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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(10):993-1004, DOI: 10.12177/emca.2026.232
Abstract:
[Objective] To address the issues in traditional flux-weakening control for electric vehicle two-phase motor drives—limited power in the flux-weakening region, decreased motor output torque as speed increases, and increased system volume and cost caused by a front-end Boost circuit—this paper proposes an integrated circuit scheme that combines a Boost converter and a two-phase half-bridge inverter based on three-phase bridge multiplexing. [Methods] To meet the wide-speed-range operation requirements of the motor drive system for electric vehicles, the working mechanisms of the Boost circuit and the two-phase half-bridge inverter circuit were analyzed, and a system topology based on three-phase bridge multiplexing was proposed and constructed. Based on this, the key parameter design and control algorithm design were carried out, and the proposed scheme was verified by combining modeling simulation with theoretical comparison. [Results] The results showed that the proposed scheme effectively improved the DC voltage utilization and achieved the integrated coordination of boost and drive functions with only a slight increase in system volume and cost. Without reducing the output torque, the motor speed regulation range was expanded by 36.08%, which verified the effectiveness of the scheme in wide-speed-range operation. [Conclusion] The proposed scheme effectively balances the requirements of wide-speed-range performance, system cost, and structural integration, providing a feasible technical path for the low-cost and highly integrated wide-speed-range implementation of electric vehicle motor drive systems, and possesses certain theoretical significance and engineering application value.
[Objective] To address the issues in traditional flux-weakening control for electric vehicle two-phase motor drives—limited power in the flux-weakening region, decreased motor output torque as speed increases, and increased system volume and cost caused by a front-end Boost circuit—this paper proposes an integrated circuit scheme that combines a Boost converter and a two-phase half-bridge inverter based on three-phase bridge multiplexing. [Methods] To meet the wide-speed-range operation requirements of the motor drive system for electric vehicles, the working mechanisms of the Boost circuit and the two-phase half-bridge inverter circuit were analyzed, and a system topology based on three-phase bridge multiplexing was proposed and constructed. Based on this, the key parameter design and control algorithm design were carried out, and the proposed scheme was verified by combining modeling simulation with theoretical comparison. [Results] The results showed that the proposed scheme effectively improved the DC voltage utilization and achieved the integrated coordination of boost and drive functions with only a slight increase in system volume and cost. Without reducing the output torque, the motor speed regulation range was expanded by 36.08%, which verified the effectiveness of the scheme in wide-speed-range operation. [Conclusion] The proposed scheme effectively balances the requirements of wide-speed-range performance, system cost, and structural integration, providing a feasible technical path for the low-cost and highly integrated wide-speed-range implementation of electric vehicle motor drive systems, and possesses certain theoretical significance and engineering application value.
2026,53(10):1005-1017, DOI: 10.12177/emca.2026.225
Abstract:
[Objective] To address the problem that traditional single grid-following (GFL) or grid-forming (GFM) control is difficult to adapt to under alternating strong and weak grid conditions in doubly-high power systems, a grid impedance identification-based GFL/GFM switching control strategy is proposed. [Methods] Grid strength was monitored and the short-circuit ratio (SCR) was determined by using a grid impedance identification technique based on specific harmonic extraction. A hysteresis switching loop was set up: GFM control was adopted when SCR was less than 2, GFL control was adopted when SCR was greater than 3, and the original control mode was maintained within 2≤SCR≤3 to avoid frequent switching in the critical interval. Transient impacts during mode switching were eliminated through a steady-state operating point pre-matching strategy, which compensated the power reference values and initial virtual excitation values. Finally, simulation verification was carried out using Matlab/Simulink. [Results] During the alternating variation of strong and weak grid conditions, the proposed strategy accomplished bidirectional switching between GFM and GFL control based on online identification results. At the switching instant, no significant step occurred in the point of common coupling voltage, and the current only exhibited short-term disturbance before rapidly recovering to steady state, with no sustained oscillation in active and reactive power. Comparison results with different switching methods further indicated that steady-state operating point pre-matching mitigated current impacts during the switching process and rendered the mode transition smoother. [Conclusion] This strategy integrates the technical advantages of GFL and GFM control. It can realize GFL/GFM switching control according to changes in grid strength, and reduces the voltage, current, and power impacts during mode switching through steady-state operating point pre-matching, thereby improving the operational adaptability and switching stability of the power conversion system under dynamically varying strong and weak grid conditions.
