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Volume 46,Issue 1,2019 Table of Contents
2019, 46(1):1-8.
Abstract:
The antidisturbance performance of permanent magnet linear synchronous motor (PMLSM) was weak, and the dynamic performance of the current loop was easily affected by the distortion of magnetic field and the dead zone of the inverter. To enhance the control quality of the current loop, linear active disturbance rejection control (LADRC) was chosen as a closed loop control strategy for qaxis current loop. Considering that the dynamic response of small lag links such as current loop inverter and lowpass filter could not be ignored while tracking high frequency signals, a new twoorder control model of the current loop was derived in the frequency domain by using the method of time domain and frequency domain analysis to link the current loop with the small lag link model, and then a threeorder current loop LADRC system was established in the time domain. An advanced correction link is designed to reduce the control lag caused by the increase of the order, and a detailed parameter tuning method of the control system was given. Compared with the traditional LADRC, simulation results showed that the new LADRC control strategy had better performance in current dynamic following and disturbance rejection, and the control system had good control performance.
The antidisturbance performance of permanent magnet linear synchronous motor (PMLSM) was weak, and the dynamic performance of the current loop was easily affected by the distortion of magnetic field and the dead zone of the inverter. To enhance the control quality of the current loop, linear active disturbance rejection control (LADRC) was chosen as a closed loop control strategy for qaxis current loop. Considering that the dynamic response of small lag links such as current loop inverter and lowpass filter could not be ignored while tracking high frequency signals, a new twoorder control model of the current loop was derived in the frequency domain by using the method of time domain and frequency domain analysis to link the current loop with the small lag link model, and then a threeorder current loop LADRC system was established in the time domain. An advanced correction link is designed to reduce the control lag caused by the increase of the order, and a detailed parameter tuning method of the control system was given. Compared with the traditional LADRC, simulation results showed that the new LADRC control strategy had better performance in current dynamic following and disturbance rejection, and the control system had good control performance.
2019, 46(1):9-14.
Abstract:
Based on the expressions of flux and torque of surface permanent magnet synchronous motor (SPMSM) direct torque control (DTC) system using the amplitude of applied voltage vector as the variable, the values of stator flux and torque at the next sampling point after applying voltage vector with different amplitude were given. The object function of flux error and torque error was proposed. The predictive control would select the optimal amplitude of voltage vector to minimize the object function. Simulation results showed that the PMSM DTC system under the control of proposed strategy worked properly. As the predictive control selected the optimal voltage vector from aggregate of voltage vectors, more voltage vectors would lead to better control performance, at the cost of heavier calculation burden. Control performances of SPMSM DTC system were given using 9 methods of dividing voltage vectors. According to control performance and calculation burden, dividing voltage vectors into three equal parts was an ideal way.
Based on the expressions of flux and torque of surface permanent magnet synchronous motor (SPMSM) direct torque control (DTC) system using the amplitude of applied voltage vector as the variable, the values of stator flux and torque at the next sampling point after applying voltage vector with different amplitude were given. The object function of flux error and torque error was proposed. The predictive control would select the optimal amplitude of voltage vector to minimize the object function. Simulation results showed that the PMSM DTC system under the control of proposed strategy worked properly. As the predictive control selected the optimal voltage vector from aggregate of voltage vectors, more voltage vectors would lead to better control performance, at the cost of heavier calculation burden. Control performances of SPMSM DTC system were given using 9 methods of dividing voltage vectors. According to control performance and calculation burden, dividing voltage vectors into three equal parts was an ideal way.
2019, 46(1):15-20.
Abstract:
In order to improve the airgap magnetic field distribution of hybrid excitation synchronous generator, a method named threelevel airgap length was introduced to optimize the rotor structure. The airgap flux densities, before and after optimization based on this method were analyzed and compared. After the rotor structure was optimized, the armature winding scheme with short pitch, distributed arrangement and skewed slots was adopted for a better voltage waveform quality. Then, prototype was tested to analyze its harmonic components of phase voltage with a power analyzer. Experimental results demonstrated that the total harmonic distortion (THD) of voltage could be restrained to the acceptable range(less than 5%) based on the combination of the threelevel airgap length and the stator skewed slots. Finally, feasibility of the eccentricdistance method used in the tangential/radial hybrid excitation synchronous generator was discussed, and the calculation results of airgap flux density were compared for the eccentricdistance method and the threelevel airgap length method.
