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Volume 50,Issue 4,2023 Table of Contents
2023, 50(4):1-7，15.
DOI: 10.12177/emca.2023.031
Abstract:
For the controllable excitation magnetic levitation linear synchronous motor (CEMLLSM), the conventional iterative learning control (ILC) has low precision, large chattering and poor resistance to external disturbances. In order to improve the tracking accuracy, a variable gain adaptive ILC algorithm based on extended state observer (ESO) is designed. Firstly, the working principle and mathematical model of the CEMLLSM are studied. Secondly, a variable gain adaptive iterative learning controller based on ESO is designed. An exponential variable gain is introduced to the fixed gain part of the controller, and an adaptive iterative term is added to iteratively learn the unknown parameters in the control law, which reduces the chattering and error of the system, and speeds up the system convergence speed. By adding ESO, the external disturbance of system can be observed, and the control quantity is compensated to enhance the anti-disturbance performance of the system. Finally, the control system is simulated and analyzed with MATLAB, and the results show that the algorithm can successfully reduce tracking error and has a good suppression impact on disturbance.
For the controllable excitation magnetic levitation linear synchronous motor (CEMLLSM), the conventional iterative learning control (ILC) has low precision, large chattering and poor resistance to external disturbances. In order to improve the tracking accuracy, a variable gain adaptive ILC algorithm based on extended state observer (ESO) is designed. Firstly, the working principle and mathematical model of the CEMLLSM are studied. Secondly, a variable gain adaptive iterative learning controller based on ESO is designed. An exponential variable gain is introduced to the fixed gain part of the controller, and an adaptive iterative term is added to iteratively learn the unknown parameters in the control law, which reduces the chattering and error of the system, and speeds up the system convergence speed. By adding ESO, the external disturbance of system can be observed, and the control quantity is compensated to enhance the anti-disturbance performance of the system. Finally, the control system is simulated and analyzed with MATLAB, and the results show that the algorithm can successfully reduce tracking error and has a good suppression impact on disturbance.
2023, 50(4):8-15.
DOI: 10.12177/emca.2023.013
Abstract:
Permanent magnet motor is the mainstream motor in the industrial servo field for its high efficiency, high power density, and large torque and inertia ratio. Servo control technology is the key to give full play to the advantages of permanent magnet motor and improve the performance of servo system. At present, permanent magnet servo system mostly adopts multiloop cascaded proportionalintegral (PI) controllers. However, due to the lag effect of the integrator, the dynamic response speed of PI is slow and the antiinterference ability is poor, which is difficult to meet the dynamic and static performance requirements of highperformance servo control such as mechanical arm and precise machining. Therefore, a composite model predictive control strategy combining generalized model predict control and finite control set model perdict control is proposed. In addition, a low computational complexity implementation method of generalized model predictive control and a mechanical parameter estimation method are also proposed. The experimental results show that the proposed composite model predictive control can improve the dynamic response speed and load disturbance rejection capability of the permanent magnet servo motor.
Permanent magnet motor is the mainstream motor in the industrial servo field for its high efficiency, high power density, and large torque and inertia ratio. Servo control technology is the key to give full play to the advantages of permanent magnet motor and improve the performance of servo system. At present, permanent magnet servo system mostly adopts multiloop cascaded proportionalintegral (PI) controllers. However, due to the lag effect of the integrator, the dynamic response speed of PI is slow and the antiinterference ability is poor, which is difficult to meet the dynamic and static performance requirements of highperformance servo control such as mechanical arm and precise machining. Therefore, a composite model predictive control strategy combining generalized model predict control and finite control set model perdict control is proposed. In addition, a low computational complexity implementation method of generalized model predictive control and a mechanical parameter estimation method are also proposed. The experimental results show that the proposed composite model predictive control can improve the dynamic response speed and load disturbance rejection capability of the permanent magnet servo motor.
2023, 50(4):16-25.
