The brushless doubly-fed machine(BDFM)is a family of multiport electric machines with two ac electrical ports and a common mechanical port.Different from the conventional singly-fed machines whose synchronous speed is...The brushless doubly-fed machine(BDFM)is a family of multiport electric machines with two ac electrical ports and a common mechanical port.Different from the conventional singly-fed machines whose synchronous speed is solely determined by a single supply frequency and the actual pole pair number,the BDFM has two supply frequencies and two different pole pair numbers to control the rotor speed.By the two accessible electrical ports,all BDFMs are endowed with more degrees of freedom for speed and power control,inherent fault-tolerant capability and high reliability.The BDFM in its broad sense has been extensively investigated as a promising alternative to the conventional slip-ring doubly-fed induction machine(DFIM)during the past decades,for both limited and wide speed range applications.This paper presents a new theoretical framework of the BDFM within which all topological variants can be closely linked by the similarities in working principle.The individualities of each machine topology are presented first,followed by the commonalities such as the modeling techniques,modes of operation,design considerations and control strategies.The challenges are identified and highlighted based on recent developments and possible opportunities are predicted considering the unique nature of this special AC machine type.展开更多
The brushless doubly-fed machine(BDFM)has been widely used due to its advantages of robustness,reliable operation,ease of maintenance,adjustable power factor,small converter capacity and low cost.BDFM is attractive fo...The brushless doubly-fed machine(BDFM)has been widely used due to its advantages of robustness,reliable operation,ease of maintenance,adjustable power factor,small converter capacity and low cost.BDFM is attractive for use in many applications such as variable frequency speed regulation systems and variable speed constant frequency generation systems.Hence,there is a rapidly growing interest in design and control of BDFM.In this paper,the origin and development of BDFM are reviewed,the structural characteristics of BDFM are discussed at length,the principles of operation and design are analyzed,and the different control methods used for BDFM are overviewed and compared in detail.Finally,challenges and opportunities of BDFM are concluded.展开更多
Brushless Doubly-Fed Machine has attracted considerable attention in recent years due to its advantages. It has the robustness of the squirrel cage induction machine, and the speed and power factor controllability of ...Brushless Doubly-Fed Machine has attracted considerable attention in recent years due to its advantages. It has the robustness of the squirrel cage induction machine, and the speed and power factor controllability of the synchronous machine as well as the absence of brushes and slip rings, and using a fractionally rated frequency converter. Hence, there are considerable benefits over the conventional machines, when the machine is applied to applications such as a wind turbine generator or high power adjustable speed drive. However, these benefits are obtained in slightly more complex structure, higher cost and larger dimensions in comparison to the conventional induction machine. This paper presents fundamental aspects of the three modes of operation of brushless doubly fed machine, i.e. simple induction mode, cascade induction mode, and synchronous mode. The investigation is performed by analyzing the spatial harmonic contents of the rotor magnetic flux density. The direct cross couplings between stator and rotor fields as well as, indirect cross coupling between stator fields by the special rotor of this machine is described. Furthermore, loss analysis of the machine in various modes is presented and the torque-speed curves for asynchronous modes are obtained. A 2-D magnetodynamic finite element model based on the D-180 4/8 pole prototype machine is extracted and simulated to verify the results.展开更多
To lower the difficulty of fault protection,a doubly-fed induction machine based shipboard propulsion system(DFIM-SPS)that is partially power decoupled is presented.In such an intrinsically safe SPS architecture,a syn...To lower the difficulty of fault protection,a doubly-fed induction machine based shipboard propulsion system(DFIM-SPS)that is partially power decoupled is presented.In such an intrinsically safe SPS architecture,a synchronous generator(SG)is employed for power generation,and the accuracy of the parameters of power generation unit(PGU)plays an important role in SPS stable operation.In this paper,the PGU parameter deviations are studied to evaluate the effects on system performance.The models of salient-pole SG,type DC1A excitation system(EXS)and DFIM are illustrated first.Besides,the corresponding control scheme is explained.For the 16 important parameters of PGU,up to 40%of parameter deviations are applied to implement parameter sensitivity analysis.Then,simulation studies are carried out to evaluate the parameter deviation effects on system performance in detail.By defining three parameter deviation effect indicators(PDEIs),the effects on the PGU output variables,which are the terminal voltage and output active power,are studied.Moreover,the increasing rates of PDEIs with different degrees of parameter deviations for the key parameters are analyzed.Furthermore,the overall system performance is investigated for the two most influential PGU parameters.This paper provides some vital clues on SG and EXS parameter identification for DFIM-SPS.展开更多