[Objective] To address the problem that traditional single grid-following (GFL) or grid-forming (GFM) control is difficult to adapt to under alternating strong and weak grid conditions in doubly-high power systems, a grid impedance identification-based GFL/GFM switching control strategy is proposed. [Methods] Grid strength was monitored and the short-circuit ratio (SCR) was determined by using a grid impedance identification technique based on specific harmonic extraction. A hysteresis switching loop was set up: GFM control was adopted when SCR was less than 2, GFL control was adopted when SCR was greater than 3, and the original control mode was maintained within 2≤SCR≤3 to avoid frequent switching in the critical interval. Transient impacts during mode switching were eliminated through a steady-state operating point pre-matching strategy, which compensated the power reference values and initial virtual excitation values. Finally, simulation verification was carried out using Matlab/Simulink. [Results] During the alternating variation of strong and weak grid conditions, the proposed strategy accomplished bidirectional switching between GFM and GFL control based on online identification results. At the switching instant, no significant step occurred in the point of common coupling voltage, and the current only exhibited short-term disturbance before rapidly recovering to steady state, with no sustained oscillation in active and reactive power. Comparison results with different switching methods further indicated that steady-state operating point pre-matching mitigated current impacts during the switching process and rendered the mode transition smoother. [Conclusion] This strategy integrates the technical advantages of GFL and GFM control. It can realize GFL/GFM switching control according to changes in grid strength, and reduces the voltage, current, and power impacts during mode switching through steady-state operating point pre-matching, thereby improving the operational adaptability and switching stability of the power conversion system under dynamically varying strong and weak grid conditions.
2026,53(10):1018-1027, DOI: 10.12177/emca.2026.229
Abstract:
[Objective] To address the output voltage fluctuation problem of voltage-source inverters during load step-up and step-down transients and break through the core bottleneck of insufficient dynamic response capability and stability, this paper introduces a voltage-current feedforward control method, aiming to effectively suppress voltage fluctuations and improve the overall system performance. [Methods] Firstly, an accurate mathematical model of the three-phase three-level full-bridge inverter was established. Secondly, the proportional-integral parameters of the traditional feedback control were designed with the expected bandwidth and phase margin as constraints. Then, the voltage-current feedforward control was introduced, and the optimal feedforward coefficient was derived using Bode plots and pole-zero distribution analysis. Finally, the effectiveness of the proposed method was verified through simulations and experiments. [Results] Simulation and experimental results indicated that after introducing the feedforward control, the output voltage fluctuation during load step-up and step-down transients were significantly reduced, and both the dynamic response speed and operational stability were effectively improved, leading to a notable enhancement in the overall system performance. [Conclusion] The proposed voltage-current feedforward control design method is correct and feasible, with clear physical significance and strong engineering operability, providing a referable idea for the forward design of control parameters in similar inverters.
[Objective] To address the output voltage fluctuation problem of voltage-source inverters during load step-up and step-down transients and break through the core bottleneck of insufficient dynamic response capability and stability, this paper introduces a voltage-current feedforward control method, aiming to effectively suppress voltage fluctuations and improve the overall system performance. [Methods] Firstly, an accurate mathematical model of the three-phase three-level full-bridge inverter was established. Secondly, the proportional-integral parameters of the traditional feedback control were designed with the expected bandwidth and phase margin as constraints. Then, the voltage-current feedforward control was introduced, and the optimal feedforward coefficient was derived using Bode plots and pole-zero distribution analysis. Finally, the effectiveness of the proposed method was verified through simulations and experiments. [Results] Simulation and experimental results indicated that after introducing the feedforward control, the output voltage fluctuation during load step-up and step-down transients were significantly reduced, and both the dynamic response speed and operational stability were effectively improved, leading to a notable enhancement in the overall system performance. [Conclusion] The proposed voltage-current feedforward control design method is correct and feasible, with clear physical significance and strong engineering operability, providing a referable idea for the forward design of control parameters in similar inverters.
