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Volume 48,Issue 4,2021 Table of Contents
2021, 48(4):1-11.
DOI: 10.12177/emca.2020.230
Abstract:
The multi-degree-of-freedom motor can realize complex motion in space, and has the advantages of simple structure and high accuracy. It has broad application prospects in robot bionic joints, mechanical arms and industrial manufacturing. Firstly, the background, basic principles and technical advantages of multi-degree-of-freedom motor are described. Multi-degree-of-freedom motors are classified according to different mechanisms, and the current domestic and foreign research status of multi-degree-of-freedom motors are summarized. In addition, based on the motion characteristics of the multi-degree-of-freedom motor, the position detection technology and motion control strategy in the motor control process are analyzed. Finally, related descriptions are made on the structure, control system, materials and manufacturing process of the multi-degree-of-freedom motor, and the development trend of the multi-degree-of-freedom motor is predicted. Through the research and analysis of the multi-degree-of-freedom motor, reference is provided for its future development.
The multi-degree-of-freedom motor can realize complex motion in space, and has the advantages of simple structure and high accuracy. It has broad application prospects in robot bionic joints, mechanical arms and industrial manufacturing. Firstly, the background, basic principles and technical advantages of multi-degree-of-freedom motor are described. Multi-degree-of-freedom motors are classified according to different mechanisms, and the current domestic and foreign research status of multi-degree-of-freedom motors are summarized. In addition, based on the motion characteristics of the multi-degree-of-freedom motor, the position detection technology and motion control strategy in the motor control process are analyzed. Finally, related descriptions are made on the structure, control system, materials and manufacturing process of the multi-degree-of-freedom motor, and the development trend of the multi-degree-of-freedom motor is predicted. Through the research and analysis of the multi-degree-of-freedom motor, reference is provided for its future development.
2021, 48(4):12-17.
DOI: 10.12177/emca.2020.223
Abstract:
Aiming at the problem of load resistance disturbance in DC-DC buck-boost converter, a cooperative controller strategy based on disturbance observer is proposed. The nonlinear disturbance observer technology is used to estimate the uncertain disturbance of the load. The observation value information is introduced into the designed cooperative controller, and a cooperative control algorithm based on the nonlinear disturbance observer is constructed. The robustness and stable track of the expected capacitor output voltage is achieved. Finally, the feasibility and effectiveness of the proposed method are verified through a series of simulations.
Aiming at the problem of load resistance disturbance in DC-DC buck-boost converter, a cooperative controller strategy based on disturbance observer is proposed. The nonlinear disturbance observer technology is used to estimate the uncertain disturbance of the load. The observation value information is introduced into the designed cooperative controller, and a cooperative control algorithm based on the nonlinear disturbance observer is constructed. The robustness and stable track of the expected capacitor output voltage is achieved. Finally, the feasibility and effectiveness of the proposed method are verified through a series of simulations.
2021, 48(4):18-25.
DOI: 10.12177/emca.2020.228
Abstract:
The commutation strategy for brushless DC motor (BLDCM) based on flux-linkage function is extremely sensitive to current noise. Especially, the values of function fluctuate greatly at low speeds, resulting in commutation lead or even mis-commutation. In order to suppress the fluctuation, a flux-linkage function with an integrator is implemented after a deep analysis of fluctuation mechanism. In addition, for eliminating the effect of zero drift and integral initial error, a structure is designed by replacing the integrator with a band pass filter. Meanwhile, an accurate commutation point can be obtained by adjusting the center frequency of the filter dynamically. Furthermore, a novel method for identification of commutation point is proposed. The effect of the fluctuation is reduced, and the accuracy and reliability of the commutation point are improved. Simulation results show that the proposed strategy based on the new flux-linkage function can obtain accurate and reliable commutation signal under the comprehensive constraints of low speed and current noise, which can ensure the stable operation of BLDCM.
