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Volume 46,Issue 4,2019 Table of Contents
2019, 46(4):1-7.
Abstract:
Aiming at the problems of highorder non linearity and load disturbance of permanent magnet synchronous motor (PMSM), a discrete speed regulation control method based on dynamic surface control (DSC), fuzzy logic system (FLS) and backstepping was proposed. The continuous model of PMSMs was discretized by Euler formula. DSC was used to overcome the “explosion of complexity” problem which emerged in classical backstepping by processing the virtual control function in every subsystem. FLS was used to approximate the nonlinearities of the system. The simulation results showed that the proposed controllers could regulate the speed effectively and exhibited strong robustness against load disturbance.
Aiming at the problems of highorder non linearity and load disturbance of permanent magnet synchronous motor (PMSM), a discrete speed regulation control method based on dynamic surface control (DSC), fuzzy logic system (FLS) and backstepping was proposed. The continuous model of PMSMs was discretized by Euler formula. DSC was used to overcome the “explosion of complexity” problem which emerged in classical backstepping by processing the virtual control function in every subsystem. FLS was used to approximate the nonlinearities of the system. The simulation results showed that the proposed controllers could regulate the speed effectively and exhibited strong robustness against load disturbance.
2019, 46(4):8-14, 26.
Abstract:
The traditional model predictive control for dual permanent magnet synchronous motor system driven by fiveleg inverter reduced the control accuracy of the two motors due to the single vector action in one control cycle. Aiming at this problem, an optimization model predictive control strategy was proposed. By distributing the duty cycles of the active voltage vector and the zero voltage vector of the two motors, the torque ripple was reduced to improve the control precision of the two motors, and then the control performance of the motor system was improved while satisfying the control independence of the two threephase motors. The feasibility and effectiveness of the proposed optimal model prediction control were verified by simulation results.
The traditional model predictive control for dual permanent magnet synchronous motor system driven by fiveleg inverter reduced the control accuracy of the two motors due to the single vector action in one control cycle. Aiming at this problem, an optimization model predictive control strategy was proposed. By distributing the duty cycles of the active voltage vector and the zero voltage vector of the two motors, the torque ripple was reduced to improve the control precision of the two motors, and then the control performance of the motor system was improved while satisfying the control independence of the two threephase motors. The feasibility and effectiveness of the proposed optimal model prediction control were verified by simulation results.
2019, 46(4):15-21.
Abstract:
In recent years, permanent magnet synchronous motors with concentrated winding and fractional slot had been widely used in servo control systems. Cyclic torque pulsation, which was detrimental to the speed and position regulation of a high performance servo system, existed in such type of motors due to poleslot combinations and imperfections in manufacturing such as mechanical errors introduced during parts machining and assembly. Therefore, an observer based torque ripple estimation and mitigation scheme was developed. Torque observer was adopted to estimate the torque ripple, and then torque ripple and position signal were processed to calculate the corresponding compensation torque current, which was in turn fedforward to the current command to suppress the resultant speed pulsation. Simulation and experiment results were obtained to verify the effectiveness of this method.
In recent years, permanent magnet synchronous motors with concentrated winding and fractional slot had been widely used in servo control systems. Cyclic torque pulsation, which was detrimental to the speed and position regulation of a high performance servo system, existed in such type of motors due to poleslot combinations and imperfections in manufacturing such as mechanical errors introduced during parts machining and assembly. Therefore, an observer based torque ripple estimation and mitigation scheme was developed. Torque observer was adopted to estimate the torque ripple, and then torque ripple and position signal were processed to calculate the corresponding compensation torque current, which was in turn fedforward to the current command to suppress the resultant speed pulsation. Simulation and experiment results were obtained to verify the effectiveness of this method.
2019, 46(4):22-26.
Abstract:
A type of continuous switched boost inverter was used to improve the control performance of permanent magnet synchronous motor (PMSM) through predictive control, aiming at the drawback of the traditional PMSM drive system. By adding a switched boost circuit between the inverted circuit and input DC power, switched boost inverter circuit was formed to achieve higher voltage gain and eliminate the dead zone. Meanwhile, the drive system had higher reliability. Moreover, predictive current control (PCC) was adopted to control PMSM. In comparison with the traditional field oriented control, PCC had faster dynamic response and could reduce current ripple. Finally, experiment results verified the feasibility of the predictive current control for PMSM based on the continuous switched boost inverter.
