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Volume 46,Issue 3,2019 Table of Contents
2019, 46(3):1-7.
Abstract:
Large inertia load was often driven by multiple motors. The steady state and dymamic performance of the whole system was closely related to the coordinated control of the multimotor drive systems. According to the existing coordinated control methods for multimotor drive systems, the related control structures and control algorithms were surveyed. By comparision, the advantages and disadvantages of each existing coodinated control method were analyzed and the corresponding applicable engineering fields were provided. Finally, according to the current industry demands, the research directions and development trends of coordinated control of multimotor drive systems were presented.
Large inertia load was often driven by multiple motors. The steady state and dymamic performance of the whole system was closely related to the coordinated control of the multimotor drive systems. According to the existing coordinated control methods for multimotor drive systems, the related control structures and control algorithms were surveyed. By comparision, the advantages and disadvantages of each existing coodinated control method were analyzed and the corresponding applicable engineering fields were provided. Finally, according to the current industry demands, the research directions and development trends of coordinated control of multimotor drive systems were presented.
2019, 46(3):8-14, 20.
Abstract:
A robust composite tracking control scheme was proposed to accomplish accurate trajectory tracking for motor servo systems subject to input saturation and unknown disturbance. The control scheme incorporated a reference generator which constructed the target state vector corresponding with the trajectory reference signal, and an extended state observer which estimated both the system states and the disturbance. The final control law adopted a combination of feedback and feedforward actions. The stability of the closedloop control system was strictly analyzed using the Lyapunov theory. Simulation studies were conducted in MATLAB, followed by an experimental verification on a DSPcontrolled XYtable driven by permanent magnet linear motors. The results indicated that the proposed control scheme could achieve superior transient performance and steadystate accuracy in various trajectory tracking tasks and was more robust against the amplitude variations of target trajectory and disturbance.
A robust composite tracking control scheme was proposed to accomplish accurate trajectory tracking for motor servo systems subject to input saturation and unknown disturbance. The control scheme incorporated a reference generator which constructed the target state vector corresponding with the trajectory reference signal, and an extended state observer which estimated both the system states and the disturbance. The final control law adopted a combination of feedback and feedforward actions. The stability of the closedloop control system was strictly analyzed using the Lyapunov theory. Simulation studies were conducted in MATLAB, followed by an experimental verification on a DSPcontrolled XYtable driven by permanent magnet linear motors. The results indicated that the proposed control scheme could achieve superior transient performance and steadystate accuracy in various trajectory tracking tasks and was more robust against the amplitude variations of target trajectory and disturbance.
2019, 46(3):15-20.
Abstract:
Permanent magnet synchronous motor (PMSM) drive system without electrolytic capacitor was widely used in the field of white home appliance owing to its cost and longevity advantages. However, small film capacitor was utilized to replace the large volume electrolytic capacitor so that the DC bus voltage fluctuated with twice the frequency of AC source voltage. The inverter ouput voltage was saturated and the control performance was deteriorated when the DC bus voltage dropped near zero periodically, and the grid input current was distorted and the power factor was low. A motor torque control loop and an inverter output voltage modification method based on high power factor control were proposed, which could reduce the grid input current harmonics and meet the guideline of IEC 6100032. The effectiveness of the proposed method was verified through simulation.
Permanent magnet synchronous motor (PMSM) drive system without electrolytic capacitor was widely used in the field of white home appliance owing to its cost and longevity advantages. However, small film capacitor was utilized to replace the large volume electrolytic capacitor so that the DC bus voltage fluctuated with twice the frequency of AC source voltage. The inverter ouput voltage was saturated and the control performance was deteriorated when the DC bus voltage dropped near zero periodically, and the grid input current was distorted and the power factor was low. A motor torque control loop and an inverter output voltage modification method based on high power factor control were proposed, which could reduce the grid input current harmonics and meet the guideline of IEC 6100032. The effectiveness of the proposed method was verified through simulation.
2019, 46(3):21-26.