DOI: 10.12177/emca.2023.025
Abstract:
Aiming at the design and adjustment of the weighting factors for model predictive torque control (MPTC) of permanent magnet synchronous motor (PMSM), the parallel form of multiobject cost functions connected by weighting factors is converted into the cascaded form of singleobject cost function, therefore to eliminate the weighting factors. The MPTC for surface PMSM based on cascaded method is established to study the effect of cascaded sequence and the number of output voltage vectors on the system control performance and calculation quantity. The method to simply the sorting comparison calculation and the optimization strategy to dynamically adjust the number of output voltage vectors using a fuzzy controller are proposed. The simulation results show the MPTC for surface PMSM based on cascaded method is feasible without the design and adjustment of weighting factors. When the first stage outputs 6 voltage vectors, the number of sorting comparison and the running time of the first stage using the simplified algorithm are reduced by 71.43% and 71.67% respectively, and the total running time is reduced by 2.28%. Compared with conventional cascaded method, the fuzzy dynamic cascaded MPTC can dynamically adjust the importance of different control objectives, decrease torque and stator flux ripple, suppress dynamic flux ripple, and optimize control performance.
Aiming at the design and adjustment of the weighting factors for model predictive torque control (MPTC) of permanent magnet synchronous motor (PMSM), the parallel form of multiobject cost functions connected by weighting factors is converted into the cascaded form of singleobject cost function, therefore to eliminate the weighting factors. The MPTC for surface PMSM based on cascaded method is established to study the effect of cascaded sequence and the number of output voltage vectors on the system control performance and calculation quantity. The method to simply the sorting comparison calculation and the optimization strategy to dynamically adjust the number of output voltage vectors using a fuzzy controller are proposed. The simulation results show the MPTC for surface PMSM based on cascaded method is feasible without the design and adjustment of weighting factors. When the first stage outputs 6 voltage vectors, the number of sorting comparison and the running time of the first stage using the simplified algorithm are reduced by 71.43% and 71.67% respectively, and the total running time is reduced by 2.28%. Compared with conventional cascaded method, the fuzzy dynamic cascaded MPTC can dynamically adjust the importance of different control objectives, decrease torque and stator flux ripple, suppress dynamic flux ripple, and optimize control performance.
2023, 50(4):26-31,38.
DOI: 10.12177/emca.2023.014
Abstract:
In order to optimize the control performance of permanent magnet synchronous motor (PMSM) servo system, a compound control strategy based on load observer and integral terminal sliding mode controller is proposed. Firstly, a PMSM model considering load disturbance is established. Then, an integral terminal sliding mode controller is designed based on the sliding mode surface and reaching law. In order to suppress the load disturbance, a load torque observer is introduced, and it is proved that the system is stable and can converge in finite time through Lyapunov′s theorem. Finally, the simulation results show that this control strategy has higher position tracking accuracy, faster response speed and stronger antiload capability.
In order to optimize the control performance of permanent magnet synchronous motor (PMSM) servo system, a compound control strategy based on load observer and integral terminal sliding mode controller is proposed. Firstly, a PMSM model considering load disturbance is established. Then, an integral terminal sliding mode controller is designed based on the sliding mode surface and reaching law. In order to suppress the load disturbance, a load torque observer is introduced, and it is proved that the system is stable and can converge in finite time through Lyapunov′s theorem. Finally, the simulation results show that this control strategy has higher position tracking accuracy, faster response speed and stronger antiload capability.
2023, 50(4):32-38.
DOI: 10.12177/emca.2023.033
Abstract:
The grille-type secondary structure of the short-primary single-sided linear induction motor (SSLIM) has problems such as small electromagnetic thrust and large normal suction. To solve these problems, an inverted trapezoidal secondary structure is proposed. The rectangular structure of the existing grid guide bar is changed into an inverted trapezoidal structure with a large upper surface area and a small lower surface area. The effective current-carrying volume and air gap magnetic density of the secondary induction plate are improved by using the large slip characteristics of the SSLIM and the resulting skin effect. Under the condition that the primary structure remains unchanged, the SSLIM finite element model of the inverted trapezoidal secondary structure is established, and compared with the traditional grille-type structure under three operating conditions of steady state, starting and braking, which verifies that the inverted trapezoidal structure has the advantages of large electromagnetic thrust and small normal suction.
