40 results about "Linear induction motor" patented technology

The invention provides an electromagnetic quasi-zero stiffness vibration isolation device and method based on a composite nested structure, and belongs to the technical field of vibration isolation. The device comprises a supporting base, two linear induction motor assemblies symmetrically arranged on the base and provided with a preset gap, and a suspension supporting frame composed of a vertical conductive supporting plate and a horizontal magnetic conductive supporting plate. The vertical conductive supporting plate can float up and down in the gap and forms a positive stiffness module for providing main supporting force and positive stiffness with the motor assembly, and the two eddy current stator pairs are symmetrically distributed on the left side and the right side of the horizontal magnetic conductive supporting plate and form a negative stiffness module for providing negative stiffness with the horizontal magnetic conductive supporting plate; each eddy current stator pair comprises an upper eddy current stator assembly and a lower eddy current stator assembly which are mutually exclusive up and down and float on the upper side and the lower side of the horizontal magnetic conductive supporting plate; the positive and negative stiffness modules are coaxially arranged and cooperate in parallel through a composite nested structure to realize the quasi-zero stiffness characteristic; the rigidity can be dynamically adjusted, and the vibration isolation effect and reliability are improved.

The present invention relates to a method for controlling the normal vibration stability of a maglev train based on a transfer function. The steps are as follows: Obtain the mechanical structure parameters and electromagnetic parameters of the linear induction motor for the maglev train, and establish a mathematical model of the normal force of the linear induction motor; Obtain the dynamic model of the medium and low-speed maglev train considering the normal force through the spring-damping coupling model of the medium and low-speed maglev train; Perform Laplace transform on both sides of the obtained dynamic model of the medium and low-speed maglev train considering the normal force; Obtain the transfer function of the normal vibration of the maglev train according to the dynamic model of the medium and low-speed maglev train considering the normal force obtained by the Laplace transform; Perform stability control on the operation of the maglev train according to the obtained transfer function. The present invention solves the problem that the existing dynamic model of the maglev train does not consider the fluctuation of the normal force of the linear induction motor when established, and cannot analyze the influence of the normal vibration of the linear induction motor on the stable operation of the maglev train.

The invention relates to a joining tool (10) for connecting at least two elements (36, 38) by driving in a connecting element in the form of a self-piercing rivet (34), comprising a drive (14) which is designed to generate an axial force in order to drive the self-piercing rivet (34) into the elements (36, 38) to be connected; and an actuator (22) which is designed to apply the force generated by the drive (14) to the self-piercing rivet (34); wherein the joining tool (10) comprises a linear induction motor (14) as a drive (14). The invention also relates to a method for connecting at least two elements (36, 38) by driving in a self-piercing rivet (34), wherein the self-piercing rivet (34) is driven into the elements (36, 38) to be connected by applying an axial force to the self-piercing rivet (34), wherein the axial force is generated by a linear induction motor (14).

The embodiment of the invention provides an induction motor transmitting device. The induction motor transmitting device comprises a motor base; an opening of the U-shaped structure faces the motor base, and the U-shaped stator framework comprises two side walls and a top wall; the stator iron cores are respectively fixed on the side walls and the top wall, and the stator iron cores are provided with coil windings; and the rotor covers the outer side of the stator framework and is connected to the motor base in a sliding manner. The linear induction motor is adopted, the motor is of an inverted-U-shaped structure, the stator iron cores are arranged on the side wall and the top wall of the U-shaped structure respectively, the structure is compact, and the space utilization rate is high; the transverse end effect of the upper motor and the transverse end effect of the upper portions of the left and right sides can be eliminated, under the same current condition, the thrust of the motor of the U-shaped structure is larger than the sum of thrust of independent operation of the left, upper and right motors, the power factor is high, the motor winding directly faces air to conduct convection heat dissipation, and the heat dissipation effect is improved.

A conveyor system for transporting goods within a warehouse facility. The system includes an array of guide tracks and carriages moveable along the guide tracks for transporting goods within the warehouse facility. A drive system includes drivers spaced along the guide tracks. The drivers may utilize linear induction motors, propels the carriages along the guide tracks. The linear induction motors utilize stepper motors, and optionally microstepping motors. A warehouse management system controls the linear drive system to transport goods throughout warehouse facility for storage and order fulfilment. The linear driver conveyor system includes perpendicular transfers at which carriages can be transferred from one conveyor line to another, without the need for mechanical processes, such as lift or buffers, to move the carriage between conveyor lines.