The commutation strategy for brushless DC motor (BLDCM) based on flux-linkage function is extremely sensitive to current noise. Especially, the values of function fluctuate greatly at low speeds, resulting in commutation lead or even mis-commutation. In order to suppress the fluctuation, a flux-linkage function with an integrator is implemented after a deep analysis of fluctuation mechanism. In addition, for eliminating the effect of zero drift and integral initial error, a structure is designed by replacing the integrator with a band pass filter. Meanwhile, an accurate commutation point can be obtained by adjusting the center frequency of the filter dynamically. Furthermore, a novel method for identification of commutation point is proposed. The effect of the fluctuation is reduced, and the accuracy and reliability of the commutation point are improved. Simulation results show that the proposed strategy based on the new flux-linkage function can obtain accurate and reliable commutation signal under the comprehensive constraints of low speed and current noise, which can ensure the stable operation of BLDCM.
2021, 48(4):26-31.
DOI: 10.12177/emca.2020.233
Abstract:
In order to improve the dynamic quality of permanent magnet synchronous motor (PMSM) speed regulation system, an integral sliding mode control algorithm based on a novel hybrid reaching law is proposed. Based on the conventional exponential reaching law, the hyperbolic tangent function, terminal attractor and adaptive factor based on power function of system state variables are introduced. Combined with integral sliding mode surface, the adaptive adjustment ability and anti-disturbance ability of the system approaching speed are improved, and the chattering level is limited. Based on the proposed reaching law, a new hybrid reaching law integral sliding mode speed controller for PMSM is designed. The control performance of the controller is compared with the traditional PI algorithm through simulation. Simulation results show that the new reaching law speed controller has better anti-load disturbance performance, very small chattering and strong robustness.
In order to improve the dynamic quality of permanent magnet synchronous motor (PMSM) speed regulation system, an integral sliding mode control algorithm based on a novel hybrid reaching law is proposed. Based on the conventional exponential reaching law, the hyperbolic tangent function, terminal attractor and adaptive factor based on power function of system state variables are introduced. Combined with integral sliding mode surface, the adaptive adjustment ability and anti-disturbance ability of the system approaching speed are improved, and the chattering level is limited. Based on the proposed reaching law, a new hybrid reaching law integral sliding mode speed controller for PMSM is designed. The control performance of the controller is compared with the traditional PI algorithm through simulation. Simulation results show that the new reaching law speed controller has better anti-load disturbance performance, very small chattering and strong robustness.
2021, 48(4):32-37,44.
DOI: 10.12177/emca.2020.236
Abstract:
Poor robustness of the traditional PI control, and chattering and less poor robustness of the traditional non-singular fast terminal control occur in permanent magnet synchronous motor (PMSM). To solve these problems, a non-singular fast terminal sliding mode (NFTSM) control strategy is adopted in the speed loop. In addition, a high gain extended observer is introduced to observe the matching disturbance of the system in real time. Then the observed value is used as feedforward compensation of the current, and the anti-disturbance capability of the system is improved. At the same time, a deadbeat current predictive control strategy is adopted in the current loop. Dynamic response is better and harmonic components are smaller in the current loop. Simulation results show that the proposed control method can effectively improve the robustness of the system and solve the problem of excessive sliding mode chattering.
Poor robustness of the traditional PI control, and chattering and less poor robustness of the traditional non-singular fast terminal control occur in permanent magnet synchronous motor (PMSM). To solve these problems, a non-singular fast terminal sliding mode (NFTSM) control strategy is adopted in the speed loop. In addition, a high gain extended observer is introduced to observe the matching disturbance of the system in real time. Then the observed value is used as feedforward compensation of the current, and the anti-disturbance capability of the system is improved. At the same time, a deadbeat current predictive control strategy is adopted in the current loop. Dynamic response is better and harmonic components are smaller in the current loop. Simulation results show that the proposed control method can effectively improve the robustness of the system and solve the problem of excessive sliding mode chattering.
2021, 48(4):38-44.
DOI: 10.12177/emca.2020.237
Abstract:
In order to obtain the stable speed and fast regulation output of brushless DC motor (BLDCM), the control and drive system of BLDCM is designed. The operation principle of BLDCM and the cause of torque ripple are analyzed, and the problem of torque ripple is solved by buck circuit. To solve the problems of slow speed, low precision and difficult parameter adjustment of traditional PID, the BP neural network is used to adjust the parameters of PID. Each module of the system is built and simulated on the MATLAB/Simulink simulation platform. The results show that the designed system has the advantages of fast regulation, small overshoot in the control process, stable speed and less torque fluctuation.
