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Volume 47,Issue 8,2020 Table of Contents
1 Overview and Prospect of High Performance Magnetic Field Modulation Permanent Magnet Linear Machine
2020, 47(8):1-12.
DOI: 10.12177/emca.2020.092
Abstract:
Permanent magnet linear machine (PMLM) can directly output power in linear motion, which has significant advantages of simple structure and high efficiency. It is suitable for some linear motion applications and attracts more and more attentions. The widely existing magnetic field modulation effect is analyzed, several typical topology structures of PMLM are taken as examples, and the application of the internal magnetic field modulation mechanism is pointed out. Meanwhile, in view of the special structure of PMLM, several modeling methods of electromagnetic parameters are discussed. Finally, the prospects of research on the magnetic field theory, topology structure and application of PMLM are analyzed, providing certain reference value for the practical engineering application of linear machines.
Permanent magnet linear machine (PMLM) can directly output power in linear motion, which has significant advantages of simple structure and high efficiency. It is suitable for some linear motion applications and attracts more and more attentions. The widely existing magnetic field modulation effect is analyzed, several typical topology structures of PMLM are taken as examples, and the application of the internal magnetic field modulation mechanism is pointed out. Meanwhile, in view of the special structure of PMLM, several modeling methods of electromagnetic parameters are discussed. Finally, the prospects of research on the magnetic field theory, topology structure and application of PMLM are analyzed, providing certain reference value for the practical engineering application of linear machines.
2020, 47(8):13-18.
DOI: 10.12177/emca.2020.073
Abstract:
The field oriented control strategy of permanent magnet synchronous motors (PMSMs) has poor robustness and slow dynamic response, complex PID parameter tuning methods are generally required, and it is difficult to obtain good dynamic and steady state performance in a larger speed range through a fixed set of PI parameters. In order to solve the above problems, a finite control set current prediction strategy is proposed for the PMSM current loop control. This method directly deals with the set of discrete switching states without the need for a complex space vector modulation process, and uses its fast torque response to construct a value function pair through current deviation. The torque ripple is optimized when the motor load is switched. Compensation for control delay reduces both the current harmonic distortion and the steady state torque ripple. Simulation results show that compared with the traditional field oriented control method, the proposed scheme has good static and dynamic performance, and at low speed and high speed, this method can effectively reduce the stator current fluctuation and suppress the motor torque ripple.
The field oriented control strategy of permanent magnet synchronous motors (PMSMs) has poor robustness and slow dynamic response, complex PID parameter tuning methods are generally required, and it is difficult to obtain good dynamic and steady state performance in a larger speed range through a fixed set of PI parameters. In order to solve the above problems, a finite control set current prediction strategy is proposed for the PMSM current loop control. This method directly deals with the set of discrete switching states without the need for a complex space vector modulation process, and uses its fast torque response to construct a value function pair through current deviation. The torque ripple is optimized when the motor load is switched. Compensation for control delay reduces both the current harmonic distortion and the steady state torque ripple. Simulation results show that compared with the traditional field oriented control method, the proposed scheme has good static and dynamic performance, and at low speed and high speed, this method can effectively reduce the stator current fluctuation and suppress the motor torque ripple.
2020, 47(8):19-23.
DOI: 10.12177/emca.2020.089
Abstract:
In view of the inaccuracy of rotor position estimation of switched reluctance motor (SRM) due to the magnetic circuit saturation under the condition of high current, a rotor position estimation method based on the combination of full cycle inductance adjacent intersection and inductance threshold is proposed. This method sets the corresponding phase inductance threshold value in the high inductance area. When the inductance is in the non magnetic circuit saturation, the “and” method is used to obtain the high inductance position estimation pulse between the intersection point pulse and the set phase inductance threshold pulse. When the inductance is in the magnetic circuit saturation, the set inductance threshold pulse is used as the high inductance position estimation pulse, and then the motor speed and rotor position are estimated by the adjacent pulse signals. Finally, the correctness of the method is verified by simulation.