The application relates to a conjugate double-sided magnetic field linear induction motor and an assembling method thereof. The conjugate double-sided magnetic field linear induction motor comprises conjugate winding primaries and composite secondaries, and a group of composite secondaries are arranged on opposite sides of the conjugate winding primaries respectively. The composite secondary comprises a back iron and a squirrel cage embedded in the back iron, and the squirrel cages of the two groups of composite secondaries are oppositely arranged. According to the conjugate double-sided magnetic field linear induction motor, a group of composite secondaries are arranged on opposite sides of the conjugate winding primaries respectively, and the multi-phase conjugate winding primary generates a double-sided conjugate symmetrical air gap magnetic field when the motor is powered and operated, the air gap magnetic field interacts with the double-sided composite secondary to generate electromagnetic force, and the air gap magnetic field utilization rate and the thrust density are higher.

A linear induction motor system for levitating a vehicle is disclosed herein The linear induction motor system comprises a linear induction motor. The linear induction motor comprises a back iron and a reaction rail adjacent to the back iron. The linear induction motor further comprises a primary separated from the reaction rail by a gap. The linear induction motor system further comprises a rear appendix adjacent to the primary, wherein the rear appendix generates magnetic poles in the primary in response to a magnetic flux density in the reaction rail and back iron.

A polyphase linear induction motor including a movable primary member (100), the primary member (100) including a magnetic material (110), a polyphase winding (120) arranged around the magnetic material, and a stationary longitudinally-extending secondary member (150) separated from the primary member (100) by a gap, the secondary member (150) including an electrically-conductive reaction plate (200) and a backing magnetic material (300), wherein the secondary member includes a middle section (205) and two outer sections (210.1, 210.2), the middle section (205) and the two outer sections (210.1, 210.2) arranged next to each other in parallel to an axis of longitudinal extension of the reaction plate (200).

The application provides an electromagnetic quasi-zero stiffness vibration isolation device and method based on a composite nested structure, and belongs to the technical field of vibration isolation. The device comprises a supporting base, two linear induction motor assemblies symmetrically arranged on the base and provided with a preset gap, and a suspension support frame composed of a vertical conductive support plate and a horizontal magnetic conductive support plate. The vertical conductive support plate can float up and down in the gap and forms a positive stiffness module with the motor assembly to provide a main supporting force and positive stiffness. Two pairs of symmetrical electric eddy current stator pairs are distributed on the left and right sides of the horizontal magnetic conductive support plate and form a negative stiffness module with the horizontal magnetic conductive support plate to provide negative stiffness. Each pair of electric eddy current stator pairs comprises an upper electric eddy current stator assembly and a lower electric eddy current stator assembly which are mutually repulsive and float up and down on the left and right sides of the horizontal magnetic conductive support plate. The positive and negative stiffness modules are coaxially arranged and are connected in parallel through a composite nested structure to realize the quasi-zero stiffness characteristic. The application can realize dynamic stiffness adjustment, improve the vibration isolation effect and reliability.

The invention discloses a linear induction motor speed sensorless control method based on a vector sum, and belongs to the technical field of segmented linear induction motor control, and the method comprises the steps: introducing a virtual secondary method according to a segmented linear induction motor mathematical model, and constructing an equivalent mathematical model based on a virtual secondary vector sum; based on the constructed equivalent mathematical model, stator current and rotor flux linkage under a two-phase static coordinate system are selected as state variables to design a sliding-mode observer; the method comprises the following steps: acquiring stator voltage and stator current signals of a motor in real time, taking the current signals as input of a sliding mode observer, taking current observed by the observer as output, and constructing a sliding mode control rate by using an error between a current observation value and an actual measurement value so as to reconstruct motor back electromotive force; integrating the back electromotive force signal to obtain a rotor flux linkage estimation value, and further calculating rotating speed information; and forming a closed-loop control system comprising an equivalent mathematical model, a sliding-mode observer and speed feedback.

A conveyor belt driven by linear motors distributed along the belt, rather than at the head thereof. These linear electric motors or of the induction type with a short primary (5) having two action sides and a long secondary (2) made of plates (8; 12) of conducting material, such as aluminium or copper. The secondary (2) plates (8; 12) are vertically fixed in the central portion of the rubber belt (1) or metal plates (22). The invention is equipped with split central load rollers (14) and return drums (3) with grooves (11) accommodating the passage of the secondary plates (8; 12) during the belt (1) path.

