The most critical obstacle for four-wheel independently driven electric vehicles(4WID-EVs)is the driving range.Being the actuators of 4WID-EVs,motors account for its major power consumption.In this sense,by properly d...The most critical obstacle for four-wheel independently driven electric vehicles(4WID-EVs)is the driving range.Being the actuators of 4WID-EVs,motors account for its major power consumption.In this sense,by properly distributing torques to minimize the power consumption,the driving range of 4WID-EV can be effectively improved.This paper proposes a model predictive control(MPC)-based torque distribution scheme,which minimizes the power consumption of 4WID-EVs while guaranteeing its tracking performance of planar motions.By incorporating the motor model considering iron losses,the optimal torque distribution can be achieved without an additional torque controller.Also,for this reason,the proposed control scheme is computationally efficient,since the power consumption term to be optimized,which is expressed as the product of the motor voltages and currents,is much simpler than that derived from the efficiency map.With reasonable simplification and linearization,the MPC problem is converted to a quadratic programming problem,which can be solved efficiently.The simulation results in MATLAB and CarSim co-simulation environments demonstrate that the proposed scheme effectively reduces power consumption with guaranteed tracking performance.展开更多
The effect of ball scribing on iron loss of conventional grain-oriented ( CGO) and high-permeability grain-oriented ( HGO) electrical steel was investigated. In this paper,ball scribing was achieved by self- designed ...The effect of ball scribing on iron loss of conventional grain-oriented ( CGO) and high-permeability grain-oriented ( HGO) electrical steel was investigated. In this paper,ball scribing was achieved by self- designed ball scribing instrument and a computer-controlled system capable of providing high accuracy and automatic measurements was developed for the magnetisation and measurement at high and low flux densities. The results showed that after ball scribing,iron loss of two types of steel ( C711 and H668 ) apparently decreases ( 5. 5% and 8. 2% respectively after 16mm scribing at 1. 2T) ,and at high and low flux densities, CGO and HGO electrical steel performs differently. Through the formation and development of free magnetic poles and secondary magnetic domains due to compressive stress,primary magnetic domain spacing of grain- oriented electrical steel becomes smaller,which reflects as a reduction of iron loss in the macroscopic magnetic properties. Through iron loss formula derivation,the effect of domain refinement on grain-oriented electrical steel was also interpreted.展开更多
A series of austenitic cast iron samples with different compositions were cast and a part of nickel in the samples was replaced by manganese for economic reason. Erosion–corrosion tests were conducted under 2wt% sulf...A series of austenitic cast iron samples with different compositions were cast and a part of nickel in the samples was replaced by manganese for economic reason. Erosion–corrosion tests were conducted under 2wt% sulfuric acid and 15wt% quartz sand. The results show that the matrix of cast irons remains austenite after a portion of nickel is replaced with manganese.（Fe,Cr）3C is a common phase in the cast irons, and nickel is the main alloying element in high-nickel cast iron; whereas,（Fe,Mn）3C is observed with the increased manganese content in low-nickel cast iron. Under erosion–corrosion tests, the weight-loss rates of the cast irons increase with increasing time. Wear plays a more important role than corrosion in determining the weight loss. It is indicated that the processes of weight loss for the cast irons with high and low nickel contents are different. The erosion resistance of the cast iron containing 7.29wt% nickel and 6.94wt% manganese is equivalent to that of the cast iron containing 13.29wt% nickel.展开更多
A pot experiment was conducted to investigate the effects of root oxidation on arsenic （As） dynamics in the rhizosphere and As sequestration on rice roots. There were significant differences （P 〈 0.05） in pH valu...A pot experiment was conducted to investigate the effects of root oxidation on arsenic （As） dynamics in the rhizosphere and As sequestration on rice roots. There were significant differences （P 〈 0.05） in pH values between rhizosphere and non-rhizosphere soils, with pH 5.68-6.16 in the rhizosphere and 6.30-6.37 in non-rhizosphere soils as well as differences in redox potentials （P 〈 0.05）. Percentage arsenite was lower （4%-16%） in rhizosphere soil solutions from rice genotypes with higher radial oxygen loss （ROL） compared with genotypes with lower ROL （P 〈 0.05）. Arsenic concentrations in iron plaque and rice straw were significantly negatively correlated （R = -0.60, P 〈 0.05）. Genotypes with higher ROL （TD71 and Yinjingmanzhau） had significantly （P 〈 0.001） lower total As in rice grains （1.35 and 0.96 mg/kg, respectively） compared with genotypes with lower ROL （IAPAR9, 1.68 mg/kg; Nanyangzhan 2.24 mg/kg） in the As treatment, as well as lower inorganic As （P 〈 0.05）. The present study showed that genotypes with higher ROL could oxidize more arsenite in rhizosphere soils, and induce more Fe plaque formation, which subsequently sequestered more As. This reduced As uptake in aboveground plant tissues and also reduced inorganic As accumulation in rice grains. The study has contributed to further understanding the mechanisms whereby ROL influences As uptake and accumulation in rice.展开更多
