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Volume 45,Issue 10,2018 Table of Contents
2018, 45(10):1-4, 33.
Abstract:
For the negative phase torque and rotational speed oscillation problems in the frequency conversion stage of the space voltage vector soft starter, the selection of the frequency conversion point was optimized according to the control method of the voltage vector. The initial value of the control angle of each frequency conversion stage was obtained with the motor load status, and the final value of the control angle was obtained with the constant voltagefrequency ratio principle, so as to optimize the control of the frequency conversion stage of the soft starter. Finally, the optimized soft starter was verified by simulation. The results showed that, when the soft starter was operating in the frequency conversion phase, the overshoot of the speed at the frequency conversion point was ameliorated, the current peak value was reduced, and no negative torque appeared.
For the negative phase torque and rotational speed oscillation problems in the frequency conversion stage of the space voltage vector soft starter, the selection of the frequency conversion point was optimized according to the control method of the voltage vector. The initial value of the control angle of each frequency conversion stage was obtained with the motor load status, and the final value of the control angle was obtained with the constant voltagefrequency ratio principle, so as to optimize the control of the frequency conversion stage of the soft starter. Finally, the optimized soft starter was verified by simulation. The results showed that, when the soft starter was operating in the frequency conversion phase, the overshoot of the speed at the frequency conversion point was ameliorated, the current peak value was reduced, and no negative torque appeared.
2018, 45(10):5-12.
Abstract:
An improved predictive current control (PCC) algorithm with stator current and disturbance observation compensation was proposed. Theoretically, the PCC for the PMSM possesses excellent control performance. However, problems including the discrete sampling delay and the timevarying electromagnetic parameters in the practical system cause serious deterioration in the control quality of the modelbased predictive current controller. A Luenberger state observer was designed to observe stator current and parameter disturbances, which was applied to compensate and improve the conventional deadbeat predictive current controller. The sampling current at the present moment was substituted by the observed stator current at the present moment for the feedback control to compensate the sampling delay. The variation of the electromagnetic parameters during operation caused a mismatch in the model parameters, the effects of which were observed in the form of voltage disturbances and compensated to the output voltage reference of the predictive control. The simulation and experimental results verified the validity of the proposed algorithm.
An improved predictive current control (PCC) algorithm with stator current and disturbance observation compensation was proposed. Theoretically, the PCC for the PMSM possesses excellent control performance. However, problems including the discrete sampling delay and the timevarying electromagnetic parameters in the practical system cause serious deterioration in the control quality of the modelbased predictive current controller. A Luenberger state observer was designed to observe stator current and parameter disturbances, which was applied to compensate and improve the conventional deadbeat predictive current controller. The sampling current at the present moment was substituted by the observed stator current at the present moment for the feedback control to compensate the sampling delay. The variation of the electromagnetic parameters during operation caused a mismatch in the model parameters, the effects of which were observed in the form of voltage disturbances and compensated to the output voltage reference of the predictive control. The simulation and experimental results verified the validity of the proposed algorithm.
2018, 45(10):13-18, 112.
Abstract:
Switched reluctance motor (SRM) is widely used, but it is difficult to model and simulate SRMs with high precision because of the nonlinearity of the internal magnetic field and the difficult analysis of the phase current. The research of motor and drive system modeling directly affects the optimization design of motor, dynamic and static performance analysis, evaluation of control strategy, etc. A modeling method for SRM and its control system was introduced. It was a joint simulation, which used the finite element model of the motor built by Flux software and that of the control system built by MATLAB. Through the experiment, the current waveforms of the motor under different operating conditions were measured and compared with the simulation results. The results showed that the current waveforms in different control modes were consistent with the simulation results, which verified the effectiveness of the modeling method.
Switched reluctance motor (SRM) is widely used, but it is difficult to model and simulate SRMs with high precision because of the nonlinearity of the internal magnetic field and the difficult analysis of the phase current. The research of motor and drive system modeling directly affects the optimization design of motor, dynamic and static performance analysis, evaluation of control strategy, etc. A modeling method for SRM and its control system was introduced. It was a joint simulation, which used the finite element model of the motor built by Flux software and that of the control system built by MATLAB. Through the experiment, the current waveforms of the motor under different operating conditions were measured and compared with the simulation results. The results showed that the current waveforms in different control modes were consistent with the simulation results, which verified the effectiveness of the modeling method.
