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Electric Machines & Control Application (CN 31-1959/TM, ISSN 1673-6540) was founded in 1959 in title of Technical Information of Small and Medium-sized Electric Machines. The title was changed to Small and Medium-sized Electric Machines in 1977, and then changed to its current title in 2005. The journal is sponsored by Shanghai Electrical Apparatus Research Institute (Group) Co., Ltd., aims to publish cutting-edge achievements in various research fields related to the electrical science. The journal is a source journal of the Comprehensive Evaluation Database of Chinese Academic Journals, and the full text articles are included in Chinese Academic Journals (CD). It has been included in Chinese Core Journals and Key Magazine of China Technology for years. Recently, it has also been included in Scopus, EBSCO, DOAJ, EuroPub, Research4Life, ICI world of Jourmals, ICI Journal Master Lister, Japan Science and Technology Agency database (JST, Japan) and Abstract Journals (AJ, Russia). The impact factor is steadily increasing year by year. Electric Machines and Control Application is published on the 10th of each month and is publicly distributed domestically and internationally. The post issuing code is 4-199.
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2026,53(6):536-546, DOI: 10.12177/emca.2026.168
Abstract:
[Objective] In the deadbeat control of surface-mounted permanent magnet synchronous motor (SPMSM), the contradiction between the number of candidate voltage vectors and the computational burden limits performance optimization. This paper aims to propose a solution that balances control accuracy and real-time performance. [Methods] Taking SPMSM as an example, the following methods were proposed: (1) The n-th order subdivision method of the inscribed circle of the voltage vector hexagon was used to generate 6n2+1 candidate voltage vectors; (2) Simplified determination method 1 was employed, fixing the traversal count to 4 times; (3) Simplified determination method 2 was introduced, directly mapping the ideal voltage vector without traversal. [Results] Simulation and experimental results showed that the 8th order subdivision method (385 candidate vectors) reduced torque ripple by 12.87% and flux linkage ripple by 30.67%; simplified determination method 1 and simplified determination method 2 reduced computational time by 42.86% and 87.94%, respectively. [Conclusion] The proposed method achieves arbitrary expansion of candidate vectors and significant reduction of computational load, providing a reference for optimizing the performance and real-time capability of deadbeat control.
[Objective] In the deadbeat control of surface-mounted permanent magnet synchronous motor (SPMSM), the contradiction between the number of candidate voltage vectors and the computational burden limits performance optimization. This paper aims to propose a solution that balances control accuracy and real-time performance. [Methods] Taking SPMSM as an example, the following methods were proposed: (1) The n-th order subdivision method of the inscribed circle of the voltage vector hexagon was used to generate 6n2+1 candidate voltage vectors; (2) Simplified determination method 1 was employed, fixing the traversal count to 4 times; (3) Simplified determination method 2 was introduced, directly mapping the ideal voltage vector without traversal. [Results] Simulation and experimental results showed that the 8th order subdivision method (385 candidate vectors) reduced torque ripple by 12.87% and flux linkage ripple by 30.67%; simplified determination method 1 and simplified determination method 2 reduced computational time by 42.86% and 87.94%, respectively. [Conclusion] The proposed method achieves arbitrary expansion of candidate vectors and significant reduction of computational load, providing a reference for optimizing the performance and real-time capability of deadbeat control.
2026,53(6):547-557, DOI: 10.12177/emca.2026.177
Abstract:
[Objective] Aiming at the issues of inaccurate position estimation and insufficient commutation current regulation in traditional sensorless brushless DC motor (BLDCM) at low-to-medium speeds and commutation regions, which lead to significant torque ripple and degraded operational stability, this paper proposes a cooperative control method that balances position estimation accuracy and commutation current regulation performance. [Methods] Within the dual vector field-oriented control framework, the position observation and current control were collaboratively designed. A sliding mode observer based on a double power piecewise smooth (DP-PS-SMO) was constructed, where different power terms were utilized to achieve rapid convergence in large error regions and high-precision estimation in small error regions. Additionally, a piecewise smooth function was employed to enhance the continuity of back electromotive force and electrical angle estimation. Finite control set model predictive current control (FCS-MPCC) was introduced, where the estimated electrical angle was used to predict the current response under the action of the inverter’s finite voltage vectors. The optimal voltage vector was selected through a cost function to suppress torque fluctuations caused by commutation discontinuity. Finally, simulation verification was conducted on the Matlab platform. [Results] The simulation results demonstrated that the proposed method effectively reduced current fluctuations in the commutation region and suppressed torque ripple caused by commutation errors. Compared with traditional sensorless control strategies, torque ripple was significantly mitigated under all four operating conditions. [Conclusion] The cooperative design of DP-PS-SMO and FCS-MPCC effectively mitigates torque ripple issues in sensorless BLDCM at low-to-medium speeds and commutation regions, enhancing system operational stability and control reliability without the need for additional position sensors.