Abstract:
The control accuracy of traditional sliding mode observer (SMO) based permanent magnet synchronous motor (PMSM) was low, which was caused by the inherent buffeting characteristics, the weakening of observed back electromotive force (EMF) amplitude and the shifting of the observed rotor phase. In order to solve this problem, an estimating method for PMSM speed and rotor position based on the secondorder hybrid terminal SMO was proposed. The method adopted a secondorder sliding mode switching surface constructed by a linear sliding mode and a hybrid terminal sliding mode. A reasonable sliding mode control law was designed to effectively suppress the inherent buffeting characteristics of the traditional sliding mode. Besides, it could avoid the weakening of the observed back EMF amplitude and the shifting of the observed rotor phase, which were brought by the use of lowpass filter, so that the accuracy of estimated rotor position and speed could be improved effectively. On this basis, the robustness of the SMO was further analyzed with perturbation of motor stator resistance and inductance. Experimental results verified the effectiveness and practicability of the hybrid terminal SMO.
The control accuracy of traditional sliding mode observer (SMO) based permanent magnet synchronous motor (PMSM) was low, which was caused by the inherent buffeting characteristics, the weakening of observed back electromotive force (EMF) amplitude and the shifting of the observed rotor phase. In order to solve this problem, an estimating method for PMSM speed and rotor position based on the secondorder hybrid terminal SMO was proposed. The method adopted a secondorder sliding mode switching surface constructed by a linear sliding mode and a hybrid terminal sliding mode. A reasonable sliding mode control law was designed to effectively suppress the inherent buffeting characteristics of the traditional sliding mode. Besides, it could avoid the weakening of the observed back EMF amplitude and the shifting of the observed rotor phase, which were brought by the use of lowpass filter, so that the accuracy of estimated rotor position and speed could be improved effectively. On this basis, the robustness of the SMO was further analyzed with perturbation of motor stator resistance and inductance. Experimental results verified the effectiveness and practicability of the hybrid terminal SMO.
2019, 46(3):27-33.
Abstract:
Parameters tuning of robot joint motor′s controller was the key of good control performance realization. A parameter tuning method was presented for joint motor sliding mode control based on alternating simultaneous iteration. Firstly, the permanent magnet synchronous joint motor was designed, and the control object of the system was determined. Secondly, the slidingmodePID control system that combined the PID current controller with the sliding mode speed controller was designed. The sliding mode controller′s parameters were set initially using engineering design methods. A redundant PID speed controller was added and its parameters were also set by engineering design methods. Using the output speed of the redundant PID speed controller and sliding mode speed controller as iterating variable, the parameters of controller were obtained via alternating simultaneous iteration. Finally, it was proved by the MATLAB/Simulink simulation that the proposed method was effective and feasible.
Parameters tuning of robot joint motor′s controller was the key of good control performance realization. A parameter tuning method was presented for joint motor sliding mode control based on alternating simultaneous iteration. Firstly, the permanent magnet synchronous joint motor was designed, and the control object of the system was determined. Secondly, the slidingmodePID control system that combined the PID current controller with the sliding mode speed controller was designed. The sliding mode controller′s parameters were set initially using engineering design methods. A redundant PID speed controller was added and its parameters were also set by engineering design methods. Using the output speed of the redundant PID speed controller and sliding mode speed controller as iterating variable, the parameters of controller were obtained via alternating simultaneous iteration. Finally, it was proved by the MATLAB/Simulink simulation that the proposed method was effective and feasible.
2019, 46(3):34-40, 63.
Abstract:
A disk permanent magnet synchronous motor with two stators was discussed, analyzed and verified by experiments. Doublestator motor had attracted more and more attention due to its high torque density, flexible control and other characteristics. However, in practical applications, in order to optimize the efficiency of the system, it was difficult to distribute the doublestator motor’s energy. A torque allocation strategy based on MAP diagram was proposed, and experiments were carried out on the experimental platform with TMS320F28335 as the main control chip. The experimental results showed that the proposed control and allocation strategy could effectively ensure the efficient operation of the doublestator motor system.
