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Volume 50,Issue 1,2023 Table of Contents
2023, 50(1):1-8.
DOI: 10.12177/emca.2022.145
Abstract:
When permanent magnet synchronous motor (PMSM) is driven by the inverter, the loss of motor can be greatly increased due to the influence of high content of time current harmonics generated by inverter, which can seriously affect safety and stability of motor operation. However, the loss suppression effect brought by traditional method of optimizing the structure of motor body is limited, which is not enough to solve this problem. For this situation, the control strategy of motor is analyzed, and a loss suppression method for PMSM based on harmonic injection algorithm is proposed. By suppressing 5th and 7th time current harmonics with highest component content, the loss of motor driven by the inverter is reduced. The fieldcircuit coupling joint simulation model is used as a calculation tool to verify the effectiveness of algorithm. The results show that the loss of motor is reduced by 24.9% after adding harmonic injection algorithm, and the effect of the proposed method is good, which provides a novel method for the loss suppression of motor.
When permanent magnet synchronous motor (PMSM) is driven by the inverter, the loss of motor can be greatly increased due to the influence of high content of time current harmonics generated by inverter, which can seriously affect safety and stability of motor operation. However, the loss suppression effect brought by traditional method of optimizing the structure of motor body is limited, which is not enough to solve this problem. For this situation, the control strategy of motor is analyzed, and a loss suppression method for PMSM based on harmonic injection algorithm is proposed. By suppressing 5th and 7th time current harmonics with highest component content, the loss of motor driven by the inverter is reduced. The fieldcircuit coupling joint simulation model is used as a calculation tool to verify the effectiveness of algorithm. The results show that the loss of motor is reduced by 24.9% after adding harmonic injection algorithm, and the effect of the proposed method is good, which provides a novel method for the loss suppression of motor.
2023, 50(1):9-13.
DOI: 10.12177/emca.2022.141
Abstract:
In view of the load torque disturbance effect on the control of the permanent magnet synchronous motor (PMSM)，an active disturbance rejection control (ADRC) strategy for PMSM based on feedforward compensation is proposed. The linear active disturbancerejection control (LADRC) is used to improve the contradiction between the rapidity and overshoot of the traditional PID controller, and the load torque feedforward compensation method is introduced. The torque observed by the load torque observer feeds back to the current loop in proportion when the load torque changes suddenly. The simulation results show that the control effect of the LADRC system with feedforward compensation is obviously optimized for the PMSM, and the speed fluctuation caused by the sudden load torque is effectively suppressed, which verifies the effectiveness of the strategy.
In view of the load torque disturbance effect on the control of the permanent magnet synchronous motor (PMSM)，an active disturbance rejection control (ADRC) strategy for PMSM based on feedforward compensation is proposed. The linear active disturbancerejection control (LADRC) is used to improve the contradiction between the rapidity and overshoot of the traditional PID controller, and the load torque feedforward compensation method is introduced. The torque observed by the load torque observer feeds back to the current loop in proportion when the load torque changes suddenly. The simulation results show that the control effect of the LADRC system with feedforward compensation is obviously optimized for the PMSM, and the speed fluctuation caused by the sudden load torque is effectively suppressed, which verifies the effectiveness of the strategy.
2023, 50(1):14-22.
DOI: 10.12177/emca.2022.152
Abstract:
The general intelligent contactor has a disadvantage of coil current pulsation. To overcome this disadvantage, a newtype intelligent control based on current feedback is innovatively applied in control and protective switch (CPS). The CPS with current feedback intelligent control module can not only keep the coil current smooth, but also improve the energysaving effect and reduce the power consumption. On this basis, a new method which can be used to simulate the dynamic characteristics of the electricmagnetic operating mechanism of CPS with current feedback intelligent control is proposed. The method builds a set of multifield equations, whose states are dynamically coupled with the feedback current signal and intertransform with time variation. The simulation result has a good agreement with the experiment result. The effects of hardware parameters on the performance of the control system of CPS are analyzed with the constructed model, and the hardware parameters are optimized by the analysis.
