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Volume 48,Issue 1,2021 Table of Contents
2021, 48(1):1-7，19.
DOI: 10.12177/emca.2020.195
Abstract:
Due to the merits of rugged structure, strong fault tolerance and high control flexibility, doubly salient electro-magnetic motor (DSEM) can compose a novel competitive aero brushless DC starter generator (SG) system. The composition and working principle of the doubly salient electro-magnetic SG system are briefly described. In response to the requirements of the special application field of aviation power supply, key technologies such as high reliability control, high efficiency and high power density control, and integrated control of the doubly salient electro-magnetic SG are summarized. The developing trends of the above key control techniques for doubly salient electro-magnetic SG are discussed.
Due to the merits of rugged structure, strong fault tolerance and high control flexibility, doubly salient electro-magnetic motor (DSEM) can compose a novel competitive aero brushless DC starter generator (SG) system. The composition and working principle of the doubly salient electro-magnetic SG system are briefly described. In response to the requirements of the special application field of aviation power supply, key technologies such as high reliability control, high efficiency and high power density control, and integrated control of the doubly salient electro-magnetic SG are summarized. The developing trends of the above key control techniques for doubly salient electro-magnetic SG are discussed.
2021, 48(1):8-13.
DOI: 10.12177/emca.2020.163
Abstract:
The magnetic levitation system of controllable excitation linear synchronous motor has the characteristics of nonlinearity and disturbance uncertainty, and the fuzzy PID control has strong pertinence. However, the fuzzy PID controller is a three-input single-output controller with too many rules, so that the design of the controller is very complex. Therefore, a synthetic fuzzy control system for the controllable excitation linear synchronous motor is proposed. The structure of the motor is studied, and the mathematical model is established. The fuzzy PID controller is composed of fuzzy PD controller and fuzzy integral controller, which can improve the steady-state accuracy of the controlled motor and reduce the number of fuzzy control rules. The fuzzy PD controller and fuzzy integral controller are designed respectively, including fuzzification, fuzzy reasoning, deblurring and so on. The simulation model of the controlled motor is established in MATLAB. The simulation results show that the synthetic fuzzy controller has good control effect, reduces the steady-state error, and improves the control accuracy.
The magnetic levitation system of controllable excitation linear synchronous motor has the characteristics of nonlinearity and disturbance uncertainty, and the fuzzy PID control has strong pertinence. However, the fuzzy PID controller is a three-input single-output controller with too many rules, so that the design of the controller is very complex. Therefore, a synthetic fuzzy control system for the controllable excitation linear synchronous motor is proposed. The structure of the motor is studied, and the mathematical model is established. The fuzzy PID controller is composed of fuzzy PD controller and fuzzy integral controller, which can improve the steady-state accuracy of the controlled motor and reduce the number of fuzzy control rules. The fuzzy PD controller and fuzzy integral controller are designed respectively, including fuzzification, fuzzy reasoning, deblurring and so on. The simulation model of the controlled motor is established in MATLAB. The simulation results show that the synthetic fuzzy controller has good control effect, reduces the steady-state error, and improves the control accuracy.
2021, 48(1):14-19.
DOI: 10.12177/emca.2020.183
Abstract:
Large current harmonics and severe fluctuations occur in active and reactive power for single vector model predictive direct power control (MPDPC) of sixphase permanent magnet synchronous generator (PMSG). Aiming at these problems, a duty cycle synthetic vector MPDPC is proposed. By reconstructing the large and mediumlarge voltage vectors of the sixphase rectifier, twelve synthetic vectors are obtained, and the harmonic currents are effectively suppressed. On this basis, aiming at further suppressing the fluctuation of active and reactive power, a synthetic vector and a zero vector are used simultaneously in each cycle, and the optimal duty cycle is calculated according to the principle of deadbeat prediction of active and reactive power. Experimental results show that the proposed duty cycle synthetic vector MPDPC can effectively reduce current harmonics and power ripples.
