Abstract: The present disclosure provides a method for reducing the electromagnetic vibration of a fractional slot concentrated winding (FSCW) permanent magnet (PM) motor, which provides a guidance for the low vibration design of FSCW PM motor. The implementation of the method includes: Based on Nyquist Shannon sampling theorem, the modulation effect of electromagnetic force in the air gap is obtained, and the electromagnetic force component that contributes the most to the electromagnetic vibration of the FSCW PM motor is determined. The equivalent analytical model of PM flux density is established to obtain the phase relationship between different flux density harmonics. According to Maxwell stress equation, the internal relationship between each order of flux density harmonics and electromagnetic force harmonics is obtained. A new magnet structure of the PM motor is designed, and specific flux density harmonics are injected to reduce the electromagnetic force and electromagnetic vibration of the FSCW PM motor.

Abstract: A single winding hybrid excitation magnetic field modulation motor includes a stator, a rotor, a winding and a permanent magnet. The stator includes a stator iron core, a permanent magnet and a winding. The stator iron core includes stator teeth and stator yoke. Each stator tooth is split into an equal number of split teeth facing the air gap side. All permanent magnets are embedded in the grooves between the split teeth on the same stator tooth, the polarity of all permanent magnets located on the same stator tooth is the same, and the polarity of the permanent magnets on the adjacent stator teeth is opposite. A single non-overlapping concentrated winding is wound on all stator teeth, and DC current and AC current are simultaneously passed into each set of windings, in which field winding and permanent magnet are excited together to form hybrid excitation.

Abstract: A model predictive decomposition control method and device for an open-winding five-phase permanent magnet synchronous motor is provided. The method includes obtaining the voltage component in the stationary coordinate system under the orientation of the rotor magnetic field, synthesizing the virtual voltage vector that can eliminate the voltage vector in harmonic space according to the vector distribution of the five-phase permanent magnet synchronous motor under the voltage source inverter. The open winding permanent magnet synchronous motor topology is equivalent to the superposition of the independent actions of two inverters. The voltage vector generated by a single inverter is predicted through the mathematical model of the motor. The expected increment is a judgment condition to determine whether the open winding system uses one of the two inverters to maintain the normal operation of the open winding system, or the first inverter is clamped and the second inverter generates the remaining increment.

Abstract: An analysis of a surface mounted permanent magnet (SPM) machine by a 2D meshless method is provided. The 2D meshless method includes steps: discrete nodes are arranged in the region to be solved; based on Taylor expansion and weighted least squares principle, the derivative value of vector potential can be approximated as a linear combination of vector potential values of each node in the support region; partial differential equations are converted into algebraic equations; by solving the algebraic equations, the vector potential of each node can be calculated, and then the distribution of the flux line and the flux density can be obtained. According to the electromagnetic calculation constraints of the machine, parameters such as the back electromotive force and electromagnetic torque of the machine can be obtained.

Abstract: The present disclosure provides a method for reducing the electromagnetic vibration of a fractional slot concentrated winding (FSCW) permanent magnet (PM) motor, which provides a guidance for the low vibration design of FSCW PM motor. The implementation of the method includes: Based on Nyquist Shannon sampling theorem, the modulation effect of electromagnetic force in the air gap is obtained, and the electromagnetic force component that contributes the most to the electromagnetic vibration of the FSCW PM motor is determined. The equivalent analytical model of PM flux density is established to obtain the phase relationship between different flux density harmonics. According to Maxwell stress equation, the internal relationship between each order of flux density harmonics and electromagnetic force harmonics is obtained. A new magnet structure of the PM motor is designed, and specific flux density harmonics are injected to reduce the electromagnetic force and electromagnetic vibration of the FSCW PM motor.

Abstract: An internal-cooling rolling tool capable of realizing variable-angle low-temperature lubrication is provided. The internal-cooling rolling tool includes a tool handle, a rotatable tool head and a medium conveying tube. The rotatable tool head includes a base, a rolling head and a ball. The bottom end of the base is mounted on the tool handle, and the top of the base is provided with a medium input port connected with the medium conveying tube. The rolling head is detachably mounted on the front end surface of the base, and the front end surface of base is provided with a plurality of spray holes in the circumferential direction of the rolling head. The medium conveying tube communicates with the spray holes through a medium flow channel. The ball is mounted on one end of the rolling head facing away from the base.

