent and power angle instability during grid fault-induced voltage sags.To address this,this paper develops a multi-loop coordinated fault ridethrough(FRT)...Grid-Forming(GFM)converters are prone to fault-induced overcurrent and power angle instability during grid fault-induced voltage sags.To address this,this paper develops a multi-loop coordinated fault ridethrough(FRT)control strategy based on a power outer loop and voltage-current inner loops,aiming to enhance the stability and current-limiting capability of GFM converters during grid fault conditions.During voltage sags,the GFM converter’s voltage source behavior is maintained by dynamically adjusting the reactive power reference to provide voltage support,thereby effectively suppressing the steady-state component of the fault current.To address the active power imbalance induced by voltage sags,a dynamic active power reference correction method based on apparent power is designed to mitigate power angle oscillations and limit transient current.Moreover,an adaptive virtual impedance loop is implemented to enhance dynamic transient current-limiting performance during the fault initiation phase.This approach improves the responsiveness of the inner loop and ensures safe system operation under various fault severities.Under asymmetric fault conditions,a negative-sequence reactive current compensation strategy is incorporated to further suppress negative-sequence voltage and improve voltage symmetry.The proposed control scheme enables coordinated operation of multiple control objectives,including voltage support,current suppression,and power angle stability,across different fault scenarios.Finally,MATLAB/Simulink simulation results validate the effectiveness of the proposed strategy,showcasing its superior performance in current limiting and power angle stability,thereby significantly enhancing the system’s fault ride-through capability.展开更多
With the depletion of fossil fuels and increasing environmental concerns,the development of renewable energy,such as wave energy,has become a critical component of global energy strategies.However,challenges persist i...With the depletion of fossil fuels and increasing environmental concerns,the development of renewable energy,such as wave energy,has become a critical component of global energy strategies.However,challenges persist in the field testing methodologies for wave energy converters(WECs).In this paper,a numerical wave field of the Dawanshan Island Sea Area in Zhuhai City is constructed based on the MIKE21 SW wave model and by using an NCEP wind field driving model.In conjunction with the IEC-62600-100 standard,by taking site testing of the“Wanshan”wave energy converter on which a sea trial has been conducted in Dawanshan Island of Zhuhai city as an example,research on-site testing method for a wave energy converter has been carried out.The wave measurement position for the“Wanshan”converter was determined by combining statistically analyzed field data with a validated numerical wave model.By comparing a valid wave height at the position where a wave rider is located with a valid wave height at the position where the“Wanshan”wave energy converter is situated,the correlation coefficient between simulation and observed data reached 0.90,with a root-mean-square error of 0.19.The representativeness of wave measurement data during site testing is verified and can be used as a basis for calculating the input energy of the“Wanshan”wave energy converter.展开更多
Power converters are essential components in modern life,being widely used in industry,automation,transportation,and household appliances.In many critical applications,their failure can lead not only to financial loss...Power converters are essential components in modern life,being widely used in industry,automation,transportation,and household appliances.In many critical applications,their failure can lead not only to financial losses due to operational downtime but also to serious risks to human safety.The capacitors forming the output filter,typically aluminumelectrolytic capacitors(AECs),are among the most critical and susceptible components in power converters.The electrolyte in AECs often evaporates over time,causing the internal resistance to rise and the capacitance to drop,ultimately leading to component failure.Detecting this fault requires measuring the current in the capacitor,rendering the method invasive and frequently impractical due to spatial constraints or operational limitations imposed by the integration of a current sensor in the capacitor branch.This article proposes the implementation of an online noninvasive fault diagnosis technique for estimating the Equivalent Series Resistance(ESR)and Capacitance(C)values of the capacitor,employing a combination of signal processing techniques(SPT)and machine learning(ML)algorithms.This solution relies solely on the converter’s input and output signals,therefore making it a non-invasive approach.The ML algorithm used was linear regression,applied to 27 attributes,21 of which were generated through feature engineering to enhance the model’s performance.The proposed solution demonstrates an R^(2) score greater than 0.99 in the estimation of both ESR and C.展开更多
