51 results about "Spatial harmonics" patented technology

Techniques of making a recording of or transmitting a sound field from either multiple monaural or directional sound signals that reproduce through multiple discrete loud speakers a sound field with spatial harmonics that substantially exactly match those of the original sound field. Monaural sound sources are positioned during mastering to use contributions of all speaker channels in order to preserve the spatial harmonics. If a particular arrangement of speakers is different than what is assumed during mastering, the speaker signals are rematrixed at the home, theater or other sound reproduction location so that the spatial harmonics of the sound field reproduced by the different speaker arrangement match those of the original sound field. An alternative includes recording or transmitting directional microphone signals, or their spatial harmonic components, and then matrixing these signals at the sound reproduction location in a manner that takes into account the specific speaker arrangement. The techniques are described for both a two dimensional sound field and the more general three dimensional case, the latter based upon using spherical harmonics.

A dynamo electric machine includes a rotor having magnetic poles with permanent magnets and a stator having armature windings concentratedly wound around teeth. When the number of pole pairs of the magnetic poles of the rotor is P, diameter of the rotor is D (meters), and a spatial harmonic order of a predetermined harmonic component of an armature magnetomotive force of the rotor is N ((N=P to the 1.5th power)×(N to the minus 4-th power)×(the square of P)×D<0.6 (in meters).

The invention relates to a method for analyzing turn-to-turn faults of a generator rotor based on a multiloop model, belonging to the technical problem of analysis and research of asymmetric fault problems of alternating current motor windings and relay protection of power system master devices. In the invention, based on a multiloop analysis method of an alternating current motor, a voltage and flux linkage equation is listed according to actual connection conditions of all stator and rotor loops in consideration of various space harmonics of air gap magnetic field caused by rotor faults, unbalance current inside a stator phase winding and the change of a topological structure of an excitation winding circuit; various loop parameters, particularly induction parameters related to an excitation winding generating turn-to-turn short circuit faults are accurately calculated, and a transient state calculation method and a stable state calculation method for the turn-to-turn short circuit faults of the excitation winding are provided. Experimental results prove the correctness and the accuracy of the two calculation methods and provide a quantified basis for designing turn-to-turn short circuit protection.

Method and apparatus are provided for displaying an image to a viewer with reduced visual artifacts. The apparatus comprises a display panel for forming the image using an array of pixels with distributed active regions, and a viewing arrangement optically situated between the display panel and the viewer for transferring the image formed on the display panel to the viewer with limited angular pixel subtense. The distributed active regions of the pixels are desirably divided into at least two simultaneously switched portions at least partly separated by or surrounding a significant portion of the non-switchable region. First order spatial harmonics and associated artifacts are reduced by the distributed apertures and second order and higher harmonics are reduced by limiting the pixel subtense angle seen by the viewer. A significant reduction in visual artifacts arising from the periodic structure of the display panel is obtained.

A reluctance motor has: a stator provided with drive coils to which multiphase drive currents are inputted; and a rotor provided with a plurality of salient poles which receive primary rotating force when magnetic fluxes generated in the drive coils are interlinked with the rotor, and the rotor has: inductor pole coils which are placed on magnetic paths on which spatial harmonic components superimposed on the magnetic fluxes generated in the drive coils are interlinked with the rotor side so that induced currents can be generated in the inductor pole coils due to the spatial harmonic components of the magnetic fluxes; rectifier elements which rectify the induced currents generated in the inductor pole coils; and electromagnet coils as defined herein, and the inductor pole coils and the electromagnet coils do not serve for each other's purposes but are placed on the rotor individually.

The invention discloses a multi-phase single winding non-bearing motor driving system, which comprises a multi-phase alternating current motor, a multi-phase inverter, an inversion driving unit, a detection unit, a torque and rotary speed control unit, a suspended control unit and a comprehensive unit, wherein the multi-phase alternating current motor has a set of windings with phase number n>=5, a motor stator winding is formed by windings whose axial lines are separated in an angle of 2 pi / n, each phase winding simultaneously comprises odd spatial harmonics and even spatial harmonics, the torque and the suspended control of the multi-phase alternating current motor are respectively finished in different control freedom degrees, two groups of currents with different phase differences of adjacent phases are simultaneously electrified into the motor through the multi-phase inverter for respectively realizing the torque driving and the rotor suspension of the driving system. The motor driving system adopts a set of multi-phase motor windings and a set of multi-phase univertor, realizes the non-bearing operation of the driving system, and has the windings with simple structure, is much easier to embed wires than a traditional double-winding non-bearing motor, is easy to realize the large power driving, and has higher reliability.

The invention discloses an automobile Lundell motor AC-generator which comprises stator windings and a rectification circuit, wherein two sets of the stator windings which are of symmetrical triphase structures are isolated at an electrical degree of 30 degrees; the two sets of stator windings are connected by a star-shaped way, and two Y windings are output in series by respective rectifier bridges. The invention completely eliminates fifth time frequency harmonics, seventh time frequency harmonics, fifth spatial harmonics and seventh spatial harmonics in the air-gap field of the generator by adopting the structure of double-Y 30-degree stator windings, thereby reducing the torque pulsation of the generator, lowering electromagnetic noise, enhancing the efficiency and enabling the performance of the generator and a system to have a greater improvement.