Abstract: Disclosed is an injection molding method for a degradable intravascular stent with a flexible mold core structure. The injection molding method includes the following steps: Step 1, winding a metal rod with a flexible metal film, and applying an inward bending stress to the flexible metal film; Step 2, fixing the flexible metal film to the metal rod, and processing a complementary structure of the degradable intravascular stent on the surface of the flexible metal film; Step 3, performing injection molding processing; Step 4, ending the injection molding, removing the mating body of the flexible metal film and the metal rod and the degradable intravascular stent formed on the surface of the flexible metal film by injection molding, performing cooling, separating the metal rod from the flexible metal film, withdrawing the metal rod, and then removing the flexible metal film to obtain a formed degradable intravascular stent.

Abstract: A short-circuit fault-tolerant control method based on deadbeat current tracking for a five-phase permanent magnet motor with a sinusoidal back-electromotive force or a trapezoidal back-electromotive force (EMF) is provided. By fully utilizing a third harmonic space of a five-phase permanent magnet motor in a fault state, the method proposes a fault-tolerant control strategy for a five-phase permanent magnet motor with a sinusoidal back-EMF or a trapezoidal back-EMF in case of a single-phase short-circuit fault. The method enables the five-phase permanent magnet motor to make full use of the third harmonic space during fault-tolerant operation, thereby improving the torque output of the motor in a fault state and improving the fault-tolerant operation efficiency of the motor. The method achieves desirable fault-tolerant performance and dynamic response of the motor, and expands the speed range of the motor during fault-tolerant operation.

Abstract: The present invention relates to a fault-tolerant modular permanent magnet assisted synchronous reluctance motor (PMaSynRM) and provides a modular winding connection method. The modular winding connection is to change the positions of inlet and outlet coils based on the slot electrical potential star vectogram. Then, each module has a separate set of winding and the left and right relative distribution will be adopted on the winding connection. The invention has the advantages of modularization in structure, high independence between the modules, effectively avoiding overlapping of magnetic lines between the modules, and improving fault tolerance and reliability of the motor. The invention has the advantages of modularization in structure, high independence between the modules, magnetic decoupling between the modules, and improvement of fault tolerance and reliability of the motor.

Abstract: A short-circuit fault-tolerant control method based on deadbeat current tracking for a five-phase permanent magnet motor with a sinusoidal back-electromotive force or a trapezoidal back-electromotive force (EMF) is provided. By fully utilizing a third harmonic space of a five-phase permanent magnet motor in a fault state, the method proposes a fault-tolerant control strategy for a five-phase permanent magnet motor with a sinusoidal back-EMF or a trapezoidal back-EMF in case of a single-phase short-circuit fault. The method enables the five-phase permanent magnet motor to make full use of the third harmonic space during fault-tolerant operation, thereby improving the torque output of the motor in a fault state and improving the fault-tolerant operation efficiency of the motor. The method achieves desirable fault-tolerant performance and dynamic response of the motor, and expands the speed range of the motor during fault-tolerant operation.

Abstract: A field modulated doubly salient motor and a design method for a distribution of salient pole teeth thereof are provided. The motor includes a stator and a mover, wherein the stator includes a stator core, two sets of windings, and two sets of permanent magnets. Each of the stator teeth is split into two field winding teeth, and each of the field winding teeth is split into two salient pole teeth. The two sets of windings are respectively armature windings and field windings, wherein the armature windings are wound around stator teeth, and the field windings are wound around adjacent field winding teeth that are split from different stator teeth. The two sets of tangentially magnetized permanent magnets are respectively placed on openings and bottoms of field winding slots, and permanent magnets placed in the same slot or at the same positions of adjacent slots have opposite polarities.

Abstract: A field modulated doubly salient motor and a design method for a distribution of salient pole teeth thereof are provided. The motor includes a stator and a mover, wherein the stator includes a stator core, two sets of windings, and two sets of permanent magnets. Each of the stator teeth is split into two field winding teeth, and each of the field winding teeth is split into two salient pole teeth. The two sets of windings are respectively armature windings and field windings, wherein the armature windings are wound around. stator teeth, and the field windings are wound around adjacent field winding teeth that are split from different stator teeth. The two sets of tangentially magnetized permanent magnets are respectively placed on openings and bottoms of field winding slots, and permanent magnets placed in the same slot or at the same positions of adjacent slots have opposite polarities.

Abstract: A parametric equivalent magnetic network modeling method for multi-objective optimization of permanent magnet motor is provided. Firstly, the disordered region and the regular region of the magnetic flux lines in the motor are divided, and the dynamic mesh model of the disordered region and the magnetic circuit model of the ordered region is constructed. Then, the dynamic mesh model and the magnetic circuit model are connected, and the parametric equivalent magnetic network model of the motor is established. The nonlinear matrix is used to solve the equations, and the magnetic potential of each node is solved to obtain the torque characteristics of the motor. Then, the variable sensitivity analyses of the average torque and torque ripple are carried out by using the parametric equivalent magnetic network model, and the response surface models of the average torque and torque ripple are established by selecting the high sensitivity variables.