In order to improve the airgap magnetic field distribution of hybrid excitation synchronous generator, a method named threelevel airgap length was introduced to optimize the rotor structure. The airgap flux densities, before and after optimization based on this method were analyzed and compared. After the rotor structure was optimized, the armature winding scheme with short pitch, distributed arrangement and skewed slots was adopted for a better voltage waveform quality. Then, prototype was tested to analyze its harmonic components of phase voltage with a power analyzer. Experimental results demonstrated that the total harmonic distortion (THD) of voltage could be restrained to the acceptable range(less than 5%) based on the combination of the threelevel airgap length and the stator skewed slots. Finally, feasibility of the eccentricdistance method used in the tangential/radial hybrid excitation synchronous generator was discussed, and the calculation results of airgap flux density were compared for the eccentricdistance method and the threelevel airgap length method.
2019, 46(1):21-27, 39.
Abstract:
In order to improve the faulttolerant performance of the machine drive system and achieve the minimum copper loss, a faulttolerant control method for faulttolerant hybridexcitation fluxswitching (FTHEFS) machine based on model predictive control algorithm was proposed. Taking a 6/13pole FTHEFS machine as the control object, under the condition of the threephase fourleg inverter topology and the open circuit failure of singlephase winding, the minimum copper loss faulttolerant methods based on the model predictive torque control and deadbeatmodel predictive flux control algorithms were studied and analyzed, respectively. The feasibility and effectiveness of the proposed faulttolerant control method were verified. The research results showed that both methods could make the speed, torque and stator fluxlinkage almost unchanged, ensuring the stable operation of the system. Compared with model predictive torque control, the deadbeatmodel predictive flux control had smaller fluxlinkage ripple before and after the open circuit failure while the switching frequency was reduced.
In order to improve the faulttolerant performance of the machine drive system and achieve the minimum copper loss, a faulttolerant control method for faulttolerant hybridexcitation fluxswitching (FTHEFS) machine based on model predictive control algorithm was proposed. Taking a 6/13pole FTHEFS machine as the control object, under the condition of the threephase fourleg inverter topology and the open circuit failure of singlephase winding, the minimum copper loss faulttolerant methods based on the model predictive torque control and deadbeatmodel predictive flux control algorithms were studied and analyzed, respectively. The feasibility and effectiveness of the proposed faulttolerant control method were verified. The research results showed that both methods could make the speed, torque and stator fluxlinkage almost unchanged, ensuring the stable operation of the system. Compared with model predictive torque control, the deadbeatmodel predictive flux control had smaller fluxlinkage ripple before and after the open circuit failure while the switching frequency was reduced.
2019, 46(1):28-33.
Abstract:
In the sensorless control of permanent magnet synchronous motor based on sliding mode observer (SMO), the observation error of position and speed was large and the chattering was strong. In order to solve this problem, the traditional SMO was analyzed. A kind of nonsingular fast terminal sliding mode surface was studied, and a sliding mode control law with integral was discussed, which could effectively improve the observation accuracy, reduce chattering and eliminate the low pass filter and rotor position compensation. The stability of the observer was proved by Lyapunov function. Finally, MATLAB/Simulink software was used for simulation, and the results showed that the control performance of the proposed observer was better than that of the traditional SMO.
In the sensorless control of permanent magnet synchronous motor based on sliding mode observer (SMO), the observation error of position and speed was large and the chattering was strong. In order to solve this problem, the traditional SMO was analyzed. A kind of nonsingular fast terminal sliding mode surface was studied, and a sliding mode control law with integral was discussed, which could effectively improve the observation accuracy, reduce chattering and eliminate the low pass filter and rotor position compensation. The stability of the observer was proved by Lyapunov function. Finally, MATLAB/Simulink software was used for simulation, and the results showed that the control performance of the proposed observer was better than that of the traditional SMO.