The general intelligent contactor has a disadvantage of coil current pulsation. To overcome this disadvantage, a newtype intelligent control based on current feedback is innovatively applied in control and protective switch (CPS). The CPS with current feedback intelligent control module can not only keep the coil current smooth, but also improve the energysaving effect and reduce the power consumption. On this basis, a new method which can be used to simulate the dynamic characteristics of the electricmagnetic operating mechanism of CPS with current feedback intelligent control is proposed. The method builds a set of multifield equations, whose states are dynamically coupled with the feedback current signal and intertransform with time variation. The simulation result has a good agreement with the experiment result. The effects of hardware parameters on the performance of the control system of CPS are analyzed with the constructed model, and the hardware parameters are optimized by the analysis.
2023, 50(1):23-29,34.
DOI: 10.12177/emca.2022.144
Abstract:
Contact and friction model of ultrasonic motors is of great importance for structure design and performance optimization. In order to describe the contact and friction problems of a ring type standing wave ultrasonic motor, a contact and friction model of the stator and rotor is proposed based on the coulomb friction law with viscous friction. The variation of frictional force on the contact surface in one vibration cycle is investigated based on the proposed model. The impacts of different radial vibration amplitudes and structural parameters of the stator on the performances of the motor are analyzed. Finally, torquespeed characteristics of the motor are measured. The experimental values are compared with the calculated values, and the good agreements are obtained. In addition, the torquespeed characteristics calculated by using the model based on coulomb friction law are also compared. The comparison results show that the model based on coulomb friction law with viscous friction describes the friction drive characteristics on the contact surface more accurately than the model based on coulomb friction law.
Contact and friction model of ultrasonic motors is of great importance for structure design and performance optimization. In order to describe the contact and friction problems of a ring type standing wave ultrasonic motor, a contact and friction model of the stator and rotor is proposed based on the coulomb friction law with viscous friction. The variation of frictional force on the contact surface in one vibration cycle is investigated based on the proposed model. The impacts of different radial vibration amplitudes and structural parameters of the stator on the performances of the motor are analyzed. Finally, torquespeed characteristics of the motor are measured. The experimental values are compared with the calculated values, and the good agreements are obtained. In addition, the torquespeed characteristics calculated by using the model based on coulomb friction law are also compared. The comparison results show that the model based on coulomb friction law with viscous friction describes the friction drive characteristics on the contact surface more accurately than the model based on coulomb friction law.
2023, 50(1):30-34.
DOI: 10.12177/emca.2022.149
Abstract:
For the analysis of the AC electrical machines, it is common to introduce rotational reference frames for the simplified analysis of AC electrical machines. Traditionally, the deduction of the governing equation under the rotational reference frames involve two steps. Step1 is constructing the voltage governing equation based on Faraday’s law under the “windingfixed reference frame”. Step2 is using the coordinate transformation to deduce of the governing equations under the rotational reference frame. The deduction processes are mathematically rigorous. However, it is difficult to understand and remember the physical meanings behind these mathematical equations. Inspired by the “inertial frame of reference” in the mechanical system, depending on whether Faraday’s law of electromagnetic induction applies, a kind of socalled “Faraday reference frame” is introduced. It is specially used to distinguish the governing equations under the windingfixed coordinate frame from the rotational reference frame. In this way, an additional “entrainment electromotive force” should be introduced for “nonFaraday reference frames” to characterize the effect of entrainment motion, motivated by the “inertia force” in the noninertial frame of reference.
For the analysis of the AC electrical machines, it is common to introduce rotational reference frames for the simplified analysis of AC electrical machines. Traditionally, the deduction of the governing equation under the rotational reference frames involve two steps. Step1 is constructing the voltage governing equation based on Faraday’s law under the “windingfixed reference frame”. Step2 is using the coordinate transformation to deduce of the governing equations under the rotational reference frame. The deduction processes are mathematically rigorous. However, it is difficult to understand and remember the physical meanings behind these mathematical equations. Inspired by the “inertial frame of reference” in the mechanical system, depending on whether Faraday’s law of electromagnetic induction applies, a kind of socalled “Faraday reference frame” is introduced. It is specially used to distinguish the governing equations under the windingfixed coordinate frame from the rotational reference frame. In this way, an additional “entrainment electromotive force” should be introduced for “nonFaraday reference frames” to characterize the effect of entrainment motion, motivated by the “inertia force” in the noninertial frame of reference.