The grille-type secondary structure of the short-primary single-sided linear induction motor (SSLIM) has problems such as small electromagnetic thrust and large normal suction. To solve these problems, an inverted trapezoidal secondary structure is proposed. The rectangular structure of the existing grid guide bar is changed into an inverted trapezoidal structure with a large upper surface area and a small lower surface area. The effective current-carrying volume and air gap magnetic density of the secondary induction plate are improved by using the large slip characteristics of the SSLIM and the resulting skin effect. Under the condition that the primary structure remains unchanged, the SSLIM finite element model of the inverted trapezoidal secondary structure is established, and compared with the traditional grille-type structure under three operating conditions of steady state, starting and braking, which verifies that the inverted trapezoidal structure has the advantages of large electromagnetic thrust and small normal suction.
2023, 50(4):39-42，48.
DOI: 10.12177/emca.2023.017
Abstract:
Compared with general motors, the large-scale submersible induction motor currently has the problem of excessive electromagnetic noise. The electromagnetic noise of largescale submersible motors can be reduced by using a radial skewed slot structure, but there are still some deficiencies. Based on the radial skewed slot structure, the electromagnetic noise is further weakened and other performances of the motor are improved by adjusting the twisting distance of the radial skewed slot. The electromagnetic noise of each scheme is analyzed and compared by using the multiphysical field coupling finite element simulation, and the correctness of the above method is verified.
Compared with general motors, the large-scale submersible induction motor currently has the problem of excessive electromagnetic noise. The electromagnetic noise of largescale submersible motors can be reduced by using a radial skewed slot structure, but there are still some deficiencies. Based on the radial skewed slot structure, the electromagnetic noise is further weakened and other performances of the motor are improved by adjusting the twisting distance of the radial skewed slot. The electromagnetic noise of each scheme is analyzed and compared by using the multiphysical field coupling finite element simulation, and the correctness of the above method is verified.
7 Influence of Cowling Structure on Convective Heat Transfer Characteristic of Motor Housing Surface
2023, 50(4):43-48.
DOI: 10.12177/emca.2023.023
Abstract:
In order to reduce the temperature rise of the components of the totally enclosed fan cooling (TEFC) motor as much as possible and avoid the damage of the insulation structure caused by the excessive temperature rise, the influence of the cowling structure on the convective heat transfer characteristic of the TEFC motor housing surface is studied by numerical calculation method. Firstly, the temperature rise experiment is carried out on a prototype. The error between the simulated value and the experimental value of the winding temperature rise is 6.2% and the feasibility of the numerical calculation method is verified. Secondly, the necessary simplification of the threedimensional model of the prototype is made in the numerical calculation. The influences of the outer diameter of the cowling, the distance between the end face of the cowling and the end face of the fin, and the motor speed on the lateral average Nusselt number of the housing surface are studied emphatically. Finally, the results show that when the fin structure on the housing surface is fixed, there is an optimal value for the outer diameter of the cowling to make the convective heat transfer effect on the housing surface optimal. When the end face of the cowling is in contact with the end face of the fin, the lateral average Nusselt number of the housing surface is the largest. In addition, the convective heat transfer capacity of the housing surface increases with the increase of the fan speed.
In order to reduce the temperature rise of the components of the totally enclosed fan cooling (TEFC) motor as much as possible and avoid the damage of the insulation structure caused by the excessive temperature rise, the influence of the cowling structure on the convective heat transfer characteristic of the TEFC motor housing surface is studied by numerical calculation method. Firstly, the temperature rise experiment is carried out on a prototype. The error between the simulated value and the experimental value of the winding temperature rise is 6.2% and the feasibility of the numerical calculation method is verified. Secondly, the necessary simplification of the threedimensional model of the prototype is made in the numerical calculation. The influences of the outer diameter of the cowling, the distance between the end face of the cowling and the end face of the fin, and the motor speed on the lateral average Nusselt number of the housing surface are studied emphatically. Finally, the results show that when the fin structure on the housing surface is fixed, there is an optimal value for the outer diameter of the cowling to make the convective heat transfer effect on the housing surface optimal. When the end face of the cowling is in contact with the end face of the fin, the lateral average Nusselt number of the housing surface is the largest. In addition, the convective heat transfer capacity of the housing surface increases with the increase of the fan speed.
2023, 50(4):49-57.