This invention discloses a method for obtaining parameters of a stationary linear induction motor based on the finite element method. The motor's rotor is stationary, and the method can account for the magnetic saturation of the primary core and secondary yoke. It is applicable to both short-primary and long-primary linear induction motors. First, the induction plate of the secondary winding is removed from the calculation model. Under current source excitation mode, an AC current with a preset current and frequency is applied to the input terminal of the primary winding. The current magnitude is varied, and the total equivalent resistance, reactance, and maximum air gap normal magnetic flux density of the motor are obtained under different current inputs. Then, the induction plate of the secondary winding is restored to the calculation model. Under current source excitation mode, an AC current with a preset current and frequency is applied to the input terminal of the primary winding, and the total equivalent resistance, reactance, and maximum air gap normal magnetic flux density of the motor are obtained. Finally, based on the above calculated values, the parameters in the T-type equivalent circuit of the induction motor are calculated.

The invention provides a linear propulsion device, a high-temperature superconducting maglev traffic structure and a control method, and relates to the technical field of maglev traffic, the linear propulsion device comprises a permanent magnet array, the permanent magnet array is laid in the extending direction of rails, and two power supply rails are arranged in the width direction of the permanent magnet array. The two power supply rails are connected with the positive electrode and the negative electrode of a power source correspondingly, and the sliding piece is suitable for being fixedly connected with a vehicle body and is in sliding connection and conduction with the power supply rails. The magnetic field of the permanent magnet array is utilized, the sliding part and the power supply rail are slidably connected and conducted, so that the sliding part can move in the extending direction of the rail, the vehicle body can move along the rail, and compared with a short-stator linear induction motor and a long-stator linear synchronous motor, the motor is low in cost and high in driving efficiency.

The application discloses a kind of excitation inductance identification method, current control method and system of linear induction motor, belong to linear motor control technical field;In each control cycle, with back electromotive force as observation, the reference model based on sliding mode observer is constructed to calculate back electromotive force observation value, and adjustable model containing excitation inductance is used to calculate back electromotive force, and the adaptive rate of excitation inductance and back emf error is calculated to calculate the corresponding excitation inductance, to realize the identification of excitation inductance.The application constructs reference model irrelevant to the change of excitation inductance, and uses sliding mode instead of current differential term, eliminates the noise caused by current differential term in existing reference model, avoids the interference of current noise on back emf observation result, improves the accuracy of excitation inductance identification;On this basis, the inherent chattering problem of sliding mode observer is further eliminated by using cascaded low-pass filter, and the accuracy of excitation inductance identification is further improved.

This invention discloses a flat-type moving primary linear induction motor, comprising a motor base, a motor stator assembly, a mover assembly, a power supply device, and a guiding device. The motor stator assembly is vertically fixed within the hollow frame of the motor base. Multiple vertically arranged guide rails are fixedly arranged on the left and right sides of the motor stator assembly. Multiple sliding contact line structures are arranged on the vertical inner wall of the motor stator assembly frame. The mover assembly includes a mover frame sleeved around the outer periphery of the motor stator assembly and a mover winding fixedly mounted in the middle of the mover frame. A sliding groove is provided on the mover frame. The guide rails are inserted into the sliding grooves, allowing the mover frame to move axially along the guide rail direction due to the constraint of the sliding grooves. Collectors are installed on the left and right sides of the mover frame, and the mover winding is powered by sliding contact through the collectors and the sliding contact line structures. This invention features high thrust density, compact structure, low cost, reliable operation, and convenient maintenance, and can be applied to high-thrust acceleration fields.

This invention provides a sensorless control method for a piecewise linear induction motor based on an extended state observer phase-locked loop (PLL), belonging to the field of motor control technology. The method includes: constructing an equivalent mathematical model of the piecewise linear induction motor without coupling coefficient terms; constructing a sliding mode observer based on an integral sliding surface combined with an exponential reaching law to obtain the back electromotive force (EMF) observation value required by the PLL; inputting the back EMF observation value into the PLL based on the extended state observer to extract the synchronous angular velocity and synchronous electrical angle, and calculating the secondary velocity estimate and secondary displacement estimate; feeding back the synchronous angular velocity, secondary velocity estimate, and secondary displacement estimate to the closed-loop control system to achieve sensorless operation of the piecewise linear induction motor. This invention can improve the speed and position estimation accuracy of the system under high dynamic conditions, and enhance the system's robustness and dynamic response performance.