A disk permanent magnet synchronous motor with two stators was discussed, analyzed and verified by experiments. Doublestator motor had attracted more and more attention due to its high torque density, flexible control and other characteristics. However, in practical applications, in order to optimize the efficiency of the system, it was difficult to distribute the doublestator motor’s energy. A torque allocation strategy based on MAP diagram was proposed, and experiments were carried out on the experimental platform with TMS320F28335 as the main control chip. The experimental results showed that the proposed control and allocation strategy could effectively ensure the efficient operation of the doublestator motor system.
2019, 46(3):41-45.
Abstract:
The threelevel inverter’s voltage output had one more step than twolevel inverter so that it had lower harmonics. Thus, the output waveform of threelevel inverter was better and was more suitable to realize sine wave. Moreover, each power device’s voltage stress of threelevel inverter was smaller than that of twolevel inverter. Then threelevel inverter was more fit for high voltage and large power volume converter development. Interior permanent magnet synchronous motor (IPMSM) was controlled with threephase sine wave input. Using threelevel inverter to drive IPMSM had such clear advantages as decreasing torque pulsation and easy to realize excellent speed modulation performance. The research of IPMSM vector control based on threelevel inverter was carried out. The simulation model of the whole system was built. Simulation results proved that the threelevel inverter voltage output was correct, IPMSM speed could follow the reference speed closely, and the dynamic and static responses were good.
The threelevel inverter’s voltage output had one more step than twolevel inverter so that it had lower harmonics. Thus, the output waveform of threelevel inverter was better and was more suitable to realize sine wave. Moreover, each power device’s voltage stress of threelevel inverter was smaller than that of twolevel inverter. Then threelevel inverter was more fit for high voltage and large power volume converter development. Interior permanent magnet synchronous motor (IPMSM) was controlled with threephase sine wave input. Using threelevel inverter to drive IPMSM had such clear advantages as decreasing torque pulsation and easy to realize excellent speed modulation performance. The research of IPMSM vector control based on threelevel inverter was carried out. The simulation model of the whole system was built. Simulation results proved that the threelevel inverter voltage output was correct, IPMSM speed could follow the reference speed closely, and the dynamic and static responses were good.
2019, 46(3):46-49.
Abstract:
Doublestator permanent magnet synchronous generator (DSPMSG) had two stators and one inbetween rotor. It was not easy to carry out electromagnetic field calculation with common software. Magnetic circuit model for DSPMSG was established. The model considered magnetic saturation according to the magnetization characteristic curve of ferromagnetic material, and took into account the influence of armature reaction of inner and outer windings on permanent magnet field. It was convenient for the timely adjustment of design variables. The calculation results using the magnetic circuit model of a 3.3 kW prototype met with the results of finite element calculation, which indicated the practicability and validity of the model.
Doublestator permanent magnet synchronous generator (DSPMSG) had two stators and one inbetween rotor. It was not easy to carry out electromagnetic field calculation with common software. Magnetic circuit model for DSPMSG was established. The model considered magnetic saturation according to the magnetization characteristic curve of ferromagnetic material, and took into account the influence of armature reaction of inner and outer windings on permanent magnet field. It was convenient for the timely adjustment of design variables. The calculation results using the magnetic circuit model of a 3.3 kW prototype met with the results of finite element calculation, which indicated the practicability and validity of the model.
2019, 46(3):50-57.
Abstract:
An analytical model was presented for a 5 kW high speed permanent magnet synchronous motor with gramme windings. The solution regions were divided into airgap subdomain, permanent magnet subdomain, slot opening subdomain and slot subdomain. The Laplace and Poisson equations in each subdomain were solved. The analytical model accounted for armature reaction field, permanent magnet field and stator slot effects. Airgap flux density, phase fluxlinkage, phase back electromotive force, cogging torque and electromagnetic torque calculated with the proposed analytical method were respectively compared with finite element calculation results and experimental data. Comparison results illustrated the accuracy of the analytical model. Finally, airgap flux density and cogging torque were studied based on different slot opening grades.
