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Volume 51,Issue 1,2024 Table of Contents
2024, 51(1):1-13.
DOI: 10.12177/emca.2023.165
Abstract:
Position sensorless motor drives have attracted increasing attention in academia and industrial applications due to their advantages of low cost, high reliability, simple hardware circuits, and low maintenance requirements. A variety of position sensorless technologies are reviewed for three operating ranges: zero-low speed domains, medium-high speed domains, and full speed domains. Firstly, the advantages and disadvantages of various position sensorless control methods at zero-low and medium-high speeds domains are comparatively analyzed, respectively. Secondly, the current switching control strategy for full-speed domains operation is sorted out and summarized. Finally, the future development trend of position sensorless control technology for permanent magnet synchronous motor is prospected, and the key problems of follow-up research are pointed out.
Position sensorless motor drives have attracted increasing attention in academia and industrial applications due to their advantages of low cost, high reliability, simple hardware circuits, and low maintenance requirements. A variety of position sensorless technologies are reviewed for three operating ranges: zero-low speed domains, medium-high speed domains, and full speed domains. Firstly, the advantages and disadvantages of various position sensorless control methods at zero-low and medium-high speeds domains are comparatively analyzed, respectively. Secondly, the current switching control strategy for full-speed domains operation is sorted out and summarized. Finally, the future development trend of position sensorless control technology for permanent magnet synchronous motor is prospected, and the key problems of follow-up research are pointed out.
2024, 51(1):14-21.
DOI: 10.12177/emca.2023.161
Abstract:
Aiming at the problems of system chattering and low observation accuracy of the traditional full order sliding mode observer during operation, a full order sliding mode control strategy with controllable boundary layer is proposed. A normalized phase-locked loop is introduced for rotational speed estimation to avoid the effect of parameter variations on the estimated value and to make the rotor position identification more accurate. The stability of the algorithm is demonstrated using the Lyapunov equation. Finally, the reliability and accuracy of the improved full order sliding mode observer sensorless control strategy are verified through simulation and experiments.
Aiming at the problems of system chattering and low observation accuracy of the traditional full order sliding mode observer during operation, a full order sliding mode control strategy with controllable boundary layer is proposed. A normalized phase-locked loop is introduced for rotational speed estimation to avoid the effect of parameter variations on the estimated value and to make the rotor position identification more accurate. The stability of the algorithm is demonstrated using the Lyapunov equation. Finally, the reliability and accuracy of the improved full order sliding mode observer sensorless control strategy are verified through simulation and experiments.
2024, 51(1):22-28.
DOI: 10.12177/emca.2023.163
Abstract:
The characteristics of new power system user-side ubiquitous resources that are scattered in distribution, large in number, small in capacity and stochastic in nature create difficulties for user-side fine-grained carbon emission calculations. In order to accurately measure and assess the level of user carbon emissions in the power system, the sources of the power flows in each node of the power system is first analyzed through the power flow tracking method to determine the indirect carbon emission responsibility of each node. Then, the distribution of carbon flows in the power system is obtained by combining the carbon intensity of different sources according to the principle of proportional sharing. Finally, through the proposed load-side indicators of various electric power emissions, the cleanliness of different nodes is assessed so as to guide the users to use cleaner energies more often in order to reduce their own carbon emissions. And the real power system data are used for example validation to verify the rationality and usability of the proposed method.
The characteristics of new power system user-side ubiquitous resources that are scattered in distribution, large in number, small in capacity and stochastic in nature create difficulties for user-side fine-grained carbon emission calculations. In order to accurately measure and assess the level of user carbon emissions in the power system, the sources of the power flows in each node of the power system is first analyzed through the power flow tracking method to determine the indirect carbon emission responsibility of each node. Then, the distribution of carbon flows in the power system is obtained by combining the carbon intensity of different sources according to the principle of proportional sharing. Finally, through the proposed load-side indicators of various electric power emissions, the cleanliness of different nodes is assessed so as to guide the users to use cleaner energies more often in order to reduce their own carbon emissions. And the real power system data are used for example validation to verify the rationality and usability of the proposed method.
2024, 51(1):29-38.