2023, 50(1):35-43.
DOI: 10.12177/emca.2022.155
Abstract:
The friction nonlinearity affects the control performance of the DC servo system. To solve this problem, a variable gain active disturbance rejection control (VGADRC) method is proposed. A differential equation model of the DC servo system with the LuGre model is established. Based on this model, a composite controller combining the friction compensation and the active disturbance rejection control (ADRC) is designed. Without increasing the observe gain, the LuGre model of the controller is used to feedforward compensate for the friction nonlinearity in the system. At the same time, the effect of measurement noise on the system is reduced. In addition, to suppress the initial moment peaking of the conventional linear extended state observer (LESO), the third-order variable gain linear extended state observer (VGLESO) is used to estimate the total disturbance in the system. Finally, the simulation results demonstrate that the proposed control method can effectively improve the low-speed tracking performance and dynamic performance of the system.
The friction nonlinearity affects the control performance of the DC servo system. To solve this problem, a variable gain active disturbance rejection control (VGADRC) method is proposed. A differential equation model of the DC servo system with the LuGre model is established. Based on this model, a composite controller combining the friction compensation and the active disturbance rejection control (ADRC) is designed. Without increasing the observe gain, the LuGre model of the controller is used to feedforward compensate for the friction nonlinearity in the system. At the same time, the effect of measurement noise on the system is reduced. In addition, to suppress the initial moment peaking of the conventional linear extended state observer (LESO), the third-order variable gain linear extended state observer (VGLESO) is used to estimate the total disturbance in the system. Finally, the simulation results demonstrate that the proposed control method can effectively improve the low-speed tracking performance and dynamic performance of the system.
2023, 50(1):44-54.
DOI: 10.12177/emca.2022.151
Abstract:
The no-load back electromotive force (EMF), air-gap flux density, cogging torque and the other performances of the outer rotor permanent magnet synchronous motor (PMSM) solved and calculated which based on the global analytical method. The analytical calculated results are in good agreement with those calculated by the finite element method, which verifies the accuracy of the global analytical method for solving the outer rotor PMSM. On this basis, the second-generation non-dominated sorting genetic algorithm (NSGA-Ⅱ) is used to optimize the multiple structural parameters and performance of the motor with multiple objectives. Compared with the original method, the overall performance of the optimized motor has been effectively improved. The simulation as well as experimental verification proves the reasonable validity of the proposed method.
The no-load back electromotive force (EMF), air-gap flux density, cogging torque and the other performances of the outer rotor permanent magnet synchronous motor (PMSM) solved and calculated which based on the global analytical method. The analytical calculated results are in good agreement with those calculated by the finite element method, which verifies the accuracy of the global analytical method for solving the outer rotor PMSM. On this basis, the second-generation non-dominated sorting genetic algorithm (NSGA-Ⅱ) is used to optimize the multiple structural parameters and performance of the motor with multiple objectives. Compared with the original method, the overall performance of the optimized motor has been effectively improved. The simulation as well as experimental verification proves the reasonable validity of the proposed method.
2023, 50(1):55-61,70.
DOI: 10.12177/emca.2022.156
Abstract:
As the flexible-controlled power source in the power system, the doubly fed-based variable speed pumped storage unit (DF-VSPSU) has a significant role in the power rebalance and the reactive power support. However, under remote grid faults, the DF-VSPSU with the conventional low-voltage ride through control employed may lose the stability due to the absence of equilibrium point. Thus, taking one DF-VSPSU infinite-bus system as a case, the quasi-steady models of the DF-VSPSU generator-side characteristic and the grid-side characteristic are established. The stable boundary and the available region of DF-VSPSU are fully descripted with different grid conditions. Then, together with the sag depth of the remote voltage, the grid short circuit ratio, the grid impedance angle, and the reactive support coefficient, the existence of the equilibrium point of the DF-VSPSU is analyzed. Finally, the MATLAB/Simulink demonstrates availability of the theoretical analysis.