An analytical model was presented for a 5 kW high speed permanent magnet synchronous motor with gramme windings. The solution regions were divided into airgap subdomain, permanent magnet subdomain, slot opening subdomain and slot subdomain. The Laplace and Poisson equations in each subdomain were solved. The analytical model accounted for armature reaction field, permanent magnet field and stator slot effects. Airgap flux density, phase fluxlinkage, phase back electromotive force, cogging torque and electromagnetic torque calculated with the proposed analytical method were respectively compared with finite element calculation results and experimental data. Comparison results illustrated the accuracy of the analytical model. Finally, airgap flux density and cogging torque were studied based on different slot opening grades.
2019, 46(3):58-63.
Abstract:
In view of the complexity of the core structure of the brushless AC exciter and the influence of saturation characteristics of the ferromagnetic material, the finite element software Maxwell was used to create a twodimensional model of the brushless AC exciter for the research and analysis of noload characteristics and rated excitation current. Taking a 28 kW brushless AC exciter as an example, the simulation analysis of the air gap magnetic field of the motor and the calculation of the noload characteristics were carried out. The calculated fundamental wave potential was consistent with the measured results, and a theoretical basis for the design of the electromagnetic field of this type of motor was provided. Based on this, through fieldcircuit coupling method, the external circuit was used to simulate the rated load condition, and the excitation current under rated condition was calculated. This method had practicality and could provided reference for the calculation of the general AC exciter excitation current.
In view of the complexity of the core structure of the brushless AC exciter and the influence of saturation characteristics of the ferromagnetic material, the finite element software Maxwell was used to create a twodimensional model of the brushless AC exciter for the research and analysis of noload characteristics and rated excitation current. Taking a 28 kW brushless AC exciter as an example, the simulation analysis of the air gap magnetic field of the motor and the calculation of the noload characteristics were carried out. The calculated fundamental wave potential was consistent with the measured results, and a theoretical basis for the design of the electromagnetic field of this type of motor was provided. Based on this, through fieldcircuit coupling method, the external circuit was used to simulate the rated load condition, and the excitation current under rated condition was calculated. This method had practicality and could provided reference for the calculation of the general AC exciter excitation current.
2019, 46(3):64-70.
Abstract:
Aiming at the problem that the switched reluctance motor (SRM) with strong coupling and strong nonlinearity was difficult to accurately resolve and model, a backpropagation (BP) neural network modeling method based on data pretreatment was proposed. Firstly, the static electromagnetic characteristics of SRM in one electrical cycle were measured by the traditional DC pulse method to obtain modeling sample data. Secondly, the motor prior knowledge was fully utilized, and the measured sample data were preprocessed through the flux linkage and torque analytical expressions which could initially reflect the nonlinear characteristics of the SRM, and then sent to the BP neural network so as to reduce the neural network fit error. Compared with the traditional BP neural network modeling, the pretreatment method could effectively reduce the number of BP neural network nodes, enhance the generalization ability of the neural network, and improve the modeling accuracy of the neural network.
Aiming at the problem that the switched reluctance motor (SRM) with strong coupling and strong nonlinearity was difficult to accurately resolve and model, a backpropagation (BP) neural network modeling method based on data pretreatment was proposed. Firstly, the static electromagnetic characteristics of SRM in one electrical cycle were measured by the traditional DC pulse method to obtain modeling sample data. Secondly, the motor prior knowledge was fully utilized, and the measured sample data were preprocessed through the flux linkage and torque analytical expressions which could initially reflect the nonlinear characteristics of the SRM, and then sent to the BP neural network so as to reduce the neural network fit error. Compared with the traditional BP neural network modeling, the pretreatment method could effectively reduce the number of BP neural network nodes, enhance the generalization ability of the neural network, and improve the modeling accuracy of the neural network.
2019, 46(3):71-75, 108.
Abstract:
To avoid the huge time consumption in the initial and optimum design of modular linear permanent magnet vernier machine when finite element method (FEM) was used to calculate the flux leakage coefficient, the equivalent magnetic network model was established for the machine. During the modeling, the fringing effect in the airgap was taken into consideration, the equivalent permeances of the permanent magnet group and the stator teeth at different relative positions were calculated, and the mathematical analytical expressions of magnetic permeability and flux leakage coefficient of the machine at different relative positions in one cycle were obtained. Finally, the FEM method was used to verify the correctness and accuracy of the mathematical analytical expressions. The research results provided a theoretical basis for the design of modular linear permanent magnet vernier machines.