[Objective] Aiming at the issues of inaccurate position estimation and insufficient commutation current regulation in traditional sensorless brushless DC motor (BLDCM) at low-to-medium speeds and commutation regions, which lead to significant torque ripple and degraded operational stability, this paper proposes a cooperative control method that balances position estimation accuracy and commutation current regulation performance. [Methods] Within the dual vector field-oriented control framework, the position observation and current control were collaboratively designed. A sliding mode observer based on a double power piecewise smooth (DP-PS-SMO) was constructed, where different power terms were utilized to achieve rapid convergence in large error regions and high-precision estimation in small error regions. Additionally, a piecewise smooth function was employed to enhance the continuity of back electromotive force and electrical angle estimation. Finite control set model predictive current control (FCS-MPCC) was introduced, where the estimated electrical angle was used to predict the current response under the action of the inverter’s finite voltage vectors. The optimal voltage vector was selected through a cost function to suppress torque fluctuations caused by commutation discontinuity. Finally, simulation verification was conducted on the Matlab platform. [Results] The simulation results demonstrated that the proposed method effectively reduced current fluctuations in the commutation region and suppressed torque ripple caused by commutation errors. Compared with traditional sensorless control strategies, torque ripple was significantly mitigated under all four operating conditions. [Conclusion] The cooperative design of DP-PS-SMO and FCS-MPCC effectively mitigates torque ripple issues in sensorless BLDCM at low-to-medium speeds and commutation regions, enhancing system operational stability and control reliability without the need for additional position sensors.
2026,53(6):558-566, DOI: 10.12177/emca.2026.171
Abstract:
[Objective] To ensure the reliability of electrical connections in cable circuits, this paper proposes a method for diagnosing loose electrical contact faults based on multi-amplitude pulse currents. [Methods] Firstly, the variation of contact resistance with key parameters such as temperature and contact area was analyzed through finite element simulation under both normal and loose contact states. Then, a self-developed electrical connection reliability testing device was used to apply pulse currents of different amplitudes, and the contact resistance and temperature were measured under normal and loose contact states, obtaining the variation curve of contact resistance with pulse current amplitude. Finally, a mathematical model of the relationship between contact resistance and current was established, and a derivative-based fault criterion for loose electrical contact was proposed by analyzing the first and second derivatives. [Results] The simulation and experimental results demonstrated that the proposed diagnostic method effectively identified loose electrical contact faults and improved the reliability of electrical connections. [Conclusion] The proposed derivative-based fault criterion provides a novel approach for diagnosing loose electrical contact faults, demonstrating practical application value.
[Objective] To ensure the reliability of electrical connections in cable circuits, this paper proposes a method for diagnosing loose electrical contact faults based on multi-amplitude pulse currents. [Methods] Firstly, the variation of contact resistance with key parameters such as temperature and contact area was analyzed through finite element simulation under both normal and loose contact states. Then, a self-developed electrical connection reliability testing device was used to apply pulse currents of different amplitudes, and the contact resistance and temperature were measured under normal and loose contact states, obtaining the variation curve of contact resistance with pulse current amplitude. Finally, a mathematical model of the relationship between contact resistance and current was established, and a derivative-based fault criterion for loose electrical contact was proposed by analyzing the first and second derivatives. [Results] The simulation and experimental results demonstrated that the proposed diagnostic method effectively identified loose electrical contact faults and improved the reliability of electrical connections. [Conclusion] The proposed derivative-based fault criterion provides a novel approach for diagnosing loose electrical contact faults, demonstrating practical application value.