A model of Fe-flow in the life cycle of steel product was put forward and analyzed. Three important resource and environmental indicators for Fe-flow analysis,that is,steel scrap index,iron ore index and iron loss ind...A model of Fe-flow in the life cycle of steel product was put forward and analyzed. Three important resource and environmental indicators for Fe-flow analysis,that is,steel scrap index,iron ore index and iron loss index were derived from this model. Illustrative examples,demonstrating the influence of the variation of steel output on steel scrap index and iron ore index were given. Case studies for estimating the values of steel scrap index of Japan,China and USA in the period of 1988-1997 were carried out. It was clarified that the main reason of severe deficiency in steel scraps for China's steel industry was its continued rapid growth. The study of iron,copper,zinc and lead cycle in China was carried out successfully according to this model.展开更多
The development, production and application of top high-grade non-grain-oriented （NGO） silicon steels at Baosteel were introduced in this paper. Top high grades refer to the highest grades in the intemational silico...The development, production and application of top high-grade non-grain-oriented （NGO） silicon steels at Baosteel were introduced in this paper. Top high grades refer to the highest grades in the intemational silicon steel product standard and above. B35A230 and B50A250 were developed at Baosteel in 2009 and have been used in inverter compressors for air-conditioners, small transformers and big hydropower generators in the Three Gorges project. Small- batch production of B35A210 and B50A230, which exceed the highest grades listed in the intemational silicon steel product standard,began in 2010. That was a breakthrough in the silicon steel making history in China. Presently,Baosteel＇ s high- grade NGO products have passed the strict qualifications of the three major electric power equipment manufacturers in China and the leading international power equipment suppliers like ALSTOM, GE, SIEMENS, VESTAS, etc. These products are characterized by low iron loss, low anisotropy, good punchability and a high lamination factor. They have been used in the 770 MW hydropower generator at Xiluodu Power Station in the three gorges area, 1 000 MW thermal power generators and 2.5 MW wind power generators.展开更多
Aiming at obtaining high power density of surface-mounted and interior permanent magnet synchronous motor(SIPMSM),it is important to accurately calculate the temperature field distribution of SIPMSM,and a magnetic-the...Aiming at obtaining high power density of surface-mounted and interior permanent magnet synchronous motor(SIPMSM),it is important to accurately calculate the temperature field distribution of SIPMSM,and a magnetic-thermal coupling method is proposed.The magnetic-thermal coupling mechanism is analyzed.The thermal network model and finite element model are built by this method,respectively.The effects of power frequency on iron losses and temperature fields are analyzed by the magnetic-thermal coupling finite element model under the condition of rated load,and the relationship between the load and temperature field is researched under the condition of the synchronous speed.In addition,the equivalent thermal network model is used to verify the magnetic-thermal coupling method.Then the temperatures of various nodes are obtained.The results show that there are advantages in both computational efficiency and accuracy for the proposed coupling method,which can be applied to other permanent magnet motors with complex structures.展开更多
The high grade non-oriented electrical steel sheets containing 3.0%Si were manufacturing processed using different cutting techniques, then they were stress relief annealed（SRA）, the profiles and textures of the cut...The high grade non-oriented electrical steel sheets containing 3.0%Si were manufacturing processed using different cutting techniques, then they were stress relief annealed（SRA）, the profiles and textures of the cutting edges were compared before and after annealing, and the magnetic properties of these specimens were tested and compared. The experimental results show that the iron loss of the specimen by water jet cutting is the lowest, but the magnetic induction under the low magnetic field is the highest, the iron loss of the specimen by laser cutting is the highest, but the magnetic induction under the low magnetic field is the lowest. It is necessary to adopt suitable production conditions and minimize the deterioration involved, and the magnetic property can be recovered by SRA effectively.展开更多
