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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 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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2025,52(6):585-595, DOI: 10.12177/emca.2025.043
Abstract:
Abstract: [Objective] To achieve high-precision identification of mechanical faults in disconnectors, a parallel hybrid network incorporating attention mechanisms is proposed, which combines temporal and image features for intelligent diagnosis. [Methods] To fully exploit the feature information of dual-channel data, a bidirectional long short-term memory network was employed in the temporal channel to extract time-domain features from vibration signals, capturing the dynamic temporal variations of the signal and effectively reflecting the time-varying characteristics of mechanical faults. In the image channel, vibration signals were converted into two-dimensional images using Gramian angular fields, where polar coordinate mapping was utilized to preserve the temporal dynamics. A convolutional neural network was then used to extract key image features. Furthermore, a self-attention mechanism was introduced in the temporal channel and a channel attention mechanism in the image channel, enabling the model to adaptively adjust the weight of each channel, thereby emphasizing critical information and effectively reducing feature redundancy. [Results] Fault simulation experiments were conducted on GW4-126 type disconnectors, and vibration signals under four operating conditions were collected. The proposed method was compared with five other deep learning models. Experimental results demonstrated that the proposed method achieves a fault recognition accuracy exceeding 97%, effectively identifying typical mechanical faults such as mechanism jamming, looseness, and phase asynchrony. [Conclusion] The proposed parallel hybrid model overcomes the limitations of single-channel approaches by integrating two distinct types of feature information. The introduction of attention mechanisms enables the model to dynamically adjust weights, highlight salient features, and enhance the accuracy of fault identification. This method provides a reliable theoretical foundation and technical reference for the condition monitoring of disconnectors, holds significant potential for future fault diagnosis and equipment maintenance, and offers new insights for the development of smart grid technologies.
Abstract: [Objective] To achieve high-precision identification of mechanical faults in disconnectors, a parallel hybrid network incorporating attention mechanisms is proposed, which combines temporal and image features for intelligent diagnosis. [Methods] To fully exploit the feature information of dual-channel data, a bidirectional long short-term memory network was employed in the temporal channel to extract time-domain features from vibration signals, capturing the dynamic temporal variations of the signal and effectively reflecting the time-varying characteristics of mechanical faults. In the image channel, vibration signals were converted into two-dimensional images using Gramian angular fields, where polar coordinate mapping was utilized to preserve the temporal dynamics. A convolutional neural network was then used to extract key image features. Furthermore, a self-attention mechanism was introduced in the temporal channel and a channel attention mechanism in the image channel, enabling the model to adaptively adjust the weight of each channel, thereby emphasizing critical information and effectively reducing feature redundancy. [Results] Fault simulation experiments were conducted on GW4-126 type disconnectors, and vibration signals under four operating conditions were collected. The proposed method was compared with five other deep learning models. Experimental results demonstrated that the proposed method achieves a fault recognition accuracy exceeding 97%, effectively identifying typical mechanical faults such as mechanism jamming, looseness, and phase asynchrony. [Conclusion] The proposed parallel hybrid model overcomes the limitations of single-channel approaches by integrating two distinct types of feature information. The introduction of attention mechanisms enables the model to dynamically adjust weights, highlight salient features, and enhance the accuracy of fault identification. This method provides a reliable theoretical foundation and technical reference for the condition monitoring of disconnectors, holds significant potential for future fault diagnosis and equipment maintenance, and offers new insights for the development of smart grid technologies.
LI Yaohua, GUO Weicha, CHONG Guochen, WANG Zichen, WANG Qinzheng, GAO Sai, XU Zhixiong, LIU Yahui, ZHANG Qian, HUANG Hanxuan
2025,52(6):596-607, DOI: 10.12177/emca.2025.045
Abstract:
Abstract: [Objective] Aiming at the problem of control performance degradation due to parameter mismatch in finite-control-set model predictive current control (FCS-MPCC) of permanent magnet synchronous motor, the model reference adaptive system (MRAS) is used to identify the motor parameters to improve the parameter robustness of FCS-MPCC. [Methods] Firstly, the parameter mismatch robustness of FCS-MPCC was analyzed. Then, in order to solve the problem of under-ranking of three parameters identified by the traditional MRAS method, only the two parameters of inductance and flux linkage, which have a greater influence, were identified, so as to make the FCS-MPCC have a stronger parameter robustness. Finally, the impact of the resistance parameters mismatch of the MRAS model on the identification results and the performance of the motor control was analyzed. [Results] In order to verify the effectiveness of the proposed method, simulation analysis was carried out based on Matlab/Simulink platform. MRAS can accurately recognize the actual values of inductance and flux linkage with high recognition accuracy when the model resistance parameters were set correctly. Although FCS-MPCC and MRAS still need to set the resistance parameters, and the mismatch of the resistance parameters has a large impact on the identification results of the flux linkage parameters of MRAS, but because FCS-MPCC has a certain degree of robustness to the parameter changes, this effect was reflected in the FCS-MPCC has little impact. [Conclusion] FCS-MPCC selects the voltage vectors whose cost function is the minimum one, which can weaken effects of parameters mismatch and make FCS-MPCC robustness. As effect of resistance parameters mismatch is weak, only inductance and flux linkage are needed to be identified, so as to avoid the problem of under-ranking. Resistance parameters affect a significant impact on MRAS-based inductance and flux linkage identification, but demonstrate minimal influence on FCS-MPCC.