Large current harmonics and severe fluctuations occur in active and reactive power for single vector model predictive direct power control (MPDPC) of sixphase permanent magnet synchronous generator (PMSG). Aiming at these problems, a duty cycle synthetic vector MPDPC is proposed. By reconstructing the large and mediumlarge voltage vectors of the sixphase rectifier, twelve synthetic vectors are obtained, and the harmonic currents are effectively suppressed. On this basis, aiming at further suppressing the fluctuation of active and reactive power, a synthetic vector and a zero vector are used simultaneously in each cycle, and the optimal duty cycle is calculated according to the principle of deadbeat prediction of active and reactive power. Experimental results show that the proposed duty cycle synthetic vector MPDPC can effectively reduce current harmonics and power ripples.
2021, 48(1):20-27，34.
DOI: 10.12177/emca.2020.175
Abstract:
In order to eliminate the weighting value of traditional model predictive torque control (MPTC) of induction motor (IM) and reduce the computational complexity of the algorithm, a deadbeat based MPTC method is proposed. According to the relationship among torque, flux and voltage, an expected voltage vector is obtained based on deadbeat control of flux linkage. By judging the position of expected voltage vector, the number of voltage control sets is reduced from 8 to 2, which reduces the computational burden of MPTC. In addition, the value function contains only one variable of torque to achieve the desired control effect, avoiding the design of weighting value. The simplified three-vector synthesis virtual voltage vector not only expands the vector selection domain, but also reduces the complexity of the traditional virtual voltage vector algorithm and improves the steadystate performance of the control. Simulation and experimental results show that the proposed method has good dynamic and static performance.
In order to eliminate the weighting value of traditional model predictive torque control (MPTC) of induction motor (IM) and reduce the computational complexity of the algorithm, a deadbeat based MPTC method is proposed. According to the relationship among torque, flux and voltage, an expected voltage vector is obtained based on deadbeat control of flux linkage. By judging the position of expected voltage vector, the number of voltage control sets is reduced from 8 to 2, which reduces the computational burden of MPTC. In addition, the value function contains only one variable of torque to achieve the desired control effect, avoiding the design of weighting value. The simplified three-vector synthesis virtual voltage vector not only expands the vector selection domain, but also reduces the complexity of the traditional virtual voltage vector algorithm and improves the steadystate performance of the control. Simulation and experimental results show that the proposed method has good dynamic and static performance.
2021, 48(1):28-34.
DOI: 10.12177/emca.2020.176
Abstract:
High common-mode voltage and large current ripple occur in the permanent magnet synchronous motor （PMSM） drive system. Aiming at these problems, near state pulse width modulation （NSPWM） combined with a three-vector model predictive current control algorithm is proposed for the control. The existing single-vector model common-mode voltage suppression strategy has a fixed voltage vector direction, a limited range of selectable vectors, and a large current ripple. The three-vector model predictive current control common-mode voltage suppression strategy is based on NSPWM, three non-zero vectors are used in each sector to synthesize the target voltage vector, and a wide vector range is covered. Combined with deadbeat current control, while common-mode voltage suppression is realized, current ripple is reduced and system dynamic response is improved. Finally, the effectiveness of the proposed control strategy is verified by simulation and experiment.
High common-mode voltage and large current ripple occur in the permanent magnet synchronous motor （PMSM） drive system. Aiming at these problems, near state pulse width modulation （NSPWM） combined with a three-vector model predictive current control algorithm is proposed for the control. The existing single-vector model common-mode voltage suppression strategy has a fixed voltage vector direction, a limited range of selectable vectors, and a large current ripple. The three-vector model predictive current control common-mode voltage suppression strategy is based on NSPWM, three non-zero vectors are used in each sector to synthesize the target voltage vector, and a wide vector range is covered. Combined with deadbeat current control, while common-mode voltage suppression is realized, current ripple is reduced and system dynamic response is improved. Finally, the effectiveness of the proposed control strategy is verified by simulation and experiment.