DOI: 10.12177/emca.2023.162
Abstract:
Aiming at the problem that the feature quantity is difficult to select in the fault diagnosis of transformer winding looseness and relying on manual experience, a diagnosis method of transformer winding looseness based on automatic encoder noise reduction, gramian angle field (GAF) and depth residual network (ResNet) recognition is proposed. The method automatically learns effective fault features from GAF images without manually extracting the feature quantity. Firstly, the vibration signal is denoised through an automatic encoder to obtain a vibration signal with a higher signal-to-noise ratio. Then, the GAF method is used to convert the vibration signal into a two-dimensional image and generate an image dataset. Based on this, ResNet is trained to construct a network model suitable for classification and recognition of transformer winding looseness faults. Finally, a transformer winding looseness fault test platform is built to collect vibration signals of the winding under different looseness and experimental currents for analysis. The experimental results show that the proposed diagnosis method has an accuracy of over 95% in identifying transformer winding looseness, and can effectively identify the looseness phase and degree. It is suitable for identifying and diagnosing transformer winding looseness faults.
Aiming at the problem that the feature quantity is difficult to select in the fault diagnosis of transformer winding looseness and relying on manual experience, a diagnosis method of transformer winding looseness based on automatic encoder noise reduction, gramian angle field (GAF) and depth residual network (ResNet) recognition is proposed. The method automatically learns effective fault features from GAF images without manually extracting the feature quantity. Firstly, the vibration signal is denoised through an automatic encoder to obtain a vibration signal with a higher signal-to-noise ratio. Then, the GAF method is used to convert the vibration signal into a two-dimensional image and generate an image dataset. Based on this, ResNet is trained to construct a network model suitable for classification and recognition of transformer winding looseness faults. Finally, a transformer winding looseness fault test platform is built to collect vibration signals of the winding under different looseness and experimental currents for analysis. The experimental results show that the proposed diagnosis method has an accuracy of over 95% in identifying transformer winding looseness, and can effectively identify the looseness phase and degree. It is suitable for identifying and diagnosing transformer winding looseness faults.
2024, 51(1):39-48.
DOI: 10.12177/emca.2023.157
Abstract:
Modal analysis is an indispensable part of the research on motor vibration and noise issues. Taking a permanent magnet motor for compressor with a rated power of 1.98 kW as an example, the effects of thermal and interference stresses on the radial natural frequencies of various modes of the motor structure are analyzed. Firstly, the influence of winding and modeling on the modal analysis of motor structure is analyzed. Then, the selection range of motor interference fit is analyzed theoretically, the thermal deformation size of the iron core and casing during the highest temperature rise of the compressor motor is analyzed through finite element simulation of thermal-structural coupling. Based on the selection range of interference fit, the optimal interference fit is selected from the perspective of vibration and noise suppression. Finally, a compressor pre-stressed modal simulation model is established, and the effects of thermal stress and interference stress on the modal natural frequency of the compressor are analyzed. Considering the effects of thermal stresses and interference stresses, the modal of the entire machine can be calculated effectively and accurately, which improves the accuracy of the NVH performance assessment of air-conditioning compressors.
Modal analysis is an indispensable part of the research on motor vibration and noise issues. Taking a permanent magnet motor for compressor with a rated power of 1.98 kW as an example, the effects of thermal and interference stresses on the radial natural frequencies of various modes of the motor structure are analyzed. Firstly, the influence of winding and modeling on the modal analysis of motor structure is analyzed. Then, the selection range of motor interference fit is analyzed theoretically, the thermal deformation size of the iron core and casing during the highest temperature rise of the compressor motor is analyzed through finite element simulation of thermal-structural coupling. Based on the selection range of interference fit, the optimal interference fit is selected from the perspective of vibration and noise suppression. Finally, a compressor pre-stressed modal simulation model is established, and the effects of thermal stress and interference stress on the modal natural frequency of the compressor are analyzed. Considering the effects of thermal stresses and interference stresses, the modal of the entire machine can be calculated effectively and accurately, which improves the accuracy of the NVH performance assessment of air-conditioning compressors.
2024, 51(1):49-59.