2019, 46(1):34-39.
Abstract:
In order to improve the dynamic performance of threephase permanent magnet synchronous motor (PMSM) speed control system improve the control performance of traditional sliding mode speed controller, suppress the system chattering, and improve the control precision, an improved sliding mode speed controller based on a newtype reaching law and a load observer was designed. MATLAB/Simulink simulation software was used to build the control system model and conduct simulation analysis. The design was verified by simulation. Good speed tracking precision and load disturbance resistance were obtained, and stability and robustness of the system were improved.
In order to improve the dynamic performance of threephase permanent magnet synchronous motor (PMSM) speed control system improve the control performance of traditional sliding mode speed controller, suppress the system chattering, and improve the control precision, an improved sliding mode speed controller based on a newtype reaching law and a load observer was designed. MATLAB/Simulink simulation software was used to build the control system model and conduct simulation analysis. The design was verified by simulation. Good speed tracking precision and load disturbance resistance were obtained, and stability and robustness of the system were improved.
2019, 46(1):40-47.
Abstract:
Switched reluctance motor (SRM) had the characteristics of torque ripple. A direct instantaneous torque control strategy combining hysteresis control and pulse width modulation (PWM) was proposed. Based on the analyses on the mechanism of large fluctuations in torque during control process, different control methods were formulated for singlephase and commutation zones. Considering the output characteristics of torque under different conditions, the PWM equivalent strategy was introduced into the hysteresis limit interval to optimize the torque control effect. Fuzzy adaptive PID controller was added to improve the response performance of the system. The simulation results showed that the control strategy had a fast response and could suppress the torque ripple of the SRM effectively.
Switched reluctance motor (SRM) had the characteristics of torque ripple. A direct instantaneous torque control strategy combining hysteresis control and pulse width modulation (PWM) was proposed. Based on the analyses on the mechanism of large fluctuations in torque during control process, different control methods were formulated for singlephase and commutation zones. Considering the output characteristics of torque under different conditions, the PWM equivalent strategy was introduced into the hysteresis limit interval to optimize the torque control effect. Fuzzy adaptive PID controller was added to improve the response performance of the system. The simulation results showed that the control strategy had a fast response and could suppress the torque ripple of the SRM effectively.
2019, 46(1):48-54.
Abstract:
When the permanent magnet synchronous motor (PMSM) was used as the driving device of the oil drilling rig system, the predictive control strategy of the PMSM in the oil drilling rig system based on feedforward compensation was proposed in view of the control requirements of fast response and strong robustness and the external disturbance in complex conditions. In this method, the predictive control based on the motor mathematical model was applied to the motor speed loop to realize the fast response and improve the robustness of the PMSM, and the extended state observer was introduced to realize the disturbance feedforward compensation. The simulation results showed that, compared with the speed PI control and dynamic matrix control of PMSM, the new control method had faster response and less overshoot, and the speed under the load interference exhibited less fluctuation and could be more quickly restored to the stable value.
When the permanent magnet synchronous motor (PMSM) was used as the driving device of the oil drilling rig system, the predictive control strategy of the PMSM in the oil drilling rig system based on feedforward compensation was proposed in view of the control requirements of fast response and strong robustness and the external disturbance in complex conditions. In this method, the predictive control based on the motor mathematical model was applied to the motor speed loop to realize the fast response and improve the robustness of the PMSM, and the extended state observer was introduced to realize the disturbance feedforward compensation. The simulation results showed that, compared with the speed PI control and dynamic matrix control of PMSM, the new control method had faster response and less overshoot, and the speed under the load interference exhibited less fluctuation and could be more quickly restored to the stable value.
2019, 46(1):55-63, 118.