Renewable generation is rapidly increasing and transforming power systems toward“new-type power systems”.The integration of renewable energy resources necessitates a shift from conventional grid-following converters...Renewable generation is rapidly increasing and transforming power systems toward“new-type power systems”.The integration of renewable energy resources necessitates a shift from conventional grid-following converters(GFLs)to advanced grid-forming controls.Although grid-forming converters(GFMs)provide grid support and enhance system stability under weak grid conditions,their deployment requires more robust hardware,complex control algorithms and system operation constraints,resulting in planning and operational trade-offs between system stability and cost efficiency.This paper studies the underexplored question of how many GFMs are needed from a techno-economic perspective.The holistic analysis integrates long-term planning,short-term operational strategies and dynamic stability considerations,thereby supporting large-scale renewable integration while ensuring system security and economic benefits.展开更多
Installing annular wave-energy converters(WECs)on the columns of floating wind platforms in the form of a coaxial-cylinder provides a convenient means of integration.Extant coaxial-cylinder-type wind-wave hybrid syste...Installing annular wave-energy converters(WECs)on the columns of floating wind platforms in the form of a coaxial-cylinder provides a convenient means of integration.Extant coaxial-cylinder-type wind-wave hybrid systems are mostly based on single-column platforms such as spars(single coaxial-cylinder hybrid system'hereafter).Systems based on multiple-column platforms such as semi-submersible platforms('multiple coaxial-cylinder hybrid systems'hereafter)are rarely seen or studied,despite their superiority in wave-power absorption due to the use of multiple WECs as well as in dynamic stability.This paper proposes a novel WindFloat-annular-WEC hybrid system,based on our study investigating its dynamic and power features,and optimizing the geometry and power take-off of the WECs.Our results show that the dynamic and power features of a multiple coaxial-cylinder hybrid system are different from those of a single coaxial-cylinder hybrid system,so the same optimization parameters cannot be directly applied.Flatter annular WECs absorb slightly more power in a wider wave-period range,but their geometry is confined by limitations in installation and structural strength.The overall effect of an oblique incident wave is greater intensity in the motions of the hybrid system in yaw and the direction perpendicular to propagation,although the difference is small and maybe negligible.展开更多
With the rapid integration of renewable energy sources,modern power systems are increasingly challenged by heightened volatility and uncertainty.Doubly-fed variable-speed pumped storage units(DFVS-PSUs)have emerged as...With the rapid integration of renewable energy sources,modern power systems are increasingly challenged by heightened volatility and uncertainty.Doubly-fed variable-speed pumped storage units(DFVS-PSUs)have emerged as promising technologies for mitigating grid oscillations and enhancing system flexibility.However,the excitation converters in DFVS-PSUs are prone to significant issues such as elevated common-mode voltage(CMV)and neutral-point voltage(NPV)fluctuations,which can lead to electromagnetic interference and degrade transient performance.To address these challenges,an optimized virtual space vector pulse width modulation(OVSVPWM)strategy is proposed,aiming to suppress CMV and NPV simultaneously through coordinated multi-objective control.Specifically,a dynamic feedback mechanism is introduced to adjust the balancing factor of basic vectors in the synthesized virtual small vector in real-time,achieving autonomous balancing of the NPV.To address the excessive switching actions introduced by the OVSVPWM strategy,a phase duty ratio-based sequence reconstruction method is adopted,which reduces the total number of switching actions to half of the original.A zero-level buffering scheme is employed to reconstruct the single-phase voltage-level output sequence,achieving peak CMV suppression down to udc/6.Simulation results demonstrate that the proposed strategy significantly improves electromagnetic compatibility and operational stability while maintaining high power quality.展开更多