A type of continuous switched boost inverter was used to improve the control performance of permanent magnet synchronous motor (PMSM) through predictive control, aiming at the drawback of the traditional PMSM drive system. By adding a switched boost circuit between the inverted circuit and input DC power, switched boost inverter circuit was formed to achieve higher voltage gain and eliminate the dead zone. Meanwhile, the drive system had higher reliability. Moreover, predictive current control (PCC) was adopted to control PMSM. In comparison with the traditional field oriented control, PCC had faster dynamic response and could reduce current ripple. Finally, experiment results verified the feasibility of the predictive current control for PMSM based on the continuous switched boost inverter.
2019, 46(4):27-31, 37.
Abstract:
In order to further improve the control performance of asynchronous motor and reduce flux and current ripple, a method of fuzzy online adjusting of weight factor was proposed for the allocation of objective cost function weight factor in traditional finite control set model predictive torque control (FCSMPTC). The TakagiSugeno model fuzzy control method was used to realize the dynamic adjustment of the weighting factor by judging the torque and flux linkage error, and the domain of fuzzy control and its reasoning rule were also built. At the same time, considering the influence of the inverter switch fault on the control system in the threephase asynchronous motor drive system, a threephase sixswitch tolerant control strategy was used as the tolerant control strategy. The simulation results showed that the control method could smooth the flux linkage and current output and reduce the current harmonics.
In order to further improve the control performance of asynchronous motor and reduce flux and current ripple, a method of fuzzy online adjusting of weight factor was proposed for the allocation of objective cost function weight factor in traditional finite control set model predictive torque control (FCSMPTC). The TakagiSugeno model fuzzy control method was used to realize the dynamic adjustment of the weighting factor by judging the torque and flux linkage error, and the domain of fuzzy control and its reasoning rule were also built. At the same time, considering the influence of the inverter switch fault on the control system in the threephase asynchronous motor drive system, a threephase sixswitch tolerant control strategy was used as the tolerant control strategy. The simulation results showed that the control method could smooth the flux linkage and current output and reduce the current harmonics.
2019, 46(4):32-37.
Abstract:
Aiming at the problems that the permanent magnet synchronous motor (PMSM) had poor starting ability in constant torque region and the path of current in constant power region was difficult to track, a stator current fluxweakening optimal control strategy based on voltage feedback current feedforward was proposed. By comparing the current which made the current feedforward loop stabilize and the current obtained from the maximum torque per ampere (MTPA) algorithm, the stator current could quickly track the MTPA curve through the current feedforward action in the constant torque region to accelerate starting process. The voltage feedback current feedforward strategy in the constant power region increased the system antiinterference capability and maximized the DC bus voltage utilization. In order to verify the feasibility of the proposed strategy, a PMSM simulation model was built and the experimental platform with dSPACE1007 as the core was constructed. The results of the simulation and experiment proved the stability and effectiveness of the strategy.
Aiming at the problems that the permanent magnet synchronous motor (PMSM) had poor starting ability in constant torque region and the path of current in constant power region was difficult to track, a stator current fluxweakening optimal control strategy based on voltage feedback current feedforward was proposed. By comparing the current which made the current feedforward loop stabilize and the current obtained from the maximum torque per ampere (MTPA) algorithm, the stator current could quickly track the MTPA curve through the current feedforward action in the constant torque region to accelerate starting process. The voltage feedback current feedforward strategy in the constant power region increased the system antiinterference capability and maximized the DC bus voltage utilization. In order to verify the feasibility of the proposed strategy, a PMSM simulation model was built and the experimental platform with dSPACE1007 as the core was constructed. The results of the simulation and experiment proved the stability and effectiveness of the strategy.
2019, 46(4):38-43.
Abstract:
In the permanent magnet synchronous motor (PMSM) AC servo control system, the phase current shows nonsinusoidal variation due to the switching of electronic devices. The direct and quadrature axis currents obtained by coordinate transformation contain abundant harmonic components, causing current loop oscillation and electromagnetic torque ripple. On the basis of analyzing the relation between the phase current and the higher harmonics of the direct and quadrature axis currents, as well as the effect of higher harmonics on the electromagnetic torque, a feedforward control strategy based on adaptive FIR filter was proposed for AC servo system. Furthermore, a variable step length factor algorithm was proposed, with which the step length factor was changed according to the error value, so as to improve the convergence speed of filter and reduce the overshoot. Compared with the traditional firstorder lowpass filter, this algorithm had no phase lag, and showed higher sensitivity and system stability. The improved control strategy was effective to reduce the direct and quadrature axis current harmonics, restrain the current loop oscillation and electromagnetic torque ripple, and improve the PMSM AC servo control system stability and dynamic response. The feasibility of this method was proved by simulation and experiment.
