36results about How to "Eliminate torque ripple" patented technology

The invention relates to a permanent magnet synchronous motor (PMSM) AC servo system, which is composed of a DSP control panel, a rotary transformer, a main power circuit and a conditioning and protecting circuit, a motor body consists of an armature winding and a permanent magnet core rotor, wherein the motor is excited by a permanent magnet, and the DSP is used for realizing an field-orientated control algorithm, communication, sampling calculation of current and configuration output of a drive; the output of the rotary transformer enables data to be transmitted to the DSP via four-path DA transform chips and SPI of the DSP or multi-channel buffering; the DSP outputs pulse width modulation, is connected with voltage signals output by a current regulator, and is connected with a PWM1-PWM3 drive inverter which can convert the voltage signals into three-phase switch signals by CLARK inverse transformation, and the inverter outputs to the armature winding so as to control the armature winding of the motor to generate a rotary round magnetic field; and the main power circuit is composed of a direct current detection circuit with controllable rectification, an inverter, a current detection circuit, an overvoltage discharging circuit, a protection circuit and a driving circuit. The invention adopts the field-orientated control algorithm which can control the torque, speed and position state of the motor in real time and has good control performance.

The invention discloses a torque pulsation inhibition method for a permanent magnet synchronous motor. The method comprises the following steps: acquiring three-phase currents ia, ib and ic of the permanent magnet synchronous motor; acquiring the d-axis component id5th and the q-axis component iq5th of the fifth harmonic current in the corresponding synchronous rotation coordinate system by use of ia, ib and ic and acquiring the d-axis component id7th and the q-axis component iq7th of the seventh harmonic current in the corresponding synchronous rotation coordinate system by use of ia, ib and ic; acquiring the d-axis compensation quantity udth and the q-axis compensation quantity uqth of the harmonic voltage from id5th, iq5th, id7th and iq7th; feeding the udth back to the d-axis voltage ud of a control system of the permanent magnet synchronous motor and feeding the uqth back to the q-axis voltage uq of the control system of the permanent magnet synchronous motor, eliminating the fifth harmonic current and the seventh harmonic current, and inhibiting the sixth torque pulsation and the twelfth torque pulsation. The method can effectively eliminate the harmonic current and can improve the effect of inhibiting the torque pulsation.

This invention relates to a dead zone compensation method for SVPWM output including: taking an expected value of the output three-phase voltage of a magnet synchronous motor as the pulse width expected value output by modulation of three bridge arm pulse width of an inverter, taking the combined value of the expected values of the pulse width output by the modulation of U, V and W as the voltage space vector output expected value of the inverter of an AC servo system, taking the designed dead zone time of the output pulse modulation as the expected value of the dead zone compensation time and utilizing the polarity of each output phase current of a magnet synchronous motor, the expected value of the voltage space vector and that of the dead zone compensation time to compute the acting time of each voltage space vector.

The invention discloses a non-flux observation doubly-fed induction generator low voltage ride-through control method and a system, which can be applied to excitation control on a rotor-side converter of the doubly-fed induction generator in the case of deep power grid fault. The specific implementation method comprises steps: once deep fault is detected to happen to the power grid, rotor current of the doubly-fed induction generator is instantly controlled to directly track stator current at a certain ratio, and a certain compensation term related to stator voltage is injected to a rotor current instruction for providing dynamic reactive support. The invention also provides a control system structure diagram for realizing the above principle. Compared with de-excitation control, flux tracking and other low voltage ride-through excitation control methods, no flux observation step is needed for generating a transient control instruction, the structure is simple, multiple control objectives such as electromagnetic torque ripple suppression or dynamic reactive power compensation can be realized, and the low voltage ride-through ability of the doubly-fed induction generator is greatly enhanced.

The invention discloses a two-dimensional dual axial piston pump which comprises a shell, a left cylinder, a right cylinder, a left piston and a right piston. The left cylinder and the right cylinder are arranged in the shell through positioning steel balls and are fixedly connected with the shell through connecting sleeves. An oil sucking and draining hole and a leaking oil return channel are formed in the shell. A left end cover is fixedly installed at the left end of the shell. The right end of the left cylinder and the left end of the right cylinder are fixedly connected with a left constant-adding and constant-subtracting curved-surface rail and a right constant-adding and constant-subtracting curved-surface rail respectively, and rolling curved surfaces of the left constant-adding and constant-subtracting curved-surface rail and the right constant-adding and constant-subtracting curved-surface rail are the same. The left constant-adding and constant-subtracting curved-surface rail and the right constant-adding and constant-subtracting curved-surface rail are arranged in a 90-degree staggered manner, and the highest point and the lowest point of the left constant-adding and constant-subtracting curved-surface rail correspond to the lowest point and the highest point of the right constant-adding and constant-subtracting curved-surface rail respectively. The two-dimensional dual axial piston pump has the advantages that the structure is novel and compact, the size is small, weight is low, transmission is simple, torque pulsation is zero, the speed is easy to adjust, and displacement is high.