Abstract:
There existed large current harmonics when the variable frequency air conditioner ran in the low frequency. When using the common repetitive control (RC), since the ratio of the sampling frequency to the fundamental frequency of current harmonics may be not an integer, there was deviation between the internal mode of repetitive control and the fundamental frequency of the current harmonics, and thus the suppression effects of the repetitive controller would be degraded drastically. Aiming at this problem, a fractionalorder RC (FORC) strategy at fixed sampling frequency was proposed. Firstly, Lagrange interpolation theory was used to approximate the fractional delay item; secondly, FIR filter was used to eliminate the error caused by low pass filter (LPF); finally, aiming at the phase lag of the FORC, phase compensation was made in all frequency bands to confirm the stability of the closed loop. The experiment results showed that the proposed strategy could effectively suppress the current harmonics of the variable frequency air conditioner running at the low frequency.
There existed large current harmonics when the variable frequency air conditioner ran in the low frequency. When using the common repetitive control (RC), since the ratio of the sampling frequency to the fundamental frequency of current harmonics may be not an integer, there was deviation between the internal mode of repetitive control and the fundamental frequency of the current harmonics, and thus the suppression effects of the repetitive controller would be degraded drastically. Aiming at this problem, a fractionalorder RC (FORC) strategy at fixed sampling frequency was proposed. Firstly, Lagrange interpolation theory was used to approximate the fractional delay item; secondly, FIR filter was used to eliminate the error caused by low pass filter (LPF); finally, aiming at the phase lag of the FORC, phase compensation was made in all frequency bands to confirm the stability of the closed loop. The experiment results showed that the proposed strategy could effectively suppress the current harmonics of the variable frequency air conditioner running at the low frequency.
2019, 46(1):64-69.
Abstract:
The parameters identification method of traditional motor often used fixed pulse width modulation (PWM) wave duty cycle, which led to uncontrollable identification current, and the accuracy of identification and was directly affected by the size of identified current. A new parameters offline identification method was proposed, which was based on the principle of constant current identification. It solved the problem of inappropriate identification current of motor by detecting the phase current of motor and controlling the fluctuation of identification current near the given value. The model of the flywheel diode and IGBT voltage was designed, which required that both daxis and qaxis inductance identification should be carried out at 270° instead of 0°, thus it could improve the identification accuracy. Finally, the method was applied to the frequency conversion refrigerator, and the experimental results were compared with the original data. This method could effectively solve problems such as inaccurate identification of the d,qaxis inductance and long identification time of the refrigerator motor with back pressure. The experimental results showed that the new method was feasible and effective.
The parameters identification method of traditional motor often used fixed pulse width modulation (PWM) wave duty cycle, which led to uncontrollable identification current, and the accuracy of identification and was directly affected by the size of identified current. A new parameters offline identification method was proposed, which was based on the principle of constant current identification. It solved the problem of inappropriate identification current of motor by detecting the phase current of motor and controlling the fluctuation of identification current near the given value. The model of the flywheel diode and IGBT voltage was designed, which required that both daxis and qaxis inductance identification should be carried out at 270° instead of 0°, thus it could improve the identification accuracy. Finally, the method was applied to the frequency conversion refrigerator, and the experimental results were compared with the original data. This method could effectively solve problems such as inaccurate identification of the d,qaxis inductance and long identification time of the refrigerator motor with back pressure. The experimental results showed that the new method was feasible and effective.
2019, 46(1):70-74.
Abstract:
The methods for reducing the thrust ripple of permanent magnet linear synchronous motor (PMLSM) were introduced and analyzed. In view of the endeffect force, the cogging force and the electromagnetic pulse force, the corresponding thrust ripple reduction methods were summed up and summarized, and the control modes were summarized. The development trend of thrust ripple reduction method for PMLSM was discussed. This research will contribute to the improvement of the performance and application of PMLSM.
The methods for reducing the thrust ripple of permanent magnet linear synchronous motor (PMLSM) were introduced and analyzed. In view of the endeffect force, the cogging force and the electromagnetic pulse force, the corresponding thrust ripple reduction methods were summed up and summarized, and the control modes were summarized. The development trend of thrust ripple reduction method for PMLSM was discussed. This research will contribute to the improvement of the performance and application of PMLSM.