2018, 45(10):19-23, 45.
Abstract:
In order to effectively stabilize the power fluctuations of the wind farm, improve the grid connection characteristics of the wind farm, and increase the economics and reliability of the wind farm to achieve gridconnected operation, a hierarchical optimization control strategy for wind storage stations that took into account the energy storage life was proposed. Firstly, from the perspective of economics, the charge and discharge characteristics of the energy storage system were analyzed, and the influence of different control methods on the life of the energy storage system was considered. Secondly, the stratifying and zoning control method was used to coordinate the wind power storage station, in which the upper layer performed coordinated power control on centralized energy storage and the entire wind farm level according to grid dispatching demand and timesharing electricity price policy, and the lower layer considered distributed energy storage in the area and coordinated power control between multiple wind turbines. Finally, the improved genetic algorithm was used to solve the hierarchical optimization control model. The results showed that the hierarchical optimization control method realized the reasonable distribution of the energy storage system and the output of the wind turbine in the wind power storage station, the energy storage life was extended, the grid’s ability to absorb wind power was enhanced, and the economic efficiency of the entire wind farm was significantly improved.
In order to effectively stabilize the power fluctuations of the wind farm, improve the grid connection characteristics of the wind farm, and increase the economics and reliability of the wind farm to achieve gridconnected operation, a hierarchical optimization control strategy for wind storage stations that took into account the energy storage life was proposed. Firstly, from the perspective of economics, the charge and discharge characteristics of the energy storage system were analyzed, and the influence of different control methods on the life of the energy storage system was considered. Secondly, the stratifying and zoning control method was used to coordinate the wind power storage station, in which the upper layer performed coordinated power control on centralized energy storage and the entire wind farm level according to grid dispatching demand and timesharing electricity price policy, and the lower layer considered distributed energy storage in the area and coordinated power control between multiple wind turbines. Finally, the improved genetic algorithm was used to solve the hierarchical optimization control model. The results showed that the hierarchical optimization control method realized the reasonable distribution of the energy storage system and the output of the wind turbine in the wind power storage station, the energy storage life was extended, the grid’s ability to absorb wind power was enhanced, and the economic efficiency of the entire wind farm was significantly improved.
2018, 45(10):24-28.
Abstract:
Based on the vector control of permanent magnet synchronous motor (PMSM), an optimized fluxweakening control method of PMSM was proposed. The interior permanent magnet synchronous motor (IPMSM) had a relatively wider speed adjustment range than the surfacemount PMSM. Taking IPMSM applied as the object, we carried out simulation and optimization of the fluxweakening speed control. PMSM used the maximumtorqueperampere constanttorque control below the base speed to reduce the motor loss and improve the efficiency of the inverter. Above the base speed, PMSM adopted constantpower speed control. The combination of crossaxis current control and directaxis current control in the fluxweakening control method could improve the PMSM power factor and extend the speed adjustment range. Aiming at the fluctuation of the weak ring speed, the fuzzy selftuning PI control method was proposed based the traditional PI control. The simulation model was established in MATLAB/Simulink, and the feasibility of the control method was verified.
Based on the vector control of permanent magnet synchronous motor (PMSM), an optimized fluxweakening control method of PMSM was proposed. The interior permanent magnet synchronous motor (IPMSM) had a relatively wider speed adjustment range than the surfacemount PMSM. Taking IPMSM applied as the object, we carried out simulation and optimization of the fluxweakening speed control. PMSM used the maximumtorqueperampere constanttorque control below the base speed to reduce the motor loss and improve the efficiency of the inverter. Above the base speed, PMSM adopted constantpower speed control. The combination of crossaxis current control and directaxis current control in the fluxweakening control method could improve the PMSM power factor and extend the speed adjustment range. Aiming at the fluctuation of the weak ring speed, the fuzzy selftuning PI control method was proposed based the traditional PI control. The simulation model was established in MATLAB/Simulink, and the feasibility of the control method was verified.
2018, 45(10):29-33.