2026,53(6):567-579, DOI: 10.12177/emca.2026.175
Abstract:
[Objective] This paper focuses on the innovative applications of additive manufacturing (3D printing) in the field of electric motors, aiming to provide theoretical support and practical references for the development of high-performance motors. [Methods] Firstly, the additive manufacturing technology is elaborated from aspects such as industry background, process principles, technical systems, and competitive advantages. Then, its innovative applications in key motor components, including stators, rotors, permanent magnets, windings, and cooling structures, are systematically reviewed to clarify its cutting-edge development directions. Finally, the trends and current challenges of additive manufacturing in motor manufacturing are deeply analyzed. [Results] By 2023, the global 3D printing market value has exceeded $15 billion, with a compound annual growth rate of over 20%. In recent years, researchers have analyzed the materials adaptability such as high-temperature alloys, composite magnetic powders, and conductive polymers using mainstream processes like laser powder bed fusion and binder jetting, while identifying technical bottlenecks in precision, surface roughness, and post-heat treatment. [Conclusion] Additive manufacturing technology, with its unique layer-by-layer deposition principle and design freedom, has brought comprehensive transformations to the motor field, ranging from material preparation to system integration.
[Objective] This paper focuses on the innovative applications of additive manufacturing (3D printing) in the field of electric motors, aiming to provide theoretical support and practical references for the development of high-performance motors. [Methods] Firstly, the additive manufacturing technology is elaborated from aspects such as industry background, process principles, technical systems, and competitive advantages. Then, its innovative applications in key motor components, including stators, rotors, permanent magnets, windings, and cooling structures, are systematically reviewed to clarify its cutting-edge development directions. Finally, the trends and current challenges of additive manufacturing in motor manufacturing are deeply analyzed. [Results] By 2023, the global 3D printing market value has exceeded $15 billion, with a compound annual growth rate of over 20%. In recent years, researchers have analyzed the materials adaptability such as high-temperature alloys, composite magnetic powders, and conductive polymers using mainstream processes like laser powder bed fusion and binder jetting, while identifying technical bottlenecks in precision, surface roughness, and post-heat treatment. [Conclusion] Additive manufacturing technology, with its unique layer-by-layer deposition principle and design freedom, has brought comprehensive transformations to the motor field, ranging from material preparation to system integration.
2026,53(6):580-591, DOI: 10.12177/emca.2026.172
Abstract:
[Objective] Under the development background of high-proportion renewable energy integration driven by the "dual carbon" goals, the parallel operation of grid-forming energy storage converter (GFESC) has become the core solution for large-scale energy storage power stations. However, the inability to accurately allocate reactive power proportionally due to line impedance mismatch in parallel operation has emerged as a critical issue that urgently needs to be addressed. [Methods] The power transmission mechanism of the parallel converter system and the generation mechanism of reactive power allocation errors were first analyzed in depth through theoretical derivation. Based on this, an improved droop control strategy based on adaptive virtual impedance was proposed, aiming to dynamically compensate for the impact of line impedance mismatch on reactive power allocation. Finally, a parallel converter system model was built based on the Matlab/Simulink simulation platform, and the effectiveness of the proposed control strategy was verified through comparative experiments. [Results] The simulation results demonstrated that the proposed reactive power allocation strategy achieved high-precision proportional distribution under conditions where the actual line impedance was unknown and no inter-converter communication was required, while effectively reducing the output voltage deviation of the converters. After the introduction of virtual impedance, the strategy significantly mitigated the conflict between high-precision reactive power allocation and point of common coupling (PCC) voltage drop observed in conventional methods, enabling effective PCC voltage compensation to restore it to the rated operating level. Meanwhile, a double closed-loop control structure consisting of an outer voltage loop and an inner current loop is adopted to effectively maintain the stability of the system’s grid voltage and frequency. [Conclusion] The strategy achieves precise matching of equivalent impedance through adaptive virtual impedance, providing a highly reliable solution for the large-scale operation of GFESC.