As the flexible-controlled power source in the power system, the doubly fed-based variable speed pumped storage unit (DF-VSPSU) has a significant role in the power rebalance and the reactive power support. However, under remote grid faults, the DF-VSPSU with the conventional low-voltage ride through control employed may lose the stability due to the absence of equilibrium point. Thus, taking one DF-VSPSU infinite-bus system as a case, the quasi-steady models of the DF-VSPSU generator-side characteristic and the grid-side characteristic are established. The stable boundary and the available region of DF-VSPSU are fully descripted with different grid conditions. Then, together with the sag depth of the remote voltage, the grid short circuit ratio, the grid impedance angle, and the reactive support coefficient, the existence of the equilibrium point of the DF-VSPSU is analyzed. Finally, the MATLAB/Simulink demonstrates availability of the theoretical analysis.
2023, 50(1):62-70.
DOI: 10.12177/emca.2022.147
Abstract:
Hybrid excited synchronous machine (HESM) is a research hotspot, and its design method is worth to discuss. The motor stator is designed by ANSYS RMxprt software and the traditional magnetic circuit method, and ANSYS Maxwell software is used to design the mixed excitation motor rotor and the motor parametric modeling is conducted. Furthermore, the Maxwell & Workbench & OptiSLang co-simulation model of 8-pole 48-slot TMPS-HESM is established. Finally, the Pareto solution set is obtained by global multiobjective optimization of the motor using particle swarm optimization (PSO) algorithm. The technique for order preference by similarity to an ideal solution (TOPSIS) method is used to objectively select the optimal design scheme from the solution set. A co-simulation design method of tangential magnetizing parallel structure hybrid excitation synchronous motor (TMPS-HESM) based on PSO algorithm is systematically proposed, and the performance of the motor is verified to meet the design requirements by the relevant finite element simulation tests.
Hybrid excited synchronous machine (HESM) is a research hotspot, and its design method is worth to discuss. The motor stator is designed by ANSYS RMxprt software and the traditional magnetic circuit method, and ANSYS Maxwell software is used to design the mixed excitation motor rotor and the motor parametric modeling is conducted. Furthermore, the Maxwell & Workbench & OptiSLang co-simulation model of 8-pole 48-slot TMPS-HESM is established. Finally, the Pareto solution set is obtained by global multiobjective optimization of the motor using particle swarm optimization (PSO) algorithm. The technique for order preference by similarity to an ideal solution (TOPSIS) method is used to objectively select the optimal design scheme from the solution set. A co-simulation design method of tangential magnetizing parallel structure hybrid excitation synchronous motor (TMPS-HESM) based on PSO algorithm is systematically proposed, and the performance of the motor is verified to meet the design requirements by the relevant finite element simulation tests.
2023, 50(1):71-76.
DOI: 10.12177/emca.2022.143
Abstract:
The rotor step skewing can effectively reduce the torque ripple of the permanent magnet synchronous motor (PMSM), but it will decrease the average output torque of the motor. In order to solve this problem, the magnetic isolation bridge is optimized on the basis of the rotor step skewing to improve the average output torque. Firstly, the influence of the rotor step skewing on the cogging torque, no-load back electromotive force (EMF), torque ripple and average output torque of the motor is analyzed, and the optimal number of rotor segments and step skewing angle are selected. The segments is 3, the step skewing angle is 5°, the torque ripple keeps unchanged. Under these conditions, the optimal magnetic isolation bridge structure is found by optimizing the rotor parameters HRib and Dmin, and the average output torque increases from 138.5 N·m to 147.2 N·m. The effectiveness of the method is verified. Meanwhile, the peak value of cogging torque decreases from 0.24 N·m to 0.18 N·m, the amplitude of no-load back EMF fundamental wave increases from 278.7 V to 288.6 V, and the harmonic distortion rate is nearly unchanged. The results indicate that other performances of the motor can be improved after optimization of the magnetic isolation bridge.