Iron loss and copper loss are the significant parts of electrical loss of machines,which are the major parts particularly under high frequency condition.High-speed permanent magnet synchronous machines(HS-PMSM)have th...Iron loss and copper loss are the significant parts of electrical loss of machines,which are the major parts particularly under high frequency condition.High-speed permanent magnet synchronous machines(HS-PMSM)have the benefits of high power density,high efficiency and wide speed range.Which causes the calculation for iron loss and copper loss in whole operating range complex.By analyzing the components and influencing factors of iron loss and copper loss in stator,we have deduced the calculation formula of iron loss and copper loss in whole operating range based on the analytical solution and finite element approach(EFA)solution.According to the calculation solution,taking the influence of operating temperature on the iron loss and copper loss into account,we propose a temperature correction factor and establish the calculation method for the iron loss and copper loss with temperature influences.Finally,by the conductor transposition,we restrain the circulating current under high-frequency operating condition.展开更多
The electromagnetic characteristics and iron loss of a high-temperature superconductor wind generator(HWG)equipped with an overlapped field coil arrangement(OFCA)are studied by comparing with the one equipped with the...The electromagnetic characteristics and iron loss of a high-temperature superconductor wind generator(HWG)equipped with an overlapped field coil arrangement(OFCA)are studied by comparing with the one equipped with the conventional field coil arrangement(CFCA).Through a quantitative analysis,it was found that HWG with OFCA exhibits better electromagnetic characteristics than HWG with CFCA and can reduce the iron loss by eliminating the magnetic flux sag caused by the adjacent field coil sides with the same current flow direction.In addition,the OFCA topology can further reduce the volume of the wind generator.展开更多
The major applications of electrical steel(ES) sheets are motors,transformers,etc.In recent years, the raise of crude oil price and increasing environmental consciousness trigger the demands for saving energy and redu...The major applications of electrical steel(ES) sheets are motors,transformers,etc.In recent years, the raise of crude oil price and increasing environmental consciousness trigger the demands for saving energy and reducing CO_2 emissions,which greatly accelerate the development of high quality ES sheets.To meet the quality requirements of high efficiency motors and transformers,high grade ES sheets with high flux density are continuously developed and introduced to the market.Meanwhile,the price competition and quality improvement of general grades are important for the lower end application.The iron loss of 50CS1300(50A1300) is significantly reduced by controlling some key parameters.Other than the normal grade,the highest grades of nonoriented (NO) ES are successfully developed recently.And all specifications of 0.50 and 0.35 mm among JIS C 2552 specification could be provided by CSC.As to the insulation coating development,the Cr-free insulation coating has been introduced to the market due to the environmental concern,and has been enormously adopted in Taiwan market.Furthermore,the thicker insulation coating technology has been successfully developed for specific wind power generator application.The newly developed products and quality improvements of electrical steel sheets in China Steel are introduced in this paper.展开更多
In order to improve the effect of the induction motor controller of the electric vehicle and meet the special requirements of the electric vehicle,an improved method-vector control method is put forward.By analyzing t...In order to improve the effect of the induction motor controller of the electric vehicle and meet the special requirements of the electric vehicle,an improved method-vector control method is put forward.By analyzing the traditional vector control method,a model of induction motor is established considering stator iron loss and rotor iron loss.This model contains physical model and mathematical model.Mathematical model is set up based on the special requirements of electric vehicles on the induction motor,that is,the induction motor must have a wide speed range and fast torque response.Then,through the extraction of the formula,the dynamic compensation proposal and static compensation proposal can be got.Ultimately,the simulation analysis testifies the effectiveness of the method.展开更多