In view of the inaccuracy of rotor position estimation of switched reluctance motor (SRM) due to the magnetic circuit saturation under the condition of high current, a rotor position estimation method based on the combination of full cycle inductance adjacent intersection and inductance threshold is proposed. This method sets the corresponding phase inductance threshold value in the high inductance area. When the inductance is in the non magnetic circuit saturation, the “and” method is used to obtain the high inductance position estimation pulse between the intersection point pulse and the set phase inductance threshold pulse. When the inductance is in the magnetic circuit saturation, the set inductance threshold pulse is used as the high inductance position estimation pulse, and then the motor speed and rotor position are estimated by the adjacent pulse signals. Finally, the correctness of the method is verified by simulation.
2020, 47(8):24-28.
DOI: 10.12177/emca.2020.070
Abstract:
Aiming at the problem that the permanent magnet synchronous motor vector control system is susceptible to motor parameter changes and load disturbances, a non singular fast terminal sliding mode control strategy based on load observation is proposed. A non singular fast terminal sliding mode speed controller is designed to replace the traditional PI regulator, which improves the system robustness. At the same time, a load torque observer is introduced to observe the load in real time, and the observed value is used as current feedforward compensation to improve the system anti load-disturbance ability. Simulation results show that compared with PI control, the proposed control strategy has a faster response speed，and has strong robustness to load disturbances.
Aiming at the problem that the permanent magnet synchronous motor vector control system is susceptible to motor parameter changes and load disturbances, a non singular fast terminal sliding mode control strategy based on load observation is proposed. A non singular fast terminal sliding mode speed controller is designed to replace the traditional PI regulator, which improves the system robustness. At the same time, a load torque observer is introduced to observe the load in real time, and the observed value is used as current feedforward compensation to improve the system anti load-disturbance ability. Simulation results show that compared with PI control, the proposed control strategy has a faster response speed，and has strong robustness to load disturbances.
2020, 47(8):29-35.
DOI: 10.12177/emca.2020.076
Abstract:
The poor robustness of permanent magnet synchronous motor (PMSM) is caused by constant sliding mode gain when the traditional super twisting algorithm second order sliding mode observer (STASSMO) is used to estimate the rotor position and speed. For this problem, a fuzzy super twisting algorithm second order sliding mode observer (FSTASSMO) is proposed under the existing stable conditions. The fuzzy controller is used to set the sliding mode gain according to the fuzzy rules. The sliding mode gain self tuning process of the super-twisting algorithm (STA) is realized, which improves the observation accuracy, broadens the effective observation range, and enhances the robustness of position sensorless vector control system of PMSM. Finally, the proposed algorithm is verified by a simulation control system built in MATLAB circumstances. The simulation result shows that the proposed algorithm is effective.
The poor robustness of permanent magnet synchronous motor (PMSM) is caused by constant sliding mode gain when the traditional super twisting algorithm second order sliding mode observer (STASSMO) is used to estimate the rotor position and speed. For this problem, a fuzzy super twisting algorithm second order sliding mode observer (FSTASSMO) is proposed under the existing stable conditions. The fuzzy controller is used to set the sliding mode gain according to the fuzzy rules. The sliding mode gain self tuning process of the super-twisting algorithm (STA) is realized, which improves the observation accuracy, broadens the effective observation range, and enhances the robustness of position sensorless vector control system of PMSM. Finally, the proposed algorithm is verified by a simulation control system built in MATLAB circumstances. The simulation result shows that the proposed algorithm is effective.
2020, 47(8):36-39.
DOI: 10.12177/emca.2020.083
Abstract:
A sensorless vector control strategy of interior permanent magnet synchronous motor (IPMSM) based on sliding mode variable structure control (SMVSC) is studied. Aiming at the chattering problem of SMVSC, the generation mechanism is analyzed and studied in detail, then the saturation function is used to replace the sign function to decrease the discontinuity of sign function. At the same time, the border layer thickness parameter of the saturation function is set to be a self adaptive variable, and the value of the border layer thickness is adjusted to slow the speed of state variables approaching sliding mode switching surface to decrease the chattering problem. The simulation results prove that the proposed control strategy is effective. It has excellent dynamic and static performances, the estimated position and speed have good precision，and the system has strong robustness.