In the permanent magnet synchronous motor (PMSM) AC servo control system, the phase current shows nonsinusoidal variation due to the switching of electronic devices. The direct and quadrature axis currents obtained by coordinate transformation contain abundant harmonic components, causing current loop oscillation and electromagnetic torque ripple. On the basis of analyzing the relation between the phase current and the higher harmonics of the direct and quadrature axis currents, as well as the effect of higher harmonics on the electromagnetic torque, a feedforward control strategy based on adaptive FIR filter was proposed for AC servo system. Furthermore, a variable step length factor algorithm was proposed, with which the step length factor was changed according to the error value, so as to improve the convergence speed of filter and reduce the overshoot. Compared with the traditional firstorder lowpass filter, this algorithm had no phase lag, and showed higher sensitivity and system stability. The improved control strategy was effective to reduce the direct and quadrature axis current harmonics, restrain the current loop oscillation and electromagnetic torque ripple, and improve the PMSM AC servo control system stability and dynamic response. The feasibility of this method was proved by simulation and experiment.
2019, 46(4):44-47, 56.
Abstract:
In order to solve the failure of an axial flow induced draft fan after the variable frequency driven conversion, the torsional stress pulsation characteristics of the fan were tested by using the wireless strain measurement technology. It was found that the torsional stress fluctuation amplitude increased sharply when the fan was running over a certain rotating speed and then kept high. In this process, the torsional stress pulsation frequency was locked and did not change with the rotation speed, which was different from the phenomenon of torsional resonance. The results showed that the unstable torsional vibration occurred in the electromechanical coupling system composed of frequency converter, motor, shaft and fan. It was proposed to solve the unstable torsional vibration problem by replacing the diaphragm coupler with the high elastic rubber coupler. The experimental results before and after replacement showed that the high elastic coupler could effectively suppress the unstable torsional vibration.
In order to solve the failure of an axial flow induced draft fan after the variable frequency driven conversion, the torsional stress pulsation characteristics of the fan were tested by using the wireless strain measurement technology. It was found that the torsional stress fluctuation amplitude increased sharply when the fan was running over a certain rotating speed and then kept high. In this process, the torsional stress pulsation frequency was locked and did not change with the rotation speed, which was different from the phenomenon of torsional resonance. The results showed that the unstable torsional vibration occurred in the electromechanical coupling system composed of frequency converter, motor, shaft and fan. It was proposed to solve the unstable torsional vibration problem by replacing the diaphragm coupler with the high elastic rubber coupler. The experimental results before and after replacement showed that the high elastic coupler could effectively suppress the unstable torsional vibration.
2019, 46(4):48-56.
Abstract:
In view of the shortcomings of traditional pulse or analog control systems in terms of realtime performance, stability and synchronization, a duallinearmotor position linkage control scheme based on EtherCAT communication was proposed. Three position linkage control modes were designed. Moreover, the distributed clock mechanism of EtherCAT was analyzed in detail. The linkage control experiment platform was built. The experiment results showed that the duallinearmotor position linkage control system based on EtherCAT communication had the advantages of fast response, good dualaxis synchronization and good alternating performance. It was suitable for applications which required high synchronization accuracy and high speed response.
In view of the shortcomings of traditional pulse or analog control systems in terms of realtime performance, stability and synchronization, a duallinearmotor position linkage control scheme based on EtherCAT communication was proposed. Three position linkage control modes were designed. Moreover, the distributed clock mechanism of EtherCAT was analyzed in detail. The linkage control experiment platform was built. The experiment results showed that the duallinearmotor position linkage control system based on EtherCAT communication had the advantages of fast response, good dualaxis synchronization and good alternating performance. It was suitable for applications which required high synchronization accuracy and high speed response.
2019, 46(4):57-64.