In order to better realize the energy recovery and storage of hybrid EVs(HEVs),a switched reluctance starter/generator(SRS/G)with both starting and power generation functions is investigated in this paper.First,the ir...In order to better realize the energy recovery and storage of hybrid EVs(HEVs),a switched reluctance starter/generator(SRS/G)with both starting and power generation functions is investigated in this paper.First,the iron loss of SRS/G is mainly studied to reduce the motor loss and improve the power generation efficiency.Then,the energy storage of hybrid EVs can be effectively improved.Secondly,a magnetic flux density(MFD)waveforms solution method is proposed to solve the difficulty in calculating the iron loss of the SRS/G.Compared with the commonly used finite element method,the proposed solution method has the advantages of simple,fast and small computational amount.Meanwhile,considering the different operating conditions of SRS/G,the iron loss models for both the time-domain and frequency-domain are established.In addition,the calculation formula of the variable coefficient Bertotti three-term loss separation is improved.As the hysteresis loss coefficient,the Steinmetz coefficient and the stray loss coefficient are respectively fitted by the Fourier fitting method.This method is also applied to solve the iron loss of SRS/G.Finally,through an experimental verification,it is indicated that the development of proposed method has high accuracy.展开更多
The common analytical models for the no-load iron loss of permanent magnet(PM)motors usually neglect the iron loss caused by the rotating magnetic field in the tooth tips and the harmonics of the magnetic fields in th...The common analytical models for the no-load iron loss of permanent magnet(PM)motors usually neglect the iron loss caused by the rotating magnetic field in the tooth tips and the harmonics of the magnetic fields in the teeth and yokes.This paper presents an analytical model for no-load iron loss of a fractional-slot surface-mounted permanent magnet motor.According to the existing analytical model of the magnetic field distribution in the slotted air gap,the magnetic flux densities considering the harmonics of the stator tooth and yoke are both derived based on the continuity of magnetic flux.Due to the complexity of the magnetic field in the tooth tip,the tangential flux density of the tooth tip is approximated by an equivalent sine wave and the radial component is regarded to be the same as that of the corresponding tooth.After obtaining the magnetic fields in stator different regions,the analytical iron loss is calculated by using the Bertotti model and the orthogonal decomposition model.A 20-pole/24-slot PM synchronous motor is taken as an example.The maximum error between the analytical model and finite element model(FEM)is 5.46%,which verifies the validity of the proposed method.展开更多
This paper presents a comprehensive evaluation of system interactions in a battery electric vehicle caused by temperature sensitivity of permanent magnet synchronous machines(PMSM).An analytical model of a PMSM consid...This paper presents a comprehensive evaluation of system interactions in a battery electric vehicle caused by temperature sensitivity of permanent magnet synchronous machines(PMSM).An analytical model of a PMSM considering iron losses and thermal impact is implemented on a field programmable gate array suitable for hardware-in-the-loop testing.By the presented virtual prototyping approach,different machine characteristics defined by the design are used to parameterize the analytical model.The investigated temperature effect is understood as an interacting influence between machine character-istics and control,which are investigated in terms of torque generation,voltage utilization and efficiency under closed-loop condition in a vehicle environment.In particular,using a surface permanent magnet rotor and an interior permanent magnet rotor,the performance of both machine designs is analyzed by varying temperature-adjusted feedforward control strategies on the basis of a driving cycle from a racetrack.The comparison shows that the machine design with surface-mounted mag-nets is associated with higher temperature sensitivity.In this case,the temperature consideration in the feedforward control provides a14%loss reduction in closed-loop vehicle test operation.It can be summarized that the electromagnetic torque is less sensitive to a temperature variation with increasing reluctance.The presented development approach demonstrates the impact of interactions in electric powertrains without the need of real prototypes.展开更多
基金supported in part by National Natural Science Foundation of China(NSFC)under Project No.51737010.