[Objective] Under the development background of high-proportion renewable energy integration driven by the "dual carbon" goals, the parallel operation of grid-forming energy storage converter (GFESC) has become the core solution for large-scale energy storage power stations. However, the inability to accurately allocate reactive power proportionally due to line impedance mismatch in parallel operation has emerged as a critical issue that urgently needs to be addressed. [Methods] The power transmission mechanism of the parallel converter system and the generation mechanism of reactive power allocation errors were first analyzed in depth through theoretical derivation. Based on this, an improved droop control strategy based on adaptive virtual impedance was proposed, aiming to dynamically compensate for the impact of line impedance mismatch on reactive power allocation. Finally, a parallel converter system model was built based on the Matlab/Simulink simulation platform, and the effectiveness of the proposed control strategy was verified through comparative experiments. [Results] The simulation results demonstrated that the proposed reactive power allocation strategy achieved high-precision proportional distribution under conditions where the actual line impedance was unknown and no inter-converter communication was required, while effectively reducing the output voltage deviation of the converters. After the introduction of virtual impedance, the strategy significantly mitigated the conflict between high-precision reactive power allocation and point of common coupling (PCC) voltage drop observed in conventional methods, enabling effective PCC voltage compensation to restore it to the rated operating level. Meanwhile, a double closed-loop control structure consisting of an outer voltage loop and an inner current loop is adopted to effectively maintain the stability of the system’s grid voltage and frequency. [Conclusion] The strategy achieves precise matching of equivalent impedance through adaptive virtual impedance, providing a highly reliable solution for the large-scale operation of GFESC.
2026,53(6):592-601, DOI: 10.12177/emca.2026.169
Abstract:
[Objective] In the context of energy scarcity and low-carbon shipping, efficient energy management is critical for hybrid electric vessels. This paper proposes an improved multi-mode power-following control strategy to address the limitations of conventional methods, such as high energy consumption and poor adaptability. [Methods] Firstly, the overall architecture of the hybrid power system was analyzed, and the parameter matching and model construction for the target vessel’s power system were completed. Subsequently, an improved multi-mode power-following energy management strategy was designed with the objective of enhancing system operational efficiency, adopting a hierarchical control architecture: decentralized power control was implemented in the first layer to achieve precise and optimal regulation of various power supply devices; the second layer utilized an improved multi-mode equivalent cost minimization strategy to holistically optimize overall energy consumption while ensuring smooth and accurate power tracking. Finally, the effectiveness of the energy management control strategy for the ship hybrid power system was validated on a Matlab-based real-time simulation platform. [Results] Simulation results demonstrated that the proposed strategy reduced hydrogen consumption by 23.81% compared to conventional strategies. [Conclusion] The proposed control strategy comprehensively considers constraints including power battery cycle life and fuel cell optimal operating range, effectively extending the service life of both core power sources while reducing overall vessel operating costs, demonstrating significant practical economic value.
[Objective] In the context of energy scarcity and low-carbon shipping, efficient energy management is critical for hybrid electric vessels. This paper proposes an improved multi-mode power-following control strategy to address the limitations of conventional methods, such as high energy consumption and poor adaptability. [Methods] Firstly, the overall architecture of the hybrid power system was analyzed, and the parameter matching and model construction for the target vessel’s power system were completed. Subsequently, an improved multi-mode power-following energy management strategy was designed with the objective of enhancing system operational efficiency, adopting a hierarchical control architecture: decentralized power control was implemented in the first layer to achieve precise and optimal regulation of various power supply devices; the second layer utilized an improved multi-mode equivalent cost minimization strategy to holistically optimize overall energy consumption while ensuring smooth and accurate power tracking. Finally, the effectiveness of the energy management control strategy for the ship hybrid power system was validated on a Matlab-based real-time simulation platform. [Results] Simulation results demonstrated that the proposed strategy reduced hydrogen consumption by 23.81% compared to conventional strategies. [Conclusion] The proposed control strategy comprehensively considers constraints including power battery cycle life and fuel cell optimal operating range, effectively extending the service life of both core power sources while reducing overall vessel operating costs, demonstrating significant practical economic value.