Abstract:
A larger frequency fluctuation will be caused when fault occurs in the power systems where the grid structure is relatively weak or isolated islands are formed after system splitting in asynchronous networking system. In this case, it is was very important to consider the frequency characteristics of the induction motor when it is modeled. Based on the first order of mechanical transient model of the induction motor, the expression of steady and dynamic state slip ratio of the system frequency under different load characteristics by analytical method was deduced. On this basis, the absorbed active power and reactive power were derived, and then the powerfrequency characteristics of the induction motor were analyzed. The fifthorder electromagnetic transient simulation model of induction motor was established in MATLAB simulation software to simulate and analyze the powerfrequency characteristics of induction motors with different load characteristics. The simulation result was consistent with the theoretical derivation, so it was correct and effective to deduce the frequency characteristics of an induction motor under the simplified model.
A larger frequency fluctuation will be caused when fault occurs in the power systems where the grid structure is relatively weak or isolated islands are formed after system splitting in asynchronous networking system. In this case, it is was very important to consider the frequency characteristics of the induction motor when it is modeled. Based on the first order of mechanical transient model of the induction motor, the expression of steady and dynamic state slip ratio of the system frequency under different load characteristics by analytical method was deduced. On this basis, the absorbed active power and reactive power were derived, and then the powerfrequency characteristics of the induction motor were analyzed. The fifthorder electromagnetic transient simulation model of induction motor was established in MATLAB simulation software to simulate and analyze the powerfrequency characteristics of induction motors with different load characteristics. The simulation result was consistent with the theoretical derivation, so it was correct and effective to deduce the frequency characteristics of an induction motor under the simplified model.
2019, 46(4):65-70.
Abstract:
The stator modal analysis was an important segment of studying the electromagnetic vibration and noise of permanent magnet synchronous mortor (PMSM), and the accurate prediction of the natural frequency of stator was the basis of suppressing the electromagnetic vibration and noise. Firstly, the main factors affecting the natural frequency of stator were analyzed by the analytical method. Secondly, the finite element simulation models of each part of the stator system were established, and the influences of the winding, case and end cover on the stator’s natural frequency were studied through finite element simulation and related data processing and analysis. The results showed that when the equivalent elastic modulus of the winding was lower than a critical value, the stator’s natural frequency would be reduced; while when the equivalent elastic modulus of the winding was higher than this critical value, the stator’s natural frequency would be increased. Both the case and the end cover could greatly increase the natural frequency of the stator.
The stator modal analysis was an important segment of studying the electromagnetic vibration and noise of permanent magnet synchronous mortor (PMSM), and the accurate prediction of the natural frequency of stator was the basis of suppressing the electromagnetic vibration and noise. Firstly, the main factors affecting the natural frequency of stator were analyzed by the analytical method. Secondly, the finite element simulation models of each part of the stator system were established, and the influences of the winding, case and end cover on the stator’s natural frequency were studied through finite element simulation and related data processing and analysis. The results showed that when the equivalent elastic modulus of the winding was lower than a critical value, the stator’s natural frequency would be reduced; while when the equivalent elastic modulus of the winding was higher than this critical value, the stator’s natural frequency would be increased. Both the case and the end cover could greatly increase the natural frequency of the stator.
2019, 46(4):71-76.
Abstract:
Based on the classical Bertotti trinomial constant coefficient iron loss calculation model and the harmonic analysis principle, a high density permanent magnet synchronous motor (PMSM) iron loss calculation model considering eddy current loss, hysteresis loss and additional loss compensation coefficient was proposed. The compensation coefficients in the model varied with the amplitude, frequency and distortion rate of magnetic density, which could better reflect the effect of fundamental wave and harmonic magnetic field on iron loss. In order to verify the validity and accuracy of this model, two PMSMs with respectively 48 slots/8 poles inner rotor and 36 slots/48 poles outer rotor were taken as examples to compare the calculated value of the model with the finite element simulation results and experimental data. The results showed that the iron loss calculation model proposed had higher accuracy, and was suitable for applications in a wide range of magnetic density amplitude and frequency especially.