The invention provides a pinning magnetic levitation magnetic track driving device, a traffic structure and a control method, and relates to the technical field of magnetic levitation traffic, the driving device comprises a permanent magnet, and the permanent magnet is laid in the extending direction of a track; the conductor piece is arranged at the top of the permanent magnet, and the extension direction of the conductor piece is parallel to the extension direction of the permanent magnet; and the power supply assembly is suitable for being fixedly connected with a vehicle body, and the power supply assembly is in sliding connection with the conductor piece and is conducted with the conductor piece. The magnetic field of the permanent magnet is utilized, and the power supply assembly and the conductor piece are slidably connected and conducted, so that the power supply assembly can move in the extending direction of the track, the vehicle body can move along the track, and compared with a short-stator linear induction motor and a long-stator linear synchronous motor, the motor is low in cost and high in driving efficiency.

The application discloses a magnetic suspension conveying device, which comprises a base, a conveying belt, a linear induction motor, a first magnet group and a second magnet group. The conveying belt is sleeved outside the base and comprises a plurality of bearing plates, which are annularly distributed and connected through hinging. The linear induction motor is used for driving the conveying belt to rotate around the base and comprises an induction primary and an induction secondary. The induction primary is installed on the base, and the induction secondary is a bearing plate or is installed on the bearing plate. The first magnet group is used for applying a thrust away from the base to the bearing plate, and the second magnet group is used for applying a lateral thrust to the bearing plate. The second magnet group comprises two groups, and the two groups of the second magnet group are respectively located on the lateral sides of the bearing plate to limit the bearing plate on the lateral sides. Compared with the prior art, the magnetic suspension conveying device can reduce friction loss, thereby prolonging the service life of the device.

The invention provides a linear induction motor with a low transverse end effect and a cell secondary structure, the linear induction motor is composed of a bilateral long primary and short secondary plates, the long primary adopts a bilateral parallel arrangement mode, and the short secondary plates are formed by a high-strength good-conductivity non-magnetic material and are symmetrically arranged in the middle of an air gap of the bilateral primary. Non-penetrating grooves are evenly formed in the two faces of each short secondary plate to form a grid groove structure, the length of each secondary plate is larger than that of a single primary, the length Lc of each groove is smaller than the width of each secondary and larger than the stacking thickness of a primary iron core, and the proposed secondary plate design can effectively standardize a secondary eddy current path, remarkably reduce the transverse end effect and remarkably improve the thrust performance of the motor. Meanwhile, due to the fact that the grooves are designed in a non-penetrating mode, secondary stress can be evenly distributed, the secondary structural strength is improved, and the structure is particularly suitable for large-power, large-thrust and ultra-high-speed application occasions.

The invention discloses a multi-motor cooperative minimum loss control method and system for linear induction motors, and belongs to the technical field of linear motor control. The method comprises the following steps: deducing a function relationship between thrust and total loss of a plurality of motors under the control of minimum loss according to a relationship between a primary flux linkage and loss of a single motor; defining a thrust distribution coefficient, and establishing a multi-motor thrust-total loss optimization model comprising a total thrust constraint, a thrust constraint of each motor, a voltage constraint and a normal force difference constraint of adjacent motors; taking the thrust distribution coefficient as an optimization variable, and adopting a sequential quadratic programming method to carry out optimization distribution on each motor thrust instruction; and finally, according to the optimized thrust instruction of each motor, realizing thrust tracking and loss regulation and control of each motor in combination with a single-motor minimum loss control strategy. According to the invention, cooperative minimum loss control from a single-machine system to a multi-machine system is realized, and the overall operation efficiency of the multi-motor system is effectively improved.

The invention discloses a linear motor iron core structure and a linear induction motor. The linear motor iron core structure comprises a frame, a linear iron core and a dovetail plate, the linear iron core comprises an iron core punching sheet, a plurality of dovetail grooves are formed in the top of the iron core punching sheet, through holes are symmetrically formed in the two ends of the upper portion of the dovetail plate, a plurality of connecting holes are formed in the side portion of the frame, the lower portion of the dovetail plate is embedded in the dovetail grooves, the upper portion of the dovetail plate is embedded in the frame, and fasteners are screwed into the through holes and the connecting holes. And the upper part of the dovetail plate is fixedly connected with the frame. The linear induction motor has the advantages of being compact in structure, high in supporting strength, high in reliability and the like, stress concentration can be reduced, and the running safety of the linear induction motor is improved.