Nested-loop secondary linear doubly-fed machine(NLS-LDFM) is a novel linear machine evolved from rotary brushless doubly-fed induction machine, which has a good application prospect in linear metro. In order to analyz...Nested-loop secondary linear doubly-fed machine(NLS-LDFM) is a novel linear machine evolved from rotary brushless doubly-fed induction machine, which has a good application prospect in linear metro. In order to analyze the performance of NLS-LDFM, the mechanism and action rules of end effects are investigated in this paper. Firstly, the mechanism of static and dynamic end effects is analyzed in aspect of direct coupling, winding asymmetry and transient secondary current. Furthermore, based on the winding theory for short primary linear machines, the machine parameters are established qualitatively considering pulsating magnetic field of NLS-LDFM. Finally, the NLS-LDFM performance analysis is supplemented by the finite element algorithm(FEA) simulation and experiments under different operating conditions.展开更多
The aim of this paper is to investigate an adaptive sensorless direct voltage control(DVC)strategy for the stand-alone ship shaft brushless doubly-fed induction generators(BDFIGs).The proposed new rotor position obser...The aim of this paper is to investigate an adaptive sensorless direct voltage control(DVC)strategy for the stand-alone ship shaft brushless doubly-fed induction generators(BDFIGs).The proposed new rotor position observer using the space vector flux relations of BDFIG may achieve the desired voltage control of the power winding(PW)in terms of magnitude and frequency,without any speed/position sensors.The proposed algorithm does not require any additional observers for obtaining the generator speed.The proposed technique can directly achieve the desired DVC based on the estimated rotor position,which may reduce the overall system cost.The stability analysis of the proposed observer is investigated and confirmed with the concept of quadratic Lyapunov function and using the multi-model representation.In addition,the sensitivity analysis of the presented method is confirmed under different issues of parameter uncertainties.Comprehensive results from both simulation and experiments are realized with a prototype wound-rotor BDFIG,which demonstrate the capability and efficacy of the proposed sensorless DVC strategy with good transient behavior under different operating conditions.Furthermore,the analysis confirms the robustness of the proposed observer via the machine parameter changes.展开更多
The brushless doubly-fed wind power system based on conventional power control strategies lacks ‘inertia’ and the ability to support grid,which leads to the decline of grid stability.Therefore,a control strategy of ...The brushless doubly-fed wind power system based on conventional power control strategies lacks ‘inertia’ and the ability to support grid,which leads to the decline of grid stability.Therefore,a control strategy of brushless doubly-fed reluctance generator(BDFRG) based on virtual synchronous generator(VSG) control is proposed to solve the problem in this paper.The output characteristics of BDFRG based on VSG are similar to a synchronous generator(SG),which can support the grid frequency and increase the system ‘inertia’.According to the mathematical model of BDFRG,the inner loop voltage source control of BDFRG is derived.In addition,the specific structure and parameter selection principle of outer loop VSG control are expounded.The voltage source control inner loop of BDFRG is combined with the VSG control outer loop to establish the overall architecture of BDFRG-VSG control strategy.Finally,the effectiveness and feasibility of the proposed strategy are verified in the simulation.展开更多
Due to their excellent efficiency,power density and constant power speed region,interior permanent-magnet(IPM)machines are very suitable for electric vehicles(EVs).This paper proposed a new IPM rotor topology,which ca...Due to their excellent efficiency,power density and constant power speed region,interior permanent-magnet(IPM)machines are very suitable for electric vehicles(EVs).This paper proposed a new IPM rotor topology,which can offer high reluctance torque,wide constant power speed range and excellent overload capability.Besides,five rotor topologies with integral-slot distributed-windings IPM machines,including four existing IPM topologies and the proposed IPM topology,are designed optimally.Their characteristics,which include d-q axis inductances,saliency ratios,electromagnetic torques,corresponding torque ripples,back-electromotive forces(EMFs),overload capabilities and flux weakening performances are evaluated quantitatively.Finally,a three phase 48s8p hybrid rotor PM machine is built to verify the performances of the proposed IPM machine.This work provides some general concepts for machine developers who are willing to build IPM machines for high-performance EV applications.展开更多