In order to obtain the stable speed and fast regulation output of brushless DC motor (BLDCM), the control and drive system of BLDCM is designed. The operation principle of BLDCM and the cause of torque ripple are analyzed, and the problem of torque ripple is solved by buck circuit. To solve the problems of slow speed, low precision and difficult parameter adjustment of traditional PID, the BP neural network is used to adjust the parameters of PID. Each module of the system is built and simulated on the MATLAB/Simulink simulation platform. The results show that the designed system has the advantages of fast regulation, small overshoot in the control process, stable speed and less torque fluctuation.
2021, 48(4):45-52.
DOI: 10.12177/emca.2020.231
Abstract:
The resolver is a commonly used motor rotor position detection device, and its detection accuracy directly affects the performance of the entire control system. In order to obtain highprecision rotor position information, a software resolvertodigital converter (RDC) combined with error compensation is analyzed. Firstly, the position angle solution method based on the threephase synchronous reference frame phaselocked loop (SRFPLL) is adopted to filter out the highfrequency jitter component in the resolver output signal. Then, aiming at the influence of the zero error, quadrature error and amplitude error in the resolver output signal, the ellipse hypothesis algorithm is used to eliminate it, and the harmonic separation method is proposed to realize the compensation of the harmonic error in the signal. Finally, a simulation model and test platform are built for analysis and verification. Simulation and test results verify the effectiveness of the proposed method.
The resolver is a commonly used motor rotor position detection device, and its detection accuracy directly affects the performance of the entire control system. In order to obtain highprecision rotor position information, a software resolvertodigital converter (RDC) combined with error compensation is analyzed. Firstly, the position angle solution method based on the threephase synchronous reference frame phaselocked loop (SRFPLL) is adopted to filter out the highfrequency jitter component in the resolver output signal. Then, aiming at the influence of the zero error, quadrature error and amplitude error in the resolver output signal, the ellipse hypothesis algorithm is used to eliminate it, and the harmonic separation method is proposed to realize the compensation of the harmonic error in the signal. Finally, a simulation model and test platform are built for analysis and verification. Simulation and test results verify the effectiveness of the proposed method.
2021, 48(4):53-57,94.
DOI: 10.12177/emca.2020.235
Abstract:
The parameters of traditional PID controller cannot be changed in real time with the change of load, which leads to the poor control effect of artillery servo system. In order to solve the problem, a three-closed-loop servo control system based on space vector control is designed. The permanent magnet synchronous motor (PMSM) is used as the executive motor, and a fuzzy controller optimized by adaptive simulated annealing particle swarm optimization (ASAPSO) is added to the position loop of the system. The proposed controller and traditional PID controller are applied to the position loop of the servo control system. The position response, anti-torque disturbance ability and target tracking ability of the two controllers are compared by building the system simulation model. The results show that the static and dynamic performances of the proposed controller are better than that of the traditional PID controller when the parameters of the fuzzy controller are optimized by ASAPSO. The system can effectively overcome the influence of nonlinear factors such as torque disturbance, and it has good target tracking performance.
The parameters of traditional PID controller cannot be changed in real time with the change of load, which leads to the poor control effect of artillery servo system. In order to solve the problem, a three-closed-loop servo control system based on space vector control is designed. The permanent magnet synchronous motor (PMSM) is used as the executive motor, and a fuzzy controller optimized by adaptive simulated annealing particle swarm optimization (ASAPSO) is added to the position loop of the system. The proposed controller and traditional PID controller are applied to the position loop of the servo control system. The position response, anti-torque disturbance ability and target tracking ability of the two controllers are compared by building the system simulation model. The results show that the static and dynamic performances of the proposed controller are better than that of the traditional PID controller when the parameters of the fuzzy controller are optimized by ASAPSO. The system can effectively overcome the influence of nonlinear factors such as torque disturbance, and it has good target tracking performance.
2021, 48(4):58-64.
