The dual three-phase PMSM(DTP-PMSM)drives have received wide attention at high-power high-efficiency applications due to their merits of high output current ability and copper-loss-free field excitation.Meanwhile,the ...The dual three-phase PMSM(DTP-PMSM)drives have received wide attention at high-power high-efficiency applications due to their merits of high output current ability and copper-loss-free field excitation.Meanwhile,the DTPPMSM drive provides higher fault-tolerant capability for highreliability applications,e.g.,pumps and actuators in aircraft.For high-power drives with limited switching frequencies and highspeed drives with large fundamental frequencies,the ratio of switching frequency to fundamental frequency,i.e.,the carrier ratio,is usually below 15,which would significantly degrade the control performance.The purpose of this paper is to review the recent work on the modulation and control schemes for improving the operation performance of DTP-PMSM drives with low carrier ratios.Specifically,three categories of methods,i.e.,the space vector modulation based control,the model predictive control(MPC),and the optimized pulse pattern(OPP)based control are reviewed with principles and performance.In addition,brief discussions regarding the comparison and future trends are presented for low-carrier-ratio(LCR)modulation and control schemes of DTP-PMSM drives.展开更多
In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature swing.The reduction of temperatur...In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature swing.The reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this paper.First,a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is proposed.Then,the optimization is transformed to a singlelevel optimization by introducing the auxiliary variable for easy solving.Considering that singleobjective optimization trades a great total copper loss for a small reduction of maximum phase copper loss,the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed,which has the same performance of temperature swing reduction but with lower total loss.In this way,the proposed control scheme can reduce maximum junction temperature by 11%.Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.展开更多
Finite-control-set model predictive control(FCSMPC)has advantages of multi-objective optimization and easy implementation.To reduce the computational burden and switching frequency,this article proposed a simplified M...Finite-control-set model predictive control(FCSMPC)has advantages of multi-objective optimization and easy implementation.To reduce the computational burden and switching frequency,this article proposed a simplified MPC for dual three-phase permanent magnet synchronous motor(DTPPMSM).The novelty of this method is the decomposition of prediction function and the switching optimization algorithm.Based on the decomposition of prediction function,the current increment vector is obtained,which is employed to select the optimal voltage vector and calculate the duty cycle.Then,the computation burden can be reduced and the current tracking performance can be maintained.Additionally,the switching optimization algorithm was proposed to optimize the voltage vector action sequence,which results in lower switching frequency.Hence,this control strategy can not only reduce the computation burden and switching frequency,but also maintain the steady-state and dynamic performance.The simulation and experimental results are presented to verify the feasibility of the proposed strategy.展开更多
Switched-capacitor/flying capacitor(FC)based multilevel converters have been gaining higher attention for their voltage-boosting ability.This feature makes them an attractive solution for renewable energy systems,such...Switched-capacitor/flying capacitor(FC)based multilevel converters have been gaining higher attention for their voltage-boosting ability.This feature makes them an attractive solution for renewable energy systems,such as low-voltage input photovoltaic power systems and electric vehicle systems.However,they usually require more high voltage rating switches and flying capacitors along with boosting capability.Furthermore,they suffer from high pulse currents at the switching transients.Aiming to solve these issues,this article proposes a new self-balancing three-phase five-level inverter based on the switched-capacitor(5L-SCTPNPC),which reduces the dc voltage requirement.The number of active switches is relatively smaller and seven active switches are required per phase.Especially,a soft-charging circuit for FC is designed to limit the impulse charging current.Compared to conventional multilevel inverters,the proposed five-level inverter reduces dc bus voltage by 50%.Significantly,the voltage stress of FC and the switches in parallel with FC are all reduced by 50%in comparison with some existing similar boosting five-level active-neutral-point-clamped(5L-BANPC)inverters.The operating principles,modulation strategy,and the design of the FC and charging inductor are provided in detailly.A comprehensive comparison study has been made to highlight the merits of the proposed inverter.Finally,the simulations and experiments validate the feasibility of the proposed topology.展开更多