Based on the classical Bertotti trinomial constant coefficient iron loss calculation model and the harmonic analysis principle, a high density permanent magnet synchronous motor (PMSM) iron loss calculation model considering eddy current loss, hysteresis loss and additional loss compensation coefficient was proposed. The compensation coefficients in the model varied with the amplitude, frequency and distortion rate of magnetic density, which could better reflect the effect of fundamental wave and harmonic magnetic field on iron loss. In order to verify the validity and accuracy of this model, two PMSMs with respectively 48 slots/8 poles inner rotor and 36 slots/48 poles outer rotor were taken as examples to compare the calculated value of the model with the finite element simulation results and experimental data. The results showed that the iron loss calculation model proposed had higher accuracy, and was suitable for applications in a wide range of magnetic density amplitude and frequency especially.
2019, 46(4):77-81, 91.
Abstract:
An analytical method for the calculation of airgap magnetic fields in a surface permanent magnet synchronous motor with eccentric magnet pole by dividing the region into parts was presented. The solution area was divided into permanent magnet region, air gap region, and stator slot region. Based on the separation variable method, the correlation coefficient was obtained by using the boundary conditions of each region. The analytic model could calculate the distribution of noload and load magnetic fields with eccentric magnet pole. The calculation results of the analytical model were compared with those of the finite element analysis. The results showed that the analytical model had high accuracy.
An analytical method for the calculation of airgap magnetic fields in a surface permanent magnet synchronous motor with eccentric magnet pole by dividing the region into parts was presented. The solution area was divided into permanent magnet region, air gap region, and stator slot region. Based on the separation variable method, the correlation coefficient was obtained by using the boundary conditions of each region. The analytic model could calculate the distribution of noload and load magnetic fields with eccentric magnet pole. The calculation results of the analytical model were compared with those of the finite element analysis. The results showed that the analytical model had high accuracy.
2019, 46(4):82-86, 114.
Abstract:
Through the theoretical analysis of shortcircuit current and shortcircuit torque in the steadystate shortcircuit condition of permanent magnet synchronous motor (PMSM), the analytical expressions of steadystate shortcircuit current and electromagnetic torque of PMSM were obtained. Combined with twodimensional finite element method, the shortcircuit current and shortcircuit torque of a 180 kW PMSM under shortcircuit condition were simulated and calculated. The variation law of shortcircuit current and shortcircuit torque versus speed of the PMSM during the steadystate shortcircuit test was determined. The threephase steadystate shortcircuit test was carried out for a PMSM. The shortcircuit current and shortcircuit torque at different speeds were recorded during the shortcircuit test. The test results were compared with theoretical analysis and simulation analysis results to verify the variation law of shortcircuit current and shortcircuit torque versus the speed.
Through the theoretical analysis of shortcircuit current and shortcircuit torque in the steadystate shortcircuit condition of permanent magnet synchronous motor (PMSM), the analytical expressions of steadystate shortcircuit current and electromagnetic torque of PMSM were obtained. Combined with twodimensional finite element method, the shortcircuit current and shortcircuit torque of a 180 kW PMSM under shortcircuit condition were simulated and calculated. The variation law of shortcircuit current and shortcircuit torque versus speed of the PMSM during the steadystate shortcircuit test was determined. The threephase steadystate shortcircuit test was carried out for a PMSM. The shortcircuit current and shortcircuit torque at different speeds were recorded during the shortcircuit test. The test results were compared with theoretical analysis and simulation analysis results to verify the variation law of shortcircuit current and shortcircuit torque versus the speed.
2019, 46(4):87-91.
Abstract:
In order to avoid the complex mathematical operation and reduce the requirement of processor data storage space, a strategy for online fast estimation of switched reluctance motor (SRM) torque with magnetic commonenergy was proposed based on voltage chopper control. The measurement method of magnetic flux characteristics was described in detail, and the calculation formula of magnetic common energy and torque was given. The simulation and experimental results showed that the error of the instantaneous torque was small, proving that this method was suitable for the online estimation of torque.
In order to avoid the complex mathematical operation and reduce the requirement of processor data storage space, a strategy for online fast estimation of switched reluctance motor (SRM) torque with magnetic commonenergy was proposed based on voltage chopper control. The measurement method of magnetic flux characteristics was described in detail, and the calculation formula of magnetic common energy and torque was given. The simulation and experimental results showed that the error of the instantaneous torque was small, proving that this method was suitable for the online estimation of torque.
2019, 46(4):92-95.
Abstract:
Water abrasion of the rotor in waterfilled submersible motor takes majority of mechanical loss of the motor. However, there is not a simple and practical method to calculate the water abrasion. Based on theoretical analysis and a large number of experiments, the main factors affecting water abrasion of the rotor were studied, and the calculation method for water abrasion of the rotor was proposed. This method was verified and employed in practical design and production.