文摘The most critical obstacle for four-wheel independently driven electric vehicles(4WID-EVs)is the driving range.Being the actuators of 4WID-EVs,motors account for its major power consumption.In this sense,by properly distributing torques to minimize the power consumption,the driving range of 4WID-EV can be effectively improved.This paper proposes a model predictive control(MPC)-based torque distribution scheme,which minimizes the power consumption of 4WID-EVs while guaranteeing its tracking performance of planar motions.By incorporating the motor model considering iron losses,the optimal torque distribution can be achieved without an additional torque controller.Also,for this reason,the proposed control scheme is computationally efficient,since the power consumption term to be optimized,which is expressed as the product of the motor voltages and currents,is much simpler than that derived from the efficiency map.With reasonable simplification and linearization,the MPC problem is converted to a quadratic programming problem,which can be solved efficiently.The simulation results in MATLAB and CarSim co-simulation environments demonstrate that the proposed scheme effectively reduces power consumption with guaranteed tracking performance.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 51174057 and 51274062)National High Technology Research and Development Program (Grant No. 2012AA03A503)
文摘The effect of ball scribing on iron loss of conventional grain-oriented ( CGO) and high-permeability grain-oriented ( HGO) electrical steel was investigated. In this paper,ball scribing was achieved by self- designed ball scribing instrument and a computer-controlled system capable of providing high accuracy and automatic measurements was developed for the magnetisation and measurement at high and low flux densities. The results showed that after ball scribing,iron loss of two types of steel ( C711 and H668 ) apparently decreases ( 5. 5% and 8. 2% respectively after 16mm scribing at 1. 2T) ,and at high and low flux densities, CGO and HGO electrical steel performs differently. Through the formation and development of free magnetic poles and secondary magnetic domains due to compressive stress,primary magnetic domain spacing of grain- oriented electrical steel becomes smaller,which reflects as a reduction of iron loss in the macroscopic magnetic properties. Through iron loss formula derivation,the effect of domain refinement on grain-oriented electrical steel was also interpreted.
基金financially supported by the National Nature Science Foundation of China (No. 51101109)
文摘A series of austenitic cast iron samples with different compositions were cast and a part of nickel in the samples was replaced by manganese for economic reason. Erosion–corrosion tests were conducted under 2wt% sulfuric acid and 15wt% quartz sand. The results show that the matrix of cast irons remains austenite after a portion of nickel is replaced with manganese.（Fe,Cr）3C is a common phase in the cast irons, and nickel is the main alloying element in high-nickel cast iron; whereas,（Fe,Mn）3C is observed with the increased manganese content in low-nickel cast iron. Under erosion–corrosion tests, the weight-loss rates of the cast irons increase with increasing time. Wear plays a more important role than corrosion in determining the weight loss. It is indicated that the processes of weight loss for the cast irons with high and low nickel contents are different. The erosion resistance of the cast iron containing 7.29wt% nickel and 6.94wt% manganese is equivalent to that of the cast iron containing 13.29wt% nickel.