2026,53(10):1028-1038, DOI: 10.12177/emca.2026.223
Abstract:
[Objective] To address the issues of large generator-side torque ripple and significant DC-bus voltage fluctuation in small off-grid vertical-axis wind turbine systems under variable wind speeds and load disturbances, a cooperative control strategy based on super-twisting algorithm direct torque control, space vector pulse width modulation (STA-SVPWM-DTC), and DC/DC voltage regulation is proposed, which simultaneously suppresses torque ripple and stabilizes the DC-bus voltage. [Methods] A hierarchical decoupling control approach was adopted, dividing the system into two main modules: generator-side rectification and DC-link voltage stabilization. For the generator-side control, a composite sliding manifold was constructed using stator flux error and electromagnetic torque error. A super-twisting sliding mode control (STSMC) was utilized to output a continuous and smooth control signal, which drove the generator-side PWM rectifier via SVPWM, thereby eliminating the high-frequency torque ripple caused by the hysteresis-based discrete switching in conventional DTC. On the DC-link side, a dual-loop DC/DC voltage regulation architecture was built with a voltage outer loop cascaded with an inductor current inner loop. An independent voltage regulation loop was used to block the transmission of load-side power fluctuations to the generator side, attenuating the reverse coupling interference between the two control channels. [Results] To verify the performance of the proposed strategy, multiple sets of simulation conditions and physical load experiments were set up for comparative testing. Under the step wind speed condition where the wind speed decreased from 12 m/s to 7 m/s, simulation results showed that, compared with the conventional DTC, the proposed STA-SVPWM-DTC and DC/DC coordinated control method reduced the peak-to-peak electromagnetic torque from 1.35 N·m to 0.4~0.5 N·m, a decrease of 60~70%. Under step wind speed, combined wind speed, and 10 Ω load experimetal conditions, the DC bus voltage was stabilized near 12 V, and the voltage and current ripples were significantly reduced. [Conclusion] The proposed STA-SVPWM-DTC and DC/DC coordinated control strategy improves the torque smoothness and DC output stability of small off-grid vertical-axis wind power systems, and provides a feasible control scheme for the stable operation of off-grid wind power supply systems.
[Objective] To address the issues of large generator-side torque ripple and significant DC-bus voltage fluctuation in small off-grid vertical-axis wind turbine systems under variable wind speeds and load disturbances, a cooperative control strategy based on super-twisting algorithm direct torque control, space vector pulse width modulation (STA-SVPWM-DTC), and DC/DC voltage regulation is proposed, which simultaneously suppresses torque ripple and stabilizes the DC-bus voltage. [Methods] A hierarchical decoupling control approach was adopted, dividing the system into two main modules: generator-side rectification and DC-link voltage stabilization. For the generator-side control, a composite sliding manifold was constructed using stator flux error and electromagnetic torque error. A super-twisting sliding mode control (STSMC) was utilized to output a continuous and smooth control signal, which drove the generator-side PWM rectifier via SVPWM, thereby eliminating the high-frequency torque ripple caused by the hysteresis-based discrete switching in conventional DTC. On the DC-link side, a dual-loop DC/DC voltage regulation architecture was built with a voltage outer loop cascaded with an inductor current inner loop. An independent voltage regulation loop was used to block the transmission of load-side power fluctuations to the generator side, attenuating the reverse coupling interference between the two control channels. [Results] To verify the performance of the proposed strategy, multiple sets of simulation conditions and physical load experiments were set up for comparative testing. Under the step wind speed condition where the wind speed decreased from 12 m/s to 7 m/s, simulation results showed that, compared with the conventional DTC, the proposed STA-SVPWM-DTC and DC/DC coordinated control method reduced the peak-to-peak electromagnetic torque from 1.35 N·m to 0.4~0.5 N·m, a decrease of 60~70%. Under step wind speed, combined wind speed, and 10 Ω load experimetal conditions, the DC bus voltage was stabilized near 12 V, and the voltage and current ripples were significantly reduced. [Conclusion] The proposed STA-SVPWM-DTC and DC/DC coordinated control strategy improves the torque smoothness and DC output stability of small off-grid vertical-axis wind power systems, and provides a feasible control scheme for the stable operation of off-grid wind power supply systems.
