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Volume 51,Issue 6,2024 Table of Contents
2024, 51(6):1-11.
DOI: 10.12177/emca.2024.038
Abstract:
Six-phase permanent magnet synchronous motors have the ability of phase-deficient operation, thus precise prediction of their high resistance connection state must be made to ensure effective disconnection for faulty lines, prevent protection misoperation caused by system disturbances, and provide reliable criteria for fault-tolerant control. A mathematical model for complete decoupling of six-phase permanent magnet synchronous motor is established based on vector space decomposition, and its control system model is established. Motor signals in normal state and high resistance connection state are collected, and their energy distance features are extracted by wavelet packet decomposition, input to the back propagation neural network for offline training, and finally applied to sense development situation of high resistance connection state online under drastic conditions. Simulations are carried out based on Matlab, and the results show that the proposed strategy can effectively identify high resistance connection state, sensitively sense its development situation, send warning signals before the high resistance faults occur, and have certain robustness to drastic conditions.
Six-phase permanent magnet synchronous motors have the ability of phase-deficient operation, thus precise prediction of their high resistance connection state must be made to ensure effective disconnection for faulty lines, prevent protection misoperation caused by system disturbances, and provide reliable criteria for fault-tolerant control. A mathematical model for complete decoupling of six-phase permanent magnet synchronous motor is established based on vector space decomposition, and its control system model is established. Motor signals in normal state and high resistance connection state are collected, and their energy distance features are extracted by wavelet packet decomposition, input to the back propagation neural network for offline training, and finally applied to sense development situation of high resistance connection state online under drastic conditions. Simulations are carried out based on Matlab, and the results show that the proposed strategy can effectively identify high resistance connection state, sensitively sense its development situation, send warning signals before the high resistance faults occur, and have certain robustness to drastic conditions.
2024, 51(6):12-19.
DOI: 10.12177/emca.2024.049
Abstract:
Induction coilgun usually generates pulsating electromagnetic force which causes the large acceleration force fluctuation of the armature during the launch process. The excessive peak of acceleration force and the inordinate acceleration force fluctuation may be harmful to the load, especially for those carrying sensitive electronic components, which limits the value of induction coil emitters in practical engineering applications. Addressing the above questions, a new type of driving circuit for multi-capacitance time-sharing triggering is proposed, and the feasibility of the circuit is illustrated by analyzing the influence of the change of capacitance value and armature triggering position on the emission efficiency of the launcher. Three modes of driving circuits are designed for comparison, and the calculation results show that: under the conditions of the same initial energy storage and the approximate muzzle velocity of the armature, compared with other circuit triggering modes, in the time-sharing triggering mode proposed, the peak of electromagnetic acceleration force of the armature is reduced by 2.04 kN, and the acceleration force fluctuation is reduced by 2.36 kN. Therefore, the driving circuit with time-sharing triggering capacitor could effectively reduce the peak acceleration force and acceleration force fluctuation, and provides reference value for the design of the induction coilgun with sensitive loads.
Induction coilgun usually generates pulsating electromagnetic force which causes the large acceleration force fluctuation of the armature during the launch process. The excessive peak of acceleration force and the inordinate acceleration force fluctuation may be harmful to the load, especially for those carrying sensitive electronic components, which limits the value of induction coil emitters in practical engineering applications. Addressing the above questions, a new type of driving circuit for multi-capacitance time-sharing triggering is proposed, and the feasibility of the circuit is illustrated by analyzing the influence of the change of capacitance value and armature triggering position on the emission efficiency of the launcher. Three modes of driving circuits are designed for comparison, and the calculation results show that: under the conditions of the same initial energy storage and the approximate muzzle velocity of the armature, compared with other circuit triggering modes, in the time-sharing triggering mode proposed, the peak of electromagnetic acceleration force of the armature is reduced by 2.04 kN, and the acceleration force fluctuation is reduced by 2.36 kN. Therefore, the driving circuit with time-sharing triggering capacitor could effectively reduce the peak acceleration force and acceleration force fluctuation, and provides reference value for the design of the induction coilgun with sensitive loads.
2024, 51(6):20-30.