A sensorless vector control strategy of interior permanent magnet synchronous motor (IPMSM) based on sliding mode variable structure control (SMVSC) is studied. Aiming at the chattering problem of SMVSC, the generation mechanism is analyzed and studied in detail, then the saturation function is used to replace the sign function to decrease the discontinuity of sign function. At the same time, the border layer thickness parameter of the saturation function is set to be a self adaptive variable, and the value of the border layer thickness is adjusted to slow the speed of state variables approaching sliding mode switching surface to decrease the chattering problem. The simulation results prove that the proposed control strategy is effective. It has excellent dynamic and static performances, the estimated position and speed have good precision，and the system has strong robustness.
2020, 47(8):40-46.
DOI: 10.12177/emca.2020.071
Abstract:
In order to improve the speed control accuracy of high power traction motor, a fuzzy adaptive control method is proposed. According to the change of external conditions, the fuzzy relationship between input and output is used to adjust the given traction/braking torque adaptively, and then the Butterworth filter is used to filter the output given torque and the integral link is used to eliminate the steady state error to obtain good control performance. Finally, taking a high power traction motor of a locomotive as the test object, the control effect tests of various complex operation conditions are carried out, and the effectiveness and superiority of the proposed algorithm are verified.
In order to improve the speed control accuracy of high power traction motor, a fuzzy adaptive control method is proposed. According to the change of external conditions, the fuzzy relationship between input and output is used to adjust the given traction/braking torque adaptively, and then the Butterworth filter is used to filter the output given torque and the integral link is used to eliminate the steady state error to obtain good control performance. Finally, taking a high power traction motor of a locomotive as the test object, the control effect tests of various complex operation conditions are carried out, and the effectiveness and superiority of the proposed algorithm are verified.
2020, 47(8):47-51.
DOI: 10.12177/emca.2020.069
Abstract:
Shaft oscillation takes place in the drive system of a large rotation inertia compressor driven by a dual-synchronous-motor system through a flexible shaft. For this problem, a control scheme with speed difference compensation and speed differentiation is designed. The control scheme introduces speed difference compensation and speed differentiation into speed loop control. By compensating the speed and torque, the purpose of increasing damping to suppress oscillation is achieved. A dual-synchronous-motor dragging compressor model and a dual-motor synchronous control model are built on the Simulink platform, and the theoretical basis of control strategies is provided. Simulation results show that the proposed control scheme can significantly suppress oscillation.
Shaft oscillation takes place in the drive system of a large rotation inertia compressor driven by a dual-synchronous-motor system through a flexible shaft. For this problem, a control scheme with speed difference compensation and speed differentiation is designed. The control scheme introduces speed difference compensation and speed differentiation into speed loop control. By compensating the speed and torque, the purpose of increasing damping to suppress oscillation is achieved. A dual-synchronous-motor dragging compressor model and a dual-motor synchronous control model are built on the Simulink platform, and the theoretical basis of control strategies is provided. Simulation results show that the proposed control scheme can significantly suppress oscillation.
2020, 47(8):52-56.
DOI: 10.12177/emca.2020.077
Abstract:
The influence of velocity and acceleration feedforward control on the dynamic performance of position servo tracking system is analyzed theoretically. Combined with the design of a radar servo system, the simulation design of the speed loop and position loop of the servo system is presented, and the traditional control and the compound control from two aspects of simulation and engineering test are compared. The results show that the compound control can significantly improve the dynamic performance and tracking accuracy of the servo system.
The influence of velocity and acceleration feedforward control on the dynamic performance of position servo tracking system is analyzed theoretically. Combined with the design of a radar servo system, the simulation design of the speed loop and position loop of the servo system is presented, and the traditional control and the compound control from two aspects of simulation and engineering test are compared. The results show that the compound control can significantly improve the dynamic performance and tracking accuracy of the servo system.
2020, 47(8):57-62.
DOI: 10.12177/emca.2020.080
Abstract:
Direct power control (DPC) is widely used in renewable power generation due to the advantages of simple implementation and fast dynamic response. An improved non-phase-locked-loop (non-PLL) DPC of doubly fed induction generator (DFIG) is proposed, which is implemented in the two phase stationary reference frame. In order to deal with the time varying characteristics of active and reactive powers for a DFIG in the stationary reference frame, the modulated active and reactive voltages are introduced. By this means, the time varying voltage matrix related dynamics of DFIG active and reactive powers are changed into a constant coefficient related equation, thereby simplifying the design of implementation system. Meanwhile, the modulated rotor voltage can be obtained from the modulated active and reactive voltages based on DFIG rotor position angle. Then, a linear controller can be introduced to achieve the decoupling regulation and fast tracking of active and reactive powers. Finally, the experimental results confirm the effectiveness and frequency adaptability of the proposed method.