2021, 48(1):35-40.
DOI: 10.12177/emca.2020.178
Abstract:
The output three-phase current of the inverter based on the control strategy of virtual synchronous generator (VSG) is unbalanced and the current amplitude is too large. To solve this problem, a VSG balanced current control strategy based on voltage feedforward is proposed. The transfer function of the feedforward controller is derived by using the control block diagram of the VSG current inner loop, and then the grid voltage is fed forward to the current inner loop through the feedforward controller. The interference of the fault voltage to the current waveform and the current distortion rate are reduced. The average values of instantaneous active power and reactive power are fed back to VSG algorithm to get the voltage reference instruction of restraining negative sequence current, which can make the grid connected current keep three-phase balance and stable amplitude during the voltage fault period. Finally, the effectiveness of the proposed control strategy is proved by MATLAB/Simulink simulation.
The output three-phase current of the inverter based on the control strategy of virtual synchronous generator (VSG) is unbalanced and the current amplitude is too large. To solve this problem, a VSG balanced current control strategy based on voltage feedforward is proposed. The transfer function of the feedforward controller is derived by using the control block diagram of the VSG current inner loop, and then the grid voltage is fed forward to the current inner loop through the feedforward controller. The interference of the fault voltage to the current waveform and the current distortion rate are reduced. The average values of instantaneous active power and reactive power are fed back to VSG algorithm to get the voltage reference instruction of restraining negative sequence current, which can make the grid connected current keep three-phase balance and stable amplitude during the voltage fault period. Finally, the effectiveness of the proposed control strategy is proved by MATLAB/Simulink simulation.
2021, 48(1):41-45，104.
DOI: 10.12177/emca.2020.181
Abstract:
Wind power forecast is of great significance for the safe and stable operation of wind farms and power grid dispatching. At present, the selection of wind power short-term forecast indicators is unreasonable and the forecast accuracy is low. Aiming at these problems, a short-term wind power forecast model based on Pearson correlation coefficient (PCC) and radial basis function (RBF) neural network is proposed. Firstly, three indicators closely related to wind power, e.g., current, temperature and wind speed, are selected by PCC. Then, these three indicators are used as the input of the forecast model for RBF samples training and short-term forecast of wind power. The results show that the proposed forecast model has smaller forecast error and higher prediction accuracy. It can meet the requirements of short-term wind power prediction and has a wide application prospect.
Wind power forecast is of great significance for the safe and stable operation of wind farms and power grid dispatching. At present, the selection of wind power short-term forecast indicators is unreasonable and the forecast accuracy is low. Aiming at these problems, a short-term wind power forecast model based on Pearson correlation coefficient (PCC) and radial basis function (RBF) neural network is proposed. Firstly, three indicators closely related to wind power, e.g., current, temperature and wind speed, are selected by PCC. Then, these three indicators are used as the input of the forecast model for RBF samples training and short-term forecast of wind power. The results show that the proposed forecast model has smaller forecast error and higher prediction accuracy. It can meet the requirements of short-term wind power prediction and has a wide application prospect.
8 Transient Stability Assessment Based on Kernel Principal Component Analysis and Deep Belief Network
2021, 48(1):46-52.
DOI: 10.12177/emca.2020.185
Abstract:
Aiming at the problems of poor real-time performance and high error rate of power system transient stability assessment, a method of transient stability assessment based on kernel principal component analysis combined with deep belief network is proposed. Firstly, a set of eigenvectors reflecting the transient stability of power system is constructed. Secondly, the feature vector set is extracted based on kernel principal component analysis, and the dimensionality of feature vector is reduced and the redundant features are filtered. The reduced eigenvectors are transmitted to the deep belief network. Finally, training analysis is carried out. The training process includes pretraining and fine tuning to optimize network parameters, and then the evaluation accuracy of deep confidence network is improved. The simulation results of New England 10-machine 39-bus system show that the method can effectively reduce the dimensionality of input data, remove redundant features, reduce the error rate and test time of transient stability assessment, as well as accurately and quickly judge the steady state of power system.