Renewable electricity-driven production of value-added sulfur and H_(2)via electrocatalytic H_(2)S decomposition represents a sustainable route to conventional thermocatalysis.Both the electrocatalyst and electrolyte ...Renewable electricity-driven production of value-added sulfur and H_(2)via electrocatalytic H_(2)S decomposition represents a sustainable route to conventional thermocatalysis.Both the electrocatalyst and electrolyte solution strongly impact the H_(2)S decomposition performance.Despite significant progress in developing sophisticated electrocatalysts,a well-designed electrolyte solution in conjunction with industrial catalysts is an attractive strategy to advance the industrialization process of electrocatalytic H_(2)S decomposition,but remains unexplored.Here,for the first time,we design a solid-liquid-gas three-phase indirect electrolysis system based on a kind of CS_(2)-N electrolyte solution and Ni-Mo_(2)C that can efficiently enable H_(2)S decomposition into valuable H_(2)and sulfur.Specifically,the solid-phase Ni-Mo_(2)C as a heterogeneous redox mediator presents excellent electrocatalytic efficiency for the H_(2)S removal efficiency of up to 99%,and the formation of liquid-phase sulfur product(CS_(2)-N electrolyte solution dissolves sulfur,yield up to 95%)with the generation of gas-phase H_(2)product(~1.32 mL min^(-1)),resulting in an interesting three-phase indirect electrolysis system.Remarkably,it enables the scale-up production(~6 g in a batch experiment)of sulfur with continuous operation for 120 h without attenuation.This work may inaugurate a new electrocatalytic H_(2)S decomposition avenue to explore porous metal materials and electrolyte systems in simultaneous production of value-added sulfur and H_(2).展开更多
The transient phenomena of re-oxidation and slag entrapment occurring in the tundish during the ladle change-over process have been proven detrimental to clean steel production.Therefore,an unsteady three-phase turbul...The transient phenomena of re-oxidation and slag entrapment occurring in the tundish during the ladle change-over process have been proven detrimental to clean steel production.Therefore,an unsteady three-phase turbulence model,coupling velocity,temperature,and phase field was established to study the effect of the ladle shroud immersion depth on the slag eye formation,slag entrainment,slag dragging,air dragging,and flow characteristics during the ladle change-over process of a two-strand tundish.The results showed that reducing the immersion depth decreases the high-velocity region area under the slag layer in the quasi-steady process.During the emptying stage,as the molten bath level gradually decreases,the outlet temperature exhibits a trend of initially decreasing and subsequently increasing across all three shroud immersion depths.However,under a 210 mm shroud immersion depth,molten slag and air are dragged into the shroud,forming slag droplets and causing significant fluctuations,with a maximum scalar velocity of 0.0764 m/s at the monitoring point.In the filling stage,air and molten slag are dragged into the molten bath,forming bubbles and slag droplets at an immersion depth of 210 mm.Bubbles are observed within the molten slag layer,which can readily cause an emulsification phenomenon,making it easier to be dragged as slag droplets.Additionally,the slag eye area measured under 210 mm immersion depth at 45 s is 0.303 m^(2),while the maximum scalar velocity of 2.4259 m/s is detected at 12 s.At an immersion depth of 360 mm,the average area of the slag eye is minimized to 0.06268 m2,with corresponding variances of 0.006753,representing the optimal immersion depth.展开更多
To achieve high power rating and low current harmonics of motor drive,this paper develops a dual three-phase open-winding permanent magnet synchronous motor(DTP-OW-PMSM)drive with the DC-link voltage ratio of 2:1:1.Ba...To achieve high power rating and low current harmonics of motor drive,this paper develops a dual three-phase open-winding permanent magnet synchronous motor(DTP-OW-PMSM)drive with the DC-link voltage ratio of 2:1:1.Based on this topology,this paper proposes a DTP four-level space vector pulse width modulation(DTP-FL SVPWM)strategy.First,two identical three-phase four-level space vector diagrams are constructed and divided.Then,three adjacent vectors nearest to the reference vector in each diagram are selected for the vector synthesis to guarantee high modulation precision and low switching frequency.Furthermore,to avoid the modulation error caused by the voltage deviation,the proposed DTP-FL SVPWM strategy is further optimized through unified duty ratio compensation(UDRC).The effectiveness of the proposed strategy is verified through experiments.展开更多
Single voltage vectors applied in the conventional model predictive torque control(MPTC)for multiphase motors do not only suffer from serious torque and stator flux ripples but also cause the large harmonic current.To...Single voltage vectors applied in the conventional model predictive torque control(MPTC)for multiphase motors do not only suffer from serious torque and stator flux ripples but also cause the large harmonic current.To address the aforementioned challenges,an MPTC using a modified dual virtual vector modulation method is proposed to improve the operational performance of a dual three-phase permanent magnet synchronous motor.Virtual voltage vectors are synthesized as the candidate control set to restrain the harmonic current.A transformation method is introduced to consider both the stator flux and torque in the duty cycle modulation.The torque and stator flux ripples are simultaneously reduced by addressing the limitations of nonuniform units.Furthermore,the null voltage vector is then inserted to expand the modulation range and improve the steady-state performance.Moreover,the sawtooth carrier is adopted to address the challenge of the asymmetric switch sequence caused by the modified modulation.Finally,the experimental results are presented to verify the effectiveness and superiority of the proposed MPTC method.展开更多