Abstract: [Objective] Aiming at the problem of control performance degradation due to parameter mismatch in finite-control-set model predictive current control (FCS-MPCC) of permanent magnet synchronous motor, the model reference adaptive system (MRAS) is used to identify the motor parameters to improve the parameter robustness of FCS-MPCC. [Methods] Firstly, the parameter mismatch robustness of FCS-MPCC was analyzed. Then, in order to solve the problem of under-ranking of three parameters identified by the traditional MRAS method, only the two parameters of inductance and flux linkage, which have a greater influence, were identified, so as to make the FCS-MPCC have a stronger parameter robustness. Finally, the impact of the resistance parameters mismatch of the MRAS model on the identification results and the performance of the motor control was analyzed. [Results] In order to verify the effectiveness of the proposed method, simulation analysis was carried out based on Matlab/Simulink platform. MRAS can accurately recognize the actual values of inductance and flux linkage with high recognition accuracy when the model resistance parameters were set correctly. Although FCS-MPCC and MRAS still need to set the resistance parameters, and the mismatch of the resistance parameters has a large impact on the identification results of the flux linkage parameters of MRAS, but because FCS-MPCC has a certain degree of robustness to the parameter changes, this effect was reflected in the FCS-MPCC has little impact. [Conclusion] FCS-MPCC selects the voltage vectors whose cost function is the minimum one, which can weaken effects of parameters mismatch and make FCS-MPCC robustness. As effect of resistance parameters mismatch is weak, only inductance and flux linkage are needed to be identified, so as to avoid the problem of under-ranking. Resistance parameters affect a significant impact on MRAS-based inductance and flux linkage identification, but demonstrate minimal influence on FCS-MPCC.
2025,52(6):608-622, DOI: 10.12177/emca.2025.046
Abstract:
Abstract: [Objective] The nonlinear characteristic of voltage source inverter causes output current distortion, which in turn leads to motor output torque pulsation and affects the control accuracy and stability of permanent magnet synchronous motor drive system. To solve this problem, an online compensation strategy based on the nonlinear disturbance observer (NDO) is proposed at the paper. [Methods] Firstly, the nonlinear factors such as inverter dead time and switching tube voltage drop were quantitatively analyzed. Then the NDO was constructed based on the synchronous rotating coordinate system current equation, the saturation gain function was designed, and the dq axis reference voltages were corrected by the feed-forward compensation channel. However, the NDO was highly sensitive to parameters. Thus, a cascade model reference adaptive parameter identification (CMRAPI) scheme was proposed. And the cascade module parameter identification task was decomposed into two groups of mutually independent identification tasks of stator resistance and permanent magnet magnetic chain as well as stator inductance, and each group of tasks realizes parameter identification through the model-referenced adaptive structure, and then realizes the transmission of the identification results through the cascade module. The proposed scheme could simultaneously identify three motor parameters such as stator resistance, permanent magnet chain and stator inductance, so as to provide parameter support for the NDO , and to reduce the compensation error caused by parameter deviation. [Results] The NDO was capable of high-precision error observation. In addition, the CMRAPI scheme can achieve accurate identification of resistance, magnetic chain and inductance. [Conclusion] The simulation results show that the NDO is able to accurately compensate the disturbance voltage caused by the nonlinear characteristics of the inverter during the long-time operation of the motor, thus effectively suppressing the output current distortion and torque pulsation.
