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Volume 45,Issue 9,2018 Table of Contents
2018, 45(9):1-8.
Abstract:
Rotating high frequency signal injection method was well suited for the rotor position detection of interior permanent magnet synchronous motor in the zero and low speed range, for the stability of the injected signals form and the independence from motor parameters. The square wave voltage injection method was used to detect the magnetic pole, and the finite element simulation was performed to select the amplitude and duration of the injected square wave voltage, effectively reducing the detecting time. The effect of filters and signal discretization on the accuracy of position estimation was analyzed. It was proposed that the phasefrequency characteristic curve near the center frequency of the bandpass filter could be fitted to a line segment in the lowspeed range. The relationship between the required compensation angle and the motor rotation speed was deduced. On the basis of the theoretical analysis, experiments were carried out on the prototype platform based on DSP28335. The results showed that the magnetic pole judgment process was stable and took a short time. The compensated position estimation was obviously improved compared with that before compensation. The dynamic performance of the system during the speed regulation process was good.
Rotating high frequency signal injection method was well suited for the rotor position detection of interior permanent magnet synchronous motor in the zero and low speed range, for the stability of the injected signals form and the independence from motor parameters. The square wave voltage injection method was used to detect the magnetic pole, and the finite element simulation was performed to select the amplitude and duration of the injected square wave voltage, effectively reducing the detecting time. The effect of filters and signal discretization on the accuracy of position estimation was analyzed. It was proposed that the phasefrequency characteristic curve near the center frequency of the bandpass filter could be fitted to a line segment in the lowspeed range. The relationship between the required compensation angle and the motor rotation speed was deduced. On the basis of the theoretical analysis, experiments were carried out on the prototype platform based on DSP28335. The results showed that the magnetic pole judgment process was stable and took a short time. The compensated position estimation was obviously improved compared with that before compensation. The dynamic performance of the system during the speed regulation process was good.
2018, 45(9):9-13.
Abstract:
An improved fast terminal sliding mode control method for permanent magnet synchronous motor was proposed. Different from the traditional sliding mode control and terminal sliding mode control methods, finite time control and fast convergence could be achieved by the proposed control method. The control law of the proposed controller was designed according to Lyapunov stability theorem. Simulation results demonstrated that the proposed improved fast terminal sliding mode control method could enhance the starting performance and disturbance rejection ability effectively.
An improved fast terminal sliding mode control method for permanent magnet synchronous motor was proposed. Different from the traditional sliding mode control and terminal sliding mode control methods, finite time control and fast convergence could be achieved by the proposed control method. The control law of the proposed controller was designed according to Lyapunov stability theorem. Simulation results demonstrated that the proposed improved fast terminal sliding mode control method could enhance the starting performance and disturbance rejection ability effectively.
2018, 45(9):14-18.
Abstract:
Aiming at the shortcomings of the traditional model reference adaptive observer in the lowspeed range of interior permanent magnet synchronous motor, including the sensitivity to changes in motor parameters, low accuracy of position detection and poor robustness, an improved sensorless control strategy was presented. Instead of using PI regulators as adaptive mechanisms in traditional model reference adaptive observers, a construction of the sliding surface by using the difference between the reference model of the motor body and the corresponding adjustable model was proposed, and the fuzzy controller was used to adjust the sliding gain adaptively to suppress the chattering of the sliding motion. The simulation model was built in the MATLAB/Simulink environment. The simulation results showed that both the estimated speed and the estimated rotor position could track the actual speed and rotor position when the external disturbance and the motor parameters changed, indicating the validity of the proposed method.
Aiming at the shortcomings of the traditional model reference adaptive observer in the lowspeed range of interior permanent magnet synchronous motor, including the sensitivity to changes in motor parameters, low accuracy of position detection and poor robustness, an improved sensorless control strategy was presented. Instead of using PI regulators as adaptive mechanisms in traditional model reference adaptive observers, a construction of the sliding surface by using the difference between the reference model of the motor body and the corresponding adjustable model was proposed, and the fuzzy controller was used to adjust the sliding gain adaptively to suppress the chattering of the sliding motion. The simulation model was built in the MATLAB/Simulink environment. The simulation results showed that both the estimated speed and the estimated rotor position could track the actual speed and rotor position when the external disturbance and the motor parameters changed, indicating the validity of the proposed method.