Phosphor-in-glass(PiG)has been prepared into various types of phosphor films owing to its simplicity process,exceptional color purity,and convenient color adjustability.Nevertheless,existing reflective PiGs films have...Phosphor-in-glass(PiG)has been prepared into various types of phosphor films owing to its simplicity process,exceptional color purity,and convenient color adjustability.Nevertheless,existing reflective PiGs films have encountered limitations in terms of stability and feasibility as reliable color converters,mainly attributed to issues related to thermal deposition and insufficient optical efficiency.Herein,we propose to use AlN substrate with superior thermal conductivity to coat the TiO_(2) layer to obtain TiO_(2)-AlN(TA),which enhances the reflectivity of blue light to facilitate the light conversion process.By incorporating highly thermally stable LuAG:Ce-PiGs on a TA substrate,the LuAG:Ce-PiTA converter exhibits a luminous flux of 1102 lm@6.4 W,and maintains a relative intensity of 94.6%at 473 K benefiting from the high thermal conductivity of 34.1 W/(m·K).The addition of CASN_(3):Eu to the color converter 50 L&10C-PiTA enables an impressive CRI of 90.7.Relative lumine scence intensities of LuAG:Ce-PiTA and 50 L&10C-PiTA only decrease by 5.35%and 3.28%,respectively,in the 24 h illumination aging decay test of the reflective laser module.The results confirm the suitability of the optimally designed TA substrate for LuAG:Ce color converter applications in high-power reflective laser illumination.展开更多
Dear Editor,This letter investigates the grid-forming control for power converters.Recently,grid-forming control based on matching of synchronous machines was suggested by using continuous measurements.In the present ...Dear Editor,This letter investigates the grid-forming control for power converters.Recently,grid-forming control based on matching of synchronous machines was suggested by using continuous measurements.In the present letter,we suggest a digital implementation using artificial delays where the controller employs the discrete-time measurements only.展开更多
Isolated power converters have emerged as an active research topic in power integrated circuit(IC)design.Reflecting this growing interest,ISSCC 2025 has featured a dedicated session on"Isolated Power and Gate Dri...Isolated power converters have emerged as an active research topic in power integrated circuit(IC)design.Reflecting this growing interest,ISSCC 2025 has featured a dedicated session on"Isolated Power and Gate Drivers".These converters enable safe and reliable power delivery across voltage domains and are widely used in renewable energy,electric vehicles,and telecommunications.Galvanic isolation prevents surge currents and ground loop issues in harsh high-voltage environments.As demand grows for compact,efficient,and high–power-density solutions,fully integrated architectures featuring on-chip transformers are increasingly favored over traditional module-based designs,offering>5 kV isolation with a smaller footprint and lower system cost[1].展开更多
Phosphor-in-glass(PiG)films have emerged as the preferred conversion materials for high-brightness laser-driven lighting due to their excellent thermal conductivity and superior optical performance.Screen printing tec...Phosphor-in-glass(PiG)films have emerged as the preferred conversion materials for high-brightness laser-driven lighting due to their excellent thermal conductivity and superior optical performance.Screen printing technology was employed to investigate the correlation between the reflective layer thickness and light conversion efficiency.A multilayer-structured Y_(3)Al_(3.5)Ga_(1.5)O_(12):Ce^(3+)(YAGG:Ce)-PiGTiO_(2)-aluminium nitride(AIN)film(YG-TAF)converter was constructed by efficiently coupling the optimal thickness of the reflective layer with the PiG layer and the AIN substrate.Notably,the YG-TAF shows an impressive thermal conductivity of 22.6 W/(m·K)and a maximum anti-laser power of 15.84 W,demonstrating superb thermal regulation capability.This anti-laser power of 15.84 W represents a breakthrough in current static laser performance research.Impressively,an YG-TAF phosphor color wheel was designed,which achieves an ultra-high-brightness 4375 lm of green light under 450 nm,88 W laser power excitation,close to that of commercial phosphor silicone color wheels.This advancement not only demonstrates the excellent performance of YG-TAF in high-brightness dynamic reflective laser applications but also indicates its strong feasibility for practical implementation.Furthermore,the developed YAGG:Ce-Y_(1.31)Ce_(0.09)Gd_(1.6)Al_5O_(12)-TAF spliced phosphor color wheel successfully mitigates the influence of photon reabsorption and achieves a color rendering index of 80.5,showing great potential for advancement of the field of reflective white light laser illumination.展开更多
This paper presents a novel active disturbance rejection control(ADRC)scheme based on a cascade connection of generalized proportional integral observers(GPIOs)with internal models designed to estimate both polynomial...This paper presents a novel active disturbance rejection control(ADRC)scheme based on a cascade connection of generalized proportional integral observers(GPIOs)with internal models designed to estimate both polynomial and resonant disturbances.In this estimator structure,referred to as Cascade GPIO(CGPIO),the total disturbance sensitivity is the product of the sensitivities at each cascade level.This approach improves system performance against both periodic and non-periodic disturbances and enhances robustness under frequency variations in harmonic components.Additionally,the decoupled nature of the estimator reduces the order of the GPIOs,thereby simplifying tuning and limiting observer gains.The proposed control scheme is supported by a frequency-domain analysis and is experimentally validated in the current control of a grid-connected converter subject to control gain uncertainties,harmonic distortion,frequency deviations,and measurement noise.Experimental results demonstrate that the CGPIO-based ADRC outperforms benchmark solutions,including proportional-integral(PI)and proportional-resonant(PR)controllers.展开更多