DOI: 10.12177/emca.2021.003
Abstract:
The drive motor for the vacuum pump has the engineering problem of the accumulation of thermal expansion of the rotor during the rated operation. According to the actual driving conditions of the vacuum pump, a flux switching stator permanent magnet synchronous motor (FSPMSM) is designed. The electromagnetic field, the temperature field and the thermal stress field of FSPMSM, surface permanent magnet synchronous motor (SPMSM) and interior permanent magnet synchronous motor (IPMSM) with the same technical requirements are compared and analyzed using finite element software. Comprehensive analysis of the performance differences of the three types of motors shows that the temperature rise and the thermal deformation of the FSPMSM are better than the rotor permanent magnet motor. It is verified that FSPMSM can better reduce the rotor loss and temperature rise during operation compared with the traditional rotor permanent magnet motor, which provides a scientific reference for the choice of topology of permanent magnet motor and the development of new products.
The drive motor for the vacuum pump has the engineering problem of the accumulation of thermal expansion of the rotor during the rated operation. According to the actual driving conditions of the vacuum pump, a flux switching stator permanent magnet synchronous motor (FSPMSM) is designed. The electromagnetic field, the temperature field and the thermal stress field of FSPMSM, surface permanent magnet synchronous motor (SPMSM) and interior permanent magnet synchronous motor (IPMSM) with the same technical requirements are compared and analyzed using finite element software. Comprehensive analysis of the performance differences of the three types of motors shows that the temperature rise and the thermal deformation of the FSPMSM are better than the rotor permanent magnet motor. It is verified that FSPMSM can better reduce the rotor loss and temperature rise during operation compared with the traditional rotor permanent magnet motor, which provides a scientific reference for the choice of topology of permanent magnet motor and the development of new products.
2021, 48(4):65-70,109.
DOI: 10.12177/emca.2020.225
Abstract:
Taking the fractional-slot permanent magnet synchronous linear motor (FPMSLM) as the research object, the analytical formula of its no-load air-gap magnetic field is deduced by the analytical method and verified by the finite element method. The analytical formula of the no-load air-gap magnetic field under the integral coupling length of the FPMSLM stator and rotor is derived. Taking two fractional-slot permanent magnet synchronous cell motors as examples, the no-load air-gap magnetic field under different relative positions of the stator and rotor is calculated by the analytical method and the finite element method at the same time. The waveforms of two methods match very well, which verifies the validity of the analytical method to calculate no-load air-gap magnetic field of FPMSLM, providing theoretical support for the optimization of no-load air-gap magnetic field of FPMSLM.
Taking the fractional-slot permanent magnet synchronous linear motor (FPMSLM) as the research object, the analytical formula of its no-load air-gap magnetic field is deduced by the analytical method and verified by the finite element method. The analytical formula of the no-load air-gap magnetic field under the integral coupling length of the FPMSLM stator and rotor is derived. Taking two fractional-slot permanent magnet synchronous cell motors as examples, the no-load air-gap magnetic field under different relative positions of the stator and rotor is calculated by the analytical method and the finite element method at the same time. The waveforms of two methods match very well, which verifies the validity of the analytical method to calculate no-load air-gap magnetic field of FPMSLM, providing theoretical support for the optimization of no-load air-gap magnetic field of FPMSLM.
2021, 48(4):71-76.
DOI: 10.12177/emca.2020.210
Abstract:
Segmented permanent magnet (PM) can effectively reduce the eddy current loss of surface permanent magnet synchronous motor (SPMSM) with minimum performance impact. The relationship between axially and circumferentially segmented PM and the eddy current loss is analyzed. The analytical solution of PM eddy current loss of SPMSM is derived. The factors that affect the eddy current loss of PMs include air gap flux density, tooth harmonic frequency (speed and slot number), pitch, PM resistivity, PM permeability, etc. The analysis shows that circumferentially segmented PM plays main role to reduce PM eddy current loss. The accuracy of this analysis result is verified.
Segmented permanent magnet (PM) can effectively reduce the eddy current loss of surface permanent magnet synchronous motor (SPMSM) with minimum performance impact. The relationship between axially and circumferentially segmented PM and the eddy current loss is analyzed. The analytical solution of PM eddy current loss of SPMSM is derived. The factors that affect the eddy current loss of PMs include air gap flux density, tooth harmonic frequency (speed and slot number), pitch, PM resistivity, PM permeability, etc. The analysis shows that circumferentially segmented PM plays main role to reduce PM eddy current loss. The accuracy of this analysis result is verified.
2021, 48(4):77-82.