2018, 45(9):19-24, 33.
Abstract:
A new threephase DC/DC converter integrated system was presented to realize a permanentmagnetdrive reconstructed onboard charger, which integrated permanent magnet machine windings and DC/AC converters into an onboard charger to achieve drivecharging integration in electric vehicle, and aimed at high space utilization, fast charging and high reliability. The structure and working principle of the integrated system were analyzed, and the mathematical model of the threephase DC/DC converter of the charging system was deduced. Based on this, the simulation model of the drivecharging integrated system was built by MATLAB/Simulink simulation software. The performances of two pulse width modulation (PWM) control strategies were evaluated based on the comparison of the ACside voltage, ACside current, DCside machine winding inductor current and DCside voltage waveform. The simulation results showed that compared with the interleaved PWM control strategy, the new reconstructed onboard charger system had better running performance under the synchronous PWM control strategy.
A new threephase DC/DC converter integrated system was presented to realize a permanentmagnetdrive reconstructed onboard charger, which integrated permanent magnet machine windings and DC/AC converters into an onboard charger to achieve drivecharging integration in electric vehicle, and aimed at high space utilization, fast charging and high reliability. The structure and working principle of the integrated system were analyzed, and the mathematical model of the threephase DC/DC converter of the charging system was deduced. Based on this, the simulation model of the drivecharging integrated system was built by MATLAB/Simulink simulation software. The performances of two pulse width modulation (PWM) control strategies were evaluated based on the comparison of the ACside voltage, ACside current, DCside machine winding inductor current and DCside voltage waveform. The simulation results showed that compared with the interleaved PWM control strategy, the new reconstructed onboard charger system had better running performance under the synchronous PWM control strategy.
2018, 45(9):25-33.
Abstract:
A novel open winding topology with common DC bus was applied to hybrid permanent magnet material brushless motor for promoting power density and elevating torque output capacity. However, in this structure, zerosequence current would be produced in the winding, which would reduce the efficiency and operation stability. In order to solve this problem, a decoupled space vector pulse width modulation strategy was proposed, which could improved the voltage utilization effectively. In addition, for eliminating the 3rd and 9th current harmonics caused by common voltage and zerosequence components in backEMF and simplifying the control system, a closedloop system with repetitive controller in zerosequence circuit was formed. The proposed control methods were illustrated by the experimental results.
A novel open winding topology with common DC bus was applied to hybrid permanent magnet material brushless motor for promoting power density and elevating torque output capacity. However, in this structure, zerosequence current would be produced in the winding, which would reduce the efficiency and operation stability. In order to solve this problem, a decoupled space vector pulse width modulation strategy was proposed, which could improved the voltage utilization effectively. In addition, for eliminating the 3rd and 9th current harmonics caused by common voltage and zerosequence components in backEMF and simplifying the control system, a closedloop system with repetitive controller in zerosequence circuit was formed. The proposed control methods were illustrated by the experimental results.
2018, 45(9):34-40.
Abstract:
The traditional predictive current control algorithm of photovoltaic gridconnected inverter would cause the beat control due to the sampling and calculation delay, so the current which was sent to the grid could not track the target current well. Meanwhile, the error between the model and the actual value of the inverter filter inductance would cause harmonic to grid current, and cause instability to inverter system. In order to overcome these shortcomings, an improved predictive current control method was proposed. In the improved predictive method, the output voltage of the gridconnected inverter was predicted in a previous sampling period, and recursive least square method was used to identify the inductance parameters online at the same time. Simulation and experimental results showed that the proposed method can effectively improve the tracking accuracy of the gridconnected current to the target current, the harmonic component of the current sent to the grid was reduced. The quality of power supported by the inverter was improved.