The paper presents an accurate analytical subdomain model for predicting the electromagnetic performance in the symmetrical dual three-phase surface-mounted permanent magnet synchronous machine(PMSM)under open-phase f...The paper presents an accurate analytical subdomain model for predicting the electromagnetic performance in the symmetrical dual three-phase surface-mounted permanent magnet synchronous machine(PMSM)under open-phase faulty conditions.The model derivations are extended from previous accurate subdomain models accounting for slotting effects.Compared with most conventional subdomain models for traditional three-phase machines with nonoverlapping winding arrangement,the subdomain model proposed in this paper applied for the 24-slot/4-pole dual three-phase machine with symmetrical overlapping winding arrangement.In order to investigate the postfault electromagnetic performance,the reconfigured phase currents and then current density distribution in stator slots under different open-circuit conditions are discussed.According to the developed model and postfault current density distribution,the steady-state electromagnetic performance,such as the electromagnetic torque and unbalanced magnetic force,under open-circuit faulty conditions are obtained.For validation purposes,finite element analysis(FEA)is employed to validate the analytical results.The result indicate that the postfault electromagnet performance can be accurately predicted by the proposed subdomain model,which is in good agreement with FEA results.展开更多
The growing demand for efficient high-power switching power supplies has spurred interest in advanced topologies.The three-phase VIENNA converter stands out for its high power factor,simplified structure,and robust pe...The growing demand for efficient high-power switching power supplies has spurred interest in advanced topologies.The three-phase VIENNA converter stands out for its high power factor,simplified structure,and robust performance.Current research focuses on its operational principles,control strategies,and behavior under various load conditions.Key considerations include component selection,thermal management,and EMI/EMC optimization.This topology finds applications across renewable energy systems,industrial equipment,telecommunications,and electric vehicle charging infrastructures.Comparative analyses with alternative topologies and cost-benefit evaluations are also addressed.Future developments are expected to emphasize the integration of wide-bandgap devices and advancements in digital control techniques to further enhance efficiency and system performance.展开更多
基金supported by the National Key Research and Development Program of China under the grant of 2022YFB3403100。
文摘The dual three-phase PMSM(DTP-PMSM)drives have received wide attention at high-power high-efficiency applications due to their merits of high output current ability and copper-loss-free field excitation.Meanwhile,the DTPPMSM drive provides higher fault-tolerant capability for highreliability applications,e.g.,pumps and actuators in aircraft.For high-power drives with limited switching frequencies and highspeed drives with large fundamental frequencies,the ratio of switching frequency to fundamental frequency,i.e.,the carrier ratio,is usually below 15,which would significantly degrade the control performance.The purpose of this paper is to review the recent work on the modulation and control schemes for improving the operation performance of DTP-PMSM drives with low carrier ratios.Specifically,three categories of methods,i.e.,the space vector modulation based control,the model predictive control(MPC),and the optimized pulse pattern(OPP)based control are reviewed with principles and performance.In addition,brief discussions regarding the comparison and future trends are presented for low-carrier-ratio(LCR)modulation and control schemes of DTP-PMSM drives.
基金supported by the National Natural Science Foundation of China(No.62271109)。
文摘In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature swing.The reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this paper.First,a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is proposed.Then,the optimization is transformed to a singlelevel optimization by introducing the auxiliary variable for easy solving.Considering that singleobjective optimization trades a great total copper loss for a small reduction of maximum phase copper loss,the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed,which has the same performance of temperature swing reduction but with lower total loss.In this way,the proposed control scheme can reduce maximum junction temperature by 11%.Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.
基金supported by the National Natural Science Foundation of China under Grant 5227705。
文摘Finite-control-set model predictive control(FCSMPC)has advantages of multi-objective optimization and easy implementation.To reduce the computational burden and switching frequency,this article proposed a simplified MPC for dual three-phase permanent magnet synchronous motor(DTPPMSM).The novelty of this method is the decomposition of prediction function and the switching optimization algorithm.Based on the decomposition of prediction function,the current increment vector is obtained,which is employed to select the optimal voltage vector and calculate the duty cycle.Then,the computation burden can be reduced and the current tracking performance can be maintained.Additionally,the switching optimization algorithm was proposed to optimize the voltage vector action sequence,which results in lower switching frequency.Hence,this control strategy can not only reduce the computation burden and switching frequency,but also maintain the steady-state and dynamic performance.The simulation and experimental results are presented to verify the feasibility of the proposed strategy.