The invention belongs to the technical field of motor control, particularly relates to a segmented linear induction motor thrust optimization control method based on a stator reconstruction identification model, and aims to solve the problem of thrust output reduction caused by parameter change of a segmented linear motor in short-time ultrahigh-speed operation. The method comprises the following steps: defining a stator length coefficient of an uncovered area of a rotor, and carrying out weighted average on segmented stator current to generate virtual stator current; a first-order low-pass filter is adopted to observe voltage of a non-coverage section, compensation reconstruction is carried out on voltage of a power supply section in combination with a length coefficient to obtain equivalent stator voltage, the equivalent stator voltage and virtual current are input into a reference model and an adjustable model respectively, and a rotor resistance identification value is generated through flux linkage errors of the equivalent stator voltage and the virtual current via a PI controller. And calculating the change rate of the identification value relative to the initial value, and synchronously adjusting the slip frequency given value to realize motor thrust optimization. According to the invention, the problem that the thrust output is reduced due to parameter change of the segmented linear motor in short-time ultrahigh-speed operation is effectively solved.

The application discloses an electric magnetic suspension tracked vehicle chassis, which comprises a vehicle body, a track assembly, a load wheel, a linear induction motor, a roller and a magnet assembly. The track assembly comprises a track plate. The linear induction motor is used for driving the track assembly to rotate, and the linear induction motor comprises an induction primary and an induction secondary. The induction primary is installed on the vehicle body, and the induction secondary is installed on the track plate. The roller is rotatably installed on the vehicle body and used for rolling contact with the side of the track plate close to the induction primary, so that the induction primary is prevented from contacting the track plate or the induction secondary. The magnet assembly is used for supporting the vehicle body, and the magnet assembly comprises a first magnet installed on an axle of the load wheel and a second magnet installed on the track plate. The second magnet on the lower track plate repels the first magnet in a magnetic manner when the two magnets are close to each other. Compared with the prior art, the electric magnetic suspension tracked vehicle chassis can reduce friction loss and improve energy utilization efficiency.

The invention relates to the technical field of linear motors, and discloses a linear induction motor with a honeycomb sandwich structure and an aircraft. The motor comprises a mover, a stator ground winding and stator supporting pieces, the stator supporting pieces are oppositely arranged on the ground, the stator ground winding is arranged on the stator supporting pieces, and the mover is arranged in the middle of the bottom of the tackle. The rotor is located between the stator ground windings and does not make contact with the stator ground windings. The rotor comprises a left rotor metal plate, a right rotor metal plate and a rotor honeycomb interlayer arranged between the left rotor metal plate and the right rotor metal plate. Therefore, while the mass of the rotor is reduced, the thrust-weight ratio of the linear induction motor system is increased, the modal frequency of the rotor is further improved, and resonance is avoided.

The invention belongs to the technical field of motor control, and particularly relates to an ultra-high-speed linear induction motor control method for frequency track self-learning planning. The objective of the invention is to solve the problem of thrust instability caused by insufficient speed measurement precision of an ultra-high-sound linear motor. According to the method, the stable operation area of the linear induction motor is determined by establishing the stable area and the stability margin solving model of the linear induction motor; a thrust and resistance self-learning model of the linear induction motor is constructed by using nonlinear least square optimization, and model parameters are accurately determined; and providing a linear induction motor frequency trajectory planning method based on the self-learning model, and realizing stable speed control of the linear induction motor under an ultra-high-speed working condition. Through simulation verification, the method can enable the actual rotor angular frequency to be gradually close to the given rotor angular frequency, effectively improves the speed control stability of the ultra-high-speed linear motor, does not need to add new hardware equipment, and provides a solution for speed-feedback-free control of the ultra-high-speed linear induction motor.

The present invention provides a method for optimizing the system-level efficiency of a linear induction motor by taking into account the characteristics of multi-traveling-wave magnetic fields. An optimization model is defined: the system is divided into two levels, namely the motor level and the control level, for optimization design; based on the chain equivalent circuit analysis model of the linear induction motor, the influence laws of the winding arrangement and the motor structure parameters on the optimization objectives are analyzed, the main optimization variables are screened out; and the optimization variables are sorted hierarchically according to the coupling relationship of the variables. The genetic algorithm is used to optimize the variables layer by layer; the final electromagnetic scheme is selected; the model predictive control based on the efficiency optimization function is used as the basic framework for motor control to solve the optimal flux linkage with the minimum system loss under various working conditions; and taking the speed overshoot as the optimization objective, the differential evolution algorithm is used to iteratively optimize the PI control parameters to seek better dynamic performance. The present invention can significantly improve the efficiency and power factor of the linear induction motor drive system and effectively ensure the dynamic response ability of the system.