Aiming at the problems of poor real-time performance and high error rate of power system transient stability assessment, a method of transient stability assessment based on kernel principal component analysis combined with deep belief network is proposed. Firstly, a set of eigenvectors reflecting the transient stability of power system is constructed. Secondly, the feature vector set is extracted based on kernel principal component analysis, and the dimensionality of feature vector is reduced and the redundant features are filtered. The reduced eigenvectors are transmitted to the deep belief network. Finally, training analysis is carried out. The training process includes pretraining and fine tuning to optimize network parameters, and then the evaluation accuracy of deep confidence network is improved. The simulation results of New England 10-machine 39-bus system show that the method can effectively reduce the dimensionality of input data, remove redundant features, reduce the error rate and test time of transient stability assessment, as well as accurately and quickly judge the steady state of power system.
2021, 48(1):53-60.
DOI: 10.12177/emca.2020.174
Abstract:
Cogging torque is one of the important problems of permanent magnet motors. Weakening the cogging torque can reduce torque ripple, reduce electromagnetic noise, and improve motor stability. The cogging torque of the surface permanent magnet synchronous motor (SPMSM) is studied based on magnetic pole parameters. Based on the energy method and Fourier decomposition, the cogging torque formulas under different permanent magnet models are derived. It is found that the change of magnetic pole parameters affects the permanent magnet remanence distribution in the air gap and the relative permeability of the air gap, thereby changing the cogging torque. Then combined with the finite element method, the cogging torque of different permanent magnet models is simulated and analyzed. It is found that the polecut structure and combined magnetic poles significantly weaken the cogging torque. The magnetic pole parameters of these two structures are optimized by the finite element method. The influence of magnetic pole parameters on other performances of the motor is analyzed. The result shows that reasonable selection of permanent magnet parameters can significantly reduce cogging torque while ensuring motor performance.
Cogging torque is one of the important problems of permanent magnet motors. Weakening the cogging torque can reduce torque ripple, reduce electromagnetic noise, and improve motor stability. The cogging torque of the surface permanent magnet synchronous motor (SPMSM) is studied based on magnetic pole parameters. Based on the energy method and Fourier decomposition, the cogging torque formulas under different permanent magnet models are derived. It is found that the change of magnetic pole parameters affects the permanent magnet remanence distribution in the air gap and the relative permeability of the air gap, thereby changing the cogging torque. Then combined with the finite element method, the cogging torque of different permanent magnet models is simulated and analyzed. It is found that the polecut structure and combined magnetic poles significantly weaken the cogging torque. The magnetic pole parameters of these two structures are optimized by the finite element method. The influence of magnetic pole parameters on other performances of the motor is analyzed. The result shows that reasonable selection of permanent magnet parameters can significantly reduce cogging torque while ensuring motor performance.
2021, 48(1):61-67.
DOI: 10.12177/emca.2020.179
Abstract:
The performance of mine fans directly influences the production safety of the coal mine. In order to maintain the same speed of the two rotors of contra-rotating dual-rotor permanent magnet synchronous motor（CDPMSM）, the dualrotor synchronization technology of the CDPMSM for the counter-rotating fan is studied. Through the special permanent magnet material selection and the dual-rotor size matching method, the synchronization of the two rotors in steady state is ensured. The characteristics of the stator coupling magnetic field are analyzed. The model of equivalent magnetic network based on parallel magnetic circuit is established by introducing stator core normal direction reluctance and tangential direction reluctance. A deviation coupling control system is established to ensure the dynamic synchronization capability of the two rotors. The research results show that the CDPMSM can maintain good speed synchronization ability under asymmetric load.