Motivation.As artificial intelligence(AI)workloads escalate exponentially,ultra-thin,high-efficiency voltage regulator modules(VRMs)with exceptional power density become essential for backside-mounted configurations[1...Motivation.As artificial intelligence(AI)workloads escalate exponentially,ultra-thin,high-efficiency voltage regulator modules(VRMs)with exceptional power density become essential for backside-mounted configurations[1].Thus,highdensity multiphase DC−DC converters are pivotal for implementing vertical power delivery(VPD)architectures in XPU platforms.Strategically positioning these converters beneath processors and maximizing spatial utilization enables core rail currents exceeding 2 kA while significantly reducing the power distribution network(PDN)losses compared to conventional solutions.The VPD configuration elevates system-level energy efficiency with>100 W power saving per processor,yielding megawatt-scale savings in a datacenter that uses~100000 processors.The synergy of 48 V power conversion architectures and advanced packaging techniques enables the industry’s commitment to balancing computational demands with CO_(2)emission reduction and environmental sustainability.展开更多
This paper presents a method for estimating the parameters of DC-link capacitors in three-level NPC voltage source inverters(3L-NPC-VSI)used in grid-tied systems.The technique uses the signals generated by the intermo...This paper presents a method for estimating the parameters of DC-link capacitors in three-level NPC voltage source inverters(3L-NPC-VSI)used in grid-tied systems.The technique uses the signals generated by the intermodulation caused by the PWM strategy and converter topology interaction to estimate the capacitor parameters of the converter DC-link.It utilizes an observer-based structure consisting of a recursive noninteger sliding discrete Fourier transform(rnSDFT)and an RLS filter improved with a forgetting factor(oSDFT-RLS)to accurately estimate the capacitance and equivalent series resistance(ESR).Importantly,this method does not require additional sensors beyond those already installed in off-the-shelf 3L-NPC-VSI systems,ensuring its noninvasiveness.Furthermore,the oSDFTRLS estimates capacitor parameters in the time-frequency domain,enabling the tracking of capacitor degradation and predicting potential faults.Experimental results from the laboratory setup demonstrate the effectiveness of the proposed condition monitoring method.展开更多
文摘Grid-Forming(GFM)converters are prone to fault-induced overcurrent and power angle instability during grid fault-induced voltage sags.To address this,this paper develops a multi-loop coordinated fault ridethrough(FRT)control strategy based on a power outer loop and voltage-current inner loops,aiming to enhance the stability and current-limiting capability of GFM converters during grid fault conditions.During voltage sags,the GFM converter’s voltage source behavior is maintained by dynamically adjusting the reactive power reference to provide voltage support,thereby effectively suppressing the steady-state component of the fault current.To address the active power imbalance induced by voltage sags,a dynamic active power reference correction method based on apparent power is designed to mitigate power angle oscillations and limit transient current.Moreover,an adaptive virtual impedance loop is implemented to enhance dynamic transient current-limiting performance during the fault initiation phase.This approach improves the responsiveness of the inner loop and ensures safe system operation under various fault severities.Under asymmetric fault conditions,a negative-sequence reactive current compensation strategy is incorporated to further suppress negative-sequence voltage and improve voltage symmetry.The proposed control scheme enables coordinated operation of multiple control objectives,including voltage support,current suppression,and power angle stability,across different fault scenarios.Finally,MATLAB/Simulink simulation results validate the effectiveness of the proposed strategy,showcasing its superior performance in current limiting and power angle stability,thereby significantly enhancing the system’s fault ride-through capability.
基金supported by the“National Ocean Technology Center Innovation Fund”under Project No.N3220Z002,led by Ning Jia.The official website of the National Ocean Technology Center is accessible at:http://www.notcsoa.org.cn/.