The traditional predictive current control algorithm of photovoltaic gridconnected inverter would cause the beat control due to the sampling and calculation delay, so the current which was sent to the grid could not track the target current well. Meanwhile, the error between the model and the actual value of the inverter filter inductance would cause harmonic to grid current, and cause instability to inverter system. In order to overcome these shortcomings, an improved predictive current control method was proposed. In the improved predictive method, the output voltage of the gridconnected inverter was predicted in a previous sampling period, and recursive least square method was used to identify the inductance parameters online at the same time. Simulation and experimental results showed that the proposed method can effectively improve the tracking accuracy of the gridconnected current to the target current, the harmonic component of the current sent to the grid was reduced. The quality of power supported by the inverter was improved.
2018, 45(9):41-47.
Abstract:
In order to improve the performance of DC speed control system, the DC speed controller was designed as a fractional order PI (FOPI) and was compared with integer order PI for the control characteristics. When determining the FOPI/PI controller parameters, optimization was performed according to different objective functions using the particle swarm optimization algorithm. The influence of the controller parameters determined by different objective functions on the performance of the speed control system was analyzed. Simulation experiments showed that FOPI controller had better control performance. In the design of controller parameters, according to the performance requirements, different objective functions could be selected to optimize the design.
In order to improve the performance of DC speed control system, the DC speed controller was designed as a fractional order PI (FOPI) and was compared with integer order PI for the control characteristics. When determining the FOPI/PI controller parameters, optimization was performed according to different objective functions using the particle swarm optimization algorithm. The influence of the controller parameters determined by different objective functions on the performance of the speed control system was analyzed. Simulation experiments showed that FOPI controller had better control performance. In the design of controller parameters, according to the performance requirements, different objective functions could be selected to optimize the design.
2018, 45(9):48-53.
Abstract:
In order to improve the power quality of threephase fourswitch (TPFS) converter in unbalanced grid, a finite control sets model predictive power control scheme was proposed. The operation principle and voltage vectors were analyzed and the power predictive model was established. A reference power calculation method using the grid voltages and their quadrature signals was designed. The optimal voltage vector could be selected based on the cost function. It was unnecessary to use phase lock loop to extract sequence components, and easy to be implemented. The simulation and experimental results showed that, under unbalanced grid voltages, the proposed method could reduce the gridconnected current harmonic distortion, eliminate power fluctuation and improve the power quality of the TPFS converter.
In order to improve the power quality of threephase fourswitch (TPFS) converter in unbalanced grid, a finite control sets model predictive power control scheme was proposed. The operation principle and voltage vectors were analyzed and the power predictive model was established. A reference power calculation method using the grid voltages and their quadrature signals was designed. The optimal voltage vector could be selected based on the cost function. It was unnecessary to use phase lock loop to extract sequence components, and easy to be implemented. The simulation and experimental results showed that, under unbalanced grid voltages, the proposed method could reduce the gridconnected current harmonic distortion, eliminate power fluctuation and improve the power quality of the TPFS converter.
2018, 45(9):54-58, 78.
Abstract:
Aiming at the problem of low utilization of DC voltage in conventional sixphase SPWM algorithm, a sixphase carrier PWM algorithm based on double zerosequence signal injection was studied. The algorithm improved sixphase inverter control performance by injecting a certain double zerosequence component into a sine wave. The change range of the double zerosequence component of the algorithm and the principle of raising the DC voltage utilization ratio were analyzed. Three double zerosequence injection methods with different output characteristics were given. Through the simulation of the mean zerosequence injection method, it was seen that the algorithm could increase the utilization of DC voltage, and the system operating characteristics was improved, so that the effectiveness and feasibility of the PWM algorithm were verified.
Aiming at the problem of low utilization of DC voltage in conventional sixphase SPWM algorithm, a sixphase carrier PWM algorithm based on double zerosequence signal injection was studied. The algorithm improved sixphase inverter control performance by injecting a certain double zerosequence component into a sine wave. The change range of the double zerosequence component of the algorithm and the principle of raising the DC voltage utilization ratio were analyzed. Three double zerosequence injection methods with different output characteristics were given. Through the simulation of the mean zerosequence injection method, it was seen that the algorithm could increase the utilization of DC voltage, and the system operating characteristics was improved, so that the effectiveness and feasibility of the PWM algorithm were verified.
2018, 45(9):59-64, 78.