To avoid the huge time consumption in the initial and optimum design of modular linear permanent magnet vernier machine when finite element method (FEM) was used to calculate the flux leakage coefficient, the equivalent magnetic network model was established for the machine. During the modeling, the fringing effect in the airgap was taken into consideration, the equivalent permeances of the permanent magnet group and the stator teeth at different relative positions were calculated, and the mathematical analytical expressions of magnetic permeability and flux leakage coefficient of the machine at different relative positions in one cycle were obtained. Finally, the FEM method was used to verify the correctness and accuracy of the mathematical analytical expressions. The research results provided a theoretical basis for the design of modular linear permanent magnet vernier machines.
2019, 46(3):76-82, 94.
Abstract:
Traditionally, the current chopping control (CCC) was applied for starting control and the angle position control (APC) was applied in mediumhigh speed operation state for the switched reluctance motor (SRM). However, in electric vehicle (EV) application field, SRM was usually controlled with traditional pulse width modulation (PWM) control strategy. A dynamic CCC based starting scheme and a hybrid PWM and APC control strategy based mediumhigh speed operation control scheme were developed, which could ensure smooth starting operation, instantaneous speedup and stable operation under different load cases. Meanwhile, the most important controller protection parts such as the overcurrent protection and motor stalling protection were also optimized, and thus the system reliability would be highly improved. To verify the validity of the control strategies and the protection methods, experiments were implemented with a 12/8 structure SRM and the STM32F103 microchip based power controller. The results showed that the motor could start up quickly and smoothly, and the current fault and stalling fault could be diagnosed immediately with the proposed methods.
Traditionally, the current chopping control (CCC) was applied for starting control and the angle position control (APC) was applied in mediumhigh speed operation state for the switched reluctance motor (SRM). However, in electric vehicle (EV) application field, SRM was usually controlled with traditional pulse width modulation (PWM) control strategy. A dynamic CCC based starting scheme and a hybrid PWM and APC control strategy based mediumhigh speed operation control scheme were developed, which could ensure smooth starting operation, instantaneous speedup and stable operation under different load cases. Meanwhile, the most important controller protection parts such as the overcurrent protection and motor stalling protection were also optimized, and thus the system reliability would be highly improved. To verify the validity of the control strategies and the protection methods, experiments were implemented with a 12/8 structure SRM and the STM32F103 microchip based power controller. The results showed that the motor could start up quickly and smoothly, and the current fault and stalling fault could be diagnosed immediately with the proposed methods.
14 ThreeDimensional CFD Thermal Analysis and Temperature Rise Test ofDrive Motor for Electric Vehicle
2019, 46(3):83-89, 108.
Abstract:
Aiming at the temperature rise problem of drive motor for electric vehicle under extreme conditions, the numerical method of fluidsolid conjugate heat transfer was used to simulate the heat dissipation performance of a permanent magnet synchronous motor. The temperature distribution of the stator and rotor under different working conditions was obtained. The slip ring module was used to solve the problem of rotor temperature rise test. The data of temperature rise test and computational fluid dynamics (CFD) simulation results of different vehicle conditions were compared to verify the accuracy of the numerical model and method. This research provided theoretical support for accurately obtaining the operating temperature of permanent magnets in the motor under driving conditions.
Aiming at the temperature rise problem of drive motor for electric vehicle under extreme conditions, the numerical method of fluidsolid conjugate heat transfer was used to simulate the heat dissipation performance of a permanent magnet synchronous motor. The temperature distribution of the stator and rotor under different working conditions was obtained. The slip ring module was used to solve the problem of rotor temperature rise test. The data of temperature rise test and computational fluid dynamics (CFD) simulation results of different vehicle conditions were compared to verify the accuracy of the numerical model and method. This research provided theoretical support for accurately obtaining the operating temperature of permanent magnets in the motor under driving conditions.
2019, 46(3):90-94.