In this paper,a new dual-stator brushless doubly-fed induction machine with a staggered dual cage rotor is proposed,with emphasis on the general interconnection rule of the conductor bars for the staggered dual cage r...In this paper,a new dual-stator brushless doubly-fed induction machine with a staggered dual cage rotor is proposed,with emphasis on the general interconnection rule of the conductor bars for the staggered dual cage rotor.Since the squirrel cage rotor offers the merits of robustness,reliable structure,high slot filling factor,and low rotor resistance comparing to the wound rotor,it is introduced to the dual-stator brushless doubly-fed induction machine to solve the problems of high copper loss and unreliable rotor structure for the dual-stator brushless doubly-fed induction machine with a wound rotor.The originality of this article is to investigate the interconnection rule of conductor bars between the inner and outer cages.The constraint condition that is supposed to be satisfied is deduced by using the rotating magneto-motive force theory,based on which diverse slot/pole combinations are investigated.The performance comparison between the existing and proposed machines is conducted.Finally,a prototype is designed and fabricated.The experimental results verify the effectiveness of the proposed topology.展开更多
A unified spiral vector model is presented that can be used to assist the finite element method-based performance analysis of brushless doubly-fed induction machines with various short-circuited rotor windings.Specifi...A unified spiral vector model is presented that can be used to assist the finite element method-based performance analysis of brushless doubly-fed induction machines with various short-circuited rotor windings.Specifically,magnet-free brushless doubly-fed induction machines working in doubly-fed or singly-fed synchronous mode are investigated.A dynamic model in spiral vector notation is developed,based on which the torque-angle and power-angle characteristics are derived.It is shown that the investigated brushless machines are equivalent to a traditional non-salient-pole synchronous machine with brushes.By introducing a conversion factor,they can also be analyzed with methods similar to the conventional phasor theory.A comparison is made between the brushless doubly-fed induction machine and non-salient-pole wound-field synchronous machine with brushes,revealing that the performance of the brushless machine degrades faster when the laminated core is saturated.A scaled-down prototype is tested to validate the effectiveness of the theoretical analysis.展开更多
The flux-weakening performance of a permanent magnet brushless AC drive was investigated using both floating-point and fixed-point DSP controllers. A significant current oscillation was observed when the drive was ope...The flux-weakening performance of a permanent magnet brushless AC drive was investigated using both floating-point and fixed-point DSP controllers. A significant current oscillation was observed when the drive was operated at high-speed in the flux-weakening mode with the fixed-point DSP. The investigation showed that this was due to the on-line compensation of the winding resistance voltage drop and quantisation errors associated with the fixed-point architecture of the DSP. A simple look-up table scheme is proposed to eliminate the oscillation and to achieve extended flux-weakening capability.展开更多
文摘The brushless doubly-fed machine(BDFM)is a family of multiport electric machines with two ac electrical ports and a common mechanical port.Different from the conventional singly-fed machines whose synchronous speed is solely determined by a single supply frequency and the actual pole pair number,the BDFM has two supply frequencies and two different pole pair numbers to control the rotor speed.By the two accessible electrical ports,all BDFMs are endowed with more degrees of freedom for speed and power control,inherent fault-tolerant capability and high reliability.The BDFM in its broad sense has been extensively investigated as a promising alternative to the conventional slip-ring doubly-fed induction machine(DFIM)during the past decades,for both limited and wide speed range applications.This paper presents a new theoretical framework of the BDFM within which all topological variants can be closely linked by the similarities in working principle.The individualities of each machine topology are presented first,followed by the commonalities such as the modeling techniques,modes of operation,design considerations and control strategies.The challenges are identified and highlighted based on recent developments and possible opportunities are predicted considering the unique nature of this special AC machine type.
基金National Natural Science Foundation of China(51537007)PhD Start-up Fund of Natural Science Foundation of Liaoning Province,China(20141072).
文摘The brushless doubly-fed machine(BDFM)has been widely used due to its advantages of robustness,reliable operation,ease of maintenance,adjustable power factor,small converter capacity and low cost.BDFM is attractive for use in many applications such as variable frequency speed regulation systems and variable speed constant frequency generation systems.Hence,there is a rapidly growing interest in design and control of BDFM.In this paper,the origin and development of BDFM are reviewed,the structural characteristics of BDFM are discussed at length,the principles of operation and design are analyzed,and the different control methods used for BDFM are overviewed and compared in detail.Finally,challenges and opportunities of BDFM are concluded.