DOI: 10.12177/emca.2024.042
Abstract:
Aiming at the problem that the hysteresis of error transfer becomes more serious with the increase of the number of motors in the traditional ring coupling control strategy, a consensus control strategy of multi-motor system based on event-triggered is proposed. The speed compensation of each motor in the multi-motor system is obtained by consensus algorithm to ensure the consistency of each motor speed and improve the tracking performance of the system. When the system reaches the steady state, the event-triggered mechanism is used to reduce unnecessary communication times and save communication resources. In addition, the ring coupling structure can ensure the synchronization performance of the system within the event-triggered threshold, and the event-triggered threshold decreases with time. Simulation results show that compared with traditional ring coupling control strategy, the proposed strategy of motor system has better synchronization performance and tracking performance, and along with the increase of the number of motor, the error transfer delay problem is improved. At the same time, the event-triggered control effectively reduce steady-state process unnecessary communication.
Aiming at the problem that the hysteresis of error transfer becomes more serious with the increase of the number of motors in the traditional ring coupling control strategy, a consensus control strategy of multi-motor system based on event-triggered is proposed. The speed compensation of each motor in the multi-motor system is obtained by consensus algorithm to ensure the consistency of each motor speed and improve the tracking performance of the system. When the system reaches the steady state, the event-triggered mechanism is used to reduce unnecessary communication times and save communication resources. In addition, the ring coupling structure can ensure the synchronization performance of the system within the event-triggered threshold, and the event-triggered threshold decreases with time. Simulation results show that compared with traditional ring coupling control strategy, the proposed strategy of motor system has better synchronization performance and tracking performance, and along with the increase of the number of motor, the error transfer delay problem is improved. At the same time, the event-triggered control effectively reduce steady-state process unnecessary communication.
2024, 51(6):31-43.
DOI: 10.12177/emca.2024.046
Abstract:
The fractional slot permanent magnet motor winding adopts a star-delta (Y-Δ) connection multi-layer winding structure, which can restrain the low order harmonic of armature magnetic field and improve the operation efficiency. However, this structure is more complex than the conventional Y connection double-layer winding structure, and the risk of inter-turn short circuit is higher. Firstly, a circuit model of inter-turn short circuit in Y-Δ connection fractional-slot permanent magnet motor (FS-PMM) is established. The fault three-phase current is derived, and fault current will be affected by the position of the inter-turn short circuit. Secondly, the whale optimization algorithm is improved by adaptive weights and Cauchy Gaussian mutation strategy. The improved whale optimization algorithm is adopted for optimizing the parameters of variational mode decomposition, and a parameter optimized variational mode decomposition algorithm for processing current signal is proposed. Finally, by calculating the multi-scale fuzzy entropy of current and torque, a fault diagnosis method for Y-Δ connection FS-PMM inter-turn short circuit is proposed. The accuracy of this fault diagnosis method can reach over 95%, and it can effectively distinguish the inter-turn short circuit fault between the Y connection part and the Δ connection part.
The fractional slot permanent magnet motor winding adopts a star-delta (Y-Δ) connection multi-layer winding structure, which can restrain the low order harmonic of armature magnetic field and improve the operation efficiency. However, this structure is more complex than the conventional Y connection double-layer winding structure, and the risk of inter-turn short circuit is higher. Firstly, a circuit model of inter-turn short circuit in Y-Δ connection fractional-slot permanent magnet motor (FS-PMM) is established. The fault three-phase current is derived, and fault current will be affected by the position of the inter-turn short circuit. Secondly, the whale optimization algorithm is improved by adaptive weights and Cauchy Gaussian mutation strategy. The improved whale optimization algorithm is adopted for optimizing the parameters of variational mode decomposition, and a parameter optimized variational mode decomposition algorithm for processing current signal is proposed. Finally, by calculating the multi-scale fuzzy entropy of current and torque, a fault diagnosis method for Y-Δ connection FS-PMM inter-turn short circuit is proposed. The accuracy of this fault diagnosis method can reach over 95%, and it can effectively distinguish the inter-turn short circuit fault between the Y connection part and the Δ connection part.
2024, 51(6):44-56.