文摘With the depletion of fossil fuels and increasing environmental concerns,the development of renewable energy,such as wave energy,has become a critical component of global energy strategies.However,challenges persist in the field testing methodologies for wave energy converters(WECs).In this paper,a numerical wave field of the Dawanshan Island Sea Area in Zhuhai City is constructed based on the MIKE21 SW wave model and by using an NCEP wind field driving model.In conjunction with the IEC-62600-100 standard,by taking site testing of the“Wanshan”wave energy converter on which a sea trial has been conducted in Dawanshan Island of Zhuhai city as an example,research on-site testing method for a wave energy converter has been carried out.The wave measurement position for the“Wanshan”converter was determined by combining statistically analyzed field data with a validated numerical wave model.By comparing a valid wave height at the position where a wave rider is located with a valid wave height at the position where the“Wanshan”wave energy converter is situated,the correlation coefficient between simulation and observed data reached 0.90,with a root-mean-square error of 0.19.The representativeness of wave measurement data during site testing is verified and can be used as a basis for calculating the input energy of the“Wanshan”wave energy converter.
文摘Power converters are essential components in modern life,being widely used in industry,automation,transportation,and household appliances.In many critical applications,their failure can lead not only to financial losses due to operational downtime but also to serious risks to human safety.The capacitors forming the output filter,typically aluminumelectrolytic capacitors(AECs),are among the most critical and susceptible components in power converters.The electrolyte in AECs often evaporates over time,causing the internal resistance to rise and the capacitance to drop,ultimately leading to component failure.Detecting this fault requires measuring the current in the capacitor,rendering the method invasive and frequently impractical due to spatial constraints or operational limitations imposed by the integration of a current sensor in the capacitor branch.This article proposes the implementation of an online noninvasive fault diagnosis technique for estimating the Equivalent Series Resistance(ESR)and Capacitance(C)values of the capacitor,employing a combination of signal processing techniques(SPT)and machine learning(ML)algorithms.This solution relies solely on the converter’s input and output signals,therefore making it a non-invasive approach.The ML algorithm used was linear regression,applied to 27 attributes,21 of which were generated through feature engineering to enhance the model’s performance.The proposed solution demonstrates an R^(2) score greater than 0.99 in the estimation of both ESR and C.
基金supported in part by the Carbon Neutrality and Energy System Transformation project and in part by EPSRC under Grant EP/Y025946/1.
文摘Renewable generation is rapidly increasing and transforming power systems toward“new-type power systems”.The integration of renewable energy resources necessitates a shift from conventional grid-following converters(GFLs)to advanced grid-forming controls.Although grid-forming converters(GFMs)provide grid support and enhance system stability under weak grid conditions,their deployment requires more robust hardware,complex control algorithms and system operation constraints,resulting in planning and operational trade-offs between system stability and cost efficiency.This paper studies the underexplored question of how many GFMs are needed from a techno-economic perspective.The holistic analysis integrates long-term planning,short-term operational strategies and dynamic stability considerations,thereby supporting large-scale renewable integration while ensuring system security and economic benefits.
基金supported by the National Natural Science Foundation of China(Nos.52201322,52222109,and 52071096)the Guangdong Basic and Applied Basic Research Foundation(Nos.2022B1515020036 and 2023A1515012144)the Natural Science Foundation of Guangzhou City(No.202201010055),China.
文摘Installing annular wave-energy converters(WECs)on the columns of floating wind platforms in the form of a coaxial-cylinder provides a convenient means of integration.Extant coaxial-cylinder-type wind-wave hybrid systems are mostly based on single-column platforms such as spars(single coaxial-cylinder hybrid system'hereafter).Systems based on multiple-column platforms such as semi-submersible platforms('multiple coaxial-cylinder hybrid systems'hereafter)are rarely seen or studied,despite their superiority in wave-power absorption due to the use of multiple WECs as well as in dynamic stability.This paper proposes a novel WindFloat-annular-WEC hybrid system,based on our study investigating its dynamic and power features,and optimizing the geometry and power take-off of the WECs.Our results show that the dynamic and power features of a multiple coaxial-cylinder hybrid system are different from those of a single coaxial-cylinder hybrid system,so the same optimization parameters cannot be directly applied.Flatter annular WECs absorb slightly more power in a wider wave-period range,but their geometry is confined by limitations in installation and structural strength.The overall effect of an oblique incident wave is greater intensity in the motions of the hybrid system in yaw and the direction perpendicular to propagation,although the difference is small and maybe negligible.