Abstract:
The control strategies were studied to solve the problem of the harmonic currents increment in the reactive power compensator consisting of capacitors and static var generator. Firstly, accurate extraction algorithm of load harmonic current based on multiple secondorder general integrator was investigated. Secondly, resonant controller was applied to control the harmonic current flowing from the pulse width modulation gridconnected converter to the grid based on the traditional d-axis gridvoltageoriented vector control, so as to suppress the harmonic current in the grid. Simulation model of the system was established and simulation research was carried out. The validity of the extraction algorithm of load harmonic current and the control strategy of harmonic suppression was verified by the simulation results.
The control strategies were studied to solve the problem of the harmonic currents increment in the reactive power compensator consisting of capacitors and static var generator. Firstly, accurate extraction algorithm of load harmonic current based on multiple secondorder general integrator was investigated. Secondly, resonant controller was applied to control the harmonic current flowing from the pulse width modulation gridconnected converter to the grid based on the traditional d-axis gridvoltageoriented vector control, so as to suppress the harmonic current in the grid. Simulation model of the system was established and simulation research was carried out. The validity of the extraction algorithm of load harmonic current and the control strategy of harmonic suppression was verified by the simulation results.
2018, 45(10):34-40.
Abstract:
The highperformance control of permanent magnet synchronous motors requires accurate information of the speed and rotor position. This information can usually be measured by mechanical sensors such as resolvers and photoelectric encoders. However, it is difficult to use highperformance mechanical sensors since their high price, difficulty in installation, and poor adaptability to harsh environments. By measuring the electrical signal of the motor, the position of the rotor and the motor speed information can be calculated based on the obtained electrical signal and the motor’s parameters. In this paper, based on the relationship between motor back electromotive force and motor speed, a sliding mode observer based on back electromotive force was designed to estimate the motor rotor position and motor speed, so as to realize the speed sensorless control of surfacemount permanent magnet synchronous motor.
The highperformance control of permanent magnet synchronous motors requires accurate information of the speed and rotor position. This information can usually be measured by mechanical sensors such as resolvers and photoelectric encoders. However, it is difficult to use highperformance mechanical sensors since their high price, difficulty in installation, and poor adaptability to harsh environments. By measuring the electrical signal of the motor, the position of the rotor and the motor speed information can be calculated based on the obtained electrical signal and the motor’s parameters. In this paper, based on the relationship between motor back electromotive force and motor speed, a sliding mode observer based on back electromotive force was designed to estimate the motor rotor position and motor speed, so as to realize the speed sensorless control of surfacemount permanent magnet synchronous motor.
2018, 45(10):41-45.
Abstract:
Aiming at the contradiction between the speed requirement of power flow calculation under frequent simulation operation instructions and the extremely limited computing resources of the embedded marine power simulation training system, a power flow calculation algorithm for marine power grid based on ordered BDL tree set was proposed. The algorithm optimized the node numbering method on the basis of common methods, and regarded the multistation marine power system in the actual openloop operation mode as the ordered BDL tree composed of multiple radial power grids. Each ordered BDL tree contained the main power distribution board, distribution layer and load layer in a single power station, and integrated the generator flow into the main power distribution board layer, avoiding the problem of node numbering mutation in the common power flow algorithms. The time complexity analysis results and the actual operation results of the algorithm were analyzed and compared, which showed that the proposed algorithm was better than the common marine power flow algorithms.
Aiming at the contradiction between the speed requirement of power flow calculation under frequent simulation operation instructions and the extremely limited computing resources of the embedded marine power simulation training system, a power flow calculation algorithm for marine power grid based on ordered BDL tree set was proposed. The algorithm optimized the node numbering method on the basis of common methods, and regarded the multistation marine power system in the actual openloop operation mode as the ordered BDL tree composed of multiple radial power grids. Each ordered BDL tree contained the main power distribution board, distribution layer and load layer in a single power station, and integrated the generator flow into the main power distribution board layer, avoiding the problem of node numbering mutation in the common power flow algorithms. The time complexity analysis results and the actual operation results of the algorithm were analyzed and compared, which showed that the proposed algorithm was better than the common marine power flow algorithms.
2018, 45(10):46-52.