Abstract:
A control scheme was proposed to achieve largestroke fast setpoint motion in typical servo systems with an inertia damping block. The control scheme initially utilizes the timeoptimal control (TOC) to accomplish fast targeting, and then smoothly switches to linear control when the motion speed falls below the specified threshold. Using the damping ratio and natural frequency of the closedloop poles within the linear control regime as the two design parameters, a fullyparameterized control law was presented. The closedloop stability was analyzed based on the Lyapunov theory. The control scheme was applied to the positionvelocity control loop in a DC motor servo system for setpoint position regulation. MATLAB simulations had been carried out, together with experimental studies based on the TMS320F28335 DSC. The results showed that the proposed control scheme could track a wide range of target references fast and accurately, and had a good performance robustness with respect to the disturbance and parameter variations.
A control scheme was proposed to achieve largestroke fast setpoint motion in typical servo systems with an inertia damping block. The control scheme initially utilizes the timeoptimal control (TOC) to accomplish fast targeting, and then smoothly switches to linear control when the motion speed falls below the specified threshold. Using the damping ratio and natural frequency of the closedloop poles within the linear control regime as the two design parameters, a fullyparameterized control law was presented. The closedloop stability was analyzed based on the Lyapunov theory. The control scheme was applied to the positionvelocity control loop in a DC motor servo system for setpoint position regulation. MATLAB simulations had been carried out, together with experimental studies based on the TMS320F28335 DSC. The results showed that the proposed control scheme could track a wide range of target references fast and accurately, and had a good performance robustness with respect to the disturbance and parameter variations.
2018, 45(9):65-72.
Abstract:
Aiming at the problem of electromagnetic vibration and noise of the motor, based on the basic theories of electromagnetic vibration noise, the finite element simulation method of electromagneticstructural weak coupling was used to analyze the radial electromagnetic force density of a permanent magnet synchronous traction motor with 12 poles and 72 slots under the conditions of different aspect ratios, slot widths and comprehensive changes of both factors. At the same time, electromagneticstructure coupled field analysis was performed on the whole motor to study the structural vibration displacement with the stator aspect ratio, slot width and comprehensive changes of both factors. By comprehensively comparing and analyzing the two simulation results, the variation law of the electromagnetic vibration noise about the aspect ratio and the slot width of the stator structure was given. Finally, the physical prototype was subjected to vibration detection and spectrum analysis under rated load conditions, and the results were compared with simulation values to verify the accuracy of simulation experiments.
Aiming at the problem of electromagnetic vibration and noise of the motor, based on the basic theories of electromagnetic vibration noise, the finite element simulation method of electromagneticstructural weak coupling was used to analyze the radial electromagnetic force density of a permanent magnet synchronous traction motor with 12 poles and 72 slots under the conditions of different aspect ratios, slot widths and comprehensive changes of both factors. At the same time, electromagneticstructure coupled field analysis was performed on the whole motor to study the structural vibration displacement with the stator aspect ratio, slot width and comprehensive changes of both factors. By comprehensively comparing and analyzing the two simulation results, the variation law of the electromagnetic vibration noise about the aspect ratio and the slot width of the stator structure was given. Finally, the physical prototype was subjected to vibration detection and spectrum analysis under rated load conditions, and the results were compared with simulation values to verify the accuracy of simulation experiments.
12 Design and Analysis of a LessRareEarth Permanent Magnet BrushlessMotor with Hybrid Permanent Magnets
2018, 45(9):73-78.
Abstract:
According to the coexcitation of rareearth and nonrareearth permanent magnets, a lessrareearth permanent magnet brushless motor with hybrid permanent magnets was proposed. Details of the topology and operation principle of the proposed motor were introduced. Then, based on the electromagnetic formula and excitation sources equivalence method, the initial design method and the corresponding design parameters of the motor were determined. And, the electromagnetic performances under the conditions of noload and rated load were investigated by the finite element analysis. The corresponding experiments of the 5 kW prototype were conducted. Both theoretical analysis and experimental results verified the effectiveness of the proposed motor and the optimization design method.