Direct power control (DPC) is widely used in renewable power generation due to the advantages of simple implementation and fast dynamic response. An improved non-phase-locked-loop (non-PLL) DPC of doubly fed induction generator (DFIG) is proposed, which is implemented in the two phase stationary reference frame. In order to deal with the time varying characteristics of active and reactive powers for a DFIG in the stationary reference frame, the modulated active and reactive voltages are introduced. By this means, the time varying voltage matrix related dynamics of DFIG active and reactive powers are changed into a constant coefficient related equation, thereby simplifying the design of implementation system. Meanwhile, the modulated rotor voltage can be obtained from the modulated active and reactive voltages based on DFIG rotor position angle. Then, a linear controller can be introduced to achieve the decoupling regulation and fast tracking of active and reactive powers. Finally, the experimental results confirm the effectiveness and frequency adaptability of the proposed method.
2020, 47(8):63-67.
DOI: 10.12177/emca.2020.075
Abstract:
In view of the serious distortion of the output current of the inverter and the oscillation of the active and reactive power of the virtual synchronous generator (VSG) under the unbalanced power grid voltage, the proportion integral plus reduced order resonant (PI ROR) controller is used to improve the traditional VSG control strategy under the unbalanced voltage. PI ROR controller can realize the no difference control of negative sequence component without the separation calculation of positive and negative sequences of current and voltage, so it can put the positive sequence and negative sequence currents on the same dq axis for unified control. Compared with the traditional positive and negative sequences controller, it not only reduces the complexity of current loop control structure, but also avoids the control delay caused by a large number of positive and negative separation calculation. Finally, the simulation results show that the PI ROR controller can improve the steady and transient state performance of VSG under unbalanced voltage condition when cosidering the three control objectives of constant active power, constant reactive power and current balance.
In view of the serious distortion of the output current of the inverter and the oscillation of the active and reactive power of the virtual synchronous generator (VSG) under the unbalanced power grid voltage, the proportion integral plus reduced order resonant (PI ROR) controller is used to improve the traditional VSG control strategy under the unbalanced voltage. PI ROR controller can realize the no difference control of negative sequence component without the separation calculation of positive and negative sequences of current and voltage, so it can put the positive sequence and negative sequence currents on the same dq axis for unified control. Compared with the traditional positive and negative sequences controller, it not only reduces the complexity of current loop control structure, but also avoids the control delay caused by a large number of positive and negative separation calculation. Finally, the simulation results show that the PI ROR controller can improve the steady and transient state performance of VSG under unbalanced voltage condition when cosidering the three control objectives of constant active power, constant reactive power and current balance.
2020, 47(8):68-74.
DOI: 10.12177/emca.2020.085
Abstract:
When the dual-active-bridge DC-DC converter works in the boost and buck state, under the traditional single-phase shift control, the voltage mismatch will affect the power distribution of the converter’s leading bridge, lagging bridge and inductor, which in turn increases the on state loss of the converter. The dual-phase shift control with internal phase shift angle can change the voltage waveforms on the input and output sides, thereby optimizing the reactive power flowing through the leading and lagging bridges, increasing the degree of freedom and flexibility of control, and changing the power characteristics of the converter. On this basis, a dual-phase shift control strategy is proposed that the converter works in the boost and buck state, and the reactive power on the inductor is the optimization goal, which is set to reducing the overall reactive power and on state loss of the converter, thereby improving the efficiency of the converter. Finally, the effectiveness and superiority of the dual-phase shift control method are verified through experiments.