Abstract:
In order to realize the natural decoupling of the torque and suspending force of a bearingless switched reluctance motor (BSRM), a novel hybrid excitation bearingless switched reluctance motor (HEBSRM) was proposed. The new motor consists of a 12/14 BSRM, an annular permanent magnet and a radial magnetic bearing. The torque flux path was completely independent of the suspending force flux path, and the decoupling of torque and suspending force was realized in the structure. In addition, the mathematical model of the radial suspending force of the motor was deduced in detail and the rationality of the structure was verified by the finite element analysis.
In order to realize the natural decoupling of the torque and suspending force of a bearingless switched reluctance motor (BSRM), a novel hybrid excitation bearingless switched reluctance motor (HEBSRM) was proposed. The new motor consists of a 12/14 BSRM, an annular permanent magnet and a radial magnetic bearing. The torque flux path was completely independent of the suspending force flux path, and the decoupling of torque and suspending force was realized in the structure. In addition, the mathematical model of the radial suspending force of the motor was deduced in detail and the rationality of the structure was verified by the finite element analysis.
2018, 45(10):53-58, 119.
Abstract:
A multiobjective optimal design solution was studied based on geneticparticle swarm optimization algorithm (GPSOA) for single winding bearingless switched reluctance motor (SWBSRM). Universal rules of radial force and efficiency about main structure variations were given by combining finite element analysis (FEA) with sensitivity analysis. On this basis, the proposed GPSOA was applied to the optimal design of SWBSRM to obtain better optimal variations, with which the radial force was bigger and the efficiency was higher. The multiobjective optimal design based on GPSOA was verified by comparing the performance of final design with initial design by the FEA.
A multiobjective optimal design solution was studied based on geneticparticle swarm optimization algorithm (GPSOA) for single winding bearingless switched reluctance motor (SWBSRM). Universal rules of radial force and efficiency about main structure variations were given by combining finite element analysis (FEA) with sensitivity analysis. On this basis, the proposed GPSOA was applied to the optimal design of SWBSRM to obtain better optimal variations, with which the radial force was bigger and the efficiency was higher. The multiobjective optimal design based on GPSOA was verified by comparing the performance of final design with initial design by the FEA.
2018, 45(10):59-65, 72.
Abstract:
A novel topology of aircore permanent magnet linear synchronous motor (PMLSM) which has an asymmetrical doubleside trapezoidal permanent magnet (PM) stator was proposed in this paper. Firstly, a 3D magnetic field analytical model of one trapezoidal PM was established based on the theory of magnetic charge, and a 3D model of the flux distribution in the airgap of a doubleside PMLSM could be obtained by the superposition principle. Expressions of the back electromotive force and the electromagnetic force are derived with considering the transverse end effect of the coil. The analytical model was used for evaluating and optimizing the distribution of airgap flux density harmonics. Subsequently, the proposed model was verified by a 3D finite element analytical model to demonstrate its accuracy.
A novel topology of aircore permanent magnet linear synchronous motor (PMLSM) which has an asymmetrical doubleside trapezoidal permanent magnet (PM) stator was proposed in this paper. Firstly, a 3D magnetic field analytical model of one trapezoidal PM was established based on the theory of magnetic charge, and a 3D model of the flux distribution in the airgap of a doubleside PMLSM could be obtained by the superposition principle. Expressions of the back electromotive force and the electromagnetic force are derived with considering the transverse end effect of the coil. The analytical model was used for evaluating and optimizing the distribution of airgap flux density harmonics. Subsequently, the proposed model was verified by a 3D finite element analytical model to demonstrate its accuracy.
2018, 45(10):66-72.
Abstract:
Permanent magnet synchronous motor (PMSM) was widely used in the field of ship electric propulsion because of its excellent torque characteristics and wide speed range. The sensorless control was an important guarantee for the reliable operation of the system. However, the parameters of the motor would change with the operating conditions due to the temperature change, the magnetic saturation effect and the cross coupling of the magnetic circuit. Therefore, realtime control of operating parameters of PMSM was an important guarantee for the control quality of the system. In view of the above problems, the model reference adaptive system was used to identify the parameters of PMSM. The full rank adjustable model was established by using the Runge-Kutta method. The adaptive law was derived based on the Popov super stability theorem. Finally, the experimental test platform was used to verify the algorithm. The simulation and experimental results showed that the online parameter identification algorithm could identify the motor parameters accurately in real time.