The invention discloses a fault-tolerant modular permanent magnet auxiliary synchronous reluctance motor which comprises modular stators and rotors. The modular stators are connected through non-conductive magnets. Grooves on both sides of each non-conductive magnet are skewed at different angles. Stator module units are connected through independent three-phase distributed windings. The rotors comprise rotor cores and asymmetric magnetic barriers. Permanent magnets are embedded in the magnetic barrier structures. N poles and S poles of adjacent permanent magnets are alternately arranged. According to the invention, due to the fact that a PMa-SynRM motor in a traditional winding distributed structure is not fault-tolerant, the modular idea is applied to the design of the motor to realize decoupling between modules and meet the requirement of high reliability of a drive motor system in the field of electric vehicles.

The invention discloses a straight-skewed composite stator winding slotless motor for an artificial heart pump and an optimization method. The straight-skewed composite stator winding slotless motor for the artificial heart pump comprises a rotation shaft located in the center, and a rotor permanent magnet, a straight-skewed composite winding and a stator iron core sequentially surrounding the rotation shaft from inside to outside, wherein an air gap is formed between the rotor permanent magnet and the straight-skewed composite winding; and the edge of the straight-skewed composite winding is flush with that of the stator iron core. The straight-skewed composite stator winding slotless motor for the artificial heart pump has the beneficial effects that after the straight-skewed composite winding is adopted, the electromagnetic torque of the motor is increased and the harmonic winding coefficient is reduced; the stator has a simple structure; and in comparison with the traditional motor structure, the stator has a slotless structure, the processing and the manufacturing are relatively simple, the cogging torque is eliminated, and copper loss is reduced.

The invention discloses a torque ripple minimum fault-tolerant control method considering a reluctance torque. The torque ripple minimum fault-tolerant control method comprises the following steps of acquiring a motor parameter by finite element simulation software, wherein the motor parameter mainly comprises a no-load counter potential and an inductance waveform; performing polynomial fitting on the obtained inductance waveform by a matrix laboratory (MATLAB); determining an expression of a fault-tolerant current according to information of a fault phase; solving an electromagnetic torque of a motor according to a magnetic functional method of the motor and according to the obtained fault-tolerant current, inductance and the counter potential, wherein the electromagnetic torque comprises a permanent-magnet torque component and a reluctance torque component; decomposing the obtained electromagnetic torque into an average torque component, a secondary torque component and a quartic torque component; determining an equation set according to a principle that the average torque before and after a fault is not changed, the torque pulse is minimum and the sum of remaining normal phase currents is zero; and solving an optimal fault-tolerant current under the optimization condition of minimum quadratic sum of current amplitudes by an MATLAB non-linear optimization tool box. The torque pulse minimum fault-tolerant control containing the reluctance torque is achieved by a current hysteresis controller.

The invention discloses a low-power-consumption high-speed double-ring magnetic steel brushless direct current motor. The motor comprises a rotor system and a stator system. The rotor system includes:an outer mounting sleeve, an outer magnetic conductive ring, outer parallel magnetizing magnetic steel, outer upper 45-degree magnetizing magnetic steel, outer lower 45-degree magnetizing magnetic steel, an outer magnetic steel lock nut, an outer assembly lock nut, a rotor shell, an inner mounting sleeve, an inner magnetic conductive ring, inner parallel magnetizing magnetic steel, inner upper 45-degree magnetizing magnetic steel, inner lower 45-degree magnetizing magnetic steel, an inner magnetic steel sheath, an inner magnetic steel lock nut and an inner assembly lock nut; the stator systemcomprises a hollow cup stator framework, a stator aluminum substrate, a winding and epoxy resin glue. According to the invention, a double-ring axial Halbach magnetic steel structure without a statorcore is adopted, magnetic hysteresis loss caused by a fixed iron core and torque pulsation caused by tooth grooves are eliminated, eddy current loss is reduced, the upper portion and the lower portion of the inner-ring magnetic steel and the lower portion of the outer-ring magnetic steel are each provided with a 45-degree magnetized magnetic steel, the magnetic circuit magnetism gathering effectis achieved, the air gap flux density is increased, the air gap flux density flat top width is widened, and the output torque and the output torque precision are improved.