DOI: 10.12177/emca.2020.227
Abstract:
In order to improve the transmission system of the whole vehicle on the basis of the original structure of the mine engineering vehicle, higher requirements are put forward on the volume of the traction motor. However, it is found that the conventional radial motor cannot meet the volume requirements. Therefore, an axial flux permanent magnet motor is designed, which can not only meet the spatial volume requirements of the motor, but also meet the requirements of operating conditions. In order to ensure the stable operation of the motor under any kind of operating conditions, the finite element analysis of the no-load and load conditions is carried out, the water structure of the motor is designed, and the finite element analysis is carried out on the temperature of the motor and the mechanical strength of the rotor.
In order to improve the transmission system of the whole vehicle on the basis of the original structure of the mine engineering vehicle, higher requirements are put forward on the volume of the traction motor. However, it is found that the conventional radial motor cannot meet the volume requirements. Therefore, an axial flux permanent magnet motor is designed, which can not only meet the spatial volume requirements of the motor, but also meet the requirements of operating conditions. In order to ensure the stable operation of the motor under any kind of operating conditions, the finite element analysis of the no-load and load conditions is carried out, the water structure of the motor is designed, and the finite element analysis is carried out on the temperature of the motor and the mechanical strength of the rotor.
2021, 48(4):83-88.
DOI: 10.12177/emca.2020.234
Abstract:
The tightening of rotor conducting bar is an important process to ensure the end stability of the rail traction motor. In order to identify the influence of the tensioning scheme on the fastening characteristics in the conducting bar slot, the rotor tensioning manufacturing process is optimized. The finite element plastic analysis method is used to obtain the stress and deformation distribution when the conducting bar is tensioned. The contact state and contact pressure in the conducting bar slot are analyzed, and the correlation influence of the conducting bar side forces under different tensioning schemes is identified. At the same time, the process verification results of this scheme are in good agreement with the simulation analysis results. It has certain guiding significance for the design and application of traction motor core structure.
The tightening of rotor conducting bar is an important process to ensure the end stability of the rail traction motor. In order to identify the influence of the tensioning scheme on the fastening characteristics in the conducting bar slot, the rotor tensioning manufacturing process is optimized. The finite element plastic analysis method is used to obtain the stress and deformation distribution when the conducting bar is tensioned. The contact state and contact pressure in the conducting bar slot are analyzed, and the correlation influence of the conducting bar side forces under different tensioning schemes is identified. At the same time, the process verification results of this scheme are in good agreement with the simulation analysis results. It has certain guiding significance for the design and application of traction motor core structure.
2021, 48(4):89-93.
DOI: 10.12177/emca.2020.238
Abstract:
A switched reluctance motor (SRM) drive system with a single power of 630 kW is developed. The dual-machine synchronous drive technology is successfully applied to the 8 000 t electric screw press in China. The electromagnetic parameters of the motor are designed and optimized, and the mechanical strength of the motor structure and connecting parts is calculated. The controller adopts the CAN isolation module to realize the real-time synchronization of the torque of multiple motors. Using composite copper bars and other technological measures to reduce the stray inductance and loop area of the main circuit, and suppress the IGBT peak voltage. The optical fiber drive mode is adopted to avoid strong magnetic field interference and ensure the signal transmission quality and system reliability. The test results show that all performance indicators of the SRM drive system meet the requirements of the 8 000 t electric screw press.
A switched reluctance motor (SRM) drive system with a single power of 630 kW is developed. The dual-machine synchronous drive technology is successfully applied to the 8 000 t electric screw press in China. The electromagnetic parameters of the motor are designed and optimized, and the mechanical strength of the motor structure and connecting parts is calculated. The controller adopts the CAN isolation module to realize the real-time synchronization of the torque of multiple motors. Using composite copper bars and other technological measures to reduce the stray inductance and loop area of the main circuit, and suppress the IGBT peak voltage. The optical fiber drive mode is adopted to avoid strong magnetic field interference and ensure the signal transmission quality and system reliability. The test results show that all performance indicators of the SRM drive system meet the requirements of the 8 000 t electric screw press.
15 Establishment and Verification of Core Loss Model of Nanocrystalline Under Square Wave Excitation
2021, 48(4):94-98.