Permanent magnet synchronous motor (PMSM) was widely used in the field of ship electric propulsion because of its excellent torque characteristics and wide speed range. The sensorless control was an important guarantee for the reliable operation of the system. However, the parameters of the motor would change with the operating conditions due to the temperature change, the magnetic saturation effect and the cross coupling of the magnetic circuit. Therefore, realtime control of operating parameters of PMSM was an important guarantee for the control quality of the system. In view of the above problems, the model reference adaptive system was used to identify the parameters of PMSM. The full rank adjustable model was established by using the Runge-Kutta method. The adaptive law was derived based on the Popov super stability theorem. Finally, the experimental test platform was used to verify the algorithm. The simulation and experimental results showed that the online parameter identification algorithm could identify the motor parameters accurately in real time.
2018, 45(10):73-76, 133.
Abstract:
The influence of permanent magnet motor stator slot width on electromagnetic noise was focused on. The relationship between electromagnetic force and the stator slot width was deduced by the analytical calculation of electromagnetic force. Electromagnetic field calculation was carried out for a permanent magnet motor for electric vehicle by Ansoft software, so as to solve the change of electromagnetic force wave with the change of stator slot width. At the same time, the 2D sound field of this permanent magnet motor was calculated by Ansys software for different slit widths. At last, experiment verification was performed. The simulation calculation result was basically identical with the experiment. This research could provide reference for weakening noise in motor designing process.
The influence of permanent magnet motor stator slot width on electromagnetic noise was focused on. The relationship between electromagnetic force and the stator slot width was deduced by the analytical calculation of electromagnetic force. Electromagnetic field calculation was carried out for a permanent magnet motor for electric vehicle by Ansoft software, so as to solve the change of electromagnetic force wave with the change of stator slot width. At the same time, the 2D sound field of this permanent magnet motor was calculated by Ansys software for different slit widths. At last, experiment verification was performed. The simulation calculation result was basically identical with the experiment. This research could provide reference for weakening noise in motor designing process.
2018, 45(10):77-81.
Abstract:
Aiming at the problem of vibration and noise of permanent magnet synchronous motor, starting from the structural modality of the motor stator system, the influence of stator parameters on motor vibration and noise was analyzed through the simulation of the influence of different iron core models and different shell thicknesses on the stator system. The reliability of the simulation was verified by experiments. Finally, the general law of the influence of various parameters on the vibration mode of stator system was obtained.
Aiming at the problem of vibration and noise of permanent magnet synchronous motor, starting from the structural modality of the motor stator system, the influence of stator parameters on motor vibration and noise was analyzed through the simulation of the influence of different iron core models and different shell thicknesses on the stator system. The reliability of the simulation was verified by experiments. Finally, the general law of the influence of various parameters on the vibration mode of stator system was obtained.
2018, 45(10):82-88.
Abstract:
Tradational circuit method was limited in quantitative analysis of the effects of rotor axial vent hole size on motor parameters. Based on a highvoltgae (HV) asynchronous motor with output of 400 kW and voltage of 6 000 V, a fieldcircuit coupled timestepping FEM model of 2D transient electromagnetic field was established. With the variation of rotor axial vent hole size and topological structure, the influence on electromagnetic parameters such as airgap flux density,losses, and radial electromagnetic force, was calculated and analyzed. Furthermore, the effect of rotor axial vent hole size and topology structure on starting and operating performance of the motor was also investigated. Finally, by comparing FEM simulation with experimental results, the correctness of this method was verified. A theoretical basis for the design and optimization of rotor axial vent hole size and topological structure was provided.