2019, 46(1):75-80.
Abstract:
To achieve accurate position regulation on servomotors, two control schemes were proposed, i.e., robust composite servo control based on extended state observer (ESO), and linear feedback control with integration of error. Using the damping ratio and natural frequency of the closedloop poles as design parameters, fullyparameterized control laws were presented in discrete time domain. The control laws were applied to a permanent magnet synchronous motor for experimental test. The results showed that the ESObased robust composite servo control could accomplish accurate setpoint motion for a wider range of target positions under various load conditions, with a desirable transient performance. In comparison, the integrationbased linear feedback control had a degraded servo performance when the target position or the load was varied, indicating a lack of robustness.
To achieve accurate position regulation on servomotors, two control schemes were proposed, i.e., robust composite servo control based on extended state observer (ESO), and linear feedback control with integration of error. Using the damping ratio and natural frequency of the closedloop poles as design parameters, fullyparameterized control laws were presented in discrete time domain. The control laws were applied to a permanent magnet synchronous motor for experimental test. The results showed that the ESObased robust composite servo control could accomplish accurate setpoint motion for a wider range of target positions under various load conditions, with a desirable transient performance. In comparison, the integrationbased linear feedback control had a degraded servo performance when the target position or the load was varied, indicating a lack of robustness.
2019, 46(1):81-87, 93.
Abstract:
A new dualpermanentmagnet excited vernier (DPMEV) machine was proposed, in which the power density and torque density were further improved to meet the low speed and high torque operating conditions of direct drive systems. Two sets of permanent magnets (PMs) were placed on stator and rotor, respectively, and the PM magnetic field could be modulated to effective harmonic magnetic field components with low polepair number and high speed by the dualmodulation effect of stator and rotor teeth. Then the armature winding was designed according to the effective harmonic magnetic fields to achieve the coupling between the magnetic fields excited by two sets of PMs and armature windings. The topology of DPMEV machine was introduced. The air gap flux density was analyzed based on the equivalent magnetic circuit method, which proved the improvement potentiality of power density and torque density based on the dualmodulation effect. The performances of DPMEV machine were calculated and analyzed by the finite element method, verifying the advantages of high power density and high torque density which were suitable for the direct drive system.
A new dualpermanentmagnet excited vernier (DPMEV) machine was proposed, in which the power density and torque density were further improved to meet the low speed and high torque operating conditions of direct drive systems. Two sets of permanent magnets (PMs) were placed on stator and rotor, respectively, and the PM magnetic field could be modulated to effective harmonic magnetic field components with low polepair number and high speed by the dualmodulation effect of stator and rotor teeth. Then the armature winding was designed according to the effective harmonic magnetic fields to achieve the coupling between the magnetic fields excited by two sets of PMs and armature windings. The topology of DPMEV machine was introduced. The air gap flux density was analyzed based on the equivalent magnetic circuit method, which proved the improvement potentiality of power density and torque density based on the dualmodulation effect. The performances of DPMEV machine were calculated and analyzed by the finite element method, verifying the advantages of high power density and high torque density which were suitable for the direct drive system.
2019, 46(1):88-93.
Abstract:
With a 4/2 geometry highspeed switched reluctance motor (SRM), the magnetic properties of nanocrystalline stator core and their effects on the motor were analyzed. First, the stator core fabricated by wireelectrode cutting was tested and compared with the silicon steel core. Then, the motors were tested in static and running in load modes. Results indicated that the nanocrystalline core had higher magnetic permeability, smaller coercivity and lower core loss, with only 1/20 of 35W300 silicon steel core loss under the excitation conditions of 1 kHz and 1 T. The motor with nanocrystalline stator core had higher phase inductance, in comparison with the silicon steel core motor, and both core loss and input power of which were reduced at a speed of 25 000 r/min and the same output power. Results could be used for the optimization and performance improvement of high speed SRM.