Abstract: [Objective] The nonlinear characteristic of voltage source inverter causes output current distortion, which in turn leads to motor output torque pulsation and affects the control accuracy and stability of permanent magnet synchronous motor drive system. To solve this problem, an online compensation strategy based on the nonlinear disturbance observer (NDO) is proposed at the paper. [Methods] Firstly, the nonlinear factors such as inverter dead time and switching tube voltage drop were quantitatively analyzed. Then the NDO was constructed based on the synchronous rotating coordinate system current equation, the saturation gain function was designed, and the dq axis reference voltages were corrected by the feed-forward compensation channel. However, the NDO was highly sensitive to parameters. Thus, a cascade model reference adaptive parameter identification (CMRAPI) scheme was proposed. And the cascade module parameter identification task was decomposed into two groups of mutually independent identification tasks of stator resistance and permanent magnet magnetic chain as well as stator inductance, and each group of tasks realizes parameter identification through the model-referenced adaptive structure, and then realizes the transmission of the identification results through the cascade module. The proposed scheme could simultaneously identify three motor parameters such as stator resistance, permanent magnet chain and stator inductance, so as to provide parameter support for the NDO , and to reduce the compensation error caused by parameter deviation. [Results] The NDO was capable of high-precision error observation. In addition, the CMRAPI scheme can achieve accurate identification of resistance, magnetic chain and inductance. [Conclusion] The simulation results show that the NDO is able to accurately compensate the disturbance voltage caused by the nonlinear characteristics of the inverter during the long-time operation of the motor, thus effectively suppressing the output current distortion and torque pulsation.
2025,52(6):623-633, DOI: 10.12177/emca.2025.049
Abstract:
Abstract: [Objective] In mechanical load measurement for large-scale wind turbines, main shaft bending moments have less chance to reach a comparable level for tower bending moments, due to the limitation of structure and size of the main shaft. During the load calibration process for main shaft bending moments, moments generated by rotor gravity at the main shaft load measurement section shall be evaluated accurately to measure main shaft tilt and yaw moments with high reliability. [Methods] Based on optimized and improved three-dimensional coordinate systems, an analytic method for main shaft bending moments generated by rotor gravity was proposed, in which the principle of analytic geometry was applied. The contribution of hub gravity on main shaft load measurement section was evaluated as a basis before the focus of blade gravity effect on the same section. To solve the problem of affecting the optimized three-dimensional coordinate system by the presence of main shaft tilt angle, a novel solution was proposed, where the direction of blade gravity vector in the improved coordinate system was adjusted with the same degree as that of the main shaft tilt angle in a specific vertical plane. The gravity vector of a rotating blade in an arbitrary azimuth angle was then decomposed into each axis of the optimized three-dimensional coordinate system. The resulting moment at the section center of main shaft bearing from every gravity component was calculated separately with details before synthesizing results in the same coordinate axis. Bending moment distribution from main shaft bearing center to load measurement section center was obtained by applying moment balance principle for both hub gravity and own gravity of all blades. The combined bending moment contribution by three blades is equivalent to a single mass point with its gravity of the sum of those of three blades. [Results] In a mechanical load test project for some type of wind turbine, the proposed load calibration analysis method was applied, where the results were compared with those by conventional main shaft bending load calibration. The main shaft load results from the proposed method demonstrated representativeness of wind turbine mechanical loads, and coincide with design specifications of wind turbine. [Conclusion] The validity and feasibility of the proposed analytic method for gravity load calibration of main shaft bending moments are verified by theoretical analysis and testing results.
Abstract: [Objective] In mechanical load measurement for large-scale wind turbines, main shaft bending moments have less chance to reach a comparable level for tower bending moments, due to the limitation of structure and size of the main shaft. During the load calibration process for main shaft bending moments, moments generated by rotor gravity at the main shaft load measurement section shall be evaluated accurately to measure main shaft tilt and yaw moments with high reliability. [Methods] Based on optimized and improved three-dimensional coordinate systems, an analytic method for main shaft bending moments generated by rotor gravity was proposed, in which the principle of analytic geometry was applied. The contribution of hub gravity on main shaft load measurement section was evaluated as a basis before the focus of blade gravity effect on the same section. To solve the problem of affecting the optimized three-dimensional coordinate system by the presence of main shaft tilt angle, a novel solution was proposed, where the direction of blade gravity vector in the improved coordinate system was adjusted with the same degree as that of the main shaft tilt angle in a specific vertical plane. The gravity vector of a rotating blade in an arbitrary azimuth angle was then decomposed into each axis of the optimized three-dimensional coordinate system. The resulting moment at the section center of main shaft bearing from every gravity component was calculated separately with details before synthesizing results in the same coordinate axis. Bending moment distribution from main shaft bearing center to load measurement section center was obtained by applying moment balance principle for both hub gravity and own gravity of all blades. The combined bending moment contribution by three blades is equivalent to a single mass point with its gravity of the sum of those of three blades. [Results] In a mechanical load test project for some type of wind turbine, the proposed load calibration analysis method was applied, where the results were compared with those by conventional main shaft bending load calibration. The main shaft load results from the proposed method demonstrated representativeness of wind turbine mechanical loads, and coincide with design specifications of wind turbine. [Conclusion] The validity and feasibility of the proposed analytic method for gravity load calibration of main shaft bending moments are verified by theoretical analysis and testing results.