Water abrasion of the rotor in waterfilled submersible motor takes majority of mechanical loss of the motor. However, there is not a simple and practical method to calculate the water abrasion. Based on theoretical analysis and a large number of experiments, the main factors affecting water abrasion of the rotor were studied, and the calculation method for water abrasion of the rotor was proposed. This method was verified and employed in practical design and production.
2019, 46(4):96-100.
Abstract:
Compared with the traditional buck circuit, the DC/DC converter based on Hbridge parallel connection can realize the bipolar output of voltage and redundancy control in case of failure, so it is very suitable for the situation that large power motor needs positive and negative rotation control. The structure of the parallel Hbridge DC/DC converter and the mode of dual pulse width modulation (PWM) were analyzed. To reduce the switching loss of Hbridge DC/DC converter under dual PWM, the passive soft switching technology was analyzed, and the performance difference between the RCD buffer circuit and the minimum stress buffer circuit was emphatically discussed. It was found that the minimum stress soft switching technology could obtain better soft switching performance. The minimum stress soft switch was used to simulate the parallel Hbridge DC/DC converter with dual PWM. Simulation results showed that the soft switching technology based on the minimum stress snubber circuit could be used in the parallel Hbridge DC/DC converter with dual PWM to achieve zero voltage switching on and zero current switching off.
Compared with the traditional buck circuit, the DC/DC converter based on Hbridge parallel connection can realize the bipolar output of voltage and redundancy control in case of failure, so it is very suitable for the situation that large power motor needs positive and negative rotation control. The structure of the parallel Hbridge DC/DC converter and the mode of dual pulse width modulation (PWM) were analyzed. To reduce the switching loss of Hbridge DC/DC converter under dual PWM, the passive soft switching technology was analyzed, and the performance difference between the RCD buffer circuit and the minimum stress buffer circuit was emphatically discussed. It was found that the minimum stress soft switching technology could obtain better soft switching performance. The minimum stress soft switch was used to simulate the parallel Hbridge DC/DC converter with dual PWM. Simulation results showed that the soft switching technology based on the minimum stress snubber circuit could be used in the parallel Hbridge DC/DC converter with dual PWM to achieve zero voltage switching on and zero current switching off.
2019, 46(4):101-105.
Abstract:
The basic concepts of edge computing and the comparison with cloud computing were introduced. At the same time, the architecture and main functions of the remote operation and maintenance system of motor were introduced in view of the requirements. On the basis of describing the data interaction process between edge equipment and remote operation and maintenance platform, the application of edge computing in remote operation and maintenance system of motor was expounded in detail.
The basic concepts of edge computing and the comparison with cloud computing were introduced. At the same time, the architecture and main functions of the remote operation and maintenance system of motor were introduced in view of the requirements. On the basis of describing the data interaction process between edge equipment and remote operation and maintenance platform, the application of edge computing in remote operation and maintenance system of motor was expounded in detail.
2019, 46(4):106-109, 125.
Abstract:
The load characteristics of the beam pumping unit were analyzed. The working principle of the switched reluctance motor (SRM) and its characteristics and advantages for applications in the pumping unit motor were briefly introduced. The control structure and control strategy for the SRM used in the pumping unit system were analyzed. The experimental platform of the SRM based on the simulated pumping unit load characteristics was built and tested. The results showed that the SRM was applied to the pumping unit with high operating efficiency and energy saving effect. The SRM had the advantages of simple structure, high reliability, flexible control, good speed regulation performance, high operating efficiency and low temperature rise. Its application to the pumping unit system had unique inherent advantages and could improve the whole operating efficiency of the pumping unit system and realize better energy saving effects. The field test results at the Xinjiang Oilfield production plant further verified this conclusion.
The load characteristics of the beam pumping unit were analyzed. The working principle of the switched reluctance motor (SRM) and its characteristics and advantages for applications in the pumping unit motor were briefly introduced. The control structure and control strategy for the SRM used in the pumping unit system were analyzed. The experimental platform of the SRM based on the simulated pumping unit load characteristics was built and tested. The results showed that the SRM was applied to the pumping unit with high operating efficiency and energy saving effect. The SRM had the advantages of simple structure, high reliability, flexible control, good speed regulation performance, high operating efficiency and low temperature rise. Its application to the pumping unit system had unique inherent advantages and could improve the whole operating efficiency of the pumping unit system and realize better energy saving effects. The field test results at the Xinjiang Oilfield production plant further verified this conclusion.