The performance of mine fans directly influences the production safety of the coal mine. In order to maintain the same speed of the two rotors of contra-rotating dual-rotor permanent magnet synchronous motor（CDPMSM）, the dualrotor synchronization technology of the CDPMSM for the counter-rotating fan is studied. Through the special permanent magnet material selection and the dual-rotor size matching method, the synchronization of the two rotors in steady state is ensured. The characteristics of the stator coupling magnetic field are analyzed. The model of equivalent magnetic network based on parallel magnetic circuit is established by introducing stator core normal direction reluctance and tangential direction reluctance. A deviation coupling control system is established to ensure the dynamic synchronization capability of the two rotors. The research results show that the CDPMSM can maintain good speed synchronization ability under asymmetric load.
2021, 48(1):68-72,77.
DOI: 10.12177/emca.2020.168
Abstract:
In wind power generators, the taper angles of the inner and outer rings of the shrink disk have a great influence on the friction, but there is a lack of relevant theoretical analysis at present. Through the finite element simulation, the stress distribution, deformation range, and stress change of the inner and outer rings after the interference fit of the shrink disk are theoretically analyzed. Line charts are plotted to compare the simulation data with the theoretical calculation data. The results show that the optimal angle of the inner and outer ring cones of the wind power generator shrink disk is about 3°. The closer the angle value is to 3°, the smaller the error between the theoretically calculated interference value and the simulated interference value. In general, from the outside to the inside, the contact pressure values of the three contact surfaces of the shrink disk gradually decrease and the corresponding contact surface interference values gradually decrease. On the contact surface between the outer ring and the inner ring, the linearity of the relationship between the interference value and the angle change is the highest, and the ratio of the interference to the angle value is about 1.38.
In wind power generators, the taper angles of the inner and outer rings of the shrink disk have a great influence on the friction, but there is a lack of relevant theoretical analysis at present. Through the finite element simulation, the stress distribution, deformation range, and stress change of the inner and outer rings after the interference fit of the shrink disk are theoretically analyzed. Line charts are plotted to compare the simulation data with the theoretical calculation data. The results show that the optimal angle of the inner and outer ring cones of the wind power generator shrink disk is about 3°. The closer the angle value is to 3°, the smaller the error between the theoretically calculated interference value and the simulated interference value. In general, from the outside to the inside, the contact pressure values of the three contact surfaces of the shrink disk gradually decrease and the corresponding contact surface interference values gradually decrease. On the contact surface between the outer ring and the inner ring, the linearity of the relationship between the interference value and the angle change is the highest, and the ratio of the interference to the angle value is about 1.38.
2021, 48(1):73-77.
DOI: 10.12177/emca.2020.169
Abstract:
IE5, published by International Electrotechnical Commission (IEC) in 2016, is currently the highest energy efficiency of motor in the world. The development of IE5 energy efficiency three-phase asynchronous motor is carried out. For the motor design, we consider to use high-quality cold rolled silicon steel sheet, try different fan structural styles and windings with unequal turns, and use cast copper rotor in low power motors, so as to lower the motor loss. For the process technology, measures to improve the machining accuracy and reduce burrs during stator and rotor punching are applied, so that the no-load loss of the motor can be further reduced. Prototype test results show that the indices including efficiency, power factor, starting current, starting torque, maximum torque and temperature rise all meet the design requirements. The goal of IE5 energy efficiency is achieved.
IE5, published by International Electrotechnical Commission (IEC) in 2016, is currently the highest energy efficiency of motor in the world. The development of IE5 energy efficiency three-phase asynchronous motor is carried out. For the motor design, we consider to use high-quality cold rolled silicon steel sheet, try different fan structural styles and windings with unequal turns, and use cast copper rotor in low power motors, so as to lower the motor loss. For the process technology, measures to improve the machining accuracy and reduce burrs during stator and rotor punching are applied, so that the no-load loss of the motor can be further reduced. Prototype test results show that the indices including efficiency, power factor, starting current, starting torque, maximum torque and temperature rise all meet the design requirements. The goal of IE5 energy efficiency is achieved.