Tradational circuit method was limited in quantitative analysis of the effects of rotor axial vent hole size on motor parameters. Based on a highvoltgae (HV) asynchronous motor with output of 400 kW and voltage of 6 000 V, a fieldcircuit coupled timestepping FEM model of 2D transient electromagnetic field was established. With the variation of rotor axial vent hole size and topological structure, the influence on electromagnetic parameters such as airgap flux density,losses, and radial electromagnetic force, was calculated and analyzed. Furthermore, the effect of rotor axial vent hole size and topology structure on starting and operating performance of the motor was also investigated. Finally, by comparing FEM simulation with experimental results, the correctness of this method was verified. A theoretical basis for the design and optimization of rotor axial vent hole size and topological structure was provided.
2018, 45(10):89-92.
Abstract:
In order to reflect the superiority of lowloss amorphous alloy, a 15 kW, 1 000 Hz motor was used to perform noload iron losses simulation. The motor stator core was made from amorphous alloy, and treated with dipping coating and curing process. The motor noload iron loss calculation includes the separation of basic iron loss of amorphous stator and the calculation of noload stray losses. It was obtained that the amorphous alloy motor stray loss was 6.03 times of the basic iron loss. Comparison was made with the 50DW310 stator. Under noload operation, the amorphous alloy noload iron loss was about 18.82% of silicon steel 50DW310 noload iron loss, and the motor efficiency could be increased by 3.48 percentage points.
In order to reflect the superiority of lowloss amorphous alloy, a 15 kW, 1 000 Hz motor was used to perform noload iron losses simulation. The motor stator core was made from amorphous alloy, and treated with dipping coating and curing process. The motor noload iron loss calculation includes the separation of basic iron loss of amorphous stator and the calculation of noload stray losses. It was obtained that the amorphous alloy motor stray loss was 6.03 times of the basic iron loss. Comparison was made with the 50DW310 stator. Under noload operation, the amorphous alloy noload iron loss was about 18.82% of silicon steel 50DW310 noload iron loss, and the motor efficiency could be increased by 3.48 percentage points.
2018, 45(10):93-95.
Abstract:
JMP super high efficiency threephase asynchronous motor for fire pump was a new energysaving special motor which was coresearched, designed and developed by Henan Yutong Electric Motor Shares Company and Xinxiang Motor System Energy Saving Engineering Technology Research Center. Its energy efficiency level could reach to IE4 energy efficiency class. At present, product development was finished and the prototype motors had passed test approved by the foreign thirdparty energy efficiency testing institution. Energy efficiency test report and certificate of exporting license were obtained. What’s more, the motor had been exported to foreign countries in batches, and had been recognized and approved by foreign customers. In this paper, the design ideas and prototype test results are introduced.
JMP super high efficiency threephase asynchronous motor for fire pump was a new energysaving special motor which was coresearched, designed and developed by Henan Yutong Electric Motor Shares Company and Xinxiang Motor System Energy Saving Engineering Technology Research Center. Its energy efficiency level could reach to IE4 energy efficiency class. At present, product development was finished and the prototype motors had passed test approved by the foreign thirdparty energy efficiency testing institution. Energy efficiency test report and certificate of exporting license were obtained. What’s more, the motor had been exported to foreign countries in batches, and had been recognized and approved by foreign customers. In this paper, the design ideas and prototype test results are introduced.
2018, 45(10):96-99.
Abstract:
Aiming at the demand for remote operation and maintenance of motor equipment, the remote operation and maintenance system of motor equipment based on cloud platform was designed on the basis of analyzing the advantages of remote operation and maintenance. The architecture and main functions of the remote operation and maintenance system were discussed in detail. The remote operation and maintenance system of motor equipment could reduce the aftersales cost, improve the quality of aftersales service, and then improve the quality of the product. At the same time, it could also reduce the user’s shutdown and maintenance time, and greatly improve the production efficiency of the user.
Aiming at the demand for remote operation and maintenance of motor equipment, the remote operation and maintenance system of motor equipment based on cloud platform was designed on the basis of analyzing the advantages of remote operation and maintenance. The architecture and main functions of the remote operation and maintenance system were discussed in detail. The remote operation and maintenance system of motor equipment could reduce the aftersales cost, improve the quality of aftersales service, and then improve the quality of the product. At the same time, it could also reduce the user’s shutdown and maintenance time, and greatly improve the production efficiency of the user.
2018, 45(10):100-105.