基金supported by the National Natural Science Foundation of China(51977069)the National Natural Science Foundation Youth Project of China(52107195)the First Key Research and JieBang Headed Program,Hunan Province,China(2021GK1250).
文摘Switched-capacitor/flying capacitor(FC)based multilevel converters have been gaining higher attention for their voltage-boosting ability.This feature makes them an attractive solution for renewable energy systems,such as low-voltage input photovoltaic power systems and electric vehicle systems.However,they usually require more high voltage rating switches and flying capacitors along with boosting capability.Furthermore,they suffer from high pulse currents at the switching transients.Aiming to solve these issues,this article proposes a new self-balancing three-phase five-level inverter based on the switched-capacitor(5L-SCTPNPC),which reduces the dc voltage requirement.The number of active switches is relatively smaller and seven active switches are required per phase.Especially,a soft-charging circuit for FC is designed to limit the impulse charging current.Compared to conventional multilevel inverters,the proposed five-level inverter reduces dc bus voltage by 50%.Significantly,the voltage stress of FC and the switches in parallel with FC are all reduced by 50%in comparison with some existing similar boosting five-level active-neutral-point-clamped(5L-BANPC)inverters.The operating principles,modulation strategy,and the design of the FC and charging inductor are provided in detailly.A comprehensive comparison study has been made to highlight the merits of the proposed inverter.Finally,the simulations and experiments validate the feasibility of the proposed topology.
基金supported by the National Natural Science Foundation of China(No.22278439 and 21776313).
文摘Renewable electricity-driven production of value-added sulfur and H_(2)via electrocatalytic H_(2)S decomposition represents a sustainable route to conventional thermocatalysis.Both the electrocatalyst and electrolyte solution strongly impact the H_(2)S decomposition performance.Despite significant progress in developing sophisticated electrocatalysts,a well-designed electrolyte solution in conjunction with industrial catalysts is an attractive strategy to advance the industrialization process of electrocatalytic H_(2)S decomposition,but remains unexplored.Here,for the first time,we design a solid-liquid-gas three-phase indirect electrolysis system based on a kind of CS_(2)-N electrolyte solution and Ni-Mo_(2)C that can efficiently enable H_(2)S decomposition into valuable H_(2)and sulfur.Specifically,the solid-phase Ni-Mo_(2)C as a heterogeneous redox mediator presents excellent electrocatalytic efficiency for the H_(2)S removal efficiency of up to 99%,and the formation of liquid-phase sulfur product(CS_(2)-N electrolyte solution dissolves sulfur,yield up to 95%)with the generation of gas-phase H_(2)product(~1.32 mL min^(-1)),resulting in an interesting three-phase indirect electrolysis system.Remarkably,it enables the scale-up production(~6 g in a batch experiment)of sulfur with continuous operation for 120 h without attenuation.This work may inaugurate a new electrocatalytic H_(2)S decomposition avenue to explore porous metal materials and electrolyte systems in simultaneous production of value-added sulfur and H_(2).
基金supported by the National Natural Science Foundation of China(Nos.52422408 and 52171031)the Liaoning Xingliao Talents-Top-notch Young Talents Project(No.XLYC2203064)+1 种基金the Excellent Youth Fund of Liaoning Natural Science Foundation(No.2023JH3/10200001)the Fundamental Research Funds for the Central Universities(No.N2425004).
文摘The transient phenomena of re-oxidation and slag entrapment occurring in the tundish during the ladle change-over process have been proven detrimental to clean steel production.Therefore,an unsteady three-phase turbulence model,coupling velocity,temperature,and phase field was established to study the effect of the ladle shroud immersion depth on the slag eye formation,slag entrainment,slag dragging,air dragging,and flow characteristics during the ladle change-over process of a two-strand tundish.The results showed that reducing the immersion depth decreases the high-velocity region area under the slag layer in the quasi-steady process.During the emptying stage,as the molten bath level gradually decreases,the outlet temperature exhibits a trend of initially decreasing and subsequently increasing across all three shroud immersion depths.However,under a 210 mm shroud immersion depth,molten slag and air are dragged into the shroud,forming slag droplets and causing significant fluctuations,with a maximum scalar velocity of 0.0764 m/s at the monitoring point.In the filling stage,air and molten slag are dragged into the molten bath,forming bubbles and slag droplets at an immersion depth of 210 mm.Bubbles are observed within the molten slag layer,which can readily cause an emulsification phenomenon,making it easier to be dragged as slag droplets.Additionally,the slag eye area measured under 210 mm immersion depth at 45 s is 0.303 m^(2),while the maximum scalar velocity of 2.4259 m/s is detected at 12 s.At an immersion depth of 360 mm,the average area of the slag eye is minimized to 0.06268 m2,with corresponding variances of 0.006753,representing the optimal immersion depth.