DOI: 10.12177/emca.2024.039
Abstract:
The rectifier is an important component of the doubly salient electromagnetic generator (DSEG), which frequently bears high voltage and large current and is prone to failure. However, due to the asymmetry and non-sinusoidal nature of the DSEG phase currents, the traditional open-circuit fault diagnosis algorithms are highly susceptible to misdetection in the transient of the variable operating conditions. To diagnose the open-circuit fault in the DSEG rectifier unit, based on phase current size positional relation, a strong robustness diagnosis strategy is proposed. By theory derivation and experimental verification, it can be concluded that the proposed strong robustness open-circuit fault diagnosis strategy does not misdiagnose in the transient states of variable load, variable excitation and variable speed. And it can detect all types of single-tube and dual-tube open-circuit faults within one fundamental wave period, and has small computation and space occupation.
The rectifier is an important component of the doubly salient electromagnetic generator (DSEG), which frequently bears high voltage and large current and is prone to failure. However, due to the asymmetry and non-sinusoidal nature of the DSEG phase currents, the traditional open-circuit fault diagnosis algorithms are highly susceptible to misdetection in the transient of the variable operating conditions. To diagnose the open-circuit fault in the DSEG rectifier unit, based on phase current size positional relation, a strong robustness diagnosis strategy is proposed. By theory derivation and experimental verification, it can be concluded that the proposed strong robustness open-circuit fault diagnosis strategy does not misdiagnose in the transient states of variable load, variable excitation and variable speed. And it can detect all types of single-tube and dual-tube open-circuit faults within one fundamental wave period, and has small computation and space occupation.
2024, 51(6):57-68.
DOI: 10.12177/emca.2024.045
Abstract:
Based on the discharge inductance model, the transient characteristics of capacitive rectifier system of pulsed homopolar inductor alternator are analyzed, and all four operating modes of this rectifier system are clarified. The critical voltage between modes and the formulas for calculating commutation delay angle and overlap angle are derived, and a transient model is established. The accuracy of the proposed theoretical calculation is verified by valve-to-valve circuit simulation and experimental results. The function of each mode in the circuit to the charging process is expounded, and the equivalent form of circuit is analyzed, and reveals the design principle of the charge voltage and the amplitude of motor electromotive force (EMF). The results of the study show that: the circuit can be seen as a form of charging a capacitor by serially connecting a DC source with an equivalent commutation reactance and an equivalent transient commutation inductance; mode 1 and mode 2 play a major role in the whole charging process; the reasonable charge voltage should be between 1.3 times and 1.5 times of the amplitude of generator′s phase EMF.
Based on the discharge inductance model, the transient characteristics of capacitive rectifier system of pulsed homopolar inductor alternator are analyzed, and all four operating modes of this rectifier system are clarified. The critical voltage between modes and the formulas for calculating commutation delay angle and overlap angle are derived, and a transient model is established. The accuracy of the proposed theoretical calculation is verified by valve-to-valve circuit simulation and experimental results. The function of each mode in the circuit to the charging process is expounded, and the equivalent form of circuit is analyzed, and reveals the design principle of the charge voltage and the amplitude of motor electromotive force (EMF). The results of the study show that: the circuit can be seen as a form of charging a capacitor by serially connecting a DC source with an equivalent commutation reactance and an equivalent transient commutation inductance; mode 1 and mode 2 play a major role in the whole charging process; the reasonable charge voltage should be between 1.3 times and 1.5 times of the amplitude of generator′s phase EMF.
2024, 51(6):69-77.
DOI: 10.12177/emca.2024.043
Abstract:
Permanent magnet synchronous motors used in electric vehicles are needed to consider not only the performance under rated operating conditions, but also the overall efficiency across the entire road spectrum. Based on this, an optimal design method for asymmetric V-shaped interior permanent magnet synchronous motor based on new European driving cycle (NEDC) driving cycle is introduced. The geometric parameters of the upper and lower parts of the permanent magnet in the above asymmetric motor are parametrically modeled as independent parameters. Taking the NEDC efficiency and torque-cost ratio as the optimization objectives, the genetic algorithm is used to optimize the symmetric and asymmetric V-shaped permanent magnet synchronous motors, respectively. Finally, the optimal design point on the Pareto front is selected for comparison of electromagnetic performance. The simulation results show that compared with the symmetrical structure, the asymmetrical rotor structure exhibits stronger torque performance due to the magnetic field offset effect. Therefore, the asymmetric V-shaped permanent magnet synchronous motor exhibits better electromagnetic performance and lower manufacturing cost, and has a broad application prospect in the field of electric vehicles.