The invention provides a modular power supply system for an ultra-high-speed long-primary bilateral linear induction motor, which belongs to the technical field of electromagnetic emission and comprises the ultra-high-speed long-primary bilateral linear induction motor, a traction converter and a connecting bus. The ultra-high-speed long-primary bilateral linear induction motor comprises a rotor and a long-primary track composed of a plurality of motor modules, and the motor modules are formed by series-parallel connection of different pole pairs according to the moving track of the rotor. The total primary voltage and the primary current of a pair of poles of each motor module are respectively equal to the working voltage and the working current of a switching device in the traction converter, and the number of parallel pole pairs of the motor modules corresponds to the number of parallel groups of the traction converter; the traction converters are arranged nearby the motor modules, and the motor modules and the traction converters are connected through connecting buses in a one-to-one correspondence mode. The method solves the problems that the bus voltage drop is large, a switching device in a traction converter is not matched and the efficiency of an overall electromagnetic emission system is low due to the fact that centralized power supply and segmented power supply are adopted in a traditional method.

The application discloses an electric double-primary direct-drive caterpillar chassis, and relates to the technical field of caterpillar vehicles, comprising a double-side linear induction motor primary and a composite caterpillar, wherein the double-side linear induction motor primary and the composite caterpillar are arranged on a chassis body, the double-side linear induction motor primary comprises a winding, the winding is used for connecting an alternating-current power supply, the composite caterpillar passes through the winding, and the double-side linear induction motor primary drives the composite caterpillar to move. After alternating current is input into the double-side linear induction motor primary, a traveling wave magnetic field is generated, the composite caterpillar induces current in the traveling wave magnetic field, and the current is forced in the magnetic field, so that the composite caterpillar obtains traction. The application directly adopts the linear induction motor to drive the composite caterpillar, omits a mechanical transmission link and a driving wheel, obtains a larger carrying space and a more flexible power cabin arrangement, and reduces transmission wear and tear, faults and mechanical noise.

The utility model relates to the technical field of magnetic suspension, and aims to solve the problems that the layout mode that a suspension electromagnet and a linear induction motor of a traditional magnetic-levitation train are independent of each other occupies a large space, and the normal force of the linear induction motor has a negative effect on the suspension force. The utility model provides a magnetic-levitation train traction suspension combined type induction rail and a traction suspension system electromagnetic structure. The traction suspension combined type induction rail comprises an electromagnet induction rail body, the electromagnet induction rail body is arranged below a track beam in the line direction, protrusions are downwards formed on the two sides of the electromagnet induction rail body, the end faces of the protrusions are the pole faces of the electromagnet induction rail body, and an installation cavity is formed between the protrusions on the two sides. A mounting rail is arranged in the mounting cavity, and the mounting rail is connected with the electromagnet induction rail; a plane is formed at the bottom of the mounting rail and is a secondary mounting surface of the linear induction motor; according to the utility model, the occupied space can be reduced, and the suspension performance of the vehicle can be improved.

The utility model discloses a heat radiation structure of a three-phase flat type linear asynchronous motor, which is characterized in that a two-end heat radiator (4) is arranged on each of two sides of a middle heat radiator (5) at the upper part of a motor primary (1), and heat conduction silica gel sheets (3) are adhered among the middle heat radiator (5), the two-end heat radiators (4) and the motor primary (1); the middle radiator (5) and the two-end radiators (4) are assembled with a yoke part of the motor primary (1) and are fixed on the motor primary (1) through screws, the motor primary (1) is fixed on the U-shaped bracket (2) through bolts, the three cooling fans (6) are fixed on a ventilation opening (7) of the U-shaped bracket (2) through screws, and the cooling fans (6) are arranged on the U-shaped side of the U-shaped bracket (2). The motor provided by the utility model is better in heat dissipation effect; heat conduction silica gel sheets are pasted on the sides, without heat dissipation tooth grooves, of the three radiators and are tightly connected with the yoke portion of the motor iron core, and the heat conduction effect between the motor iron core and the radiators is improved.