2026,53(6):602-611, DOI: 10.12177/emca.2026.180
Abstract:
[Objective] Aiming at the issues of high permanent magnet cost, excessive air-gap magnetic field harmonics, and poor high-temperature demagnetization resistance in rare-earth permanent magnet motors for scraper conveyors, this paper proposes a hybrid-pole low-speed permanent magnet synchronous motor (PMSM) excited by both ferrite and NdFeB. The design leverages the advantages of ferrite magnets, such as low cost and strong high-temperature demagnetization resistance, to address these problems. [Methods] The electromagnetic design of the PMSM was first conducted to determine its fundamental parameters. To enhance permanent magnet material utilization, five distinct rotor structures were designed and comparatively analyzed under identical magnet usage conditions, from which the configuration with optimal torque output capability was selected. Subsequently, three hybrid-pole magnetic circuit designs were developed for comparative evaluation. Finally, finite element analysis software was employed to perform comprehensive assessments of the finalized design, including electromagnetic performance analysis, temperature field verification, and high-temperature demagnetization resistance evaluation, thereby validating the effectiveness of the hybrid-pole solution. [Results] Compared with traditional rare-earth permanent magnet motors, the hybrid-pole rotor structure reduced the permanent magnet cost by 15.5% while maintaining the rated torque, decreased the torque ripple by 16.7%, and significantly enhanced the high-temperature demagnetization resistance. [Conclusion] The hybrid-pole rotor structure demonstrates remarkable effectiveness in reducing permanent magnet costs, optimizing motor performance, and improving high-temperature stability, providing reliable technical support for energy-saving, emission reduction, and reduced maintenance requirements in scraper conveyors.
[Objective] Aiming at the issues of high permanent magnet cost, excessive air-gap magnetic field harmonics, and poor high-temperature demagnetization resistance in rare-earth permanent magnet motors for scraper conveyors, this paper proposes a hybrid-pole low-speed permanent magnet synchronous motor (PMSM) excited by both ferrite and NdFeB. The design leverages the advantages of ferrite magnets, such as low cost and strong high-temperature demagnetization resistance, to address these problems. [Methods] The electromagnetic design of the PMSM was first conducted to determine its fundamental parameters. To enhance permanent magnet material utilization, five distinct rotor structures were designed and comparatively analyzed under identical magnet usage conditions, from which the configuration with optimal torque output capability was selected. Subsequently, three hybrid-pole magnetic circuit designs were developed for comparative evaluation. Finally, finite element analysis software was employed to perform comprehensive assessments of the finalized design, including electromagnetic performance analysis, temperature field verification, and high-temperature demagnetization resistance evaluation, thereby validating the effectiveness of the hybrid-pole solution. [Results] Compared with traditional rare-earth permanent magnet motors, the hybrid-pole rotor structure reduced the permanent magnet cost by 15.5% while maintaining the rated torque, decreased the torque ripple by 16.7%, and significantly enhanced the high-temperature demagnetization resistance. [Conclusion] The hybrid-pole rotor structure demonstrates remarkable effectiveness in reducing permanent magnet costs, optimizing motor performance, and improving high-temperature stability, providing reliable technical support for energy-saving, emission reduction, and reduced maintenance requirements in scraper conveyors.
2026,53(6):612-622, DOI: 10.12177/emca.2026.176
Abstract:
[Objective] This study aims to address the issue of electromagnetic vibration and noise caused by complex air-gap electromagnetic force waves in dual-rotor synchronous motor (DRSM) with fractional-slot concentrated windings and low pole-slot numbers. [Methods] The 6-slot stator and 2/4-pole DRSM were selected as the research object to analyze the characteristics and modulation mechanism of electromagnetic force waves under no-load and load conditions. The magnetomotive force and air-gap flux density analytical expressions were derived based on the magnetic potential-permeance method, while the force wave characteristics were theoretically analyzed using Maxwell’s stress tensor method. The finite element model was validated through no-load back-electromotive force experiments, and the time-space spectrum of force waves as well as armature reaction effects were investigated through simulations. For the yoke-less stator design, a tooth shoe structure was developed, and its vibration and noise suppression effectiveness was evaluated via multiphysics field simulations. [Results] The spatial orders of the electromagnetic force waves were found to be multiples of the greatest common divisor of the pole number and slot number, while the temporal frequencies were even multiples of the fundamental frequency. The load current was observed to only alter the amplitude of the force waves without changing their order characteristics. The tooth shoe structure was demonstrated to reduce the amplitude of the first-order magnetic permeability-modulated force waves by 31.01%, with significant attenuation observed in the 4th-order vibration acceleration and high-frequency noise. [Conclusion] The tooth shoe structure effectively suppresses specific-order electromagnetic force waves by modulating the magnetic permeability distribution, providing both theoretical foundations and engineering solutions for vibration and noise reduction in DRSM.