2026,53(10):1039-1052, DOI: 10.12177/emca.2026.231
Abstract:
[Objective] To address the transition issue during the switching process of an power conversion system from off-grid mode to grid-connected mode, this paper studies a pre-synchronization strategy based on virtual synchronous generator (VSG) control. [Methods] Detailed dynamic mathematical models were established for the off-grid operation mode, the pre-synchronization control mode, and the grid-connected operation mode, respectively. Before the grid-connection transition, a pre-synchronization link was introduced to compensate for the voltage amplitude and phase deviations between the inverter output and the grid bus. After incorporating the pre-synchronization proportional-integral (PI) regulator into the original off-grid model, the overall order of the system’s mathematical model was increased from the original second order to third order. The Routh stability criterion was applied to analyze the system stability, and feasible selection guidelines for the control parameters in the pre-synchronization control loop were provided. Furthermore, the root locus method was adopted to investigate the variation of the closed-loop system’s root locus with key parameters after the addition of pre-synchronization control. The considered parameters included virtual inertia, damping coefficient, and the proportional and integral gains of the pre-synchronization control. By analyzing the intersection points of the root loci with the imaginary axis and the movement trends of the dominant pole pairs, the influences of each parameter on system stability and response speed were systematically summarized. [Results] The research results indicated that during the pre-synchronization control process, the inertia time constant of the VSG had a relatively limited impact on the response speed. In contrast, the damping coefficient, along with the proportional and integral gains of the pre-synchronization PI controller, constituted the key factors determining the quality of the system’s dynamic response. The simulation scenarios systematically covered typical operating conditions under different combinations of virtual inertia, damping coefficients, and pre-synchronization PI parameters. The simulation results not only confirmed that the virtual inertia had a weak influence on response speed, but also quantitatively demonstrated the regulation effects of damping and PI parameters on response time, overshoot, and other performance metrics. [Conclusion] The theoretical models and analytical methods established in this paper provide a theoretical basis and practical guidance for the engineering parameter tuning of smooth grid-connection control strategies for microgrids.
[Objective] To address the transition issue during the switching process of an power conversion system from off-grid mode to grid-connected mode, this paper studies a pre-synchronization strategy based on virtual synchronous generator (VSG) control. [Methods] Detailed dynamic mathematical models were established for the off-grid operation mode, the pre-synchronization control mode, and the grid-connected operation mode, respectively. Before the grid-connection transition, a pre-synchronization link was introduced to compensate for the voltage amplitude and phase deviations between the inverter output and the grid bus. After incorporating the pre-synchronization proportional-integral (PI) regulator into the original off-grid model, the overall order of the system’s mathematical model was increased from the original second order to third order. The Routh stability criterion was applied to analyze the system stability, and feasible selection guidelines for the control parameters in the pre-synchronization control loop were provided. Furthermore, the root locus method was adopted to investigate the variation of the closed-loop system’s root locus with key parameters after the addition of pre-synchronization control. The considered parameters included virtual inertia, damping coefficient, and the proportional and integral gains of the pre-synchronization control. By analyzing the intersection points of the root loci with the imaginary axis and the movement trends of the dominant pole pairs, the influences of each parameter on system stability and response speed were systematically summarized. [Results] The research results indicated that during the pre-synchronization control process, the inertia time constant of the VSG had a relatively limited impact on the response speed. In contrast, the damping coefficient, along with the proportional and integral gains of the pre-synchronization PI controller, constituted the key factors determining the quality of the system’s dynamic response. The simulation scenarios systematically covered typical operating conditions under different combinations of virtual inertia, damping coefficients, and pre-synchronization PI parameters. The simulation results not only confirmed that the virtual inertia had a weak influence on response speed, but also quantitatively demonstrated the regulation effects of damping and PI parameters on response time, overshoot, and other performance metrics. [Conclusion] The theoretical models and analytical methods established in this paper provide a theoretical basis and practical guidance for the engineering parameter tuning of smooth grid-connection control strategies for microgrids.