Abstract:
With the development of intelligent manufacturing, China’s manufacturing industry has generated an urgent demand for automation and information technology. It is a practical requirement for manufacturers to establish a remote debugging system with convenient operation, low initial input and low maintenance cost for factory equipment. We developed a lowcost remote debugging system, which could quickly build a dedicated channel from the factory to the maintenance center for remote debugging. The system could be widely applied to remote maintenance of motor production line. The system architecture was introduced, and the development key points of the core devices were described in detail. Finally, the practical applications of the system were demonstrated.
With the development of intelligent manufacturing, China’s manufacturing industry has generated an urgent demand for automation and information technology. It is a practical requirement for manufacturers to establish a remote debugging system with convenient operation, low initial input and low maintenance cost for factory equipment. We developed a lowcost remote debugging system, which could quickly build a dedicated channel from the factory to the maintenance center for remote debugging. The system could be widely applied to remote maintenance of motor production line. The system architecture was introduced, and the development key points of the core devices were described in detail. Finally, the practical applications of the system were demonstrated.
2019, 46(3):95-101.
Abstract:
Data acquisition system was very important for the implementation of intelligent manufacturing electric machines digital factory. For a newenergy vehicle (NEV) electric machine digital factory, with configuration software as the core processing layer, key production parameters such as production equipment parameters, production personnel information, material information and quality data were collected through industrial Ethernet network to construct the exchange of workshop production site comprehensive data. This data acquisition system could provide data support for the upper management system of intelligent manufacturing, realizing the intelligent manufacturing of electric machines.
Data acquisition system was very important for the implementation of intelligent manufacturing electric machines digital factory. For a newenergy vehicle (NEV) electric machine digital factory, with configuration software as the core processing layer, key production parameters such as production equipment parameters, production personnel information, material information and quality data were collected through industrial Ethernet network to construct the exchange of workshop production site comprehensive data. This data acquisition system could provide data support for the upper management system of intelligent manufacturing, realizing the intelligent manufacturing of electric machines.
2019, 46(3):102-108.
Abstract:
Monitoring the permanent magnet temperature of permanent magnet motors was critical to the life of the motor, because the excessive permanent magnet temperature increased the risk of irreversible demagnetization. A method based on particle swarm optimization (PSO) algorithm for permanent magnet motor thermal network temperature identification was proposed to monitor the temperature of permanent magnets. In this method, the thermal network model of the permanent magnet motor was established, and the PSO algorithm was combined with the temperature data obtained by the motor temperature rise experiment to identify the main thermal parameters of the model. This method was used to identify the temperature online, and the identification process could be quickly converged with good accuracy. Finally, the feasibility and accuracy of the method were verified by comparing the temperature of the simulation with the experimental data.
Monitoring the permanent magnet temperature of permanent magnet motors was critical to the life of the motor, because the excessive permanent magnet temperature increased the risk of irreversible demagnetization. A method based on particle swarm optimization (PSO) algorithm for permanent magnet motor thermal network temperature identification was proposed to monitor the temperature of permanent magnets. In this method, the thermal network model of the permanent magnet motor was established, and the PSO algorithm was combined with the temperature data obtained by the motor temperature rise experiment to identify the main thermal parameters of the model. This method was used to identify the temperature online, and the identification process could be quickly converged with good accuracy. Finally, the feasibility and accuracy of the method were verified by comparing the temperature of the simulation with the experimental data.
2019, 46(3):109-114.
Abstract:
In asynchronous motors, colored Gaussian noises will be produced in stator current after lowpass filter. For this reason, the precision of rotor fault detection methods was restricted. In order to solve this problem, a method for the rotor fault detection in asynchronous motors which could restrain colored Gaussian noises was proposed. Firstly, inverse rotation transform was used to pretreat the sampling stator current and eliminate the fundamental frequency, with which the estimation error of direct detection without pretreatment could be avoided. Then, considering that crosscorrelation function (CCF) could restrain colored Gaussian noises, crosscorrelation function Hankel total least squares (CCFHTLS) algorithm was proposed to detect motor rotor fault. The experimental result of broken rotor bars and eccentric fault detection indicated that CCFHTLS algorithm remarkably restrained colored Gaussian noises and accurately preserved available information of faults, significantly promoting the detection precision.