2019, 46(4):110-114.
Abstract:
In the current fault diagnosis technology of asynchronous motors, frequency resolution for short time data was low and hardware overhead was high. For the sake of solving these shortcomings, a novel approach for rotor fault based on rotating filtermatrix pencil of short time data was proposed. Matrix pencil algorithm was used to accurately estimate the fundamental frequency component in stator current, and the fundamental frequency component was removed by inverse and forward rotation transform. Accurate estimation of frequency and amplitude in stator current was realized with the short time data by using matrix pencil algorithm, which broke through the limited resolution of traditional method based on fast Fourier transform (FFT) analysis. The simulation and experimental verification showed that rotating filtermatrix pencil method was valid for broken rotor bar faults with short time data.
In the current fault diagnosis technology of asynchronous motors, frequency resolution for short time data was low and hardware overhead was high. For the sake of solving these shortcomings, a novel approach for rotor fault based on rotating filtermatrix pencil of short time data was proposed. Matrix pencil algorithm was used to accurately estimate the fundamental frequency component in stator current, and the fundamental frequency component was removed by inverse and forward rotation transform. Accurate estimation of frequency and amplitude in stator current was realized with the short time data by using matrix pencil algorithm, which broke through the limited resolution of traditional method based on fast Fourier transform (FFT) analysis. The simulation and experimental verification showed that rotating filtermatrix pencil method was valid for broken rotor bar faults with short time data.
2019, 46(4):115-120.
Abstract:
Aiming at the problems of narrow working wind speed range and low utilization rate of wind energy in wind power generation systems, a disktype dualrotor counterrotating permanent magnet wind generator was designed, which operated with dualrotor contrarotating. On the basis of introducing the structure and operation principle of the motor, the power dimension equation of the motor was deduced, and the preliminary design method of the motor was given. The threedimensional modeling and dynamic simulation analysis of the motor were carried out by using finite element software. The magnetic circuit characteristics and electromagnetic performance were obtained, and the effectiveness of the proposed design method was verified.
Aiming at the problems of narrow working wind speed range and low utilization rate of wind energy in wind power generation systems, a disktype dualrotor counterrotating permanent magnet wind generator was designed, which operated with dualrotor contrarotating. On the basis of introducing the structure and operation principle of the motor, the power dimension equation of the motor was deduced, and the preliminary design method of the motor was given. The threedimensional modeling and dynamic simulation analysis of the motor were carried out by using finite element software. The magnetic circuit characteristics and electromagnetic performance were obtained, and the effectiveness of the proposed design method was verified.
2019, 46(4):121-125.
Abstract:
Traditional doubly fed induction generator (DFIG) control had chattering phenomenon, which was easy to cause instability of the system. In order to reduce the chattering phenomenon of control and improve the stability of control, the mathematical model of DFIG was established on the basis of analyzing the dynamic characteristics of DFIG. The superhelix secondorder sliding mode controller was designed, and the control performance of the sliding mode controller in the case of sudden wind was studied. Simulation was carried out using MATLAB/Simulink. Simulation results showed that the sliding mode controller had good abilities of tracking optimal torque and adjusting reactive power. Compared with general control methods, it had strong robustness of rotor continuous voltage control. Furthermore, this sliding mode controller could significantly reduce the chattering and greatly improve the stability of the system.
Traditional doubly fed induction generator (DFIG) control had chattering phenomenon, which was easy to cause instability of the system. In order to reduce the chattering phenomenon of control and improve the stability of control, the mathematical model of DFIG was established on the basis of analyzing the dynamic characteristics of DFIG. The superhelix secondorder sliding mode controller was designed, and the control performance of the sliding mode controller in the case of sudden wind was studied. Simulation was carried out using MATLAB/Simulink. Simulation results showed that the sliding mode controller had good abilities of tracking optimal torque and adjusting reactive power. Compared with general control methods, it had strong robustness of rotor continuous voltage control. Furthermore, this sliding mode controller could significantly reduce the chattering and greatly improve the stability of the system.
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沪ICP备16038578号-3
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.