The invention discloses a servo limited angle torque motor, which comprises a stator core, a rotor, a rotation angle detection device and a structural support component, wherein the stator core is matched with the rotor based on stator teeth to generate a uniformly-distributed magnetic force line loop with low magnetic resistance; and the rotor generates excitation magnetomotive force with uniformamplitude in the air gap circumferential direction based on radially-magnetized magnetic steel to form a magnetic force line loop with low magnetic resistance and output torque. According to the invention, the tops of the stator teeth in the stator core are set to be crescent-shaped, and are matched with the tile-shaped long-strip-shaped magnetic steel having a certain pole arc size and equal inthickness direction of the rotor, so that the magnetic force lines generated by the magnetic steel are uniformly distributed at the tops of the stator teeth and form the low-magnetic-resistance magnetic force line loop, local saturation of the teeth due to improper shapes of the teeth is eliminated, a cogging-free area of the limited angle motor is maximized, and cogging torque fluctuation of therotor rotating in a working angle range is almost completely eliminated.

A motor controller has both a basic-frequency current component and a harmonic current component at the same time. A prior art does not allow the simultaneous cancellation of torque ripples generated in a motor because the harmonic current components (6f, 24f) cannot be compensated at the same time. The motor controller is constituted of a rotation measuring section (4), a current measuring section (5), a high-order control section (20), a second current command generator (15), second simulation observer (12), first control section (10), second control section (9), third control section (13), and second voltage command synthesis section (14). The second voltage command synthesis section (14) is constituted of three position converters, three reverse coordinate converters, and an adder.

The present invention discloses a novel five-phase salient-pole synchronous reluctance motor and an inhibition method of a torque ripple thereof. The novel five-phase salient-pole synchronous reluctance motor comprises an outer stator and an inner rotor; the outer stator is provided with a distributed winding; the inner rotor comprises a magnetic conductive bridge, a plurality of salient poles anda location hole. The pole-arc coefficients of the adjacent salient poles are different, and the deviation angles of each pair salient poles are different. The inhibition method provided by the invention concretely comprises the steps of: selecting different pole-arc coefficients of adjacent poles, selecting repeat units, performing excursion and calculating the excursion angles. The asymmetric design method and the magnetic pole offset method are employed to facilitate inhibition of the torque ripple and can be utilized to a synchronous reluctance motors, a permanent magnet assisted synchronous reluctance motor and a permanent magnet motor. Formulas are employed to quickly calculate the optimal pole-arc coefficient difference of the adjacent poles and the interval deviation angles of therepeat units so as to achieve the optimal effect while reducing the design period.

The invention belongs to the technical field of medical instruments, and discloses a whole body fixing frame for tumor radiotherapy. The device is provided with an upper bed plate, a main bed plate, alower bed plate, a head fixing belt, a body fixing belt, a leg fixing belt, an upper bed plate motor, a lower bed plate motor, a gear, a bearing, a program controller, and bed legs. The upper bed plate motor is connected with the bearing through the gear, and the lower bed plate motor is connected with the bearing through the gear. The upper bed plate motor and lower bed plate motor are connectedwith the program controller through data lines. When a person is in the radiation treatment, the frame can precisely fix the upper and lower limbs and the head, and can be adjusted to a proper angleaccording to the stages in the treatment process, so the frame facilitates the treatment and also can enable a patient to feel comfortable for the posture in the treatment process.

The invention relates to a double-reverse-speed axial flux permanent magnet motor based on a PCB. According to the double-reverse-speed axial flux permanent magnet motor based on the PCB, two sets ofstator windings, namely the first PCB winding and the second PCB winding, are adopted, and double-reverse-speed operation of the motor can be realized without an intermediate reversing device. Moreover, the PCB windings are arranged in order and diverse in form, and for an axial magnetic flux motor with a compact structure, the problem that the conventional loose winding mode is difficult to be offline is solved, and the lightweight design of the motor is also realized. The stator iron core is of a gullet-free structure, physical decoupling between the two sets of PCBs is achieved while iron loss is reduced and torque ripple is eliminated, and double-rotation-speed output of the motor is achieved conveniently. And the integrated design of the PCB winding and the drive control is beneficialto realizing the integration of the motor and the drive control, so that the occupied space is greatly reduced. In addition, the expansibility of the mechanism is high, and the design and adjustmentof the motor are more flexible, simpler and more convenient.