GAO Dapeng, LUO Pan, LI Jie, HE Liang, LIU Pinchao, CHEN Kaixuan, HAN Jianbo, ZHOU Bingcheng, LIU Tangsheng
2025,52(6):634-645, DOI: 10.12177/emca.2025.050
Abstract:
Abstract: [Objective] The output terminal of the permanent magnet synchronous motor (PMSM) drive system is often connected to an LC filter, which is used to eliminate high-frequency voltage pulse. However, the introduction of an LC output filter can induce inherent resonance, leading to instability in the PMSM control system. In order to suppress the resonant caused by LC output filter in permanent magnet synchronous motors drive system, a resonance suppression strategy based on active damping via capacitor current feedback is proposed at the paper. [Methods] Firstly, a mathematical model of the PMSM control system with LC output filter was established. Meanwhile, the causes of resonance were analyzed and located by analyzing the transfer function and Bode diagram of the control system. Then, a control method based on active damping of capacitive current was designed. The effectiveness of the method was analyzed and confirmed by the frequency domain perspective. Subsequently, in order to ensure the stability of the control system, the parameter design of the current regulator and the design of the active damping coefficient was carried out. To verify the effectiveness of the proposed method, it was compared with traditional vector control methods and passive damping control methods. [Results] Compared with traditional vector control methods, the capacitor current active damping control strategy proposed in this paper has a small overshoot and response time, which exhibited better stability. Compared with passive damping control methods, the proposed strategy achieved a good solution to the resonance problem of the control circuit without increasing hardware, which showed good anti-interference ability in the case of sudden load loading and unloading.[Conclusion] The above work indicates that, for PMSM control systems with LC output filters, the capacitor current active damping method proposed in this paper can achieve smooth control of motor speed and effectively solve the problem of control system resonance.
Abstract: [Objective] The output terminal of the permanent magnet synchronous motor (PMSM) drive system is often connected to an LC filter, which is used to eliminate high-frequency voltage pulse. However, the introduction of an LC output filter can induce inherent resonance, leading to instability in the PMSM control system. In order to suppress the resonant caused by LC output filter in permanent magnet synchronous motors drive system, a resonance suppression strategy based on active damping via capacitor current feedback is proposed at the paper. [Methods] Firstly, a mathematical model of the PMSM control system with LC output filter was established. Meanwhile, the causes of resonance were analyzed and located by analyzing the transfer function and Bode diagram of the control system. Then, a control method based on active damping of capacitive current was designed. The effectiveness of the method was analyzed and confirmed by the frequency domain perspective. Subsequently, in order to ensure the stability of the control system, the parameter design of the current regulator and the design of the active damping coefficient was carried out. To verify the effectiveness of the proposed method, it was compared with traditional vector control methods and passive damping control methods. [Results] Compared with traditional vector control methods, the capacitor current active damping control strategy proposed in this paper has a small overshoot and response time, which exhibited better stability. Compared with passive damping control methods, the proposed strategy achieved a good solution to the resonance problem of the control circuit without increasing hardware, which showed good anti-interference ability in the case of sudden load loading and unloading.[Conclusion] The above work indicates that, for PMSM control systems with LC output filters, the capacitor current active damping method proposed in this paper can achieve smooth control of motor speed and effectively solve the problem of control system resonance.
2025,52(6):646-657, DOI: 10.12177/emca.2025.042
Abstract:
Abstract: [Objective] The existing capacitor voltage full-feedback scheme for LCL-type inverters presents issues such as inadequate suppression capability for high-order harmonics. To address the contradiction between the actual harmonic suppression effect of the strategy in high frequency band and the stability of the system, an adaptive capacitor voltage full feedback method is proposed in this paper. [Methods] Firstly, the impact of digital time delay on the actual harmonic suppression performance of the capacitor voltage full-feedback scheme was analyzed, and a first-order inertia link was utilized to simulate the phase-frequency characteristics of the digital delay, compensating for phase deviations caused by neglecting digital delay in the full-feedback function. Secondly, virtual impedance correction method was proposed. By introducing an impedance coefficient into the second-order feedback loop, the equivalent virtual resistance was adjusted to ensure the stability of the grid-connected system and the lower limit of impedance coefficients that triggers system instability was theoretically derived. Subsequently, the influence of the impedance coefficient value on the actual harmonic suppression effect of the capacitor voltage full feedback strategy was analyzed. An adaptive impedance coefficient adjustment method was proposed, which was designed to dynamically regulate the impedance coefficient in response to real-time system harmonic content. The function of each module was elaborated in detail, with the specific parameter determination method for critical components provided. Finally, a 10 kVA grid-connected inverter prototype was developed to experimentally validate the efficacy of the proposed adaptive capacitor voltage full feedback scheme. [Results] Experimental results demonstrated that adaptive capacitor voltage full feedback schemes can adjust the impedance coefficient according to the harmonic content of the grid-connected current. This adaptive regulation ensures system stability while maintaining strong suppression efficacy against higher-order harmonics. [Conclusion] The proposed method effectively solves the contradiction between system stability margin and high harmonic suppression effect, significantly enhance the suppression capability of the capacitor voltage full-feedback strategy to high-order harmonics of the grid-connected current, which demonstrates strong applicability in the present weak grid environment with wide range of grid impedance variation and high randomness of harmonic distribution.