[Objective] This study aims to address the issue of electromagnetic vibration and noise caused by complex air-gap electromagnetic force waves in dual-rotor synchronous motor (DRSM) with fractional-slot concentrated windings and low pole-slot numbers. [Methods] The 6-slot stator and 2/4-pole DRSM were selected as the research object to analyze the characteristics and modulation mechanism of electromagnetic force waves under no-load and load conditions. The magnetomotive force and air-gap flux density analytical expressions were derived based on the magnetic potential-permeance method, while the force wave characteristics were theoretically analyzed using Maxwell’s stress tensor method. The finite element model was validated through no-load back-electromotive force experiments, and the time-space spectrum of force waves as well as armature reaction effects were investigated through simulations. For the yoke-less stator design, a tooth shoe structure was developed, and its vibration and noise suppression effectiveness was evaluated via multiphysics field simulations. [Results] The spatial orders of the electromagnetic force waves were found to be multiples of the greatest common divisor of the pole number and slot number, while the temporal frequencies were even multiples of the fundamental frequency. The load current was observed to only alter the amplitude of the force waves without changing their order characteristics. The tooth shoe structure was demonstrated to reduce the amplitude of the first-order magnetic permeability-modulated force waves by 31.01%, with significant attenuation observed in the 4th-order vibration acceleration and high-frequency noise. [Conclusion] The tooth shoe structure effectively suppresses specific-order electromagnetic force waves by modulating the magnetic permeability distribution, providing both theoretical foundations and engineering solutions for vibration and noise reduction in DRSM.
2026,53(6):623-631, DOI: 10.12177/emca.2026.173
Abstract:
[Objective] To address the stringent requirements of high reliability, strong robustness, and smooth full-speed-range control for underwater thruster drive systems in complex environments, a hybrid high-frequency square-wave injection method/sliding mode observer (HFI/SMO) sensorless control strategy is proposed. [Methods] A dual-mode switching strategy of HFI/SMO was adopted: the HFI was used in the zero/low-speed range, and the SMO based on a phase-locked loop was employed in the medium/high-speed range. Smooth transition was achieved through a weight-switching module. The dynamic and static performance of the proposed algorithm, as well as its engineering practicability, were verified through simulations. [Results] The simulation results demonstrated that the proposed hybrid HFI/SMO control strategy maintained high-precision control across the full speed range. At low speed (200 r/min), the speed fluctuation was maintained within ±5 r/min (±2.5% error). At high speed (3 000 r/min), the fluctuation was constrained within ±8 r/min (±0.27% error), achieving high-precision speed regulation standards. During acceleration from 0 to 3 000 r/min, the maximum tracking error was suppressed below 40 r/min without overshoot, exhibiting superior dynamic tracking performance. [Conclusion] The proposed hybrid HFI/SMO control strategy meets the precise speed regulation requirements of underwater thrusters, providing a practical solution for high-performance sensorless drives.
[Objective] To address the stringent requirements of high reliability, strong robustness, and smooth full-speed-range control for underwater thruster drive systems in complex environments, a hybrid high-frequency square-wave injection method/sliding mode observer (HFI/SMO) sensorless control strategy is proposed. [Methods] A dual-mode switching strategy of HFI/SMO was adopted: the HFI was used in the zero/low-speed range, and the SMO based on a phase-locked loop was employed in the medium/high-speed range. Smooth transition was achieved through a weight-switching module. The dynamic and static performance of the proposed algorithm, as well as its engineering practicability, were verified through simulations. [Results] The simulation results demonstrated that the proposed hybrid HFI/SMO control strategy maintained high-precision control across the full speed range. At low speed (200 r/min), the speed fluctuation was maintained within ±5 r/min (±2.5% error). At high speed (3 000 r/min), the fluctuation was constrained within ±8 r/min (±0.27% error), achieving high-precision speed regulation standards. During acceleration from 0 to 3 000 r/min, the maximum tracking error was suppressed below 40 r/min without overshoot, exhibiting superior dynamic tracking performance. [Conclusion] The proposed hybrid HFI/SMO control strategy meets the precise speed regulation requirements of underwater thrusters, providing a practical solution for high-performance sensorless drives.