基金supported in part by the National Natural Science Foundation of China under Grant 62303333in part by the Project of Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone under Grant HZQB-KCZYB-2020083.
文摘To achieve high power rating and low current harmonics of motor drive,this paper develops a dual three-phase open-winding permanent magnet synchronous motor(DTP-OW-PMSM)drive with the DC-link voltage ratio of 2:1:1.Based on this topology,this paper proposes a DTP four-level space vector pulse width modulation(DTP-FL SVPWM)strategy.First,two identical three-phase four-level space vector diagrams are constructed and divided.Then,three adjacent vectors nearest to the reference vector in each diagram are selected for the vector synthesis to guarantee high modulation precision and low switching frequency.Furthermore,to avoid the modulation error caused by the voltage deviation,the proposed DTP-FL SVPWM strategy is further optimized through unified duty ratio compensation(UDRC).The effectiveness of the proposed strategy is verified through experiments.
基金Supported by the National Natural Science Foundation of China under Grant 51977099the Natural Science Foundation of Jiangsu Province under Grant BK20191225the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Single voltage vectors applied in the conventional model predictive torque control(MPTC)for multiphase motors do not only suffer from serious torque and stator flux ripples but also cause the large harmonic current.To address the aforementioned challenges,an MPTC using a modified dual virtual vector modulation method is proposed to improve the operational performance of a dual three-phase permanent magnet synchronous motor.Virtual voltage vectors are synthesized as the candidate control set to restrain the harmonic current.A transformation method is introduced to consider both the stator flux and torque in the duty cycle modulation.The torque and stator flux ripples are simultaneously reduced by addressing the limitations of nonuniform units.Furthermore,the null voltage vector is then inserted to expand the modulation range and improve the steady-state performance.Moreover,the sawtooth carrier is adopted to address the challenge of the asymmetric switch sequence caused by the modified modulation.Finally,the experimental results are presented to verify the effectiveness and superiority of the proposed MPTC method.
基金supported in part by National Natural Science Foundation of China(NSFC)under Project No.51737010in part by State Key Laboratory of Electrical Insulation and Power Equipment(EIPE19109)。
文摘The paper presents an accurate analytical subdomain model for predicting the electromagnetic performance in the symmetrical dual three-phase surface-mounted permanent magnet synchronous machine(PMSM)under open-phase faulty conditions.The model derivations are extended from previous accurate subdomain models accounting for slotting effects.Compared with most conventional subdomain models for traditional three-phase machines with nonoverlapping winding arrangement,the subdomain model proposed in this paper applied for the 24-slot/4-pole dual three-phase machine with symmetrical overlapping winding arrangement.In order to investigate the postfault electromagnetic performance,the reconfigured phase currents and then current density distribution in stator slots under different open-circuit conditions are discussed.According to the developed model and postfault current density distribution,the steady-state electromagnetic performance,such as the electromagnetic torque and unbalanced magnetic force,under open-circuit faulty conditions are obtained.For validation purposes,finite element analysis(FEA)is employed to validate the analytical results.The result indicate that the postfault electromagnet performance can be accurately predicted by the proposed subdomain model,which is in good agreement with FEA results.
文摘The growing demand for efficient high-power switching power supplies has spurred interest in advanced topologies.The three-phase VIENNA converter stands out for its high power factor,simplified structure,and robust performance.Current research focuses on its operational principles,control strategies,and behavior under various load conditions.Key considerations include component selection,thermal management,and EMI/EMC optimization.This topology finds applications across renewable energy systems,industrial equipment,telecommunications,and electric vehicle charging infrastructures.Comparative analyses with alternative topologies and cost-benefit evaluations are also addressed.Future developments are expected to emphasize the integration of wide-bandgap devices and advancements in digital control techniques to further enhance efficiency and system performance.