Abstract: [Objective] The existing capacitor voltage full-feedback scheme for LCL-type inverters presents issues such as inadequate suppression capability for high-order harmonics. To address the contradiction between the actual harmonic suppression effect of the strategy in high frequency band and the stability of the system, an adaptive capacitor voltage full feedback method is proposed in this paper. [Methods] Firstly, the impact of digital time delay on the actual harmonic suppression performance of the capacitor voltage full-feedback scheme was analyzed, and a first-order inertia link was utilized to simulate the phase-frequency characteristics of the digital delay, compensating for phase deviations caused by neglecting digital delay in the full-feedback function. Secondly, virtual impedance correction method was proposed. By introducing an impedance coefficient into the second-order feedback loop, the equivalent virtual resistance was adjusted to ensure the stability of the grid-connected system and the lower limit of impedance coefficients that triggers system instability was theoretically derived. Subsequently, the influence of the impedance coefficient value on the actual harmonic suppression effect of the capacitor voltage full feedback strategy was analyzed. An adaptive impedance coefficient adjustment method was proposed, which was designed to dynamically regulate the impedance coefficient in response to real-time system harmonic content. The function of each module was elaborated in detail, with the specific parameter determination method for critical components provided. Finally, a 10 kVA grid-connected inverter prototype was developed to experimentally validate the efficacy of the proposed adaptive capacitor voltage full feedback scheme. [Results] Experimental results demonstrated that adaptive capacitor voltage full feedback schemes can adjust the impedance coefficient according to the harmonic content of the grid-connected current. This adaptive regulation ensures system stability while maintaining strong suppression efficacy against higher-order harmonics. [Conclusion] The proposed method effectively solves the contradiction between system stability margin and high harmonic suppression effect, significantly enhance the suppression capability of the capacitor voltage full-feedback strategy to high-order harmonics of the grid-connected current, which demonstrates strong applicability in the present weak grid environment with wide range of grid impedance variation and high randomness of harmonic distribution.
2025,52(6):658-668, DOI: 10.12177/emca.2025.038
Abstract:
Abstract: [Objective] Accurate analysis of the air gap magnetic field is the focus of research in the field of precision permanent magnet linear synchronous motor (PMLSM). [Methods] Two-dimensional air gap magnetic field of a secondary trapezoidal Halbach permanent magnet array coreless PMLSM was taken as the research object at the paper. On the basis of the equivalent surface current method, an improved equivalent analytical algorithm with a trapezoidal side length unit was proposed. The equivalent analytical model of the magnetic induction vector of the two-dimensional air gap was established. [Results] And the air gap magnetic field of the trapezoidal Halbach array coreless PMLSM was calculated. The results showed that α and αw have a significant influence on the Bpeak and THDB of the central magnetic field air gap. With the synergy of α and αw, identified the flux convergence effect, which makes the maximum range of Bpeak α>90° and αw<0.5. And the equilateral effect, which causes the minimum region of THDB to change linearly. [Conclusion] The calculation results of the established improved equivalent surface current analytical model in this paper agree with those verified by the finite element method. The calculation is convenient, and the accuracy of the result is high. This research provides a new method for analyzing the air gap magnetic field of a permanent magnet with a nonrectangular cross-section, and also prorides a reference for optimizing the PMLSM pole model.
Abstract: [Objective] Accurate analysis of the air gap magnetic field is the focus of research in the field of precision permanent magnet linear synchronous motor (PMLSM). [Methods] Two-dimensional air gap magnetic field of a secondary trapezoidal Halbach permanent magnet array coreless PMLSM was taken as the research object at the paper. On the basis of the equivalent surface current method, an improved equivalent analytical algorithm with a trapezoidal side length unit was proposed. The equivalent analytical model of the magnetic induction vector of the two-dimensional air gap was established. [Results] And the air gap magnetic field of the trapezoidal Halbach array coreless PMLSM was calculated. The results showed that α and αw have a significant influence on the Bpeak and THDB of the central magnetic field air gap. With the synergy of α and αw, identified the flux convergence effect, which makes the maximum range of Bpeak α>90° and αw<0.5. And the equilateral effect, which causes the minimum region of THDB to change linearly. [Conclusion] The calculation results of the established improved equivalent surface current analytical model in this paper agree with those verified by the finite element method. The calculation is convenient, and the accuracy of the result is high. This research provides a new method for analyzing the air gap magnetic field of a permanent magnet with a nonrectangular cross-section, and also prorides a reference for optimizing the PMLSM pole model.