In asynchronous motors, colored Gaussian noises will be produced in stator current after lowpass filter. For this reason, the precision of rotor fault detection methods was restricted. In order to solve this problem, a method for the rotor fault detection in asynchronous motors which could restrain colored Gaussian noises was proposed. Firstly, inverse rotation transform was used to pretreat the sampling stator current and eliminate the fundamental frequency, with which the estimation error of direct detection without pretreatment could be avoided. Then, considering that crosscorrelation function (CCF) could restrain colored Gaussian noises, crosscorrelation function Hankel total least squares (CCFHTLS) algorithm was proposed to detect motor rotor fault. The experimental result of broken rotor bars and eccentric fault detection indicated that CCFHTLS algorithm remarkably restrained colored Gaussian noises and accurately preserved available information of faults, significantly promoting the detection precision.
19 DC Voltage Compensation and Control of Low Voltage Ride ThroughDevice of Power Auxiliary Inverter
2019, 46(3):115-120, 126.
Abstract:
In view of the problem that power generating unit will shut down due to the drop of the stationservice voltage, low voltage ride through (LVRT) device based on the inverter DC bus voltage compensation was designed. For the auxiliary inverter, direct torque control was adopted. For the main circuit of the LRVT device, ternary staggered parallel boost converter structure was used, which maintained the DC bus voltage stability during the voltage drop and reduced the high frequency ripple of the output current. Considering the current balancing problem of the parallel modules caused by parameter difference, current balancing loop was added to the outer loop of the traditional voltage and current doubleclosedloop control, so that the circulating current was eliminated and the current stress of switch devices was more balanced. Because of the nonlinear and strong coupling characteristics of the control system, conventional PI controller was limited, so fuzzy control algorithm was used to optimize the parameters of PI controller. Finally, simulation was carried out to prove the proposed method.
In view of the problem that power generating unit will shut down due to the drop of the stationservice voltage, low voltage ride through (LVRT) device based on the inverter DC bus voltage compensation was designed. For the auxiliary inverter, direct torque control was adopted. For the main circuit of the LRVT device, ternary staggered parallel boost converter structure was used, which maintained the DC bus voltage stability during the voltage drop and reduced the high frequency ripple of the output current. Considering the current balancing problem of the parallel modules caused by parameter difference, current balancing loop was added to the outer loop of the traditional voltage and current doubleclosedloop control, so that the circulating current was eliminated and the current stress of switch devices was more balanced. Because of the nonlinear and strong coupling characteristics of the control system, conventional PI controller was limited, so fuzzy control algorithm was used to optimize the parameters of PI controller. Finally, simulation was carried out to prove the proposed method.
2019, 46(3):121-126.
Abstract:
The slip device of 300 MVA motor generator (MG) was introduced. The startup process of the MG with slip mode was analyzed and modeled. According to the actual electrical waveforms, the equivalent model of the liquid resistor of the slip device was established by using the nonlinear programming model. And the MG startup process was simulated by using these models with the parameters of MG. The simulation results basically tallied with the measured waveforms. The feasibility of the models was verified. On this basis, in order to reach the rated speed of the MG, the scheme of short connection after incorporating twostage solid metal resistor into the liquid resistor was put forward. The theoretical parameters such as the resistance of the twostage solid metal resistor were given, and the feasibility of the scheme was verified by simulation. The models could be used as an important tool to study the dynamic characteristics of the MG startup process under different parameters and different control strategies.
The slip device of 300 MVA motor generator (MG) was introduced. The startup process of the MG with slip mode was analyzed and modeled. According to the actual electrical waveforms, the equivalent model of the liquid resistor of the slip device was established by using the nonlinear programming model. And the MG startup process was simulated by using these models with the parameters of MG. The simulation results basically tallied with the measured waveforms. The feasibility of the models was verified. On this basis, in order to reach the rated speed of the MG, the scheme of short connection after incorporating twostage solid metal resistor into the liquid resistor was put forward. The theoretical parameters such as the resistance of the twostage solid metal resistor were given, and the feasibility of the scheme was verified by simulation. The models could be used as an important tool to study the dynamic characteristics of the MG startup process under different parameters and different control strategies.
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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.