基金supported by the National Natural Science Foundation of China(No.41201493)the Environmental Protection’s Special Scientific Research for Public Welfare Industry(No.201109056)
文摘A pot experiment was conducted to investigate the effects of root oxidation on arsenic （As） dynamics in the rhizosphere and As sequestration on rice roots. There were significant differences （P 〈 0.05） in pH values between rhizosphere and non-rhizosphere soils, with pH 5.68-6.16 in the rhizosphere and 6.30-6.37 in non-rhizosphere soils as well as differences in redox potentials （P 〈 0.05）. Percentage arsenite was lower （4%-16%） in rhizosphere soil solutions from rice genotypes with higher radial oxygen loss （ROL） compared with genotypes with lower ROL （P 〈 0.05）. Arsenic concentrations in iron plaque and rice straw were significantly negatively correlated （R = -0.60, P 〈 0.05）. Genotypes with higher ROL （TD71 and Yinjingmanzhau） had significantly （P 〈 0.001） lower total As in rice grains （1.35 and 0.96 mg/kg, respectively） compared with genotypes with lower ROL （IAPAR9, 1.68 mg/kg; Nanyangzhan 2.24 mg/kg） in the As treatment, as well as lower inorganic As （P 〈 0.05）. The present study showed that genotypes with higher ROL could oxidize more arsenite in rhizosphere soils, and induce more Fe plaque formation, which subsequently sequestered more As. This reduced As uptake in aboveground plant tissues and also reduced inorganic As accumulation in rice grains. The study has contributed to further understanding the mechanisms whereby ROL influences As uptake and accumulation in rice.
基金The Fundamental Research Funds for the Central Universities(N09042018)
文摘A model of Fe-flow in the life cycle of steel product was put forward and analyzed. Three important resource and environmental indicators for Fe-flow analysis,that is,steel scrap index,iron ore index and iron loss index were derived from this model. Illustrative examples,demonstrating the influence of the variation of steel output on steel scrap index and iron ore index were given. Case studies for estimating the values of steel scrap index of Japan,China and USA in the period of 1988-1997 were carried out. It was clarified that the main reason of severe deficiency in steel scraps for China's steel industry was its continued rapid growth. The study of iron,copper,zinc and lead cycle in China was carried out successfully according to this model.
文摘The development, production and application of top high-grade non-grain-oriented （NGO） silicon steels at Baosteel were introduced in this paper. Top high grades refer to the highest grades in the intemational silicon steel product standard and above. B35A230 and B50A250 were developed at Baosteel in 2009 and have been used in inverter compressors for air-conditioners, small transformers and big hydropower generators in the Three Gorges project. Small- batch production of B35A210 and B50A230, which exceed the highest grades listed in the intemational silicon steel product standard,began in 2010. That was a breakthrough in the silicon steel making history in China. Presently,Baosteel＇ s high- grade NGO products have passed the strict qualifications of the three major electric power equipment manufacturers in China and the leading international power equipment suppliers like ALSTOM, GE, SIEMENS, VESTAS, etc. These products are characterized by low iron loss, low anisotropy, good punchability and a high lamination factor. They have been used in the 770 MW hydropower generator at Xiluodu Power Station in the three gorges area, 1 000 MW thermal power generators and 2.5 MW wind power generators.
基金This work was supported by Natural Science Foundation of China(Item number:51777060,U1361109)Natural Science Foundation of Henan province(Item number:162300410117)the he innovative research team plan of Henan Polytechnic University(Item number:T2015-2).
文摘Aiming at obtaining high power density of surface-mounted and interior permanent magnet synchronous motor(SIPMSM),it is important to accurately calculate the temperature field distribution of SIPMSM,and a magnetic-thermal coupling method is proposed.The magnetic-thermal coupling mechanism is analyzed.The thermal network model and finite element model are built by this method,respectively.The effects of power frequency on iron losses and temperature fields are analyzed by the magnetic-thermal coupling finite element model under the condition of rated load,and the relationship between the load and temperature field is researched under the condition of the synchronous speed.In addition,the equivalent thermal network model is used to verify the magnetic-thermal coupling method.Then the temperatures of various nodes are obtained.The results show that there are advantages in both computational efficiency and accuracy for the proposed coupling method,which can be applied to other permanent magnet motors with complex structures.