2025,52(6):669-679, DOI: 10.12177/emca.2025.039
Abstract:
Abstract: [Objective] Aiming at the problem of non-dominant pole harmonics generated by double rotor asynchronous motors with fractional-slot concentrated winding (FSCW) structure, this study aims at proposing an efficient harmonic suppression method to reduce the harmonic-induced efficiency loss of the motor and to improve the operational stability and overall performance of the motor. [Methods] Firstly, based on the phase band division and arrangement of the FSCW, the distribution coefficients of even-slot and odd-slot were derived by the definition method and the harmonic synthesis method, respectively, and the peaks and valleys of the harmonic magnetic potentials at the axial position under the different pole-pair numbers were clarified. Secondly, combined with the theoretical analysis of the distribution coefficients, two compensation winding configurations were proposed: the direct compensation method by adjusting the phase relationship between the compensation windings and the main winding, so that the peaks and valleys of the magnetic potentials of the harmonics to be suppressed were superimposed with the main harmonics in reverse direction; and the phase-shifting compensation method by the phase-shifting design of multiple sets of compensation windings, so as to achieve the active offset of the specific subharmonics. In addition, a three-dimensional motor model based on finite element simulation was established to verify the effectiveness of the compensation method. [Results] The theoretical calculation and finite element simulation verified that the proposed methods can effectively suppress specific harmonic components and enhance the operating harmonics in small amounts, which improves the operation stability and efficiency of the motor. [Conclusion] This study shows that the direct compensation method and the phase-shift compensation method can be flexibly applied to the suppression of non-dominant pole harmonics based on the characteristics of harmonic peaks and valleys distribution. The former is suitable for the scenario where the peaks and valleys of the proposed harmonic suppression and the operating harmonics are reversed, while the latter solves the harmonic cancellation problem when the peaks and valleys of the two are in the same direction. Both methods can moderately enhance the working harmonics while suppressing the target harmonics, providing a theoretical basis and technical support for high-precision motor design and harmonic management.
Abstract: [Objective] Aiming at the problem of non-dominant pole harmonics generated by double rotor asynchronous motors with fractional-slot concentrated winding (FSCW) structure, this study aims at proposing an efficient harmonic suppression method to reduce the harmonic-induced efficiency loss of the motor and to improve the operational stability and overall performance of the motor. [Methods] Firstly, based on the phase band division and arrangement of the FSCW, the distribution coefficients of even-slot and odd-slot were derived by the definition method and the harmonic synthesis method, respectively, and the peaks and valleys of the harmonic magnetic potentials at the axial position under the different pole-pair numbers were clarified. Secondly, combined with the theoretical analysis of the distribution coefficients, two compensation winding configurations were proposed: the direct compensation method by adjusting the phase relationship between the compensation windings and the main winding, so that the peaks and valleys of the magnetic potentials of the harmonics to be suppressed were superimposed with the main harmonics in reverse direction; and the phase-shifting compensation method by the phase-shifting design of multiple sets of compensation windings, so as to achieve the active offset of the specific subharmonics. In addition, a three-dimensional motor model based on finite element simulation was established to verify the effectiveness of the compensation method. [Results] The theoretical calculation and finite element simulation verified that the proposed methods can effectively suppress specific harmonic components and enhance the operating harmonics in small amounts, which improves the operation stability and efficiency of the motor. [Conclusion] This study shows that the direct compensation method and the phase-shift compensation method can be flexibly applied to the suppression of non-dominant pole harmonics based on the characteristics of harmonic peaks and valleys distribution. The former is suitable for the scenario where the peaks and valleys of the proposed harmonic suppression and the operating harmonics are reversed, while the latter solves the harmonic cancellation problem when the peaks and valleys of the two are in the same direction. Both methods can moderately enhance the working harmonics while suppressing the target harmonics, providing a theoretical basis and technical support for high-precision motor design and harmonic management.