DOI: 10.12177/emca.2023.170
Abstract:
The hybrid high voltage direct current (HVDC) transmission system consists of the line-commutated converter based HVDC (LCC-HVDC) transmission system and the voltage source converter based HVDC (VSC-HVDC) transmission system, which have different fault characteristics than conventional HVDC transmission system. To solve this problem, the DC side fault transient current characteristics in hybrid DC transmission systems are investigated. Firstly, a two terminal hybrid HVDC transmission system with LCC converter station in the sending-end grid and VSC converter station in the receiving-end grid is established. The equivalent circuit in case of DC side fault is derived by using laplace transform theorem, and the simple expressions of DC fault current on LCC side and VSC side are analyzed. Secondly, on the basis of the simple expressions, the accurate fault current expressions on both sides are further analyzed by fully considering the dynamic change process of the trigger angle of the LCC converter station at the sender side and the feed-in of the AC current from the VSC converter station at the receiver side. Then, the variation characteristics of DC side fault current in three HVDC systems are comparatively analyzed in terms of fault current amplitude and harmonic. Finally, the correctness of the proposed analytical expression of DC side fault current is verified by MATLAB/Simulink simulation.
The hybrid high voltage direct current (HVDC) transmission system consists of the line-commutated converter based HVDC (LCC-HVDC) transmission system and the voltage source converter based HVDC (VSC-HVDC) transmission system, which have different fault characteristics than conventional HVDC transmission system. To solve this problem, the DC side fault transient current characteristics in hybrid DC transmission systems are investigated. Firstly, a two terminal hybrid HVDC transmission system with LCC converter station in the sending-end grid and VSC converter station in the receiving-end grid is established. The equivalent circuit in case of DC side fault is derived by using laplace transform theorem, and the simple expressions of DC fault current on LCC side and VSC side are analyzed. Secondly, on the basis of the simple expressions, the accurate fault current expressions on both sides are further analyzed by fully considering the dynamic change process of the trigger angle of the LCC converter station at the sender side and the feed-in of the AC current from the VSC converter station at the receiver side. Then, the variation characteristics of DC side fault current in three HVDC systems are comparatively analyzed in terms of fault current amplitude and harmonic. Finally, the correctness of the proposed analytical expression of DC side fault current is verified by MATLAB/Simulink simulation.
2024, 51(1):60-76.
DOI: 10.12177/emca.2023.155
Abstract:
With the development of green aviation and the continuous progress of new energy technology, electric aircraft have also been developed rapidly. As the core of electric aircraft, the electric propulsion system is also achieving more and more attention. Permanent magnet synchronous motor (PMSM) has become an ideal solution for electric propulsion system of electric aircraft due to its high power density and high efficiency. As its independent of position sensor, the sensorless control technology of PMSM can better satisfy the requirement of high reliability under the high altitude and complex environment of electric aircraft. Firstly, the main methods of sensorless control of PMSM for electric propulsion system of electric aircraft is summarized and compared. Secondly, the key technologies and difficulties of sensorless control of PMSM are analyzed, including rotor starting position detection, low-speed startup, and medium and high-speed operation. Finally, the problems existing in the current research are summarized, and the future development is prospected.
With the development of green aviation and the continuous progress of new energy technology, electric aircraft have also been developed rapidly. As the core of electric aircraft, the electric propulsion system is also achieving more and more attention. Permanent magnet synchronous motor (PMSM) has become an ideal solution for electric propulsion system of electric aircraft due to its high power density and high efficiency. As its independent of position sensor, the sensorless control technology of PMSM can better satisfy the requirement of high reliability under the high altitude and complex environment of electric aircraft. Firstly, the main methods of sensorless control of PMSM for electric propulsion system of electric aircraft is summarized and compared. Secondly, the key technologies and difficulties of sensorless control of PMSM are analyzed, including rotor starting position detection, low-speed startup, and medium and high-speed operation. Finally, the problems existing in the current research are summarized, and the future development is prospected.
2024, 51(1):77-86.