Abstract: A double virtual voltage vectors predictive torque control method without weighting factor for five-phase permanent magnet synchronous motor includes: obtaining the current component in the two-phase stationary coordinate system and the outputting voltage at k interval; one step delay compensation is performed to obtain the current component in the two-phase stationary coordinate system at k+1 interval; predicting the flux and torque of motor at k+1 interval; calculating the reference voltage vector needed by the motor at k+1 interval according to the deadbeat principle and selecting the first virtual voltage vector; selecting the second virtual voltage vector according to the voltage error tracking principle and calculating the duration of the first virtual voltage vector and the second virtual voltage vector respectively and then synthesizing the two vectors and outputting.

Abstract: A parametric equivalent magnetic network modeling method for multi-objective optimization of permanent magnet motor is provided. Firstly, the disordered region and the regular region of the magnetic flux lines in the motor are divided, and the dynamic mesh model of the disordered region and the magnetic circuit model of the ordered region is constructed. Then, the dynamic mesh model and the magnetic circuit model are connected, and the parametric equivalent magnetic network model of the motor is established. The nonlinear matrix is used to solve the equations, and the magnetic potential of each node is solved to obtain the torque characteristics of the motor. Then, the variable sensitivity analyses of the average torque and torque ripple are carried out by using the parametric equivalent magnetic network model, and the response surface models of the average torque and torque ripple are established by selecting the high sensitivity variables.

Abstract: Disclosed is an injection molding method for a degradable intravascular stent with a flexible mold core structure. The injection molding method includes the following steps: Step 1, winding a metal rod with a flexible metal film, and applying an inward bending stress to the flexible metal film; Step 2, fixing the flexible metal film to the metal rod, and processing a complementary structure of the degradable intravascular stent on the surface of the flexible metal film; Step 3, performing injection molding processing: Step 4, ending the injection molding, removing the mating body of the flexible metal film and the metal rod and the degradable intravascular stent formed on the surface of the flexible metal film by injection molding, performing cooling, separating the metal rod from the flexible metal film, withdrawing the metal rod, and then removing the flexible metal film to obtain a formed degradable intravascular stent.

Abstract: A double virtual voltage vectors predictive torque control method without weighting factor for five-phase permanent magnet synchronous motor includes: obtaining the current component in the two-phase stationary coordinate system and the outputting voltage at k interval; one step delay compensation is performed to obtain the current component in the two-phase stationary coordinate system at k+1 interval; predicting the flux and torque of motor at k+1 interval; calculating the reference voltage vector needed by the motor at k±1 interval according to the deadbeat principle and selecting the first virtual voltage vector; selecting the second virtual voltage vector according to the voltage error tracking principle and calculating the duration of the first virtual voltage vector and the second virtual voltage vector respectively and then synthesizing the two vectors and outputting.

Abstract: The present invention relates to a fault-tolerant modular permanent magnet assisted synchronous reluctance motor (PMaSynRM) and provides a modular winding connection method. The modular winding connection is to change the positions of inlet and outlet coils based on the slot electrical potential star vectogram. Then, each module has a separate set of winding and the left and right relative distribution will be adopted on the winding connection. The invention has the advantages of modularization in structure, high independence between the modules, effectively avoiding overlapping of magnetic lines between the modules, and improving fault tolerance and reliability of the motor. The invention has the advantages of modularization in structure, high independence between the modules, magnetic decoupling between the modules, and improvement of fault tolerance and reliability of the motor.

Abstract: This invention proposes a method to regulate high efficiency region of permanent magnet motor. The internal relationship between the point with maximum efficiency and the points around it is firstly revealed. Then, the optimal combination of copper loss, iron loss and permanent magnet eddy-current loss is presented when maximum efficiency point moves toward different directions. Hence, the method for regulating high efficiency region can be obtained. This method can be suitable for any type of permanent magnet motors, which can adjust high efficiency region to the dense working point area of the motor under different operating conditions according to design requirements. If this method is used into electric vehicle, it can combine the high efficiency region with the electric vehicle driving cycle to reduce energy consumption and enhance the life mileage of electric vehicle effectively.

Abstract: A permanent magnet brushless motor has a stator, an armature winding, a rotor, and a permanent magnet. The stator is provided with an armature groove. The armature winding is placed in the armature groove. The stator and the rotor are spaced apart by an air gap; the permanent magnet is attached to the surface of the rotor, and is magnetized by a Halbach array structure. The motor is an eight-phase motor, and phases are evenly distributed at a phase belt angle of 45°. The motor and the proposed control algorithm have good fault-tolerant effects, and the average torque after fault tolerance is basically consistent with that in normal operation.