Abstract:
The motors’ fluxlinkage, current and angle obtained from the system with sensors were chosen as the sample data, and the predictive model of rotor position based on relevance vector machine was built by training these sample data. In order to improve the fitting precision and generalization ability of the predictive model, the kernel function parameter in relevance vector machine was optimized by the particle swarm algorithm. By simulation on the test motor, it was verified that the proposed predictive model could estimate the rotor position accurately in the simulation condition and had satisfactory estimation precision.
The motors’ fluxlinkage, current and angle obtained from the system with sensors were chosen as the sample data, and the predictive model of rotor position based on relevance vector machine was built by training these sample data. In order to improve the fitting precision and generalization ability of the predictive model, the kernel function parameter in relevance vector machine was optimized by the particle swarm algorithm. By simulation on the test motor, it was verified that the proposed predictive model could estimate the rotor position accurately in the simulation condition and had satisfactory estimation precision.
2018, 45(10):106-112.
Abstract:
The selfsensing magnetic bearing could reduce the cost and the axial size of the magnetic bearing and increase its reliability. A selfsensing control method based on mixedkernel least squares support vector machine (LSSVM) forecasting model was proposed for an axial active magnetic bearing (AAMB). The principle and mathematical model of the active magnetic bearing were introduced; based on the principle of the mixedkernel LSSVM, the nonlinear forecasting model between the current and the displacement which realized the displacement selfsensing control was built through parameter optimization. The control system of the AAMB with selfsensing was constructed. The simulation results showed that the prediction model could accurately detect the rotor axial displacement. Further experimental results also showed that the method had a good ability of axial displacement selfsensing. The AAMB could realize stable suspension operation without displacement sensors.
The selfsensing magnetic bearing could reduce the cost and the axial size of the magnetic bearing and increase its reliability. A selfsensing control method based on mixedkernel least squares support vector machine (LSSVM) forecasting model was proposed for an axial active magnetic bearing (AAMB). The principle and mathematical model of the active magnetic bearing were introduced; based on the principle of the mixedkernel LSSVM, the nonlinear forecasting model between the current and the displacement which realized the displacement selfsensing control was built through parameter optimization. The control system of the AAMB with selfsensing was constructed. The simulation results showed that the prediction model could accurately detect the rotor axial displacement. Further experimental results also showed that the method had a good ability of axial displacement selfsensing. The AAMB could realize stable suspension operation without displacement sensors.
2018, 45(10):113-119.
Abstract:
In order to reveal the friction and wear performance of the slipper pair of highpressure axial piston pump, a highprecision, highperformance the slipper pair friction tester with electronic control and a stable and reliable spindle speed was required. However, in the slipper pair test, it was very difficult to realize the precise control of the spindle speed and the tester displacement. And when the spindle speed of the tester increased from 3 000 r/min, the oil temperature of the tester rose sharply, which would have a great influence on the accuracy of the slipper pair performance test. Aiming at this problem, the electronic control system for the MCMS10 testing machine was studied, the control scheme of the electrical control system was analyzed, the hardware diagram of the electronic control system was designed, and the satisfactory PID algorithm was used to control the rotation speed and displacement of the testing machine’s main spindle. Finally, through the configuration software realtime monitoring and experiment, it was found that, when the satisfactory PID algorithm was applied to the MCMS10 test control system, not only the accuracy was very high, but 65 ℃ for the spindle speed around 3 200 r/min. This study could be a good reference the oil temperature was always kept at around for similar researches in the future.
In order to reveal the friction and wear performance of the slipper pair of highpressure axial piston pump, a highprecision, highperformance the slipper pair friction tester with electronic control and a stable and reliable spindle speed was required. However, in the slipper pair test, it was very difficult to realize the precise control of the spindle speed and the tester displacement. And when the spindle speed of the tester increased from 3 000 r/min, the oil temperature of the tester rose sharply, which would have a great influence on the accuracy of the slipper pair performance test. Aiming at this problem, the electronic control system for the MCMS10 testing machine was studied, the control scheme of the electrical control system was analyzed, the hardware diagram of the electronic control system was designed, and the satisfactory PID algorithm was used to control the rotation speed and displacement of the testing machine’s main spindle. Finally, through the configuration software realtime monitoring and experiment, it was found that, when the satisfactory PID algorithm was applied to the MCMS10 test control system, not only the accuracy was very high, but 65 ℃ for the spindle speed around 3 200 r/min. This study could be a good reference the oil temperature was always kept at around for similar researches in the future.
