49results about How to "Suppression of thrust fluctuations" patented technology

The invention discloses a short-circuit fault-tolerant vector control method for an embedded hybrid magnetic material fault-tolerant cylindrical linear motor. The short-circuit fault-tolerant vector control method comprises the following steps: building a five-phase embedded hybrid magnetic material fault-tolerant cylindrical linear motor model; compensating normal thrust missing caused by a short-circuit fault phase and suppressing a thrust ripple caused by phase short-circuit current with non-fault phase current of the motor; and obtaining expected phase voltage by adopting a series of coordinate conversion and voltage feed-forward compensation strategies, and achieving a fault-tolerant vector control after the phase short-circuit fault of the motor by a zero-sequence voltage harmonic injection-based CPWM modulation mode. According to the short-circuit fault-tolerant vector control method, the motor can suppress the thrust ripple of the motor under the condition of a phase short-circuit fault-tolerant operation; more importantly, the dynamic property, the steady-state performance and the properties in a normal state are consistent; the switching frequency of a voltage source inverter is constant; a CPU is low in overhead; and a natural coordinate system only needs to counterclockwise rotate a certain angle in any phase short-circuit fault, so that the motor fault-tolerant operation can be achieved.

The invention relates to a low-speed high-thrust-density linear motor which comprises a motor short primary and a motor long secondary arranged opposite to the motor short primary, wherein an air gap (5) is reserved between the motor short primary and the motor long secondary; the motor short primary comprises a stator core (1), stator teeth (3) uniformly distributed at the periphery of the stator core (1), a stator winding (2) and stator permanent magnets (4); the stator core (1) is of an open slot stator structure, i.e., the stator core (1) is provided with a stator slot (8), the stator permanent magnets (4) are uniformly distributed between every two adjacent stator teeth (3), and the stator winding (2) is inserted into the stator slot (8); the motor long secondary comprises an active cell yoke (7) and active cell permanent magnets (6); and the active cell permanent magnets (6) are embedded into the active cell yoke (7) alternately and equidistantly in a horizontal direction. In the low-speed high-thrust-density linear motor provided by the invention, the magnetic modulation rings in a magnetic gear are replaced by the stator teeth, thereby simplifying the machining process, improving the reliability of the device and reducing the system manufacturing cost.

The invention discloses a thrust ripple suppressing method of a primary permanent magnet linear motor. Positioning force of the primary permanent magnet linear motor is obtained by measuring in practice by a finite element simulation or torque testing instrument. The waveform of the positioning force undergoes harmonic spectral analysis to confirm the component of base waves and main ultraharmonics in the positioning force. The no-load counter emf wave form of a finite element simulation motor is utilized to calculate out the three-phase current component which is used for counteracting the harmonic component of the positioning force so that additional electromagnetic force is equal to the component of the base waves and the main ultraharmonics in the positioning force in terms of amplitude, but opposite in terms of phase. Three-phase harmonic currents are filled into a current hysteresis vector control system to suppress thrust ripple of the permanent magnet linear motor. The body of the motor does not need transforming and a control strategy can be used for achieving suppression. The thrust ripple of the motor can be obviously hindered, noise in operation of the motor is reduced and characteristics of the motor such as no-load magnetic potentials and thrust outputting capability are kept unchanged.

The invention discloses a permanent magnet synchronous linear motor with bilateral asymmetric V-shaped magnetic poles. A flat-plate-shaped secondary pole of the motor is composed of a yoke plate and bilateral magnetic poles, wherein each magnetic pole is in a V shape formed by a plurality of sections of permanent magnets, the inclination directions of V-shaped magnetic pole sections located at mirror symmetry positions are different, that is, the directions of V openings are different, a bilateral asymmetric state is formed, and the inclination angles and the side lengths of the V-shaped magnetic pole sections located at the mirror symmetry positions are equal; a primary armature is composed of an iron core and windings, wherein the current directions of the bilateral windings at mirror symmetry positions are opposite, and the primary armature and bilateral magnetic poles form a series magnetic circuit and interact to generate same-direction electromagnetic thrust. According to the invention, the asymmetric V-shaped skewed poles have multiple combination forms, so it is guaranteed that electromagnetic thrust does not drop drastically while thrust fluctuation of the motor is reduced, and good thrust characteristics are achieved.