GAO Dapeng, HE Liang, LUO Pan, LIU Pinchao, HAN Jianbo, CHEN Kaixuan, ZHOU Bingcheng, LIU Tangsheng, XIE Feng
2025,52(6):680-689, DOI: 10.12177/emca.2025.051
Abstract:
Abstract: ［Objective］ The circulation water pump adopts a shielded three-phase AC asynchronous pole-changing motor. During the high-speed to low-speed mode transition and the low-speed to high-speed mode transition, this motor requires an extended power interruption period, resulting in significant drops in both motor speed and process loop flow rate. To address this mode transition challenge, a novel bidirectional control strategy for seamless switching between high-speed and low-speed operation modes is proposed at the paper. ［Methods］ First, taking the pole-changing motor of the circulation water pump as the analysis object, a simulation model of the pole-changing motor was established based on the pole-changing principle and the mathematical equations of AC asynchronous motors. A simulation model for low-speed and high-speed drive control of the pole-changing motor was then constructed. To minimize the flow rate drop during the switching process, with the goal of reducing motor speed drop, the dynamic characteristics of parameters such as the motor's residual electromotive force and speed during mutual switching between high-speed and low-speed modes were investigated. Concurrently, considering the operational constraints during pole-changing motor mode transition, a control strategy for switching from low-speed to high-speed and from high-speed to low-speed was designed. The proposed control strategy was applied to the development of the frequency converter power supply for the circulation water pump. Bench tests demonstrated excellent compatibility between the power supply and the circulation water pump. ［Results］ The experimental results confirmed that smooth switching between high-speed and low-speed operation modes were achieved, and operation mode switching requirements for circulation water pump. During the transition from high-speed to low-speed mode, the speed fluctuation was controlled within 22.7% and the flow fluctuation was maintained within 22.7%. Conversely, during the transition from low-speed to high-speed mode, the speed fluctuation was limited to 25.4% and the flow fluctuation was kept within 25.5%. ［Conclusion］ The pole-changing strategy proposed in this paper for switching between high-speed and low-speed operation modes of circulating water pump motors effectively resolves the challenges of operational mode transition, demonstrating significant engineering applicability.
Abstract: ［Objective］ The circulation water pump adopts a shielded three-phase AC asynchronous pole-changing motor. During the high-speed to low-speed mode transition and the low-speed to high-speed mode transition, this motor requires an extended power interruption period, resulting in significant drops in both motor speed and process loop flow rate. To address this mode transition challenge, a novel bidirectional control strategy for seamless switching between high-speed and low-speed operation modes is proposed at the paper. ［Methods］ First, taking the pole-changing motor of the circulation water pump as the analysis object, a simulation model of the pole-changing motor was established based on the pole-changing principle and the mathematical equations of AC asynchronous motors. A simulation model for low-speed and high-speed drive control of the pole-changing motor was then constructed. To minimize the flow rate drop during the switching process, with the goal of reducing motor speed drop, the dynamic characteristics of parameters such as the motor's residual electromotive force and speed during mutual switching between high-speed and low-speed modes were investigated. Concurrently, considering the operational constraints during pole-changing motor mode transition, a control strategy for switching from low-speed to high-speed and from high-speed to low-speed was designed. The proposed control strategy was applied to the development of the frequency converter power supply for the circulation water pump. Bench tests demonstrated excellent compatibility between the power supply and the circulation water pump. ［Results］ The experimental results confirmed that smooth switching between high-speed and low-speed operation modes were achieved, and operation mode switching requirements for circulation water pump. During the transition from high-speed to low-speed mode, the speed fluctuation was controlled within 22.7% and the flow fluctuation was maintained within 22.7%. Conversely, during the transition from low-speed to high-speed mode, the speed fluctuation was limited to 25.4% and the flow fluctuation was kept within 25.5%. ［Conclusion］ The pole-changing strategy proposed in this paper for switching between high-speed and low-speed operation modes of circulating water pump motors effectively resolves the challenges of operational mode transition, demonstrating significant engineering applicability.
2025,52(6):690-699, DOI: 10.12177/emca.2025.047
Abstract:
Abstract: [Objective] In order to improve the disturbance resistance and robustness of the current controller of permanent magnet synchronous motor (PMSM), and to solve the overshoot and dq axis current ripple problems of traditional proportional integral (PI) control under speed and load changes, a PMSM current controller based sliding mode control with full-order observer (FO) is proposed. [Methods] Firstly, considering the inevitable disturbances such as dead time in the inverter, parameter changes, and abrupt changes, an actual mathematical model of the PMSM was established. Secondly, a FO was used to calculate the disturbance of the dq axis current model, and analyzed the influence of parameters on the observer. Furthermore, considering the observation disturbance, a PMSM dq axis current controller was designed based on sliding mode control. In addition, the stability of the FO was analyzed, and the stability of the controller was analyzed using Lyapunov functions. [Results] To verify the effectiveness of the method, Matlab/Simulink simulation platform and TMS320F28035 experimental platform were built. Comparative results demonstrated that the proposed method features a simpler structure and lower steady-state error than the other two controllers. The simulation and experimental results showed that compared with traditional PI controllers, the current controller of this method exhibits good robustness in dealing with parameter changes, load or speed changes, and can suppress dq axis current pulsation, ensuring the stability of the system. [Conclusion] The sliding mode controller with FO proposed in this paper improves the system’s disturbance resistance ability and enhances its dynamic response performance. This study provides technical support for the application of PMSM in new energy vehicles, rail transit, and related fields.