2021, 48(1):78-82.
DOI: 10.12177/emca.2020.171
Abstract:
Due to its material characteristics and microstructure, soft magnetic composite (SMC) material has the advantages of low eddy current loss coefficient, isotropy and so on. It is suitable for the design of ultra-high-speed permanent magnet synchronous motor (PMSM), which can effectively reduce the motor iron loss. Taking a PMSM with a rotation speed of 4 000 r/min and a frequency of 533.33 Hz as an example, the comparison analysis and finite element simulation calculation of SMC materials and silicon steel sheets are carried out from the aspects of electromagnetic properties and iron loss analysis. The validity of SMC material analysis results is verified by prototype test. The analytical method is used and a 120 000 r/min ultra-high-speed PMSM using SMC material is taken as an example to compare and analyze the influence of different pole and slot matching on electromagnetic performance. It provides certain guidance for the application of SMC materials to ultra-high-speed PMSM.
Due to its material characteristics and microstructure, soft magnetic composite (SMC) material has the advantages of low eddy current loss coefficient, isotropy and so on. It is suitable for the design of ultra-high-speed permanent magnet synchronous motor (PMSM), which can effectively reduce the motor iron loss. Taking a PMSM with a rotation speed of 4 000 r/min and a frequency of 533.33 Hz as an example, the comparison analysis and finite element simulation calculation of SMC materials and silicon steel sheets are carried out from the aspects of electromagnetic properties and iron loss analysis. The validity of SMC material analysis results is verified by prototype test. The analytical method is used and a 120 000 r/min ultra-high-speed PMSM using SMC material is taken as an example to compare and analyze the influence of different pole and slot matching on electromagnetic performance. It provides certain guidance for the application of SMC materials to ultra-high-speed PMSM.
14 A Hybrid Modulation Strategy for Modular Multilevel Converter Operating at Low Switching Frequency
2021, 48(1):83-89,94.
DOI: 10.12177/emca.2020.167
Abstract:
In recent years, voltage source HVDC transmission technology based on modular multilevel converter (MMC) has been widely used. In order to reduce the voltage fluctuation of the sub-module capacitor as much as possible without increasing the switching frequency, and reduce the harmonic content in the system output, a hybrid modulation strategy which can meet the requirements of HVDC transmission is proposed by combining the advantages of nearest level approximation modulation (NLM) and pulse width modulation (PWM). In this method, PWM is added on the basis of step modulation, and the error signal is modulated twice. The sub-module unit selection method is used to construct capacitor voltage average, balance control and current closed-loop control, so as to carry out real-time feedback correction for the switching state of each sub-module, so that the system can still control the voltage fluctuation of the sub-module capacitor and the output harmonic content at a lower switching frequency. Finally, the method is proved to be effective and feasible on the MATLAB/Simulink platform.
In recent years, voltage source HVDC transmission technology based on modular multilevel converter (MMC) has been widely used. In order to reduce the voltage fluctuation of the sub-module capacitor as much as possible without increasing the switching frequency, and reduce the harmonic content in the system output, a hybrid modulation strategy which can meet the requirements of HVDC transmission is proposed by combining the advantages of nearest level approximation modulation (NLM) and pulse width modulation (PWM). In this method, PWM is added on the basis of step modulation, and the error signal is modulated twice. The sub-module unit selection method is used to construct capacitor voltage average, balance control and current closed-loop control, so as to carry out real-time feedback correction for the switching state of each sub-module, so that the system can still control the voltage fluctuation of the sub-module capacitor and the output harmonic content at a lower switching frequency. Finally, the method is proved to be effective and feasible on the MATLAB/Simulink platform.
15 Application of 10 kV Converter in Motor Control of Centrifugal Pump in Oil Transportation Station
2021, 48(1):90-94.