DOI: 10.12177/emca.2020.226
Abstract:
In order to realize the development requirements of miniaturization and lightweight of electric locomotives, the overall volume and weight of transformer are reduced by increasing the working frequency of transformer. As the key component of high-frequency transformer, the iron core can accurately calculate the core loss, which plays an important role in the design and optimization of medium and high-frequency transformer. Aiming at the characteristics of high-frequency transformer cores that usually work under non-sinusoidal excitation such as square wave or pulse width modulation (PWM) wave, the traditional Steinmetz loss calculation model is optimized and improved. The Steinmetz improved loss model considering the change rate of magnetic density and the influence of waveform coefficient on the loss is given. At the same time, in order to improve the generality of the loss model at different characteristic frequencies, the nonlinearity of the loss model coefficients is further studied, and the nonlinear relation function between the model coefficients and the frequency is given. Finally, the finite element calculation results are compared with the physical measurement results, which proves the accuracy of the loss model for the calculation of nanocrystalline core under square wave excitation.
In order to realize the development requirements of miniaturization and lightweight of electric locomotives, the overall volume and weight of transformer are reduced by increasing the working frequency of transformer. As the key component of high-frequency transformer, the iron core can accurately calculate the core loss, which plays an important role in the design and optimization of medium and high-frequency transformer. Aiming at the characteristics of high-frequency transformer cores that usually work under non-sinusoidal excitation such as square wave or pulse width modulation (PWM) wave, the traditional Steinmetz loss calculation model is optimized and improved. The Steinmetz improved loss model considering the change rate of magnetic density and the influence of waveform coefficient on the loss is given. At the same time, in order to improve the generality of the loss model at different characteristic frequencies, the nonlinearity of the loss model coefficients is further studied, and the nonlinear relation function between the model coefficients and the frequency is given. Finally, the finite element calculation results are compared with the physical measurement results, which proves the accuracy of the loss model for the calculation of nanocrystalline core under square wave excitation.
2021, 48(4):99-103.
DOI: 10.12177/emca.2020.222
Abstract:
According to functional safety standards, different automotive safety integration levels (ASIL) correspond to different hardware metrics. Through the analysis of hardware metrics and diagnostic coverage, a steering system controller scheme that meets the requirements of functional safety hardware metrics is proposed. The program includes torque sensors, motor position sensors, motor current sensors, micro controllers，etc. The conformity of the system hardware metrics is analyzed and verified.
According to functional safety standards, different automotive safety integration levels (ASIL) correspond to different hardware metrics. Through the analysis of hardware metrics and diagnostic coverage, a steering system controller scheme that meets the requirements of functional safety hardware metrics is proposed. The program includes torque sensors, motor position sensors, motor current sensors, micro controllers，etc. The conformity of the system hardware metrics is analyzed and verified.
2021, 48(4):104-109.
DOI: 10.12177/emca.2021.001
Abstract:
PV array P-U characteristic curve in partial shadow state has multiple peaks. To solve this problem, a three-step global maximum power point tracking (GMPPT) strategy based on search-calculation-determination is proposed. The improved disturbance observation method is used to search the first peak point in reverse direction, and the search area is reduced by calculation and judgment. The multi-peak value search can be indirectly transformed into a single peak value search, which overcomes the problem of falling into local extremum in the search process. Through the establishment of three kinds of shadow state models, this method is compared with the existing maximum power point tracking (MPPT) algorithm, and the corresponding experiments are established. The simulation and experimental results show that the method can stably realize the GMPPT in the state of shadow and noshadow, and effectively improve the tracking accuracy and speed.
PV array P-U characteristic curve in partial shadow state has multiple peaks. To solve this problem, a three-step global maximum power point tracking (GMPPT) strategy based on search-calculation-determination is proposed. The improved disturbance observation method is used to search the first peak point in reverse direction, and the search area is reduced by calculation and judgment. The multi-peak value search can be indirectly transformed into a single peak value search, which overcomes the problem of falling into local extremum in the search process. Through the establishment of three kinds of shadow state models, this method is compared with the existing maximum power point tracking (MPPT) algorithm, and the corresponding experiments are established. The simulation and experimental results show that the method can stably realize the GMPPT in the state of shadow and noshadow, and effectively improve the tracking accuracy and speed.
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Electric Machines & Control Application ® 2025
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沪ICP备16038578号-3
Electric Machines & Control Application ® 2025
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