2026,53(10):1053-1061, DOI: 10.12177/emca.2026.224
Abstract:
[Objective] To address the issues of poor steady-state control performance and stagnation of current increment updates in the model-free predictive current control (MFPCC) for permanent magnet synchronous motor, an improved MFPCC method based on discrete space vector modulation (DSVM) is proposed. [Methods] Firstly, DSVM technology was introduced to expand the voltage vector set. By dividing one control cycle into three equal segments to synthesize 37 virtual voltage vectors, the steady-state control performance of the system was effectively enhanced. Secondly, by defining unit voltage vectors and representing the voltage vector in a coordinate form, the current increment update was transformed into unit current increment establishment, thereby resolving the issue of current increment update stagnation in traditional methods. Furthermore, the theoretical coordinate range of the optimal voltage vector was analytically derived using the reference current increment to achieve voltage vector pre-screening, reducing the candidate vectors from 37 to 4. This significantly mitigated the sharp increase in computational burden caused by evaluating all voltage vectors. Finally, systematic experimental validation was conducted on a 2 kW experimental platform to verify the feasibility and effectiveness of the proposed method. [Results] Experimental results demonstrated that, compared with conventional MFPCC, the proposed method reduced the dq-axis current ripple from 5.4 A and 5.0 A to 3.1 A and 3.0 A under steady-state conditions at 900 r/min and 5 N·m load. The phase current total harmonic distortion was reduced from 17.36% to 7.43%, and torque ripple was effectively suppressed. Under dynamic conditions with speed stepping from 500 r/min to 1 000 r/min, the dynamic adjustment time was approximately 60 ms, which was comparable to that of traditional MFPCC. The execution time of the proposed method was 29.5 μs, only 1.9 μs longer than that of traditional MFPCC, supporting inverter switching frequencies up to 30 kHz. [Conclusion] The proposed improved MFPCC effectively enhances the steady-state performance of the MFPCC while maintaining low computational load.
[Objective] To address the issues of poor steady-state control performance and stagnation of current increment updates in the model-free predictive current control (MFPCC) for permanent magnet synchronous motor, an improved MFPCC method based on discrete space vector modulation (DSVM) is proposed. [Methods] Firstly, DSVM technology was introduced to expand the voltage vector set. By dividing one control cycle into three equal segments to synthesize 37 virtual voltage vectors, the steady-state control performance of the system was effectively enhanced. Secondly, by defining unit voltage vectors and representing the voltage vector in a coordinate form, the current increment update was transformed into unit current increment establishment, thereby resolving the issue of current increment update stagnation in traditional methods. Furthermore, the theoretical coordinate range of the optimal voltage vector was analytically derived using the reference current increment to achieve voltage vector pre-screening, reducing the candidate vectors from 37 to 4. This significantly mitigated the sharp increase in computational burden caused by evaluating all voltage vectors. Finally, systematic experimental validation was conducted on a 2 kW experimental platform to verify the feasibility and effectiveness of the proposed method. [Results] Experimental results demonstrated that, compared with conventional MFPCC, the proposed method reduced the dq-axis current ripple from 5.4 A and 5.0 A to 3.1 A and 3.0 A under steady-state conditions at 900 r/min and 5 N·m load. The phase current total harmonic distortion was reduced from 17.36% to 7.43%, and torque ripple was effectively suppressed. Under dynamic conditions with speed stepping from 500 r/min to 1 000 r/min, the dynamic adjustment time was approximately 60 ms, which was comparable to that of traditional MFPCC. The execution time of the proposed method was 29.5 μs, only 1.9 μs longer than that of traditional MFPCC, supporting inverter switching frequencies up to 30 kHz. [Conclusion] The proposed improved MFPCC effectively enhances the steady-state performance of the MFPCC while maintaining low computational load.
2026,53(10):1062-1072, DOI: 10.12177/emca.2026.221
Abstract:
[Objective] To address the issue of low position estimation accuracy in sensorless permanent magnet synchronous motor control systems under complex signal interference environments, this paper proposes an adaptive-bandwidth linear active disturbance rejection control (AB-LADRC) strategy. [Methods] Firstly, a multi-source disturbance error model incorporating current sampling noise, quantization errors, and zero-drift was established to explicitly quantify system uncertainties. Secondly, a phase-locked loop closed-loop architecture based on a third-order linear extended state observer was constructed to dynamically observe and actively compensate for the aggregated disturbances. Furthermore, a bandwidth separation filtering strategy was introduced to suppress high-frequency noise amplification. Additionally, an adaptive bandwidth adjustment mechanism was designed to enable the dynamic optimization of observation parameters based on real-time operating states. [Results] The experimental results indicated that, compared with the conventional phase-locked loop strategy, the proposed AB-LADRC strategy limited the speed dip to only 7 r/min during load transient and shortened the recovery time to within 40 ms. Furthermore, under strong noise conditions, the root mean square error of speed estimation decreased by 69.5%. With 12-bit low-resolution sampling, the speed ripple was strictly limited to within ±1.59 r/min. Meanwhile, the amplitude of subharmonic low-frequency pulsation caused by zero-point drift attenuated by 78%. [Conclusion] By decoupling the control dynamics from external noise, the strategy significantly enhances the system’s noise-rejection robustness and high-precision servo performance under harsh operating conditions.