DOI: 10.12177/emca.2023.166
Abstract:
Modular multilevel converter (MMC) generates circulating currents flowing between phases due to fluctuations in capacitor voltage, which increases energy loss and adversely affects the insulated gate bipolar transistors (IGBTs) in the sub-modules. In order to suppress the circulating current, a proportional controller capable of generating inverse doubling components is designed based on the dynamic mathematical model of the circulating current. The conventional quasi-resonant controller is improved for the high harmonics in the circulating current. And the proposed strategy is verified by simulation, the simulation results show that the proportional control strategy quickly reaches the steady-state suppression of the circulating current after only 0.2 s. The improved quasi-resonant control strategy optimizes the THD value by 3.56% compared with the pre-improvement one, which further reduces the high-frequency harmonic components and verifies the feasibility of the proposed strategy.
Modular multilevel converter (MMC) generates circulating currents flowing between phases due to fluctuations in capacitor voltage, which increases energy loss and adversely affects the insulated gate bipolar transistors (IGBTs) in the sub-modules. In order to suppress the circulating current, a proportional controller capable of generating inverse doubling components is designed based on the dynamic mathematical model of the circulating current. The conventional quasi-resonant controller is improved for the high harmonics in the circulating current. And the proposed strategy is verified by simulation, the simulation results show that the proportional control strategy quickly reaches the steady-state suppression of the circulating current after only 0.2 s. The improved quasi-resonant control strategy optimizes the THD value by 3.56% compared with the pre-improvement one, which further reduces the high-frequency harmonic components and verifies the feasibility of the proposed strategy.
9 Low Complexity Dual Vector Model Predictive Control Strategy for Permanent Magnet Synchronous Motor
2024, 51(1):87-96.
DOI: 10.12177/emca.2023.171
Abstract:
In order to solve the problems of large computation and current fluctuations in the model predictive current control of permanent magnet synchronous motor, a low complexity dual vector model predictive voltage control strategy is proposed. This method predicts and evaluates three non-adjacent effective voltage vectors only through cost functions, and two adjacent optimal effective voltage vectors can be determined accurately and quickly based on the relationship between the values of three cost functions, without traversing all the voltage vectors. The optimal and effective voltage vector selection can reduce the prediction calculation, and the dq axis voltage difference action time calculation method is introduced to calculate the optimal effective voltage vector action time in order to reduce the calculation. The simulation results show that compared to the duty cycle strategy and the traditional dual vector model predictive current control strategy, the proposed control strategy can effectively reduce the computational complexity and current fluctuation and improve the torque ripple on the basis of ensuring the steady-state and dynamic performance of the system.
In order to solve the problems of large computation and current fluctuations in the model predictive current control of permanent magnet synchronous motor, a low complexity dual vector model predictive voltage control strategy is proposed. This method predicts and evaluates three non-adjacent effective voltage vectors only through cost functions, and two adjacent optimal effective voltage vectors can be determined accurately and quickly based on the relationship between the values of three cost functions, without traversing all the voltage vectors. The optimal and effective voltage vector selection can reduce the prediction calculation, and the dq axis voltage difference action time calculation method is introduced to calculate the optimal effective voltage vector action time in order to reduce the calculation. The simulation results show that compared to the duty cycle strategy and the traditional dual vector model predictive current control strategy, the proposed control strategy can effectively reduce the computational complexity and current fluctuation and improve the torque ripple on the basis of ensuring the steady-state and dynamic performance of the system.
2024, 51(1):97-105.
DOI: 10.12177/emca.2023.158
Abstract:
In view of the traditional flower pollination algorithm for parameter identification in permanent magnet synchronous motors, the late iteration often results in easily plunging into a local optimum, leading to slow convergence speed and the defect of low optimization accuracy. An improved flower pollination algorithm based on t-distributed perturbation and Gaussian perturbation (tGFPA) is proposed to realize high-precision identification of permanent magnet synchronous motors. Firstly, the individual position of flowers is initialized by chaotic logistic mapping, and then t-distribution perturbation is introduced in the global pollination process to improve the diversity of search space. Gaussian perturbation is added during local pollination to enhance the ability to jump out of the local optimal solution. Finally, comparing the simulation results show that the flower pollinate algorithm based on double perturbation strategy to improve convergence speed is faster and have higher precision, which has important significance for improving control performance of permanent magnet synchronous motor.