The invention provides a vehicle motor control system and a control method. The vehicle motor control system is connected between an inverter and a vehicle motor, the vehicle motor control system comprises an anti-aliasing filter unit, and the inverter is used for providing an input current for a vehicle motor so as to drive the vehicle motor to rotate; the anti-aliasing filter unit is used for obtaining a filtered d-axis output current sampling value and a filtered q-axis output current sampling value of the vehicle motor according to the output current of the vehicle motor; and a closed-loop regulation unit of the inverter is used for regulating an input current according to a filtered d-axis output current sampling value and a filtered q-axis output current sampling value. According to the invention, a problem of low-frequency torque pulsation of the motor control system caused by an existing sampling aliasing phenomenon can be solved.

The invention discloses a non-flux observation doubly-fed induction generator low voltage ride-through control method and a system, which can be applied to excitation control on a rotor-side converter of the doubly-fed induction generator in the case of deep power grid fault. The specific implementation method comprises steps: once deep fault is detected to happen to the power grid, rotor current of the doubly-fed induction generator is instantly controlled to directly track stator current at a certain ratio, and a certain compensation term related to stator voltage is injected to a rotor current instruction for providing dynamic reactive support. The invention also provides a control system structure diagram for realizing the above principle. Compared with de-excitation control, flux tracking and other low voltage ride-through excitation control methods, no flux observation step is needed for generating a transient control instruction, the structure is simple, multiple control objectives such as electromagnetic torque ripple suppression or dynamic reactive power compensation can be realized, and the low voltage ride-through ability of the doubly-fed induction generator is greatly enhanced.

The invention discloses a magnetic cap screwing device which comprises a hollow shaft, an adjusting ring, a power transmitting sleeve, a fixed sleeve, an upper magnetic ring, a lower magnetic ring and a magnetism permeable ring. A cap screwing mould is mounted at the lower end of the hollow shaft, the fixed sleeve is fixedly connected with the power transmitting sleeve, the adjusting ring and the fixed sleeve are fixed through a rotating angle adjusting device, the lower end and the upper end of the hollow shaft are rotationally mounted in the adjusting ring and the fixed sleeve through a bearing, the magnetism permeable ring is fixed on the periphery of the hollow shaft, the upper magnetic ring sleeves the hollow shaft and is fixed with the fixed sleeve, the lower magnetic ring sleeves the hollow shaft and is fixed with the adjusting ring, 2-6 N magnetic regions and S magnetic regions are arranged on the upper magnetic ring and are uniformly and circumferentially distributed, and the lower magnetic ring is provided with S magnetic regions and N magnetic regions, which are uniformly distributed, and the logarithms of the S magnetic regions and the N magnetic regions are the same. Magnetic poles of the magnetic regions of the lower magnetic ring and the upper magnetic ring are staggered. The magnetic cap screwing device applies constant and sooth torque on bottle caps, eliminates pulse of the torque and preventing the bottle caps from being too tight.

A motor controller has both a basic-frequency current component and a harmonic current component at the same time. A prior art does not allow the simultaneous cancellation of torque ripples generated in a motor because the harmonic current components (6f, 24f) cannot be compensated at the same time. The motor controller is constituted of a rotation measuring section (4), a current measuring section (5), a high-order control section (20), a second current command generator (15), second simulation observer (12), first control section (10), second control section (9), third control section (13), and second voltage command synthesis section (14). The second voltage command synthesis section (14) is constituted of three position converters, three reverse coordinate converters, and an adder.

The embodiment of the invention discloses a switching frequency switching method and device for a motor controller, electronic equipment and an automobile, and aims to reduce voltage leap caused when the motor controller controls switching frequency switching so as to eliminate torque pulsation generated by the voltage leap of the motor. The method comprises the following steps: receiving a switching frequency switching instruction; executing a switching frequency switching instruction, and switching the switching frequency from the current switching frequency to a target switching frequency; wherein the duty ratio in the first switching period after the switching frequency switching instruction is executed is the transition duty ratio, the duty ratio in the remaining switching period after the switching frequency switching instruction is executed is recovered to be the duty ratio before the switching frequency switching, and the transition duty ratio is different from the duty ratio before the switching frequency switching.