[Objective] To address the issue of low position estimation accuracy in sensorless permanent magnet synchronous motor control systems under complex signal interference environments, this paper proposes an adaptive-bandwidth linear active disturbance rejection control (AB-LADRC) strategy. [Methods] Firstly, a multi-source disturbance error model incorporating current sampling noise, quantization errors, and zero-drift was established to explicitly quantify system uncertainties. Secondly, a phase-locked loop closed-loop architecture based on a third-order linear extended state observer was constructed to dynamically observe and actively compensate for the aggregated disturbances. Furthermore, a bandwidth separation filtering strategy was introduced to suppress high-frequency noise amplification. Additionally, an adaptive bandwidth adjustment mechanism was designed to enable the dynamic optimization of observation parameters based on real-time operating states. [Results] The experimental results indicated that, compared with the conventional phase-locked loop strategy, the proposed AB-LADRC strategy limited the speed dip to only 7 r/min during load transient and shortened the recovery time to within 40 ms. Furthermore, under strong noise conditions, the root mean square error of speed estimation decreased by 69.5%. With 12-bit low-resolution sampling, the speed ripple was strictly limited to within ±1.59 r/min. Meanwhile, the amplitude of subharmonic low-frequency pulsation caused by zero-point drift attenuated by 78%. [Conclusion] By decoupling the control dynamics from external noise, the strategy significantly enhances the system’s noise-rejection robustness and high-precision servo performance under harsh operating conditions.
2026,53(10):1073-1084, DOI: 10.12177/emca.2026.227
Abstract:
[Objective] To address the issues of speed fluctuation, additional load disturbance, and insufficient driving robustness in airport roller serpentine conveyor vehicles during large-inclination ramp conveying, this paper takes a single electric drum drive unit as the object and proposes a composite anti-disturbance control method based on parameter scheduling and feedforward-observer for permanent magnet synchronous motor (PMSM). [Methods] Firstly, the medium-speed operating condition was determined based on the drum diameter and the engineering conveying speed range, and a vector control model for the single-drum PMSM was established. Secondly, an equivalent ramp load model related to the slope angle was constructed, and the proportional-integral (PI) parameters of the speed loop were designed with the slope angle θ as the scheduling variable, enabling the controller gain to be adaptively adjusted with the inclination angle. Then, the calculable ramp load was compensated into the q-axis current command through gravity feedforward to reduce the feedback regulation pressure on the speed loop. Finally, for the unknown additional disturbances remaining after feedforward compensation, a residual compensation structure of a direction-adaptive sliding mode disturbance observer (SMDO) was constructed, and effective q-axis compensation current was generated through disturbance estimation bias correction, slope-direction gain adjustment, and compensation current limiting. [Results] The simulation results indicated that under the variable-inclination conditions of 0°→8°→16°→24° uphill and 0°→-8°→-16°→-24° downhill, the maximum speed deviation was reduced by the parameter-scheduled field-oriented control (FOC) compared with the fixed-parameter FOC, and the improvement became more obvious with the increase of the inclination angle. Under the condition of ±24° ramp, the speed deviation was significantly decreased and the output burden of the speed loop PI was greatly reduced by the gravity feedforward. When unknown additional disturbances were superimposed, the speed drop under uphill resistance disturbance and the speed overshoot under downhill assistance disturbance were respectively reduced by the direction-adaptive SMDO residual compensation. [Conclusion] The proposed composite anti-disturbance control method based on parameter scheduling and feedforward-observer improves the speed maintenance capability of the single-drum drive unit under variable-inclination angles and additional disturbances, and provides an executive-layer control foundation for subsequent research on multi-drum coordinated control.