文摘With the rapid integration of renewable energy sources,modern power systems are increasingly challenged by heightened volatility and uncertainty.Doubly-fed variable-speed pumped storage units(DFVS-PSUs)have emerged as promising technologies for mitigating grid oscillations and enhancing system flexibility.However,the excitation converters in DFVS-PSUs are prone to significant issues such as elevated common-mode voltage(CMV)and neutral-point voltage(NPV)fluctuations,which can lead to electromagnetic interference and degrade transient performance.To address these challenges,an optimized virtual space vector pulse width modulation(OVSVPWM)strategy is proposed,aiming to suppress CMV and NPV simultaneously through coordinated multi-objective control.Specifically,a dynamic feedback mechanism is introduced to adjust the balancing factor of basic vectors in the synthesized virtual small vector in real-time,achieving autonomous balancing of the NPV.To address the excessive switching actions introduced by the OVSVPWM strategy,a phase duty ratio-based sequence reconstruction method is adopted,which reduces the total number of switching actions to half of the original.A zero-level buffering scheme is employed to reconstruct the single-phase voltage-level output sequence,achieving peak CMV suppression down to udc/6.Simulation results demonstrate that the proposed strategy significantly improves electromagnetic compatibility and operational stability while maintaining high power quality.
文摘Phosphor-in-glass(PiG)has been prepared into various types of phosphor films owing to its simplicity process,exceptional color purity,and convenient color adjustability.Nevertheless,existing reflective PiGs films have encountered limitations in terms of stability and feasibility as reliable color converters,mainly attributed to issues related to thermal deposition and insufficient optical efficiency.Herein,we propose to use AlN substrate with superior thermal conductivity to coat the TiO_(2) layer to obtain TiO_(2)-AlN(TA),which enhances the reflectivity of blue light to facilitate the light conversion process.By incorporating highly thermally stable LuAG:Ce-PiGs on a TA substrate,the LuAG:Ce-PiTA converter exhibits a luminous flux of 1102 lm@6.4 W,and maintains a relative intensity of 94.6%at 473 K benefiting from the high thermal conductivity of 34.1 W/(m·K).The addition of CASN_(3):Eu to the color converter 50 L&10C-PiTA enables an impressive CRI of 90.7.Relative lumine scence intensities of LuAG:Ce-PiTA and 50 L&10C-PiTA only decrease by 5.35%and 3.28%,respectively,in the 24 h illumination aging decay test of the reflective laser module.The results confirm the suitability of the optimally designed TA substrate for LuAG:Ce color converter applications in high-power reflective laser illumination.
基金supported by the National Natural Science Foundation of China(62403296,62303292,62173218).
文摘Dear Editor,This letter investigates the grid-forming control for power converters.Recently,grid-forming control based on matching of synchronous machines was suggested by using continuous measurements.In the present letter,we suggest a digital implementation using artificial delays where the controller employs the discrete-time measurements only.
基金supported in part by the National Natural Science Foundation of China under Grant U23A20353.
文摘Isolated power converters have emerged as an active research topic in power integrated circuit(IC)design.Reflecting this growing interest,ISSCC 2025 has featured a dedicated session on"Isolated Power and Gate Drivers".These converters enable safe and reliable power delivery across voltage domains and are widely used in renewable energy,electric vehicles,and telecommunications.Galvanic isolation prevents surge currents and ground loop issues in harsh high-voltage environments.As demand grows for compact,efficient,and high–power-density solutions,fully integrated architectures featuring on-chip transformers are increasingly favored over traditional module-based designs,offering>5 kV isolation with a smaller footprint and lower system cost[1].