The invention discloses a five-phase permanent magnet embedded fault tolerant linear motor adjacent two-phase open circuit fault tolerant vector control method. Based on the principles that the magnetic motive force of traveling waves remains unchanged before and after a fault occurs and that the non-fault phase current sum stays at zero and taking the equality of the non-adjacent two-phase current amplitude as a constrained condition, the non-fault phase fault tolerant current is obtained to further deduce the generalized Clark transform matrix from the natural coordinate system of the non-fault phase to the two-phase stationary coordinate system. The non-fault opposite potential is observed by the transpose matrix of the transform matrix. A current internal model controller, a first-order inertial feed-forward voltage compensator and a counter-electromotive force observer are used to convert the nonlinear close coupling system of such motor under the condition of an adjacent two-phase open-circuit fault into a first-order inertial system. According to the invention, not only the thrust fluctuation caused by motor failure is restrained, but also more importantly, the dynamic performance and the steady-state performance are consistent with those under a normal condition to realize the fast response to non-overshoot and the stable switching frequency of a voltage source inverter.

The invention discloses a thrust fluctuation active compensation type linear permanent magnet synchronous motor and belongs to the technical field of motors. By the thrust fluctuation active compensation type linear permanent magnet synchronous motor, the problems that the thrust fluctuation of a linear motor can be only restrained to a certain extent and an effective thrust of the motor can be reduced by using the conventional method for reducing the thrust fluctuation of the linear motor are solved. An air gap is formed between a primary and a secondary; the primary comprises an armature core and an armature winding; and the armature winding of the primary has a surface mounted structure or the primary has a tooth groove structure. The thrust fluctuation generated by a thrust fluctuation compensation unit arranged at the end of the armature core is counteracted with the thrust fluctuation generated by the linear permanent magnet synchronous motor by controlling current of a compensation winding through a compensation controller or by serially connecting the compensation winding and the armature winding; therefore, an aim of actively eliminating or reducing the thrust fluctuation of the linear motor can be fulfilled. The invention is applicable to linear permanent magnet synchronous motors.

The invention discloses a five-phase permanent-magnet embedded fault-tolerant linear-motor non-adjacent two-phase fault-tolerant vector control method. According to principles that magnetomotive forces before and after a two-phase open-circuit fault are invariant and a non-fault-phase current sum is zero, a condition that adjacent two phase current amplitudes are equal is taken as a constraint condition so as to derive and popularize a Clark transformation matrix; matrix transposition is used to estimate a counter potential; and an inner model controller, a first-order inertia feedforward voltage compensator and a counter potential observer are used to change a nonlinear strong coupling system of the motor under a fault state into a first-order inertia system. According to a principle that a synthesized magnetomotive force of a non-fault-phase short circuit compensation current and a short circuit fault phase current is zero, a short circuit compensation voltage is calculated. The voltage is superposed with an output voltage of a vector control device. By using the method of the invention, a motor thrust fluctuation caused by one phase short circuit and one phase open circuit of non-adjacent two phases of the motor is restrained, and dynamic performance and stable state performance are consistent with the performance under a normal state.

The invention provides a bilateral 180 DEG-staggered tooth low-thrust ripple continuous pole permanent magnet synchronous linear motor, which belongs to the technical field of motors. The bilateral 180 DEG-staggered tooth low-thrust ripple continuous pole permanent magnet synchronous linear motor comprises a first primary assembly, a second primary assembly and a secondary assembly, wherein both the first primary assembly and the second primary assembly are formed by armature windings and primary iron cores; the secondary assembly is composed of permanent magnets, iron poles and back yokes; the permanent magnets all have the same polarity and are arranged alternatively with the iron poles; the permanent magnets are attached to the upper surface and the lower surface of a yoke plate; the iron poles and the yoke plate are integrally formed; the first primary assembly and the second primary assembly are located at two sides of the secondary assembly, and two air gap structures are formed with the secondary assembly; and the first primary assembly and the second primary assembly are staggered for a 180-DEG electrical angle in a horizontal direction, that is, a distance of displacement S=ktau (k is an uneven number and tau is the pole pitch of the motor) is staggered. A three-phase winding on the first primary assembly is arranged in an iron core slot according to a sequence of A-B-C, a three-phase winding on the second primary assembly is arranged in an iron core slot according to a sequence of A-B-C, and in-phase windings on the first primary assembly and the second primary assembly have opposite winding directions. The structure can reduce the thrust ripple of the motor, and a unilateral magnetic pulling force and the ripple thereof can be reduced.

The invention relates to the field of permanent-magnet linear motors, and discloses a low-resistance coreless unilateral permanent magnet synchronous linear motor that includes a linear guide rail, wherein permanent magnets are laid on the linear guide rail at intervals in the axial direction. The motor also comprises a mover seat that is in sliding fit with the linear guide rail; a first rail anda second rail are symmetrically arranged on the linear guide rail in parallel in the axial direction. A first guide groove and a second guide groove of which the groove walls are cavities are correspondingly formed in the mover seat; at least one long steel magnet is arranged on at least one axial side wall of each of the first rail and the second rail in the vertical direction; the groove bottoms of the first guide groove, the second guide groove and the long steel magnets on the same side are connected with piezoelectric ceramics; coils are arranged in adjacent groove wall cavities, and thecoils are connected with the piezoelectric ceramics through wires. The guide effect of the guide rail is reserved; when the mover seat bears load and is pressed, the positive voltage effect of piezoelectric ceramic is used for providing current for the coil, so upward lifting force is generated on the mover seat under cutting of a symmetric magnetic field of the long steel magnets, thrust fluctuation is restrained, and the robustness of an advancing system is improved.