According to the coexcitation of rareearth and nonrareearth permanent magnets, a lessrareearth permanent magnet brushless motor with hybrid permanent magnets was proposed. Details of the topology and operation principle of the proposed motor were introduced. Then, based on the electromagnetic formula and excitation sources equivalence method, the initial design method and the corresponding design parameters of the motor were determined. And, the electromagnetic performances under the conditions of noload and rated load were investigated by the finite element analysis. The corresponding experiments of the 5 kW prototype were conducted. Both theoretical analysis and experimental results verified the effectiveness of the proposed motor and the optimization design method.
2018, 45(9):79-82.
Abstract:
The heat resistance, environmental protection performance and storage stability of T1168H environmentfriendly high temperature impregnating resin were studied. The application performance of T1168H in traction motor was tested on a sample coil. The results showed that the temperature index of T1168H resin reached 222 ℃. Besides, T1168H resin had the advantages of low volatile content, no toxicity and environmental protection, and storage stability. The coil impregnated with T1168H resin exhibited excellent insulation performances in breakdown voltage, insulation resistance and dielectric loss factor. This material could meet the traction motor insulation requirements.
The heat resistance, environmental protection performance and storage stability of T1168H environmentfriendly high temperature impregnating resin were studied. The application performance of T1168H in traction motor was tested on a sample coil. The results showed that the temperature index of T1168H resin reached 222 ℃. Besides, T1168H resin had the advantages of low volatile content, no toxicity and environmental protection, and storage stability. The coil impregnated with T1168H resin exhibited excellent insulation performances in breakdown voltage, insulation resistance and dielectric loss factor. This material could meet the traction motor insulation requirements.
14 Rotor Current PerformanceGuaranteed Virtual SynchronousControl for DoublyFed Induction Generators
2018, 45(9):83-88, 96.
Abstract:
With the rapid development and high penetration of renewable energy, it is becoming more important that renewable generators, including doublyfed induction generator (DFIG), participate in the frequency regulation of the power grid. However, the rotorside converter (RSC) of DFIGs usually had relatively small current limitations, which could be exceeded during frequency regulation. A novel rotor current performanceguaranteed virtual synchronous controller for DFIGs was proposed. Firstly, the DFIG model was analyzed and a current control model was developed. Then, using an error transformation function and Lyapunov synthesis, a performanceguaranteed controller was proposed to strictly guarantee the rotor current within the predefined bounds. Thus the proposed controller could well deal with the frequency regulation demand and the current limitation. Finally, the effectiveness of the controller was verified via simulations. The enhanced rotor current control effect brought by performanceguaranteed control was also examined.
With the rapid development and high penetration of renewable energy, it is becoming more important that renewable generators, including doublyfed induction generator (DFIG), participate in the frequency regulation of the power grid. However, the rotorside converter (RSC) of DFIGs usually had relatively small current limitations, which could be exceeded during frequency regulation. A novel rotor current performanceguaranteed virtual synchronous controller for DFIGs was proposed. Firstly, the DFIG model was analyzed and a current control model was developed. Then, using an error transformation function and Lyapunov synthesis, a performanceguaranteed controller was proposed to strictly guarantee the rotor current within the predefined bounds. Thus the proposed controller could well deal with the frequency regulation demand and the current limitation. Finally, the effectiveness of the controller was verified via simulations. The enhanced rotor current control effect brought by performanceguaranteed control was also examined.
2018, 45(9):89-96.
Abstract:
In order to study the subsynchronous oscillation problem of the directdrive permanent magnet synchronous wind turbine generator, a typical mathematical model of wind power system was established. Based on the traditional eigenvalue analysis method, the state variables corresponding to the eigenvalues of system oscillation mode were identified intuitively and accurately by using the homotopy function instead of the participation factor method. On this basis, the influence of corresponding parameters of state variables on the eigenvalue of system oscillation mode was further analyzed. Finally, time domain simulation was carried out on the PSCAD/EMTDC platform. The results showed that the outer ring integration coefficient of DC voltage control and the inner ring proportionality coefficient of current control influenced the subsynchronous oscillation of system greatly.
In order to study the subsynchronous oscillation problem of the directdrive permanent magnet synchronous wind turbine generator, a typical mathematical model of wind power system was established. Based on the traditional eigenvalue analysis method, the state variables corresponding to the eigenvalues of system oscillation mode were identified intuitively and accurately by using the homotopy function instead of the participation factor method. On this basis, the influence of corresponding parameters of state variables on the eigenvalue of system oscillation mode was further analyzed. Finally, time domain simulation was carried out on the PSCAD/EMTDC platform. The results showed that the outer ring integration coefficient of DC voltage control and the inner ring proportionality coefficient of current control influenced the subsynchronous oscillation of system greatly.