Permanent magnet synchronous motors used in electric vehicles are needed to consider not only the performance under rated operating conditions, but also the overall efficiency across the entire road spectrum. Based on this, an optimal design method for asymmetric V-shaped interior permanent magnet synchronous motor based on new European driving cycle (NEDC) driving cycle is introduced. The geometric parameters of the upper and lower parts of the permanent magnet in the above asymmetric motor are parametrically modeled as independent parameters. Taking the NEDC efficiency and torque-cost ratio as the optimization objectives, the genetic algorithm is used to optimize the symmetric and asymmetric V-shaped permanent magnet synchronous motors, respectively. Finally, the optimal design point on the Pareto front is selected for comparison of electromagnetic performance. The simulation results show that compared with the symmetrical structure, the asymmetrical rotor structure exhibits stronger torque performance due to the magnetic field offset effect. Therefore, the asymmetric V-shaped permanent magnet synchronous motor exhibits better electromagnetic performance and lower manufacturing cost, and has a broad application prospect in the field of electric vehicles.
2024, 51(6):78-87.
DOI: 10.12177/emca.2024.051
Abstract:
The inter-turn short-circuit (ITSC) fault of stator winding is one of the most common faults of permanent magnet synchronous motor (PMSM). A large current will be generated in the shorted portion of the winding when the fault occurs, which will pose a great threat to the safe operation of PMSM. In order to diagnose the ITSC fault, the effect of ITSC fault on the stator current of PMSM is analyzed. The stator currents of PMSM with different ITSC faults are obtained by finite element simulation and experimental measurements. And the effect of ITSC fault on stator current of PMSM is analyzed by current imbalance, negative-sequence current, and wavelet energy spectrum. The analysis results show that with the increase of short-circuited turns and the decrease of contact resistance, the current imbalance, negative-sequence current, and the energy gradient of D1 in wavelet energy spectrum increase. Thus, the increase of these three indicators can be used as the basis for diagnosing the ITSC fault.
The inter-turn short-circuit (ITSC) fault of stator winding is one of the most common faults of permanent magnet synchronous motor (PMSM). A large current will be generated in the shorted portion of the winding when the fault occurs, which will pose a great threat to the safe operation of PMSM. In order to diagnose the ITSC fault, the effect of ITSC fault on the stator current of PMSM is analyzed. The stator currents of PMSM with different ITSC faults are obtained by finite element simulation and experimental measurements. And the effect of ITSC fault on stator current of PMSM is analyzed by current imbalance, negative-sequence current, and wavelet energy spectrum. The analysis results show that with the increase of short-circuited turns and the decrease of contact resistance, the current imbalance, negative-sequence current, and the energy gradient of D1 in wavelet energy spectrum increase. Thus, the increase of these three indicators can be used as the basis for diagnosing the ITSC fault.
2024, 51(6):88-97.
DOI: 10.12177/emca.2024.047
Abstract:
In order to solve the pole frequency vibration problem of a 10-pole and 12-slot surface-mount permanent magnet synchronous motor, a weakening scheme of the pole structure with axially unequal width is proposed. This scheme can effectively reduce the extreme frequency vibration of the motor under the premise of ensuring the torque density of the motor. Firstly, based on the Maxwell stress tensor method, an analytical expression for the radial electromagnetic force of the motor is derived, and a model of the electromagnetic force acting on the stator teeth of the motor is established. Simultaneously, factors contributing to the generation of pole frequency electromagnetic force harmonics in the prototype are analyzed. Then, through finite element simulation analysis, the basic mechanism of reducing pole frequency electromagnetic force by using the magnetic pole structure with axially unequal width is explained. And comparison analysis of the motor′s electromagnetic performance and vibration acceleration before and after optimization is conducted. Finally, the results show that the polar structure with axially unequal width can effectively reduce the harmonics and vibrations of the polar electromagnetic force while maintaining the torque density of the motor, which confirms the effectiveness of the optimization scheme.