[Objective] To address the issues of speed fluctuation, additional load disturbance, and insufficient driving robustness in airport roller serpentine conveyor vehicles during large-inclination ramp conveying, this paper takes a single electric drum drive unit as the object and proposes a composite anti-disturbance control method based on parameter scheduling and feedforward-observer for permanent magnet synchronous motor (PMSM). [Methods] Firstly, the medium-speed operating condition was determined based on the drum diameter and the engineering conveying speed range, and a vector control model for the single-drum PMSM was established. Secondly, an equivalent ramp load model related to the slope angle was constructed, and the proportional-integral (PI) parameters of the speed loop were designed with the slope angle θ as the scheduling variable, enabling the controller gain to be adaptively adjusted with the inclination angle. Then, the calculable ramp load was compensated into the q-axis current command through gravity feedforward to reduce the feedback regulation pressure on the speed loop. Finally, for the unknown additional disturbances remaining after feedforward compensation, a residual compensation structure of a direction-adaptive sliding mode disturbance observer (SMDO) was constructed, and effective q-axis compensation current was generated through disturbance estimation bias correction, slope-direction gain adjustment, and compensation current limiting. [Results] The simulation results indicated that under the variable-inclination conditions of 0°→8°→16°→24° uphill and 0°→-8°→-16°→-24° downhill, the maximum speed deviation was reduced by the parameter-scheduled field-oriented control (FOC) compared with the fixed-parameter FOC, and the improvement became more obvious with the increase of the inclination angle. Under the condition of ±24° ramp, the speed deviation was significantly decreased and the output burden of the speed loop PI was greatly reduced by the gravity feedforward. When unknown additional disturbances were superimposed, the speed drop under uphill resistance disturbance and the speed overshoot under downhill assistance disturbance were respectively reduced by the direction-adaptive SMDO residual compensation. [Conclusion] The proposed composite anti-disturbance control method based on parameter scheduling and feedforward-observer improves the speed maintenance capability of the single-drum drive unit under variable-inclination angles and additional disturbances, and provides an executive-layer control foundation for subsequent research on multi-drum coordinated control.
2026,53(10):1085-1094, DOI: 10.12177/emca.2026.228
Abstract:
[Objective] To address the problem of high costs in manufacturing new energy vehicle drive motors caused by the scarcity and high price of rare earth materials, this study aims to reduce manufacturing costs by using low-cost ferrite materials to replace some of the neodymium iron boron permanent magnets. [Methods] Taking the U-shaped interior permanent magnet drive motor of an electric bus as the research object, three types of hybrid permanent magnet rotor structures combining neodymium iron boron and ferrite were designed. The finite element method was used to analyze the influence of different permanent magnet arrangements on the motor’s output torque, reluctance torque performance, and air-gap flux density distortion, and an asymmetric magnetic pole arrangement structure with obvious advantages in reluctance torque and output torque was selected. On the premise of unchanged permanent magnet usage, multi-parameter optimization was performed on the permanent magnet angle, distance, and magnetic bridge spacing. Finally, used an existing 110 kW neodymium iron boron prototype, the motor’s back electromotive force and torque-current characteristics were tested, and the measured data were compared with the simulation data. [Results] Compared with other arrangements, the single-pole asymmetric and two-pole symmetric magnetic pole arrangement structure achieves higher reluctance torque and output torque. After multi-parameter optimization, the motor’s output torque improved by 4.4% and the reluctance torque increased by 2.5%. The experimentally measured back-electromotive force and torque-current characteristics of the prototype shows a high degree of agreement with the finite element simulation values. [Conclusion] This solution partially replaces neodymium iron boron permanent magnets, which effectively reduces the manufacturing cost of the motor. At the same time, through multi-parameter optimization of various magnetic pole arrangement structures, such as single-pole asymmetric and two-pole symmetric structures, it achieves improved torque performance without increasing the amount of permanent magnet material used. Furthermore, experimental tests on an existing prototype verify the correctness and accuracy of the finite element simulation calculation method used in this paper.
[Objective] To address the problem of high costs in manufacturing new energy vehicle drive motors caused by the scarcity and high price of rare earth materials, this study aims to reduce manufacturing costs by using low-cost ferrite materials to replace some of the neodymium iron boron permanent magnets. [Methods] Taking the U-shaped interior permanent magnet drive motor of an electric bus as the research object, three types of hybrid permanent magnet rotor structures combining neodymium iron boron and ferrite were designed. The finite element method was used to analyze the influence of different permanent magnet arrangements on the motor’s output torque, reluctance torque performance, and air-gap flux density distortion, and an asymmetric magnetic pole arrangement structure with obvious advantages in reluctance torque and output torque was selected. On the premise of unchanged permanent magnet usage, multi-parameter optimization was performed on the permanent magnet angle, distance, and magnetic bridge spacing. Finally, used an existing 110 kW neodymium iron boron prototype, the motor’s back electromotive force and torque-current characteristics were tested, and the measured data were compared with the simulation data. [Results] Compared with other arrangements, the single-pole asymmetric and two-pole symmetric magnetic pole arrangement structure achieves higher reluctance torque and output torque. After multi-parameter optimization, the motor’s output torque improved by 4.4% and the reluctance torque increased by 2.5%. The experimentally measured back-electromotive force and torque-current characteristics of the prototype shows a high degree of agreement with the finite element simulation values. [Conclusion] This solution partially replaces neodymium iron boron permanent magnets, which effectively reduces the manufacturing cost of the motor. At the same time, through multi-parameter optimization of various magnetic pole arrangement structures, such as single-pole asymmetric and two-pole symmetric structures, it achieves improved torque performance without increasing the amount of permanent magnet material used. Furthermore, experimental tests on an existing prototype verify the correctness and accuracy of the finite element simulation calculation method used in this paper.