DOI: 10.12177/emca.2023.035
Abstract:
For the interconnected and high energy consumption industrial power grid with largescale new energy access, the fluctuation of new energy power will inevitably lead to the fluctuation of tie line power and additional standby capacity costs, which is not conducive to the economic operation of the industrial power grid. In order to deeply explore the frequency modulation resources on both sides of the source and load, based on the IEEE standard tworegion model, a cooperative frequency control strategy of the source and load considering the windaluminum combination is proposed. Firstly, the coupling relationship model between active power consumption and DC voltage of electrolytic aluminum load is established based on self saturating reactor. Secondly, based on the characteristics of electrolytic aluminum load, a power grid auxiliary frequency modulation strategy with electrolytic aluminum participation is proposed. At the same time, considering the fast frequency response ability of the wind turbine inertia control, the electrolytic aluminum load is combined with the wind turbine frequency modulation means to jointly participate in the system frequency regulation. Finally, the simulation results verify that the proposed control strategy can effectively suppress the frequency fluctuations of isolated power grid, and make the power system have stronger antiinterference and faster dynamic response.
For the interconnected and high energy consumption industrial power grid with largescale new energy access, the fluctuation of new energy power will inevitably lead to the fluctuation of tie line power and additional standby capacity costs, which is not conducive to the economic operation of the industrial power grid. In order to deeply explore the frequency modulation resources on both sides of the source and load, based on the IEEE standard tworegion model, a cooperative frequency control strategy of the source and load considering the windaluminum combination is proposed. Firstly, the coupling relationship model between active power consumption and DC voltage of electrolytic aluminum load is established based on self saturating reactor. Secondly, based on the characteristics of electrolytic aluminum load, a power grid auxiliary frequency modulation strategy with electrolytic aluminum participation is proposed. At the same time, considering the fast frequency response ability of the wind turbine inertia control, the electrolytic aluminum load is combined with the wind turbine frequency modulation means to jointly participate in the system frequency regulation. Finally, the simulation results verify that the proposed control strategy can effectively suppress the frequency fluctuations of isolated power grid, and make the power system have stronger antiinterference and faster dynamic response.
2023, 50(4):58-68,76.
DOI: 10.12177/emca.2023.019
Abstract:
With the increasing of wind power permeability, largescale wind power participation in frequency modulation becomes the most important part of wind power development, and power allocation method needs to be more intelligent and simple. Therefore, the objective function optimization method is used to optimize the power allocation of wind farm layer. Firstly, the frequency modulation power function of the whole wind farm is modeled so that the realtime power change value of the whole wind farm tracks the power to be distributed in the whole wind farm, and the minimum deviation between the above two is taken as the objective function. Secondly, the upper and lower limits of wind speed and active power output of each wind turbine in a certain period are obtained by ultrashortterm prediction method, and the variation limit of the pitch angle is taken as the restriction condition. Finally, the optimized power deviation value of each wind turbine is obtained and superimposed on the basic value of each wind turbine output for frequency modulation. By comparing with other power allocation methods, the superiority of the objective function optimization method is verified, which can improve the speed and reliability of wind farm frequency modulation.
With the increasing of wind power permeability, largescale wind power participation in frequency modulation becomes the most important part of wind power development, and power allocation method needs to be more intelligent and simple. Therefore, the objective function optimization method is used to optimize the power allocation of wind farm layer. Firstly, the frequency modulation power function of the whole wind farm is modeled so that the realtime power change value of the whole wind farm tracks the power to be distributed in the whole wind farm, and the minimum deviation between the above two is taken as the objective function. Secondly, the upper and lower limits of wind speed and active power output of each wind turbine in a certain period are obtained by ultrashortterm prediction method, and the variation limit of the pitch angle is taken as the restriction condition. Finally, the optimized power deviation value of each wind turbine is obtained and superimposed on the basic value of each wind turbine output for frequency modulation. By comparing with other power allocation methods, the superiority of the objective function optimization method is verified, which can improve the speed and reliability of wind farm frequency modulation.
2023, 50(4):69-76.