The invention discloses a novel short-circuit fault tolerance control method of a five-phase permanent magnetic motor. The method comprises the following steps: a five-phase fault tolerance permanent magnetic motor mode is established; when a certain phase of a motor generates a short-circuit fault, due to existence of short-circuit currents, the short-circuited phase generates a torque ripple which is different from what it is like under a normal condition yet the frequency and the phase of which can both be determined, through changing phases of currents of other normal phases, all the normal phases can each generate a torque ripple having the same frequency and phase as the short-circuited phase; then amplitude of the currents of other normal phases is changed, a torque ripple vector sum generated by rotation of each phase is enabled to be zero, and at the same time, it has to be satisfied that a finally synthesized average torque is equal to the normal condition; and then simulation analysis is carried out. According to concrete conditions of motor zero-load counterelectromotive forces, one-phase short-circuit fault tolerance control is performed on the motor, the fault is enabled to be equalized with output torque output under a normal operation state, the torque ripple is reduced, and the five-phase fault tolerance permanent magnetic motor can run with the short-circuit fault.

The invention discloses a torque ripple minimum fault-tolerant control method considering a reluctance torque. The torque ripple minimum fault-tolerant control method comprises the following steps of acquiring a motor parameter by finite element simulation software, wherein the motor parameter mainly comprises a no-load counter potential and an inductance waveform; performing polynomial fitting on the obtained inductance waveform by a matrix laboratory (MATLAB); determining an expression of a fault-tolerant current according to information of a fault phase; solving an electromagnetic torque of a motor according to a magnetic functional method of the motor and according to the obtained fault-tolerant current, inductance and the counter potential, wherein the electromagnetic torque comprises a permanent-magnet torque component and a reluctance torque component; decomposing the obtained electromagnetic torque into an average torque component, a secondary torque component and a quartic torque component; determining an equation set according to a principle that the average torque before and after a fault is not changed, the torque pulse is minimum and the sum of remaining normal phase currents is zero; and solving an optimal fault-tolerant current under the optimization condition of minimum quadratic sum of current amplitudes by an MATLAB non-linear optimization tool box. The torque pulse minimum fault-tolerant control containing the reluctance torque is achieved by a current hysteresis controller.

The invention discloses a stator, and the stator comprises a stator core; the stator core is provided with at least one group of A-phase, b-phase, C-phase, a-phase, B-phase and c-phase which are arranged in sequence; each phase comprises at least two groups of pitches; and the stator further comprises element windings arranged in the pitches in a one-to-one correspondence mode, B-phase auxiliary windings wound on the A-phase, the C-phase and the B-phase auxiliary windings; the winding direction of the B-phase auxiliary winding is opposite to that of the adjacent b-phase element winding, and the B-phase auxiliary winding is wound on all the group pitches in the A phase at the same time; the winding direction of the A-phase auxiliary winding is opposite to that of the adjacent a-phase element winding, and the A-phase auxiliary winding is wound on all the group pitches in the C phase at the same time; and the winding direction of the C-phase auxiliary winding is opposite to that of the adjacent c-phase element winding, and the C-phase auxiliary winding is wound on all the group pitches in the B phase at the same time. By arranging the auxiliary winding on the stator, the cogging torque and the torque ripple of the permanent magnet brushless direct current motor with the stator can be reduced.

The invention discloses a fault-tolerant modular permanent magnet auxiliary synchronous reluctance motor which comprises modular stators and rotors. The modular stators are connected through non-conductive magnets. Grooves on both sides of each non-conductive magnet are skewed at different angles. Stator module units are connected through independent three-phase distributed windings. The rotors comprise rotor cores and asymmetric magnetic barriers. Permanent magnets are embedded in the magnetic barrier structures. N poles and S poles of adjacent permanent magnets are alternately arranged. According to the invention, due to the fact that a PMa-SynRM motor in a traditional winding distributed structure is not fault-tolerant, the modular idea is applied to the design of the motor to realize decoupling between modules and meet the requirement of high reliability of a drive motor system in the field of electric vehicles.