2026,53(10):1095-1115, DOI: 10.12177/emca.2026.233
Abstract:
[Objective] To address the issues of low-speed integral drift, high-speed parameter mismatch, and insufficient robustness of the traditional hybrid model flux observer (HMFO) in surface-mounted permanent magnet synchronous motors for new energy buses under complex operating conditions such as sudden load changes and wide-speed-range operation, this study proposes an improved HMFO control strategy that integrates closed-loop sliding mode correction and feedforward extended state observer (ESO) compensation. [Methods] Under the voltage-current hybrid model architecture, a compensated first-order low-pass filter cascaded with a high-pass filter was first employed to replace the pure integrator for the elimination of DC bias and integral saturation. Secondly, a closed-loop feedback with the active flux linkage difference between the two models as the sliding surface was constructed, and the error was driven to converge in finite time by using sliding mode control. Finally, an ESO was introduced to compensate for parameter perturbations and load disturbances in a feedforward manner, which effectively suppressed sliding mode chattering and improved steady-state observation accuracy. [Results] Simulation results showed that under sudden load change and speed step conditions, the peak speed errors of the improved HMFO converged to ±0.4 r/min and ±0.6 r/min, respectively, and the dynamic adjustment times were compressed to within 4 ms and 10 ms, respectively. The transient error peaks of the position angle were reduced to below 1.6×10-5 rad and 2.5×10-5 rad, respectively. No obvious high-frequency chattering was observed in the steady-state error, and the observation stability was significantly superior to that of the traditional scheme. [Conclusion] The strategy successfully balances high dynamic response and strong robustness, effectively overcoming the integral drift and saturation problems of traditional HMFO. Simulation results preliminarily verify the application potential of this method under complex operating conditions of new energy buses.
[Objective] To address the issues of low-speed integral drift, high-speed parameter mismatch, and insufficient robustness of the traditional hybrid model flux observer (HMFO) in surface-mounted permanent magnet synchronous motors for new energy buses under complex operating conditions such as sudden load changes and wide-speed-range operation, this study proposes an improved HMFO control strategy that integrates closed-loop sliding mode correction and feedforward extended state observer (ESO) compensation. [Methods] Under the voltage-current hybrid model architecture, a compensated first-order low-pass filter cascaded with a high-pass filter was first employed to replace the pure integrator for the elimination of DC bias and integral saturation. Secondly, a closed-loop feedback with the active flux linkage difference between the two models as the sliding surface was constructed, and the error was driven to converge in finite time by using sliding mode control. Finally, an ESO was introduced to compensate for parameter perturbations and load disturbances in a feedforward manner, which effectively suppressed sliding mode chattering and improved steady-state observation accuracy. [Results] Simulation results showed that under sudden load change and speed step conditions, the peak speed errors of the improved HMFO converged to ±0.4 r/min and ±0.6 r/min, respectively, and the dynamic adjustment times were compressed to within 4 ms and 10 ms, respectively. The transient error peaks of the position angle were reduced to below 1.6×10-5 rad and 2.5×10-5 rad, respectively. No obvious high-frequency chattering was observed in the steady-state error, and the observation stability was significantly superior to that of the traditional scheme. [Conclusion] The strategy successfully balances high dynamic response and strong robustness, effectively overcoming the integral drift and saturation problems of traditional HMFO. Simulation results preliminarily verify the application potential of this method under complex operating conditions of new energy buses.
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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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Electric Machines & Control Application ® 2026
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