2018, 45(9):97-102.
Abstract:
In order to improve the control performance of the doubly fed wind generator, the fractional order sliding mode control was used in the direct power control system of the doubly fed wind generator. The fractional order calculus was introduced into the sliding mode control to constitute a fractional order sliding mode controller, which weakened the chattering of the traditional sliding mode control by using the fractional order genetic attenuation characteristics. The fractional order sliding mode control law was derived for doubly fed induction generator, and the stability of the system was proved by Lyapunov stability theorem. The proposed fractional order sliding mode control system saved the current loop control, simplified the control structure, and realized the effective control of active power and reactive power. The simulation and experimental results showed the effectiveness of the proposed fractional order sliding mode control system and the weakening of the chattering in the traditional sliding mode control.
In order to improve the control performance of the doubly fed wind generator, the fractional order sliding mode control was used in the direct power control system of the doubly fed wind generator. The fractional order calculus was introduced into the sliding mode control to constitute a fractional order sliding mode controller, which weakened the chattering of the traditional sliding mode control by using the fractional order genetic attenuation characteristics. The fractional order sliding mode control law was derived for doubly fed induction generator, and the stability of the system was proved by Lyapunov stability theorem. The proposed fractional order sliding mode control system saved the current loop control, simplified the control structure, and realized the effective control of active power and reactive power. The simulation and experimental results showed the effectiveness of the proposed fractional order sliding mode control system and the weakening of the chattering in the traditional sliding mode control.
2018, 45(9):103-107, 124.
Abstract:
An 8 kW switched reluctance motor (SRM) with amorphous cores was manufactured for electricity vehicle (EV) traction. The core magnetic performance and motor static parameters were tested and compared with the same type motor with 50W350 cores. Then, according to the character of EV traction, the motor′s dynamic performance was simulated by finite element analysis (FEA) method. The test and calculation results showed that the amorphous cores had higher magnetic permeability compared with 50W350, which made the motor keep stable phase inductance in the high frequency excitation condition. In addition, amorphous cores significantly reduced motor core loss, and obvioushy increased motor efficiency (about 3%~9%) at high speed with small torque conditions. However, amorphous cores had lower saturated magnetic density, and the amorphous motor flux linkagecurrent curve was different from that of the motor with 50W350 cores, so the operating flux density, geometry and control parameters should be optimized to get the best performance.
An 8 kW switched reluctance motor (SRM) with amorphous cores was manufactured for electricity vehicle (EV) traction. The core magnetic performance and motor static parameters were tested and compared with the same type motor with 50W350 cores. Then, according to the character of EV traction, the motor′s dynamic performance was simulated by finite element analysis (FEA) method. The test and calculation results showed that the amorphous cores had higher magnetic permeability compared with 50W350, which made the motor keep stable phase inductance in the high frequency excitation condition. In addition, amorphous cores significantly reduced motor core loss, and obvioushy increased motor efficiency (about 3%~9%) at high speed with small torque conditions. However, amorphous cores had lower saturated magnetic density, and the amorphous motor flux linkagecurrent curve was different from that of the motor with 50W350 cores, so the operating flux density, geometry and control parameters should be optimized to get the best performance.
2018, 45(9):108-111, 131.
Abstract:
The weight reduction design of vehicle permanent magnet synchronous motor (PMSM) brought about more serious vibration and noise of the motor. An accurate modal calculation was the basis for the study of the vibration and noise characteristics of PMSM. The finite element method was used to perform the modal simulation of the PMSM. Through the reasonable simplification and equivalence of the motor model, the first 6 orders natural frequencies and corresponding modes of the motor under the free state were calculated. After that, the accuracy of the finite element model was verified by the hammering modal experiment of the prototype.