The rotor step skewing can effectively reduce the torque ripple of the permanent magnet synchronous motor (PMSM), but it will decrease the average output torque of the motor. In order to solve this problem, the magnetic isolation bridge is optimized on the basis of the rotor step skewing to improve the average output torque. Firstly, the influence of the rotor step skewing on the cogging torque, no-load back electromotive force (EMF), torque ripple and average output torque of the motor is analyzed, and the optimal number of rotor segments and step skewing angle are selected. The segments is 3, the step skewing angle is 5°, the torque ripple keeps unchanged. Under these conditions, the optimal magnetic isolation bridge structure is found by optimizing the rotor parameters HRib and Dmin, and the average output torque increases from 138.5 N·m to 147.2 N·m. The effectiveness of the method is verified. Meanwhile, the peak value of cogging torque decreases from 0.24 N·m to 0.18 N·m, the amplitude of no-load back EMF fundamental wave increases from 278.7 V to 288.6 V, and the harmonic distortion rate is nearly unchanged. The results indicate that other performances of the motor can be improved after optimization of the magnetic isolation bridge.
2023, 50(1):77-82.
DOI: 10.12177/emca.2022.153
Abstract:
Based on the Taguchi's orthogonal design experiment, taking the maximum temperature of the stator winding as the experimental index, the influence of the parameters of the cooling ribs on the heat dissipation performance of the motor is analyzed by the numerical simulation. Through the range analysis, it is found that the order of the factors affecting the maximum temperature of the stator winding is， the height of the cooling ribs, the spacing of the cooling ribs, and the width of the cooling ribs. Considering the material cost and the weight reduction requirements of the motor, the best level combination is obtained as the height of the cooling rib is 30 mm, the width of the cooling rib is 4 mm, and the spacing of the cooling rib is 20 mm.
Based on the Taguchi's orthogonal design experiment, taking the maximum temperature of the stator winding as the experimental index, the influence of the parameters of the cooling ribs on the heat dissipation performance of the motor is analyzed by the numerical simulation. Through the range analysis, it is found that the order of the factors affecting the maximum temperature of the stator winding is， the height of the cooling ribs, the spacing of the cooling ribs, and the width of the cooling ribs. Considering the material cost and the weight reduction requirements of the motor, the best level combination is obtained as the height of the cooling rib is 30 mm, the width of the cooling rib is 4 mm, and the spacing of the cooling rib is 20 mm.
12 Fault Area Determination Technology of Grid-Connected Photovoltaic Microgrid in 4D Coordinate System
2023, 50(1):83-89.
DOI: 10.12177/emca.2022.148
Abstract:
In order to reasonably divide the microgrid topology and accurately determine the fault area under various microgrid faults, a fault area determination technology of grid connected photovoltaic microgrid in 4D coordinate system is proposed. The microgrid topology is taken as a constellation diagram and the equipment nodes are selected as constellation points. On the basis of maximizing the minimum Euclidean distance between constellation points and minimizing the number of average nearest neighbor constellation points, using the set division method of ball filling 4D constellation point set to divide the microgrid topology and obtain the microgrid division area. Taking each divided area as the node and the circuit breaker as the edge, the microgrid fault mathematical model is constructed by graph theory algorithm. According to the power change before and after the fault and the direction of regional fault current, the fault area judgment matrix is established to realize the fault area judgment. The experiments show that this technology can effectively divide the microgrid topology and improve the signal transmission effect of microgrid. In case of multiple faults, twophase faults and system side faults, the technology can accurately determine the fault area.
In order to reasonably divide the microgrid topology and accurately determine the fault area under various microgrid faults, a fault area determination technology of grid connected photovoltaic microgrid in 4D coordinate system is proposed. The microgrid topology is taken as a constellation diagram and the equipment nodes are selected as constellation points. On the basis of maximizing the minimum Euclidean distance between constellation points and minimizing the number of average nearest neighbor constellation points, using the set division method of ball filling 4D constellation point set to divide the microgrid topology and obtain the microgrid division area. Taking each divided area as the node and the circuit breaker as the edge, the microgrid fault mathematical model is constructed by graph theory algorithm. According to the power change before and after the fault and the direction of regional fault current, the fault area judgment matrix is established to realize the fault area judgment. The experiments show that this technology can effectively divide the microgrid topology and improve the signal transmission effect of microgrid. In case of multiple faults, twophase faults and system side faults, the technology can accurately determine the fault area.
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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.