With a 4/2 geometry highspeed switched reluctance motor (SRM), the magnetic properties of nanocrystalline stator core and their effects on the motor were analyzed. First, the stator core fabricated by wireelectrode cutting was tested and compared with the silicon steel core. Then, the motors were tested in static and running in load modes. Results indicated that the nanocrystalline core had higher magnetic permeability, smaller coercivity and lower core loss, with only 1/20 of 35W300 silicon steel core loss under the excitation conditions of 1 kHz and 1 T. The motor with nanocrystalline stator core had higher phase inductance, in comparison with the silicon steel core motor, and both core loss and input power of which were reduced at a speed of 25 000 r/min and the same output power. Results could be used for the optimization and performance improvement of high speed SRM.
2019, 46(1):94-100.
Abstract:
The traditional medium and small power twelvephase synchronous generatorrectifier had a low voltage level, and its rectifying device was usually composed of four sets of parallel uncontrolled rectifier units. With the development of medium voltage DC integrated power technology for ship, the capacity of the generation system and the voltage level were greatly improved. The rectification unit adopted twoparalleltwoseries topology to avoid excessive voltage design value of the generator winding, and the rectifying terminal neutral line could lead to the equalization control for the electric propulsion speed regulating device. So the topology was gradually adopted. The different connection combinations of twoparalleltwoseries topologies were analyzed. The DCside voltage waveforms under two feasible topologies were analyzed and calculated. The correctness of theoretical analysis was verified by simulation and experiment. The (Y1//Y3)+(Y2//Y4) topology was the optimal combination with the best DC voltage quality.
The traditional medium and small power twelvephase synchronous generatorrectifier had a low voltage level, and its rectifying device was usually composed of four sets of parallel uncontrolled rectifier units. With the development of medium voltage DC integrated power technology for ship, the capacity of the generation system and the voltage level were greatly improved. The rectification unit adopted twoparalleltwoseries topology to avoid excessive voltage design value of the generator winding, and the rectifying terminal neutral line could lead to the equalization control for the electric propulsion speed regulating device. So the topology was gradually adopted. The different connection combinations of twoparalleltwoseries topologies were analyzed. The DCside voltage waveforms under two feasible topologies were analyzed and calculated. The correctness of theoretical analysis was verified by simulation and experiment. The (Y1//Y3)+(Y2//Y4) topology was the optimal combination with the best DC voltage quality.
2019, 46(1):101-107.
Abstract:
In view of the problem that the current model of the model reference adaptive asynchronous motor based on flux linkage was influenced by the rotor time constant and the voltage model contained the pure integral link, a model that could identify the rotational speed and the rotor time constant at the same time was established, which improved the accuracy of the current model. The integrator containing two neuron adaptive filters was used to replace the integrator of the traditional voltage model, which eliminated the influence of the DC drift and the initial integration conditions. The simulation results showed that the proposed model reference adaptive system was not affected by the change of the rotor time constant and the DC drift, and the dynamic performance of the system was good. Finally, experiments were carried out on the DSP motor control experimental platform to verify the effectiveness and high performance of this method.
In view of the problem that the current model of the model reference adaptive asynchronous motor based on flux linkage was influenced by the rotor time constant and the voltage model contained the pure integral link, a model that could identify the rotational speed and the rotor time constant at the same time was established, which improved the accuracy of the current model. The integrator containing two neuron adaptive filters was used to replace the integrator of the traditional voltage model, which eliminated the influence of the DC drift and the initial integration conditions. The simulation results showed that the proposed model reference adaptive system was not affected by the change of the rotor time constant and the DC drift, and the dynamic performance of the system was good. Finally, experiments were carried out on the DSP motor control experimental platform to verify the effectiveness and high performance of this method.
2019, 46(1):108-113.
Abstract:
As the core component of wind turbines, gearboxes frequently fail. It is significant to study the fault diagnosis methods of the wind turbine gearboxes. Considering that the Knearest neighbors (KNN) diagnosis method was insensitive to noise and the accuracy of fault diagnosis was low, a fault diagnosis method based on wavelet packet and improved kernel Knearest neighbors algorithm was proposed. This method used wavelet packet analysis technology to extract the fault features, and eliminated the noise by mutual nearest neighbor criterion. Then, an improved Knearest neighbors classification decision rule based on kernel method was established. Experiments showed that this method could effectively improve fault diagnosis accuracy and robustness, and provide new ideas for the research of intelligent diagnosis technology.