The invention provides a magnetic bush, an electric machine rotor and an electric machine. The magnetic tile includes a back EMF fundamental wave generating section and a back EMF harmonic wave generating section, the back EMF harmonic wave generating section being located outside the radial direction of the back EMF fundamental wave generating section. According to the invention, a magnetic bush,an electric machine rotor and an electric machine can realize noise reduction effect by superposing harmonic components in the magnetic bush and synthesizing with a current fundamental wave to cancelthe toothed groove torque.

The invention provides a magnetic bush, an electric machine rotor and an electric machine. The magnetic tile includes a back EMF fundamental wave generating section and a back EMF harmonic wave generating section, the back EMF harmonic wave generating section being located outside the radial direction of the back EMF fundamental wave generating section. According to the invention, a magnetic bush,an electric machine rotor and an electric machine can realize noise reduction effect by superposing harmonic components in the magnetic bush and synthesizing with a current fundamental wave to cancelthe toothed groove torque.

Disclosed is a high-precision dual-ring magnetic steel brushless direct current motor. The high-precision dual-ring magnetic steel brushless direct current motor comprises a rotor system and a statorsystem; the rotor system comprises an outer mounting sleeve, an outer magnetic conducting ring, an outer magnetic conducting ring locking nut, an outer trapezoidal magnetic steel, an outer upper trapezoidal cushion ring, an outer lower trapezoidal cushion ring, an outer magnetic steel locking nut, a rotary plate, an outer assembly locking nut, an inner mounting sleeve, an inner magnetic conductingring, an inner magnetic conducting ring locking nut, an inner trapezoidal magnetic steel, an inner upper trapezoidal cushion ring, an inner lower trapezoidal cushion ring, an inner magnetic steel locking nut and an inner assembly locking nut; and the stator system comprises a stator framework, an aluminum substrate, a winding and epoxy resin adhesive. By adoption of the stator-iron-core-less dual-ring non-uniform-thickness tile type magnetic steel structure, magnetic hysteresis and eddy current loss caused by the iron core can be overcome, torque pulsation generated by a toothed groove can beeliminated, air gap flux density is increased and output torque is increased; and in addition, by adoption of the dual-ring non-uniform-thickness tile type magnetic steel to compensate leakage flux in the magnetic steel spliced position, the flat width of the air gap flux density is expanded, torque pulsation is further lowered and the torque precision is improved.

The invention provides a nine-state control strategy for a three-phase electro-magnetic doubly-salient motor. According to the nine-state control strategy, counter emf of the motor is fully utilized, the positive onset interval of each phase of the motor is prolonged, the electrical angles of the positive onset intervals of all phases exceed 120 degrees, nine working states are formed in one electrification period, the electric current change rate of a phase winding is increased when commutation of the motor is conducted, the up-down power tube dead-time is eliminated while the positive onset intervals of all the phases are prolonged, and a torque gap generated by excitation reluctance is offset through the generated phase torque; for the problem that the three-phase electromagnetic property of the electro-magnetic doubly-salient motor is not symmetrical, the positive onset intervals of all phases are optimized, so that the motor torque peak is restrained, the motor torque valley value is increased, and the torque pulses are reduced.

The invention discloses a low-power-consumption high-speed double-ring magnetic steel brushless direct current motor. The motor comprises a rotor system and a stator system. The rotor system includes:an outer mounting sleeve, an outer magnetic conductive ring, outer parallel magnetizing magnetic steel, outer upper 45-degree magnetizing magnetic steel, outer lower 45-degree magnetizing magnetic steel, an outer magnetic steel lock nut, an outer assembly lock nut, a rotor shell, an inner mounting sleeve, an inner magnetic conductive ring, inner parallel magnetizing magnetic steel, inner upper 45-degree magnetizing magnetic steel, inner lower 45-degree magnetizing magnetic steel, an inner magnetic steel sheath, an inner magnetic steel lock nut and an inner assembly lock nut; the stator systemcomprises a hollow cup stator framework, a stator aluminum substrate, a winding and epoxy resin glue. According to the invention, a double-ring axial Halbach magnetic steel structure without a statorcore is adopted, magnetic hysteresis loss caused by a fixed iron core and torque pulsation caused by tooth grooves are eliminated, eddy current loss is reduced, the upper portion and the lower portion of the inner-ring magnetic steel and the lower portion of the outer-ring magnetic steel are each provided with a 45-degree magnetized magnetic steel, the magnetic circuit magnetism gathering effectis achieved, the air gap flux density is increased, the air gap flux density flat top width is widened, and the output torque and the output torque precision are improved.