The invention provides a method for inhibiting the velocity fluctuation of an electric vehicle driving system. The method comprises the following steps: obtaining a rotor position by adopting an encoder, and transmitting the rotor position to a velocity control ring; and adopting a parallel mode combining a prediction PI joint controller, a repetitive controller and a nonlinear adaptive feedback observer by the velocity control ring, adopting the parallel mode of the prediction PI joint controller and the repetitive controller during electric start, substituting two continuous sampling values into a prediction domain of the prediction PI joint controller by the encoder, switching to the parallel mode of the repetitive controller and the nonlinear adaptive feedback observer when an electric vehicle enters a stable operation mode, and then transmitting an output signal of the velocity control ring. According to the method provided by the invention, the prediction PI joint control, the nonlinear adaptive feedback observation control, the repetitive control and the vector control are combined together to improve the stability, the accuracy and the dynamic response ability of the electric vehicle driving system and inhibit the velocity fluctuation in an electric vehicle running process.

The invention discloses a double-side staggered-tooth tau/2 low-thrust-ripple permanent magnet synchronous linear motor. A first primary assembly and a second primary assembly are both composed of anarmature winding and a primary iron core, each primary iron core is of a tooth groove structure, and the armature windings are wound on teeth; the first primary assembly and the second primary assembly are located on the two sides of a secondary assembly and form air gaps with the secondary assembly respectively; the secondary assembly comprises a yoke plate and a plurality of permanent magnets, each pair of poles comprises four permanent magnets, the first permanent magnet and the second permanent magnet of each pair of poles are located on the same side of the yoke plate, the third permanentmagnet and the fourth permanent magnet of each pair of poles are located on the same side of the yoke plate, the positions of the first permanent magnets and the third permanent magnets are opposite,the positions of the second permanent magnets and the fourth permanent magnets are opposite, the magnetizing directions of the first permanent magnets and the third permanent magnets are the same, the magnetizing directions of the second permanent magnets and the fourth permanent magnets are the same, and the magnetizing directions of the first permanent magnets and the second permanent magnets are opposite; the displacement of the first primary assembly and the second primary assembly in the transverse direction is S which is equal to tau/2, and tau is the polar distance of the motor. By means of the structure, the thrust ripple of the motor can be reduced, and meanwhile unilateral magnetic tension and fluctuation of the unilateral magnetic tension are reduced.

The invention discloses a phase-shifting and shifting unit combined permanent magnet synchronous linear motor, and belongs to the technical field of a linear motor. The phase-shifting and shifting unit combined permanent magnet synchronous linear motor is formed by a first unit motor, a motor spacer, a second unit unit, a mover, a first stator core, a second stator core, a first stator coil and asecond stator coil. A conventional linear motor is split into two unit motors and phase-shifting and shifting are carried out; and by utilizing a superposition principle, thrust ripples respectively generated by two unit motors are reversely superposed to be weakened or eliminated so as to effectively inhibit a thrust ripple of the permanent magnet linear motor. An air or magnetic isolation material is positioned between two adjacent unit motors so as to effectively eliminate magnetic field interference between two unit motors. A plurality of unit motors can also be adopted to be combined in series, and meanwhile, phase-shifting and shifting are carried out, so that an effect of synthesizing a high thrust motor by utilizing low thrust motors can be achieved. The phase-shifting and shiftingunit combined permanent magnet synchronous linear motor has the advantages of simple process, low cost, obvious effect of inhibiting the thrust ripple and the like, and has very high theoretical significance and engineering practical value.

The invention discloses a linear motor and an optimization and verification method for improving operation efficiency of the same, wherein the linear motor comprises a primary iron core (1), a primary coil (2), a secondary iron core (3) and a permanent magnet (4), the primary iron core (1) comprises a plurality of tooth grooves, the primary coil (2) winds the tooth among the adjacent tooth grooves, the secondary iron core (3) is arranged below the primary iron core to be a substrate of a given length, the permanent magnet (4) is fixedly arranged on the secondary iron core (3), and the ratio between the polar distance of the permanent magnet (4) and the tooth distance of the tooth groove is a fraction. The linear motor has a simple structure and can be stably and conveniently operated, and the thrust ripple can be reduced to a certain extent.