The weight reduction design of vehicle permanent magnet synchronous motor (PMSM) brought about more serious vibration and noise of the motor. An accurate modal calculation was the basis for the study of the vibration and noise characteristics of PMSM. The finite element method was used to perform the modal simulation of the PMSM. Through the reasonable simplification and equivalence of the motor model, the first 6 orders natural frequencies and corresponding modes of the motor under the free state were calculated. After that, the accuracy of the finite element model was verified by the hammering modal experiment of the prototype.
2018, 45(9):112-116.
Abstract:
For the threephase asynchronous motorgenerator of a “steamelectric doubledrive” system of shanghai Motor Factory Co., Ltd., which was 6 800 kW, 750 r/min, the transient performance was analyzed based on Ansoft software using fieldcircuit coupling method. Analyses and calculations were carried out for three different conditions: noload start, fan load start, and big load start. The process of the motor being switched from the state of motor to the state of generator was simulated. Instantaneous starting current, electromagnetic torque, the air gap flux density and other electrical parameters of the threephase asynchronous motorgenerator in different states were obtained. The transient performance of the asynchronous motor and the corresponding electromagnetic field distribution were analyzed.
For the threephase asynchronous motorgenerator of a “steamelectric doubledrive” system of shanghai Motor Factory Co., Ltd., which was 6 800 kW, 750 r/min, the transient performance was analyzed based on Ansoft software using fieldcircuit coupling method. Analyses and calculations were carried out for three different conditions: noload start, fan load start, and big load start. The process of the motor being switched from the state of motor to the state of generator was simulated. Instantaneous starting current, electromagnetic torque, the air gap flux density and other electrical parameters of the threephase asynchronous motorgenerator in different states were obtained. The transient performance of the asynchronous motor and the corresponding electromagnetic field distribution were analyzed.
2018, 45(9):117-124.
Abstract:
Doublyfed induction generator (DFIG) was widely used in wind power industry. In terms of its structure, the bearing was a very important part of the motor, and its status determined the overall performance of the motor. In the actual wind farm, the motor bearings would be replaced periodically, but this method could not avoid the early fault of the bearing. Therefore, the early diagnosis of the fault was particularly important. First, the bearing fault generation mechanism and failure modes of DFIG were introduced. Then the diagnostic methods frequently used in recent years were classified and described. Finally, based on the existing achievements, the future development trend of DFIG bearing fault diagnosis method was analyzed, so as to make preparations for the possible breakthrough in the field and after the proposal of new methods.
Doublyfed induction generator (DFIG) was widely used in wind power industry. In terms of its structure, the bearing was a very important part of the motor, and its status determined the overall performance of the motor. In the actual wind farm, the motor bearings would be replaced periodically, but this method could not avoid the early fault of the bearing. Therefore, the early diagnosis of the fault was particularly important. First, the bearing fault generation mechanism and failure modes of DFIG were introduced. Then the diagnostic methods frequently used in recent years were classified and described. Finally, based on the existing achievements, the future development trend of DFIG bearing fault diagnosis method was analyzed, so as to make preparations for the possible breakthrough in the field and after the proposal of new methods.
21 Fault Diagnosis of Power Converter for Switched Reluctance Motor SystemBased on Wavelet Transform
2018, 45(9):125-131.
Abstract:
The power converter applied to switched reluctance motor (SRM) drive system was a key link to the system reliability. Abnormal operation with faults for a long time could cause the collapse of the whole system, which indicated that the fault diagnosis for power converter in SRM had a large significance. The discrete wavelet transform method was used to extract the ratio of phase current mean to standard deviation which could be taken as the diagnostic feature. Four types of faults of power converter were analyzed and discussed. Determination of fault types and fault devices was implemented. Finally, the feasibility and effectiveness of the proposed method were proved by simulation and experiment.
The power converter applied to switched reluctance motor (SRM) drive system was a key link to the system reliability. Abnormal operation with faults for a long time could cause the collapse of the whole system, which indicated that the fault diagnosis for power converter in SRM had a large significance. The discrete wavelet transform method was used to extract the ratio of phase current mean to standard deviation which could be taken as the diagnostic feature. Four types of faults of power converter were analyzed and discussed. Determination of fault types and fault devices was implemented. Finally, the feasibility and effectiveness of the proposed method were proved by simulation and experiment.
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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.