2018, 45(10):120-125.
Abstract:
In actual production, the rotor winding state monitoring of doublyfed induction generator (DFIG) could effectively improve the operation reliability of wind turbine. The complete experimental program for research on rotor winding fault of DFIG was provided. Firstly, the basic principle and field experimental devices of the experimental platform, as well as the solutions to problems in the process of platform building were introduced so as to ensure the accuracy of experimental data. Then, taking the converter side current as the research object, we analyzed the propagation of fault information through the power converter electronic device, and extracted the diagnostic characteristics of rotor winding unbalance fault based on current spectrum. Finally, the current spectra of rotor windings before and after the unbalance fault caused by threephase unbalance loads were obtained by experiments, and, in combination with the theory of electrical fault characteristic frequency on the rotor side, the fault characteristic frequencies were analyzed. According to the experimental results, 100 Hz, 200 Hz and several characteristic frequency components of rotor converter side current spectrum were selected as the diagnostic characteristics of the rotor winding unbalance fault. It was significant to take 3sf and (2±3s)f (s: slip ratio;f: fundamental frequency) as the characteristic frequencies of rotor threephase unbalance load fault in engineering and experiments.
In actual production, the rotor winding state monitoring of doublyfed induction generator (DFIG) could effectively improve the operation reliability of wind turbine. The complete experimental program for research on rotor winding fault of DFIG was provided. Firstly, the basic principle and field experimental devices of the experimental platform, as well as the solutions to problems in the process of platform building were introduced so as to ensure the accuracy of experimental data. Then, taking the converter side current as the research object, we analyzed the propagation of fault information through the power converter electronic device, and extracted the diagnostic characteristics of rotor winding unbalance fault based on current spectrum. Finally, the current spectra of rotor windings before and after the unbalance fault caused by threephase unbalance loads were obtained by experiments, and, in combination with the theory of electrical fault characteristic frequency on the rotor side, the fault characteristic frequencies were analyzed. According to the experimental results, 100 Hz, 200 Hz and several characteristic frequency components of rotor converter side current spectrum were selected as the diagnostic characteristics of the rotor winding unbalance fault. It was significant to take 3sf and (2±3s)f (s: slip ratio;f: fundamental frequency) as the characteristic frequencies of rotor threephase unbalance load fault in engineering and experiments.
2018, 45(10):126-133.
Abstract:
The rotor windings interturn short circuit fault is one of the common faults in turbine generator. When a generator runs in asymmetric condition emerging negative sequence magnetic field, the deterioration rate of interturn short circuit fault in rotor windings can be accelerated. In this paper, a 300 MW turbine generator running under asymmetric operation was studied as an example. Considering damping system, the variations of generator fault characteristics after rotor winding interturn short circuit were studied, including rotor current, rotor winding induced electromotive force, short circuit loop current and damping current. What’s more, the influences of rotor short circuit coil turns and pitch and shortcircuit point transition resistance under negative sequence magnetic field on the rotor short current were studied, also the heating condition of the short circuit point was roughly analyzed. The results provided a reliable decision support for repairing interturn short circuit in rotor winding after a generator experienced bad operating conditions.
The rotor windings interturn short circuit fault is one of the common faults in turbine generator. When a generator runs in asymmetric condition emerging negative sequence magnetic field, the deterioration rate of interturn short circuit fault in rotor windings can be accelerated. In this paper, a 300 MW turbine generator running under asymmetric operation was studied as an example. Considering damping system, the variations of generator fault characteristics after rotor winding interturn short circuit were studied, including rotor current, rotor winding induced electromotive force, short circuit loop current and damping current. What’s more, the influences of rotor short circuit coil turns and pitch and shortcircuit point transition resistance under negative sequence magnetic field on the rotor short current were studied, also the heating condition of the short circuit point was roughly analyzed. The results provided a reliable decision support for repairing interturn short circuit in rotor winding after a generator experienced bad operating conditions.
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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.