As the core component of wind turbines, gearboxes frequently fail. It is significant to study the fault diagnosis methods of the wind turbine gearboxes. Considering that the Knearest neighbors (KNN) diagnosis method was insensitive to noise and the accuracy of fault diagnosis was low, a fault diagnosis method based on wavelet packet and improved kernel Knearest neighbors algorithm was proposed. This method used wavelet packet analysis technology to extract the fault features, and eliminated the noise by mutual nearest neighbor criterion. Then, an improved Knearest neighbors classification decision rule based on kernel method was established. Experiments showed that this method could effectively improve fault diagnosis accuracy and robustness, and provide new ideas for the research of intelligent diagnosis technology.
2019, 46(1):114-118.
Abstract:
The traditional pneumatic brake system occupies large space for the compressor, brake reservoir and air pipe. Replacing the pneumatic brake system with electromechanical brate (EMB) system could reduce the space significantly. In addition, it could reduce the latency time and control the clamping force precisely. Taking electric urban bus as the research target, the scheme of EMB actuator was discussed. The locked torque and the noload speed were deduced according to the maximum clamping force of the traditional pneumatic disc brake. Based on this, a permanent magnet brushless direct current (BLDC) drive motor was designed, with the locked torque of 10 N·m and noload speed of 370 r/min. Then the finite element model of motor was established by using Maxwell 2D, and the braking performance during the phases of eliminating clearance and clamping force increasing was analyzed. The results showed that the braking performance of the designed drive motor could meet the requirements.
The traditional pneumatic brake system occupies large space for the compressor, brake reservoir and air pipe. Replacing the pneumatic brake system with electromechanical brate (EMB) system could reduce the space significantly. In addition, it could reduce the latency time and control the clamping force precisely. Taking electric urban bus as the research target, the scheme of EMB actuator was discussed. The locked torque and the noload speed were deduced according to the maximum clamping force of the traditional pneumatic disc brake. Based on this, a permanent magnet brushless direct current (BLDC) drive motor was designed, with the locked torque of 10 N·m and noload speed of 370 r/min. Then the finite element model of motor was established by using Maxwell 2D, and the braking performance during the phases of eliminating clearance and clamping force increasing was analyzed. The results showed that the braking performance of the designed drive motor could meet the requirements.
2019, 46(1):119-125.
Abstract:
A nonlinear controller based on feedback linearization technique was proposed to mitigate subsynchronous control interaction (SSCI) in seriescompensated doubly fed induction generator (DFIG). The feedback linearization controller was developed for rotor side converter (RSC) and grid side converter (GSC) through four necessary steps, i.e., assessment of the feedback linearizability, coordinate transformation, feedback linearization, and derivation of control laws. A DFIGbased wind farm adapted from the IEEE first benchmark model was utilized to evaluate the performance of the designed controller at varied wind speeds and compensation levels, and the capability of the proposed controller in mitigating SSCI was compared to a welltuned proportionalintegral (PI) controller. The simulation results demonstrated the superior damping performance of the designed controller.
A nonlinear controller based on feedback linearization technique was proposed to mitigate subsynchronous control interaction (SSCI) in seriescompensated doubly fed induction generator (DFIG). The feedback linearization controller was developed for rotor side converter (RSC) and grid side converter (GSC) through four necessary steps, i.e., assessment of the feedback linearizability, coordinate transformation, feedback linearization, and derivation of control laws. A DFIGbased wind farm adapted from the IEEE first benchmark model was utilized to evaluate the performance of the designed controller at varied wind speeds and compensation levels, and the capability of the proposed controller in mitigating SSCI was compared to a welltuned proportionalintegral (PI) controller. The simulation results demonstrated the superior damping performance of the designed controller.
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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.