文摘Brushless Doubly-Fed Machine has attracted considerable attention in recent years due to its advantages. It has the robustness of the squirrel cage induction machine, and the speed and power factor controllability of the synchronous machine as well as the absence of brushes and slip rings, and using a fractionally rated frequency converter. Hence, there are considerable benefits over the conventional machines, when the machine is applied to applications such as a wind turbine generator or high power adjustable speed drive. However, these benefits are obtained in slightly more complex structure, higher cost and larger dimensions in comparison to the conventional induction machine. This paper presents fundamental aspects of the three modes of operation of brushless doubly fed machine, i.e. simple induction mode, cascade induction mode, and synchronous mode. The investigation is performed by analyzing the spatial harmonic contents of the rotor magnetic flux density. The direct cross couplings between stator and rotor fields as well as, indirect cross coupling between stator fields by the special rotor of this machine is described. Furthermore, loss analysis of the machine in various modes is presented and the torque-speed curves for asynchronous modes are obtained. A 2-D magnetodynamic finite element model based on the D-180 4/8 pole prototype machine is extracted and simulated to verify the results.
基金the National Natural Science Foundation of China under Grant 52007071 and 51907073the China Postdoctoral Science Foundation under Grant 3004131154 and 2020M672355the Applied Basic Frontier Program of Wuhan under Grant 2020010601012207。
文摘To lower the difficulty of fault protection,a doubly-fed induction machine based shipboard propulsion system(DFIM-SPS)that is partially power decoupled is presented.In such an intrinsically safe SPS architecture,a synchronous generator(SG)is employed for power generation,and the accuracy of the parameters of power generation unit(PGU)plays an important role in SPS stable operation.In this paper,the PGU parameter deviations are studied to evaluate the effects on system performance.The models of salient-pole SG,type DC1A excitation system(EXS)and DFIM are illustrated first.Besides,the corresponding control scheme is explained.For the 16 important parameters of PGU,up to 40%of parameter deviations are applied to implement parameter sensitivity analysis.Then,simulation studies are carried out to evaluate the parameter deviation effects on system performance in detail.By defining three parameter deviation effect indicators(PDEIs),the effects on the PGU output variables,which are the terminal voltage and output active power,are studied.Moreover,the increasing rates of PDEIs with different degrees of parameter deviations for the key parameters are analyzed.Furthermore,the overall system performance is investigated for the two most influential PGU parameters.This paper provides some vital clues on SG and EXS parameter identification for DFIM-SPS.
基金supported in part by the National Natural Science Foundations of China under Grants 52277050 and 51877093the fund from Science,Technology,Shenzhen International Collaboration under Grant GJHZ20210705142539007+1 种基金the Key Research and Development Program of Sichuan Province under Grant 2021YFG0081the fund from Science,Technology and Innovation Commission of Shenzhen Municipality under Grant JCYJ20190809101205546。
文摘Nested-loop secondary linear doubly-fed machine(NLS-LDFM) is a novel linear machine evolved from rotary brushless doubly-fed induction machine, which has a good application prospect in linear metro. In order to analyze the performance of NLS-LDFM, the mechanism and action rules of end effects are investigated in this paper. Firstly, the mechanism of static and dynamic end effects is analyzed in aspect of direct coupling, winding asymmetry and transient secondary current. Furthermore, based on the winding theory for short primary linear machines, the machine parameters are established qualitatively considering pulsating magnetic field of NLS-LDFM. Finally, the NLS-LDFM performance analysis is supplemented by the finite element algorithm(FEA) simulation and experiments under different operating conditions.
基金This work was supported in part by the National Natural Science Foundation of China(NSFC)under Grants 51707079 and 51877093in part by the National Key Research and Development Program of China(Project ID:YS2018YFGH000200)in part by the Fundamental Research Funds for the Central Universities(Project ID:2019kfyXMBZ031).
文摘The aim of this paper is to investigate an adaptive sensorless direct voltage control(DVC)strategy for the stand-alone ship shaft brushless doubly-fed induction generators(BDFIGs).The proposed new rotor position observer using the space vector flux relations of BDFIG may achieve the desired voltage control of the power winding(PW)in terms of magnitude and frequency,without any speed/position sensors.The proposed algorithm does not require any additional observers for obtaining the generator speed.The proposed technique can directly achieve the desired DVC based on the estimated rotor position,which may reduce the overall system cost.The stability analysis of the proposed observer is investigated and confirmed with the concept of quadratic Lyapunov function and using the multi-model representation.In addition,the sensitivity analysis of the presented method is confirmed under different issues of parameter uncertainties.Comprehensive results from both simulation and experiments are realized with a prototype wound-rotor BDFIG,which demonstrate the capability and efficacy of the proposed sensorless DVC strategy with good transient behavior under different operating conditions.Furthermore,the analysis confirms the robustness of the proposed observer via the machine parameter changes.