基金Project supported by the National Natural Science Foundation of China(1237040868)。
文摘Phosphor-in-glass(PiG)films have emerged as the preferred conversion materials for high-brightness laser-driven lighting due to their excellent thermal conductivity and superior optical performance.Screen printing technology was employed to investigate the correlation between the reflective layer thickness and light conversion efficiency.A multilayer-structured Y_(3)Al_(3.5)Ga_(1.5)O_(12):Ce^(3+)(YAGG:Ce)-PiGTiO_(2)-aluminium nitride(AIN)film(YG-TAF)converter was constructed by efficiently coupling the optimal thickness of the reflective layer with the PiG layer and the AIN substrate.Notably,the YG-TAF shows an impressive thermal conductivity of 22.6 W/(m·K)and a maximum anti-laser power of 15.84 W,demonstrating superb thermal regulation capability.This anti-laser power of 15.84 W represents a breakthrough in current static laser performance research.Impressively,an YG-TAF phosphor color wheel was designed,which achieves an ultra-high-brightness 4375 lm of green light under 450 nm,88 W laser power excitation,close to that of commercial phosphor silicone color wheels.This advancement not only demonstrates the excellent performance of YG-TAF in high-brightness dynamic reflective laser applications but also indicates its strong feasibility for practical implementation.Furthermore,the developed YAGG:Ce-Y_(1.31)Ce_(0.09)Gd_(1.6)Al_5O_(12)-TAF spliced phosphor color wheel successfully mitigates the influence of photon reabsorption and achieves a color rendering index of 80.5,showing great potential for advancement of the field of reflective white light laser illumination.
文摘This paper presents a novel active disturbance rejection control(ADRC)scheme based on a cascade connection of generalized proportional integral observers(GPIOs)with internal models designed to estimate both polynomial and resonant disturbances.In this estimator structure,referred to as Cascade GPIO(CGPIO),the total disturbance sensitivity is the product of the sensitivities at each cascade level.This approach improves system performance against both periodic and non-periodic disturbances and enhances robustness under frequency variations in harmonic components.Additionally,the decoupled nature of the estimator reduces the order of the GPIOs,thereby simplifying tuning and limiting observer gains.The proposed control scheme is supported by a frequency-domain analysis and is experimentally validated in the current control of a grid-connected converter subject to control gain uncertainties,harmonic distortion,frequency deviations,and measurement noise.Experimental results demonstrate that the CGPIO-based ADRC outperforms benchmark solutions,including proportional-integral(PI)and proportional-resonant(PR)controllers.
文摘Motivation.As artificial intelligence(AI)workloads escalate exponentially,ultra-thin,high-efficiency voltage regulator modules(VRMs)with exceptional power density become essential for backside-mounted configurations[1].Thus,highdensity multiphase DC−DC converters are pivotal for implementing vertical power delivery(VPD)architectures in XPU platforms.Strategically positioning these converters beneath processors and maximizing spatial utilization enables core rail currents exceeding 2 kA while significantly reducing the power distribution network(PDN)losses compared to conventional solutions.The VPD configuration elevates system-level energy efficiency with>100 W power saving per processor,yielding megawatt-scale savings in a datacenter that uses~100000 processors.The synergy of 48 V power conversion architectures and advanced packaging techniques enables the industry’s commitment to balancing computational demands with CO_(2)emission reduction and environmental sustainability.
基金funded by the Brazilian National Council for Scientific and Technological Development—CNPq(CNPq grant number 405997/2022-1)supported by the EMBRAPII VIRTUS Competence Center in Intelligent Hardware for Industry—VIRTUS-CC(MCTI grant number 055/2023).
文摘This paper presents a method for estimating the parameters of DC-link capacitors in three-level NPC voltage source inverters(3L-NPC-VSI)used in grid-tied systems.The technique uses the signals generated by the intermodulation caused by the PWM strategy and converter topology interaction to estimate the capacitor parameters of the converter DC-link.It utilizes an observer-based structure consisting of a recursive noninteger sliding discrete Fourier transform(rnSDFT)and an RLS filter improved with a forgetting factor(oSDFT-RLS)to accurately estimate the capacitance and equivalent series resistance(ESR).Importantly,this method does not require additional sensors beyond those already installed in off-the-shelf 3L-NPC-VSI systems,ensuring its noninvasiveness.Furthermore,the oSDFTRLS estimates capacitor parameters in the time-frequency domain,enabling the tracking of capacitor degradation and predicting potential faults.Experimental results from the laboratory setup demonstrate the effectiveness of the proposed condition monitoring method.