When the dual-active-bridge DC-DC converter works in the boost and buck state, under the traditional single-phase shift control, the voltage mismatch will affect the power distribution of the converter’s leading bridge, lagging bridge and inductor, which in turn increases the on state loss of the converter. The dual-phase shift control with internal phase shift angle can change the voltage waveforms on the input and output sides, thereby optimizing the reactive power flowing through the leading and lagging bridges, increasing the degree of freedom and flexibility of control, and changing the power characteristics of the converter. On this basis, a dual-phase shift control strategy is proposed that the converter works in the boost and buck state, and the reactive power on the inductor is the optimization goal, which is set to reducing the overall reactive power and on state loss of the converter, thereby improving the efficiency of the converter. Finally, the effectiveness and superiority of the dual-phase shift control method are verified through experiments.
2020, 47(8):75-81.
DOI: 10.12177/emca.2020.043
Abstract:
A novel type of three level bidirectional DC-DC converter is proposed based on the advantages of three level circuit structure, omitting a pair of flying capacitors in traditional three level bidirectional DC-DC converters. Electrical stress of switch and harmonic component are reduced in the novel three level bidirectional DC-DC converter. By using the control strategy of interleaving phase shifting, zero voltage switching (ZVS) is realized for all switches in the novel converter. The performance of the novel three level bidirectional DC-DC converter is excellent through the 2.4 kW prototype experiment. Compared with traditional bidirectional DC-DC converter, the efficiency is significantly improved in the novel converter.
A novel type of three level bidirectional DC-DC converter is proposed based on the advantages of three level circuit structure, omitting a pair of flying capacitors in traditional three level bidirectional DC-DC converters. Electrical stress of switch and harmonic component are reduced in the novel three level bidirectional DC-DC converter. By using the control strategy of interleaving phase shifting, zero voltage switching (ZVS) is realized for all switches in the novel converter. The performance of the novel three level bidirectional DC-DC converter is excellent through the 2.4 kW prototype experiment. Compared with traditional bidirectional DC-DC converter, the efficiency is significantly improved in the novel converter.
2020, 47(8):82-86.
DOI: 10.12177/emca.2020.051
Abstract:
For the generators of old small hydropower stations in Xinjiang, the dual winding reactance shunt self excitation constant voltage system is commonly used, which is prone to oscillation, demagnetization and even out of step disconnection during grid connected operation. For these problems, a new excitation method with simple transformation, low cost, reliable grid connected operation and good safety, namely, the two phase half wave reactance shunt excitation system, is proposed. Test results show that the new system has a larger voltage setting range than the original system, and it is economical in hydropower station transformation and can support reliable grid connected operation. It is recommended to use this system in the operation of self excited constant voltage synchronous generators of small hydropower stations in rural areas.
For the generators of old small hydropower stations in Xinjiang, the dual winding reactance shunt self excitation constant voltage system is commonly used, which is prone to oscillation, demagnetization and even out of step disconnection during grid connected operation. For these problems, a new excitation method with simple transformation, low cost, reliable grid connected operation and good safety, namely, the two phase half wave reactance shunt excitation system, is proposed. Test results show that the new system has a larger voltage setting range than the original system, and it is economical in hydropower station transformation and can support reliable grid connected operation. It is recommended to use this system in the operation of self excited constant voltage synchronous generators of small hydropower stations in rural areas.
2020, 47(8):87-92.
DOI: 10.12177/emca.2020.088
Abstract:
Design and optimization of high performance external fans are important to improve the efficiency of large and medium high efficiency motors. We propose an optimal design method of centrifugal fans with backward blades by analyzing the characteristics of centrifugal fans. Taking a YXKK710 4 high efficiency motor as the object, the performance and working point of the centrifugal fan are analyzed, and the effects of the centrifugal fan on the efficiency, noise and temperature rise of the motor are tested. The results show that in comparison with the original design, the optimized centrifugal fan is closer to the working point, and the performance data such as efficiency and noise are better. The rationality and reliability of the proposed method are verified. This research can provide guidance for the improvement of motor performance and efficiency, and for the development of series high efficiency motor products as well.
Design and optimization of high performance external fans are important to improve the efficiency of large and medium high efficiency motors. We propose an optimal design method of centrifugal fans with backward blades by analyzing the characteristics of centrifugal fans. Taking a YXKK710 4 high efficiency motor as the object, the performance and working point of the centrifugal fan are analyzed, and the effects of the centrifugal fan on the efficiency, noise and temperature rise of the motor are tested. The results show that in comparison with the original design, the optimized centrifugal fan is closer to the working point, and the performance data such as efficiency and noise are better. The rationality and reliability of the proposed method are verified. This research can provide guidance for the improvement of motor performance and efficiency, and for the development of series high efficiency motor products as well.