DOI: 10.12177/emca.2023.027
Abstract:
A dead time compensation strategy based on constant frequency hysteresis control is proposed to solve the problems of control accuracy degradation and harmonic content increase caused by inverter dead time. A constant frequency hysteresis control method for phase to phase current error is introduced, and the extended state observer is used to improve the sector judgment method. Through the current path before and after the switch action, it is analyzed that the error during the dead time will exceed the upper or lower limit of the hysteresis width. The magnitude of the error exceeding the loop width is calculated in real-time, and the actual ring width is adjusted to make the error just reach the expected ring width, so as to achieve the purpose of dead time compensation. The simulation of the inverter based on constant frequency hysteresis control verifies that the proposed strategy can accurately compensate the dead time.
A dead time compensation strategy based on constant frequency hysteresis control is proposed to solve the problems of control accuracy degradation and harmonic content increase caused by inverter dead time. A constant frequency hysteresis control method for phase to phase current error is introduced, and the extended state observer is used to improve the sector judgment method. Through the current path before and after the switch action, it is analyzed that the error during the dead time will exceed the upper or lower limit of the hysteresis width. The magnitude of the error exceeding the loop width is calculated in real-time, and the actual ring width is adjusted to make the error just reach the expected ring width, so as to achieve the purpose of dead time compensation. The simulation of the inverter based on constant frequency hysteresis control verifies that the proposed strategy can accurately compensate the dead time.
SUN Shitao
,
LEI Yu
,
LU Yi
,
SONG Peng
,
HAO Guowen
,
ZHANG Jie
,
DI Hongwei
,
ZHU Shouduo
,
MEI Jun
2023, 50(4):77-84，90.
DOI: 10.12177/emca.2023.018
Abstract:
The rotor of large hydro-generator, including the pump storage generator, is an explicit-pole rotor with multi-turn and long winding. The traditional fault diagnosing method of winding inter-turn short circuit based on AC impedance measurement has shortcomings in sensitivity and convenience. Based on the theory of multi-conductor transmission line, the port frequency domain characteristic model of the explicit-pole rotor winding is established, and the fault diagnosing and locating methods are proposed through the simulation analysis. Finally, the validity of the diagnosis method is verified by the fault simulation and test of the real rotor. The simulation and test results show that the proposed method can realize the diagnosis and location of winding inter-turn short circuit fault without disconnecting the electrical connection between magnetic poles.
The rotor of large hydro-generator, including the pump storage generator, is an explicit-pole rotor with multi-turn and long winding. The traditional fault diagnosing method of winding inter-turn short circuit based on AC impedance measurement has shortcomings in sensitivity and convenience. Based on the theory of multi-conductor transmission line, the port frequency domain characteristic model of the explicit-pole rotor winding is established, and the fault diagnosing and locating methods are proposed through the simulation analysis. Finally, the validity of the diagnosis method is verified by the fault simulation and test of the real rotor. The simulation and test results show that the proposed method can realize the diagnosis and location of winding inter-turn short circuit fault without disconnecting the electrical connection between magnetic poles.
2023, 50(4):85-90.
DOI: 10.12177/emca.2023.026
Abstract:
As an important part of aero-generator, rectifier circuit has many problems, such as frequent faults and difficult maintenance. In order to realize the fault diagnosis of doubly salient electro-magnetic generator (DSEG) rectifier circuit, a fault diagnosis method based on longshort term memory (LSTM) network is studied. Firstly, the three-phase armature current signals of the generator under various fault modes are collected. Secondly, different signal processing methods are used to process fault signals to obtain fault characteristic information. Then, the obtained fault characteristic data are divided into training and test samples and input to LSTM network for fault classification. Finally, the diagnosis results are calculated and analyzed. The simulation and experimental results show that the proposed method has a good fault diagnosis effect.
As an important part of aero-generator, rectifier circuit has many problems, such as frequent faults and difficult maintenance. In order to realize the fault diagnosis of doubly salient electro-magnetic generator (DSEG) rectifier circuit, a fault diagnosis method based on longshort term memory (LSTM) network is studied. Firstly, the three-phase armature current signals of the generator under various fault modes are collected. Secondly, different signal processing methods are used to process fault signals to obtain fault characteristic information. Then, the obtained fault characteristic data are divided into training and test samples and input to LSTM network for fault classification. Finally, the diagnosis results are calculated and analyzed. The simulation and experimental results show that the proposed method has a good fault diagnosis effect.
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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.