Abstract: [Objective] In order to improve the disturbance resistance and robustness of the current controller of permanent magnet synchronous motor (PMSM), and to solve the overshoot and dq axis current ripple problems of traditional proportional integral (PI) control under speed and load changes, a PMSM current controller based sliding mode control with full-order observer (FO) is proposed. [Methods] Firstly, considering the inevitable disturbances such as dead time in the inverter, parameter changes, and abrupt changes, an actual mathematical model of the PMSM was established. Secondly, a FO was used to calculate the disturbance of the dq axis current model, and analyzed the influence of parameters on the observer. Furthermore, considering the observation disturbance, a PMSM dq axis current controller was designed based on sliding mode control. In addition, the stability of the FO was analyzed, and the stability of the controller was analyzed using Lyapunov functions. [Results] To verify the effectiveness of the method, Matlab/Simulink simulation platform and TMS320F28035 experimental platform were built. Comparative results demonstrated that the proposed method features a simpler structure and lower steady-state error than the other two controllers. The simulation and experimental results showed that compared with traditional PI controllers, the current controller of this method exhibits good robustness in dealing with parameter changes, load or speed changes, and can suppress dq axis current pulsation, ensuring the stability of the system. [Conclusion] The sliding mode controller with FO proposed in this paper improves the system’s disturbance resistance ability and enhances its dynamic response performance. This study provides technical support for the application of PMSM in new energy vehicles, rail transit, and related fields.
2025,52(6):700-709, DOI: 10.12177/emca.2025.041
Abstract:
Abstract: [Objective] This study addresses the challenges of slow dynamic response, insufficient tracking accuracy, and complex parameter tuning in permanent magnet synchronous linear motor under multi-source disturbances. Reduced-full-order switched active disturbance rejection control based on particle swarm optimization (PSO-RSADRC) algorithm is proposed to enhance control precision. [Methods] First, an intelligent switching active disturbance rejection control (SADRC) architecture was constructed, optimizing disturbance rejection performance through linear/nonlinear dynamic switching. Then, reduced-full-order SADRC (RSADRC) to simplify the observer structure and reduce parameter coupling was proposed. Finally, to address the multi-parameter coupling issue in the nonlinear error feedback module, a PSO-RSADRC approach was developed, and simulation and experimental validation were conducted based on a fourth-order S-curve motion planning model. [Results] Simulation results demonstrated that PSO-RSADRC achieved an integral time-weighted absolute error of 0.95 and maximum dynamic error of 19 μm under 1 A step disturbance, improving precision by 98% compared to conventional linear ADRC. During platform validation, the settling time was reduced to 57 ms with a 32% enhancement in response speed. [Conclusion] The proposed PSO-RSADRC strategy effectively resolves precision motion control challenges under multi-source disturbances, demonstrating significantly superior parameter tuning efficiency and disturbance rejection robustness compared to conventional methods. This solution provides a reliable technical approach for high-precision industrial applications such as microelectronics packaging.
Abstract: [Objective] This study addresses the challenges of slow dynamic response, insufficient tracking accuracy, and complex parameter tuning in permanent magnet synchronous linear motor under multi-source disturbances. Reduced-full-order switched active disturbance rejection control based on particle swarm optimization (PSO-RSADRC) algorithm is proposed to enhance control precision. [Methods] First, an intelligent switching active disturbance rejection control (SADRC) architecture was constructed, optimizing disturbance rejection performance through linear/nonlinear dynamic switching. Then, reduced-full-order SADRC (RSADRC) to simplify the observer structure and reduce parameter coupling was proposed. Finally, to address the multi-parameter coupling issue in the nonlinear error feedback module, a PSO-RSADRC approach was developed, and simulation and experimental validation were conducted based on a fourth-order S-curve motion planning model. [Results] Simulation results demonstrated that PSO-RSADRC achieved an integral time-weighted absolute error of 0.95 and maximum dynamic error of 19 μm under 1 A step disturbance, improving precision by 98% compared to conventional linear ADRC. During platform validation, the settling time was reduced to 57 ms with a 32% enhancement in response speed. [Conclusion] The proposed PSO-RSADRC strategy effectively resolves precision motion control challenges under multi-source disturbances, demonstrating significantly superior parameter tuning efficiency and disturbance rejection robustness compared to conventional methods. This solution provides a reliable technical approach for high-precision industrial applications such as microelectronics packaging.
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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 ® 2025
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Electric Machines & Control Application ® 2025
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