In view of the traditional flower pollination algorithm for parameter identification in permanent magnet synchronous motors, the late iteration often results in easily plunging into a local optimum, leading to slow convergence speed and the defect of low optimization accuracy. An improved flower pollination algorithm based on t-distributed perturbation and Gaussian perturbation (tGFPA) is proposed to realize high-precision identification of permanent magnet synchronous motors. Firstly, the individual position of flowers is initialized by chaotic logistic mapping, and then t-distribution perturbation is introduced in the global pollination process to improve the diversity of search space. Gaussian perturbation is added during local pollination to enhance the ability to jump out of the local optimal solution. Finally, comparing the simulation results show that the flower pollinate algorithm based on double perturbation strategy to improve convergence speed is faster and have higher precision, which has important significance for improving control performance of permanent magnet synchronous motor.
2024, 51(1):106-116.
DOI: 10.12177/emca.2023.169
Abstract:
Aiming at the problems of low traveling wave detection accuracy, mode mixing, weak anti-noise ability, and poor real-time fault location in the use of collective empirical mode decomposition (EEMD) for traveling wave faults localization in doubly-fed wind farm transmission lines, a traveling wave fault localization method based on the combination of fast ensemble empirical modal decomposition (FEEMD) and the improved Teager energy operator (NTEO) is proposed. This method uses FEEMD to decompose the fault current traveling wave signal into stationary intrinsic mode components and residual components, eliminating the noise components and preserving the signal integrity. Then the NTEO algorithm is used to denoise the decomposed high-frequency signal again to enhance the faulty traveling wave mutation characteristics and and accurately calibrate the traveling wave head. Simulation results show that the proposed method can accurately and quickly calibrate the fault traveling wave head precisely with good denoising effect, which improves the accuracy and speed of fault location compared with FEEMD-TEO and EEMD-NTEO traveling wave detection methods.
Aiming at the problems of low traveling wave detection accuracy, mode mixing, weak anti-noise ability, and poor real-time fault location in the use of collective empirical mode decomposition (EEMD) for traveling wave faults localization in doubly-fed wind farm transmission lines, a traveling wave fault localization method based on the combination of fast ensemble empirical modal decomposition (FEEMD) and the improved Teager energy operator (NTEO) is proposed. This method uses FEEMD to decompose the fault current traveling wave signal into stationary intrinsic mode components and residual components, eliminating the noise components and preserving the signal integrity. Then the NTEO algorithm is used to denoise the decomposed high-frequency signal again to enhance the faulty traveling wave mutation characteristics and and accurately calibrate the traveling wave head. Simulation results show that the proposed method can accurately and quickly calibrate the fault traveling wave head precisely with good denoising effect, which improves the accuracy and speed of fault location compared with FEEMD-TEO and EEMD-NTEO traveling wave detection methods.
2024, 51(1):117-125.
DOI: 10.12177/emca.2023.167
Abstract:
The single-phase cascaded H-bridge rectifier is taken as the object of study，and its control strategy is studied. Firstly, based on the double closed-loop control strategy, the dq feed-forward decoupling model is constructed, and the influence of the virtual AC component on the system is improved by the second-order generalized integral algorithm, the fast and accurate tracking of grid-side current to voltage phase and frequency is realized. Secondly, the traditional voltage balancing control algorithm is improved by defining the power balancing relationship, the output voltage square is taken as the control signal to enhance the adaptive ability of the system and improve the dynamic performance of the system during load switching. Finally, simulations based on MATLAB/Simulink software are performed to verify the correctness and effectiveness of the proposed strategy.
The single-phase cascaded H-bridge rectifier is taken as the object of study，and its control strategy is studied. Firstly, based on the double closed-loop control strategy, the dq feed-forward decoupling model is constructed, and the influence of the virtual AC component on the system is improved by the second-order generalized integral algorithm, the fast and accurate tracking of grid-side current to voltage phase and frequency is realized. Secondly, the traditional voltage balancing control algorithm is improved by defining the power balancing relationship, the output voltage square is taken as the control signal to enhance the adaptive ability of the system and improve the dynamic performance of the system during load switching. Finally, simulations based on MATLAB/Simulink software are performed to verify the correctness and effectiveness of the proposed strategy.
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Electric Machines & Control Application ® 2025
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
沪ICP备16038578号-3
Electric Machines & Control Application ® 2025
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