2020, 47(8):93-97.
DOI: 10.12177/emca.2020.067
Abstract:
Hair pin motor is widely used in new energy vehicles as it has high slot full rate, good heat dissipation, small volume and good cost performance. But its winding is small size electromagnetic wire normally. Compared with small size wire motors, large size wire motors supply more power. The structure and forming difficulties of the big size hair pin enamel membrane insulated winding are described in detail, and the problems appearing during the forming process of the U shaped section and the end by punch forming and extrusion forming techniques are analyzed. The forming technique is optimized in terms of process, mould, wire and operation, and satisfactory winding forming results are obtained.
Hair pin motor is widely used in new energy vehicles as it has high slot full rate, good heat dissipation, small volume and good cost performance. But its winding is small size electromagnetic wire normally. Compared with small size wire motors, large size wire motors supply more power. The structure and forming difficulties of the big size hair pin enamel membrane insulated winding are described in detail, and the problems appearing during the forming process of the U shaped section and the end by punch forming and extrusion forming techniques are analyzed. The forming technique is optimized in terms of process, mould, wire and operation, and satisfactory winding forming results are obtained.
2020, 47(8):98-103.
DOI: 10.12177/emca.2020.084
Abstract:
To solve the technological difficulties of squirrel cage asynchronous wind generator (FYS02) with high power density, whose stator uses different multi layer and large section coils and alternative reversal inserting, systematic analysis and optimization of coil production and inserting are implemented. Problems in prototype trial production are settled by innovations of step by step winding, insulation reinforcement of single coil nose, adjustment of expansion equipment program, optimization of coil insulation structure, and optimization of the inserting positioning, which make it possible to successfully complete the mass production. This is an important transition of new structure wind power products from research and development concept to actual output, which establishes a technical foundation for the overseas development of wind power industry.
To solve the technological difficulties of squirrel cage asynchronous wind generator (FYS02) with high power density, whose stator uses different multi layer and large section coils and alternative reversal inserting, systematic analysis and optimization of coil production and inserting are implemented. Problems in prototype trial production are settled by innovations of step by step winding, insulation reinforcement of single coil nose, adjustment of expansion equipment program, optimization of coil insulation structure, and optimization of the inserting positioning, which make it possible to successfully complete the mass production. This is an important transition of new structure wind power products from research and development concept to actual output, which establishes a technical foundation for the overseas development of wind power industry.
CHEN Wenlu
,
FENG Tong
,
SUN Jianan
,
KONG Delin
,
QIU Jinji
,
LIU Ludi
,
WANG Lei
,
LIU Wei
,
LI Rongning
,
HAO Shuanghui
2020, 47(8):104-110.
DOI: 10.12177/emca.2020.079
Abstract:
A scheme of absolute multi-pole magneto-electric encoder is proposed. The linear Hall and switch Hall sensors are used to measure the position relationship and absolute angle between the two groups of multi-pole permanent magnets with coprime number of pole-pairs. The absolute angle calculation scheme of the magneto-electric encoder is determined based on the existing achievements of the magneto-electric encoder. Then through the combination of theoretical analysis, drawing analysis and theoretical derivation, the number relationship of permanent magnet poles, the layout of Hall elements and the specific pole recognition process are determined. The MATLAB software is used to simulate the working process of the magneto electric encoder, which proves the feasibility of the absolute angle calculation scheme.
A scheme of absolute multi-pole magneto-electric encoder is proposed. The linear Hall and switch Hall sensors are used to measure the position relationship and absolute angle between the two groups of multi-pole permanent magnets with coprime number of pole-pairs. The absolute angle calculation scheme of the magneto-electric encoder is determined based on the existing achievements of the magneto-electric encoder. Then through the combination of theoretical analysis, drawing analysis and theoretical derivation, the number relationship of permanent magnet poles, the layout of Hall elements and the specific pole recognition process are determined. The MATLAB software is used to simulate the working process of the magneto electric encoder, which proves the feasibility of the absolute angle calculation scheme.
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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.