基金Funded by the High Technology Research and Development Program of China(2011AA11A238)
文摘The high grade non-oriented electrical steel sheets containing 3.0%Si were manufacturing processed using different cutting techniques, then they were stress relief annealed（SRA）, the profiles and textures of the cutting edges were compared before and after annealing, and the magnetic properties of these specimens were tested and compared. The experimental results show that the iron loss of the specimen by water jet cutting is the lowest, but the magnetic induction under the low magnetic field is the highest, the iron loss of the specimen by laser cutting is the highest, but the magnetic induction under the low magnetic field is the lowest. It is necessary to adopt suitable production conditions and minimize the deterioration involved, and the magnetic property can be recovered by SRA effectively.
基金This work was supported by the National Natural Science Foundation of China(51677144).
文摘Iron loss and copper loss are the significant parts of electrical loss of machines,which are the major parts particularly under high frequency condition.High-speed permanent magnet synchronous machines(HS-PMSM)have the benefits of high power density,high efficiency and wide speed range.Which causes the calculation for iron loss and copper loss in whole operating range complex.By analyzing the components and influencing factors of iron loss and copper loss in stator,we have deduced the calculation formula of iron loss and copper loss in whole operating range based on the analytical solution and finite element approach(EFA)solution.According to the calculation solution,taking the influence of operating temperature on the iron loss and copper loss into account,we propose a temperature correction factor and establish the calculation method for the iron loss and copper loss with temperature influences.Finally,by the conductor transposition,we restrain the circulating current under high-frequency operating condition.
基金partly supported by the National Natural Science Foundation of China under Grants No.61473061 and No.61104104the Sichuan Science and Technology Program under Grant No.2020YFSY0012the Program for New Century Excellent Talents in University under Grant No.NCET-13-0091。
文摘The electromagnetic characteristics and iron loss of a high-temperature superconductor wind generator(HWG)equipped with an overlapped field coil arrangement(OFCA)are studied by comparing with the one equipped with the conventional field coil arrangement(CFCA).Through a quantitative analysis,it was found that HWG with OFCA exhibits better electromagnetic characteristics than HWG with CFCA and can reduce the iron loss by eliminating the magnetic flux sag caused by the adjacent field coil sides with the same current flow direction.In addition,the OFCA topology can further reduce the volume of the wind generator.
文摘The major applications of electrical steel(ES) sheets are motors,transformers,etc.In recent years, the raise of crude oil price and increasing environmental consciousness trigger the demands for saving energy and reducing CO_2 emissions,which greatly accelerate the development of high quality ES sheets.To meet the quality requirements of high efficiency motors and transformers,high grade ES sheets with high flux density are continuously developed and introduced to the market.Meanwhile,the price competition and quality improvement of general grades are important for the lower end application.The iron loss of 50CS1300(50A1300) is significantly reduced by controlling some key parameters.Other than the normal grade,the highest grades of nonoriented (NO) ES are successfully developed recently.And all specifications of 0.50 and 0.35 mm among JIS C 2552 specification could be provided by CSC.As to the insulation coating development,the Cr-free insulation coating has been introduced to the market due to the environmental concern,and has been enormously adopted in Taiwan market.Furthermore,the thicker insulation coating technology has been successfully developed for specific wind power generator application.The newly developed products and quality improvements of electrical steel sheets in China Steel are introduced in this paper.