2026,53(6):632-643, DOI: 10.12177/emca.2026.179
Abstract:
[Objective] To address the issue of high harmonic content in the air-gap magnetic field and deteriorated induced voltage waveform caused by the traditional constant slot-tooth width ratio structure, this study designs an axial-flux counter-rotating dual-rotor synchronous generator (CR-DRSG) with a stator-radially variable slot-tooth width ratio (S-RVSWR). [Methods] A three-phase 6-slot fractional-slot concentrated winding modular stator was proposed, featuring a variable slot-tooth width ratio structure where the tooth width remained constant and the slot width increased linearly with the stator’s circumferential radius. Distributed-winding rotors with 24 slots were placed on both sides of the stator, with dominant pole pairs of 2 and 4, respectively. The magnetic fields generated by DC excitation of the dual rotors were coupled with the stator’s dominant pole pair fields. The integral cancellation mechanism of non-working harmonic fluxes was derived using the magnetomotive force-permeance model and radial integration theory. The electromagnetic performance of the traditional and new structures was compared and analyzed through three-dimensional finite element simulations and a prototype experiment platform. [Results] The simulation and experimental results demonstrated that the S-RVSWR structure significantly improved the induced voltage waveform, making it closer to a sine wave. Compared to the traditional constant slot-tooth width ratio structure, the total harmonic distortion of the no-load phase voltage (5 Hz) was reduced from 24.31% to 5.20%, with the amplitudes of the 5th, 7th, and 11th harmonics notably decreased. [Conclusion] The structure effectively suppresses low-frequency harmonics in the induced voltage by leveraging the integral cancellation effect generated by the stator’s radial geometric non-uniformity. And the effetiveness of the S-RVSWR design has been verified.
[Objective] To address the issue of high harmonic content in the air-gap magnetic field and deteriorated induced voltage waveform caused by the traditional constant slot-tooth width ratio structure, this study designs an axial-flux counter-rotating dual-rotor synchronous generator (CR-DRSG) with a stator-radially variable slot-tooth width ratio (S-RVSWR). [Methods] A three-phase 6-slot fractional-slot concentrated winding modular stator was proposed, featuring a variable slot-tooth width ratio structure where the tooth width remained constant and the slot width increased linearly with the stator’s circumferential radius. Distributed-winding rotors with 24 slots were placed on both sides of the stator, with dominant pole pairs of 2 and 4, respectively. The magnetic fields generated by DC excitation of the dual rotors were coupled with the stator’s dominant pole pair fields. The integral cancellation mechanism of non-working harmonic fluxes was derived using the magnetomotive force-permeance model and radial integration theory. The electromagnetic performance of the traditional and new structures was compared and analyzed through three-dimensional finite element simulations and a prototype experiment platform. [Results] The simulation and experimental results demonstrated that the S-RVSWR structure significantly improved the induced voltage waveform, making it closer to a sine wave. Compared to the traditional constant slot-tooth width ratio structure, the total harmonic distortion of the no-load phase voltage (5 Hz) was reduced from 24.31% to 5.20%, with the amplitudes of the 5th, 7th, and 11th harmonics notably decreased. [Conclusion] The structure effectively suppresses low-frequency harmonics in the induced voltage by leveraging the integral cancellation effect generated by the stator’s radial geometric non-uniformity. And the effetiveness of the S-RVSWR design has been verified.
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The impact of largescale access of wind farms on the transient stability of power grids could not be ignored. Taking the extended twomachine system with doublyfed wind turbines as an example, the equivalent model of doublyfed induction generator was established, and the twomachine system could be equivalent to a singlemachine infinity system. Based on the law of equal area, the analytic formula of critical clearing angle of the system was deduced in detail after wind power accessed. The analytic formula was used to quantitatively analyze the variation trends of the critical clearing angle with wind power ratio, wind turbine grid connection position, fault location and load access position. The influence laws of the above four factors on the stability of transient power angle were summarized. The simulation models of the extended twomachine system with doublyfed induction generator was established in BPA and FASTEST, and the accuracy of the theoretical analysis was verified.