DOI: 10.12177/emca.2020.165
Abstract:
In order to verify the practical application effect of asynchronous motor variable frequency speed regulation in oil transportation station, the working characteristics of the variable frequency speed regulating pump (centrifugal pump), the energy analysis of the moving fluid and the power factor of the motor are analyzed. Then, the operation data of the frequency conversion centrifugal pump and non-frequency conversion (power frequency) centrifugal pump installed in series and operated at the same time in an oil transportation station are analyzed and verified. The results of theoretical analysis and statistical analysis are consistent. It is proved that the variable frequency speed regulation (frequency reduction) of asynchronous motor has remarkable energy saving effect, the oil pipeline pressure regulation range is wider, and the motor power factor is improved.
In order to verify the practical application effect of asynchronous motor variable frequency speed regulation in oil transportation station, the working characteristics of the variable frequency speed regulating pump (centrifugal pump), the energy analysis of the moving fluid and the power factor of the motor are analyzed. Then, the operation data of the frequency conversion centrifugal pump and non-frequency conversion (power frequency) centrifugal pump installed in series and operated at the same time in an oil transportation station are analyzed and verified. The results of theoretical analysis and statistical analysis are consistent. It is proved that the variable frequency speed regulation (frequency reduction) of asynchronous motor has remarkable energy saving effect, the oil pipeline pressure regulation range is wider, and the motor power factor is improved.
2021, 48(1):95-100.
DOI: 10.12177/emca.2020.172
Abstract:
In order to realize the system integration of controller，sensors application and execution unit in wind generator operation and maintenance robot, a design method of host computer control interface is proposed. This method mainly solves the problem of system integration between host computer (including control system and control interface in host computer) and lower computer (including vision system，magnetic measurement system and driver system). Meanwhile, according to coordinate value and angle value from the vision system, it is judged that if the actual value meets the requirement of reference value by the background program of control interface in the host computer. Then, it is determined whether the bolts in wind generator are loose or not. The actual value of magnetic flux and stress from the magnetic measurement system is compared with the reference value to determine whether the bolt is damaged. The host computer control interface is developed in the control system to realize the combined control of vision system, magnetic measurement system and driver system. Meanwhile, this system has the function of detecting the damaged or loosen bolts.
In order to realize the system integration of controller，sensors application and execution unit in wind generator operation and maintenance robot, a design method of host computer control interface is proposed. This method mainly solves the problem of system integration between host computer (including control system and control interface in host computer) and lower computer (including vision system，magnetic measurement system and driver system). Meanwhile, according to coordinate value and angle value from the vision system, it is judged that if the actual value meets the requirement of reference value by the background program of control interface in the host computer. Then, it is determined whether the bolts in wind generator are loose or not. The actual value of magnetic flux and stress from the magnetic measurement system is compared with the reference value to determine whether the bolt is damaged. The host computer control interface is developed in the control system to realize the combined control of vision system, magnetic measurement system and driver system. Meanwhile, this system has the function of detecting the damaged or loosen bolts.
2021, 48(1):101-104.
DOI: 10.12177/emca.2020.184
Abstract:
The multi-pole motor features numerous slots, short span and high copper space factor. For such motors, adopting the common copper wire insertion technology for three-phase asynchronous motors will make it difficult to operate and increase failure rate of stator core winding. To deal with this problem, an improvement scheme of 15 kW generator′s winding stator technology is introduced, by which the winding inserting will become easier with the failure rate lowered and working efficiency improved.
The multi-pole motor features numerous slots, short span and high copper space factor. For such motors, adopting the common copper wire insertion technology for three-phase asynchronous motors will make it difficult to operate and increase failure rate of stator core winding. To deal with this problem, an improvement scheme of 15 kW generator′s winding stator technology is introduced, by which the winding inserting will become easier with the failure rate lowered and working efficiency 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.