文摘In order to improve the effect of the induction motor controller of the electric vehicle and meet the special requirements of the electric vehicle,an improved method-vector control method is put forward.By analyzing the traditional vector control method,a model of induction motor is established considering stator iron loss and rotor iron loss.This model contains physical model and mathematical model.Mathematical model is set up based on the special requirements of electric vehicles on the induction motor,that is,the induction motor must have a wide speed range and fast torque response.Then,through the extraction of the formula,the dynamic compensation proposal and static compensation proposal can be got.Ultimately,the simulation analysis testifies the effectiveness of the method.
基金supported in part by the Shenzhen Collaborative Innovation Special Plan International Cooperation Research Project(No.GJHZ20220913144400001)the General Research Project of Shenzhen Science and Technology Plan(No.JCYJ20220818100000001).
文摘In order to better realize the energy recovery and storage of hybrid EVs(HEVs),a switched reluctance starter/generator(SRS/G)with both starting and power generation functions is investigated in this paper.First,the iron loss of SRS/G is mainly studied to reduce the motor loss and improve the power generation efficiency.Then,the energy storage of hybrid EVs can be effectively improved.Secondly,a magnetic flux density(MFD)waveforms solution method is proposed to solve the difficulty in calculating the iron loss of the SRS/G.Compared with the commonly used finite element method,the proposed solution method has the advantages of simple,fast and small computational amount.Meanwhile,considering the different operating conditions of SRS/G,the iron loss models for both the time-domain and frequency-domain are established.In addition,the calculation formula of the variable coefficient Bertotti three-term loss separation is improved.As the hysteresis loss coefficient,the Steinmetz coefficient and the stray loss coefficient are respectively fitted by the Fourier fitting method.This method is also applied to solve the iron loss of SRS/G.Finally,through an experimental verification,it is indicated that the development of proposed method has high accuracy.
基金Supported by the Major Science and Technology Project Servo Drive and Motor Test Specification and Standard Research and Test Platform(2012ZX04001051).
文摘The common analytical models for the no-load iron loss of permanent magnet(PM)motors usually neglect the iron loss caused by the rotating magnetic field in the tooth tips and the harmonics of the magnetic fields in the teeth and yokes.This paper presents an analytical model for no-load iron loss of a fractional-slot surface-mounted permanent magnet motor.According to the existing analytical model of the magnetic field distribution in the slotted air gap,the magnetic flux densities considering the harmonics of the stator tooth and yoke are both derived based on the continuity of magnetic flux.Due to the complexity of the magnetic field in the tooth tip,the tangential flux density of the tooth tip is approximated by an equivalent sine wave and the radial component is regarded to be the same as that of the corresponding tooth.After obtaining the magnetic fields in stator different regions,the analytical iron loss is calculated by using the Bertotti model and the orthogonal decomposition model.A 20-pole/24-slot PM synchronous motor is taken as an example.The maximum error between the analytical model and finite element model(FEM)is 5.46%,which verifies the validity of the proposed method.
文摘This paper presents a comprehensive evaluation of system interactions in a battery electric vehicle caused by temperature sensitivity of permanent magnet synchronous machines(PMSM).An analytical model of a PMSM considering iron losses and thermal impact is implemented on a field programmable gate array suitable for hardware-in-the-loop testing.By the presented virtual prototyping approach,different machine characteristics defined by the design are used to parameterize the analytical model.The investigated temperature effect is understood as an interacting influence between machine character-istics and control,which are investigated in terms of torque generation,voltage utilization and efficiency under closed-loop condition in a vehicle environment.In particular,using a surface permanent magnet rotor and an interior permanent magnet rotor,the performance of both machine designs is analyzed by varying temperature-adjusted feedforward control strategies on the basis of a driving cycle from a racetrack.The comparison shows that the machine design with surface-mounted mag-nets is associated with higher temperature sensitivity.In this case,the temperature consideration in the feedforward control provides a14%loss reduction in closed-loop vehicle test operation.It can be summarized that the electromagnetic torque is less sensitive to a temperature variation with increasing reluctance.The presented development approach demonstrates the impact of interactions in electric powertrains without the need of real prototypes.