The impact of largescale access of wind farms on the transient stability of power grids could not be ignored. Taking the extended twomachine system with doublyfed wind turbines as an example, the equivalent model of doublyfed induction generator was established, and the twomachine system could be equivalent to a singlemachine infinity system. Based on the law of equal area, the analytic formula of critical clearing angle of the system was deduced in detail after wind power accessed. The analytic formula was used to quantitatively analyze the variation trends of the critical clearing angle with wind power ratio, wind turbine grid connection position, fault location and load access position. The influence laws of the above four factors on the stability of transient power angle were summarized. The simulation models of the extended twomachine system with doublyfed induction generator was established in BPA and FASTEST, and the accuracy of the theoretical analysis was verified.
Abstract:
Multimotor synchronous and coordinate system was widely used in the field of motor control. The control strategy played a important role in the performance of multimotor synchronization system. Domestic and foreign scholars had conducted deep research, who aimed at the problem of multimotor synchronization.They put forward a variety of synchronization control strategies. The control strategies proposed at home and abroad were reviewed. The accuracy of tracking, robustness and capacity of antiload of the control object were analyzed. The new prospect of multimotor synchronization control was proposed.
Multimotor synchronous and coordinate system was widely used in the field of motor control. The control strategy played a important role in the performance of multimotor synchronization system. Domestic and foreign scholars had conducted deep research, who aimed at the problem of multimotor synchronization.They put forward a variety of synchronization control strategies. The control strategies proposed at home and abroad were reviewed. The accuracy of tracking, robustness and capacity of antiload of the control object were analyzed. The new prospect of multimotor synchronization control was proposed.
Abstract:
Inwheel motor drive technology represents an essential development direction in new energy vehicle drive system. The technical requirements and drive form were introduced. The technical requirements and drive form of inwheel motor drive were summarized. Current research situation of inwheel motor drive technology was compared and analyzed briefly. The key technique problems of inwheel motor technology were proposed. The essential technologies in descreasing unsprung mass, restraining vertical vibration effect and reducing torque ripple of inwheel motor were discussed, which were supposed to be solved urgently. The development trend of inwheel motor drive technology was predicted.
Inwheel motor drive technology represents an essential development direction in new energy vehicle drive system. The technical requirements and drive form were introduced. The technical requirements and drive form of inwheel motor drive were summarized. Current research situation of inwheel motor drive technology was compared and analyzed briefly. The key technique problems of inwheel motor technology were proposed. The essential technologies in descreasing unsprung mass, restraining vertical vibration effect and reducing torque ripple of inwheel motor were discussed, which were supposed to be solved urgently. The development trend of inwheel motor drive technology was predicted.
2024,51(9):70-79, DOI: 10.12177/emca.2024.090
Abstract:
To address the issue of high torque ripple in permanent magnet assisted synchronous reluctance motor (PMA-SynRM), a multi-objective optimization design method based on the non-dominated sorting genetic algorithm II (NSGA-II) was proposed. First, the basic structure and working principle of the PMA-SynRM were introduced. Next, the rotor structure of the PMA-SynRM was improved by constructing air barriers and designing asymmetric auxiliary slots. Then, sensitivity analysis was conducted to identify the parameters that had the most significant impact on the optimization objectives of the PMA-SynRM, and multi-objective optimization was performed using NSGA-II. The optimal topology was selected from the generated Pareto front. Finally, the torque performance of the optimized motor was compared with that of the initial motor using finite element analysis software. Simulation results showed that the performance of the PMA-SynRM optimized through NSGA-II was significantly improved.
To address the issue of high torque ripple in permanent magnet assisted synchronous reluctance motor (PMA-SynRM), a multi-objective optimization design method based on the non-dominated sorting genetic algorithm II (NSGA-II) was proposed. First, the basic structure and working principle of the PMA-SynRM were introduced. Next, the rotor structure of the PMA-SynRM was improved by constructing air barriers and designing asymmetric auxiliary slots. Then, sensitivity analysis was conducted to identify the parameters that had the most significant impact on the optimization objectives of the PMA-SynRM, and multi-objective optimization was performed using NSGA-II. The optimal topology was selected from the generated Pareto front. Finally, the torque performance of the optimized motor was compared with that of the initial motor using finite element analysis software. Simulation results showed that the performance of the PMA-SynRM optimized through NSGA-II was significantly improved.
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Electric Machines & Control Application ® 2026
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沪ICP备16038578号-3
Electric Machines & Control Application ® 2026
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
