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

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 servo limited-rotation-angle torque motor, which includes a stator core, a rotor, a rotation angle detection device, and a structural support component, wherein the stator core is based on the cooperation of the stator teeth and the rotor to form a magnetic field line circuit with low reluctance and uniform distribution, and the rotor is based on the The radially magnetized magnetic steel produces an excitation magnetomotive force of uniform amplitude in the circumferential direction of the air gap, forming a low reluctance magnetic force line circuit and output torque. In the present invention, the shape of the top of the stator tooth in the stator core is set as a crescent shape, and is matched with the tile-shaped elongated magnetic steel with a certain pole arc size and equal thickness along the radial direction of the rotor, so that the magnetic force lines generated by the magnetic steel are uniform. Distributed on the top of the stator teeth and form a low reluctance magnetic field line circuit, which eliminates the partial saturation of the teeth caused by improper tooth shape, and maximizes the cogging-free area of ​​the limited-rotation-angle motor, thereby almost completely eliminating the rotor in the working angle range Rotational cogging torque fluctuations.

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.

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 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 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 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.