In order to solve the pole frequency vibration problem of a 10-pole and 12-slot surface-mount permanent magnet synchronous motor, a weakening scheme of the pole structure with axially unequal width is proposed. This scheme can effectively reduce the extreme frequency vibration of the motor under the premise of ensuring the torque density of the motor. Firstly, based on the Maxwell stress tensor method, an analytical expression for the radial electromagnetic force of the motor is derived, and a model of the electromagnetic force acting on the stator teeth of the motor is established. Simultaneously, factors contributing to the generation of pole frequency electromagnetic force harmonics in the prototype are analyzed. Then, through finite element simulation analysis, the basic mechanism of reducing pole frequency electromagnetic force by using the magnetic pole structure with axially unequal width is explained. And comparison analysis of the motor′s electromagnetic performance and vibration acceleration before and after optimization is conducted. Finally, the results show that the polar structure with axially unequal width can effectively reduce the harmonics and vibrations of the polar electromagnetic force while maintaining the torque density of the motor, which confirms the effectiveness of the optimization scheme.
2024, 51(6):98-106.
DOI: 10.12177/emca.2024.041
Abstract:
A fault-tolerant control scheme based on command filtered backstepping method is proposed for the failure of a single motor in a four-motor servo system. Firstly, a dynamic model of the fault servo system with unknown inertia and unbalanced torque is established. Subsequently, the controller is designed using command filtered backstepping technology, in which an error compensation system is designed to improve the control accuracy. In addition, the neural network is used to deal with the nonlinear disturbance caused by the faulty motor, and synchronization error signals are designed to achieve synchronization control of the system. Finally, based on the Lyapunov stability theory, the stability of the closed-loop system under the condition of single motor failure is proved. And simulation is designed to verify the effectiveness and superiority of the proposed control method.
A fault-tolerant control scheme based on command filtered backstepping method is proposed for the failure of a single motor in a four-motor servo system. Firstly, a dynamic model of the fault servo system with unknown inertia and unbalanced torque is established. Subsequently, the controller is designed using command filtered backstepping technology, in which an error compensation system is designed to improve the control accuracy. In addition, the neural network is used to deal with the nonlinear disturbance caused by the faulty motor, and synchronization error signals are designed to achieve synchronization control of the system. Finally, based on the Lyapunov stability theory, the stability of the closed-loop system under the condition of single motor failure is proved. And simulation is designed to verify the effectiveness and superiority of the proposed control method.
2024, 51(6):107-116.
DOI: 10.12177/emca.2024.050
Abstract:
When the permanent magnet synchronous motor is under high frequency conditions, the core loss of the stator and rotor and the eddy current loss of the permanent magnet will increase, which will increase the temperature of the motor, resulting in insulation aging and permanent magnet demagnetization. In order to solve the problem of increasing loss at high frequency, a double claw pole motor with axially segmented claw pole stator and single-stage claw pole rotor with soft magnetic composite materials for stator and rotor core materials is designed. Similar to the problem of excessive torque ripple in the double-salient structure, a combination of rotor magnetic pole offset and stator oblique pole to reduce torque ripple is used. Finally, the electromagnetic design and temperature distribution of the motor are analyzed to verify the rationality of the design. For the selection of claw pole parameters, the effects of the main size ratio, polar arc coefficient, rotor magnetic pole offset distance and stator oblique pole angle on the air gap magnetic density, no-load back electromotive force, torque and torque ripple of the double claw pole motor are studied.
When the permanent magnet synchronous motor is under high frequency conditions, the core loss of the stator and rotor and the eddy current loss of the permanent magnet will increase, which will increase the temperature of the motor, resulting in insulation aging and permanent magnet demagnetization. In order to solve the problem of increasing loss at high frequency, a double claw pole motor with axially segmented claw pole stator and single-stage claw pole rotor with soft magnetic composite materials for stator and rotor core materials is designed. Similar to the problem of excessive torque ripple in the double-salient structure, a combination of rotor magnetic pole offset and stator oblique pole to reduce torque ripple is used. Finally, the electromagnetic design and temperature distribution of the motor are analyzed to verify the rationality of the design. For the selection of claw pole parameters, the effects of the main size ratio, polar arc coefficient, rotor magnetic pole offset distance and stator oblique pole angle on the air gap magnetic density, no-load back electromotive force, torque and torque ripple of the double claw pole motor are studied.
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沪ICP备16038578号-3
Electric Machines & Control Application ® 2025
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
沪ICP备16038578号-3
Electric Machines & Control Application ® 2025
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