基金supported in part by the National Natural Science Foundation of China under Grant 51537007。
文摘The brushless doubly-fed wind power system based on conventional power control strategies lacks ‘inertia’ and the ability to support grid,which leads to the decline of grid stability.Therefore,a control strategy of brushless doubly-fed reluctance generator(BDFRG) based on virtual synchronous generator(VSG) control is proposed to solve the problem in this paper.The output characteristics of BDFRG based on VSG are similar to a synchronous generator(SG),which can support the grid frequency and increase the system ‘inertia’.According to the mathematical model of BDFRG,the inner loop voltage source control of BDFRG is derived.In addition,the specific structure and parameter selection principle of outer loop VSG control are expounded.The voltage source control inner loop of BDFRG is combined with the VSG control outer loop to establish the overall architecture of BDFRG-VSG control strategy.Finally,the effectiveness and feasibility of the proposed strategy are verified in the simulation.
基金This work was supported by the Key Research and Development Program of Jiangsu Province(BE2018107)by the Six Talent Peaks Project of Jiangsu Province(2017-KTHY-011)by the Graduate Scientific Research Innovation Project of Jiangsu Province(KYCX18_2248).
文摘Due to their excellent efficiency,power density and constant power speed region,interior permanent-magnet(IPM)machines are very suitable for electric vehicles(EVs).This paper proposed a new IPM rotor topology,which can offer high reluctance torque,wide constant power speed range and excellent overload capability.Besides,five rotor topologies with integral-slot distributed-windings IPM machines,including four existing IPM topologies and the proposed IPM topology,are designed optimally.Their characteristics,which include d-q axis inductances,saliency ratios,electromagnetic torques,corresponding torque ripples,back-electromotive forces(EMFs),overload capabilities and flux weakening performances are evaluated quantitatively.Finally,a three phase 48s8p hybrid rotor PM machine is built to verify the performances of the proposed IPM machine.This work provides some general concepts for machine developers who are willing to build IPM machines for high-performance EV applications.
基金supported by the National Natural Science Foundation of China (Grant No.61973073)。
文摘In this paper,a new dual-stator brushless doubly-fed induction machine with a staggered dual cage rotor is proposed,with emphasis on the general interconnection rule of the conductor bars for the staggered dual cage rotor.Since the squirrel cage rotor offers the merits of robustness,reliable structure,high slot filling factor,and low rotor resistance comparing to the wound rotor,it is introduced to the dual-stator brushless doubly-fed induction machine to solve the problems of high copper loss and unreliable rotor structure for the dual-stator brushless doubly-fed induction machine with a wound rotor.The originality of this article is to investigate the interconnection rule of conductor bars between the inner and outer cages.The constraint condition that is supposed to be satisfied is deduced by using the rotating magneto-motive force theory,based on which diverse slot/pole combinations are investigated.The performance comparison between the existing and proposed machines is conducted.Finally,a prototype is designed and fabricated.The experimental results verify the effectiveness of the proposed topology.
文摘A unified spiral vector model is presented that can be used to assist the finite element method-based performance analysis of brushless doubly-fed induction machines with various short-circuited rotor windings.Specifically,magnet-free brushless doubly-fed induction machines working in doubly-fed or singly-fed synchronous mode are investigated.A dynamic model in spiral vector notation is developed,based on which the torque-angle and power-angle characteristics are derived.It is shown that the investigated brushless machines are equivalent to a traditional non-salient-pole synchronous machine with brushes.By introducing a conversion factor,they can also be analyzed with methods similar to the conventional phasor theory.A comparison is made between the brushless doubly-fed induction machine and non-salient-pole wound-field synchronous machine with brushes,revealing that the performance of the brushless machine degrades faster when the laminated core is saturated.A scaled-down prototype is tested to validate the effectiveness of the theoretical analysis.
文摘The flux-weakening performance of a permanent magnet brushless AC drive was investigated using both floating-point and fixed-point DSP controllers. A significant current oscillation was observed when the drive was operated at high-speed in the flux-weakening mode with the fixed-point DSP. The investigation showed that this was due to the on-line compensation of the winding resistance voltage drop and quantisation errors associated with the fixed-point architecture of the DSP. A simple look-up table scheme is proposed to eliminate the oscillation and to achieve extended flux-weakening capability.