A rotating induction machine, containing five or more different phases, having windings distributed according to a sinc function with a cutoff frequency allowing low-order spatial harmonics but preventing higher order spatial harmonics from flowing. In a preferred embodiment, the machine is connected to drive means capable of injecting third harmonic into the machine. In a further preferred embodiment, the windings are connected to the drive means with a mesh connection and the machine has five phases.

A plurality of conductive strip elements compose multilayer loading structures on top and bottom surfaces of a dielectric transmission substrate, by which a part of intra-substrate transmission components of a electromagnetic wave are leaked out of the surfaces. Each multilayer loading structure includes a first conductive strip group of conductive strip elements within a first plane, and a second conductive strip group of conductive strip elements within a second plane, and the first and second conductive strip groups are formed to be capacitively coupled to each other. In each of the first and second conductive strip groups, the conductive strip elements are placed at intervals of a distance of a quarter or less of a reference adjacent distance, where the reference adjacent distance is defined as a distance for generating spatial harmonics of the electromagnetic wave on the surfaces of the dielectric transmission substrate.

A reluctance motor has: a stator provided with drive coils to which multiphase drive currents are inputted; and a rotor provided with a plurality of salient poles which receive primary rotating force when magnetic fluxes generated in the drive coils are interlinked with the rotor, and the rotor has: inductor pole coils which are placed on magnetic paths on which spatial harmonic components superimposed on the magnetic fluxes generated in the drive coils are interlinked with the rotor side so that induced currents can be generated in the inductor pole coils due to the spatial harmonic components of the magnetic fluxes; rectifier elements which rectify the induced currents generated in the inductor pole coils; and electromagnet coils as defined herein, and the inductor pole coils and the electromagnet coils do not serve for each other's purposes but are placed on the rotor individually.

The invention discloses an efficient terahertz artificial surface plasmon directional coupler and a coupling method. A metal cylindrical periodic array is coupled with an SSP waveguide, the terahertzwave transmitting the metal cylindrical periodic array generates a spectral folding effect, and abundant space harmonic waves are generated; when the tangential wave loss of the n-order space harmonicwave meets an SSP wave mismatching condition, an SSP mode is coupled on the surface of the SSP waveguide; through reasonable design of parameters, the conversion efficiency from a free space beam tothe SSP mode is improved, the coupling direction and the working frequency band of the plasmon can be freely regulated and controlled, and a powerful promotion effect on practical application of the SSP mode in the terahertz wave band is achieved; due to the fact that the coupler is of a full-metal structure, the loss of the coupler can be reduced; and meanwhile, the coupler is of a periodic cylindrical structure, and compared with a traditional coupler, the coupler is simple in structure and easy to process, low in cost and high in integration level, and can be widely applied to a terahertz communication system and an imaging system.

Methods and systems for solving measurement models of complex device structures with reduced computational effort and memory requirements are presented. The computational efficiency of electromagnetic simulation algorithms based on truncated spatial harmonic series is improved for periodic targets that exhibit a fundamental spatial period and one or more approximate periods that are integer fractions of the fundamental spatial period. Spatial harmonics are classified according to each distinct period of the target exhibiting multiple periodicity. A distinct truncation order is selected for each group of spatial harmonics. This approach produces optimal, sparse truncation order sampling patterns, and ensures that only harmonics with significant contributions to the approximation of the target are selected for computation. Metrology systems employing these techniques are configured to measure process parameters and structural and material characteristics associated with different semiconductor fabrication processes.

The invention discloses an axial gap rotation motor of a big electromagnetic torque winding excitation structure axial gap type rotary motor which is obtained through high order spatial harmonic flux generated by an armature coil. The axial gap rotation motor (100) has: two rotord (120,130) which performs rotation driving with an axis (101) as a center and a stator (110), the two sides of which in an axial direction are opposite to the rotors; the axial gap rotation motor (100) comprises a plurality of armature coils (11) which are configured at the circumference of the axis of the stator, multiple induction coils (21) and multiple excitation coils (22) which are arranged on the circumference of the two rotors, and a diode which perform rectification on the induction current generated by the induction coils in order to provide the excitation coil; the windings of the armature coils, the induction coils and the excitation coil are winding coils which are wound into an alpha coil on an iron core (15,25) in an axial direction.

A method for improving computation efficiency for diffraction signals in optical metrology is described. The method includes simulating a set of spatial harmonics orders for a grating structure. The set of spatial harmonics orders is truncated to provide a first truncated set of spatial harmonics orders based on a first pattern. The first truncated set of spatial harmonics orders is modified by an iterative process to provide a second truncated set of spatial harmonics orders based on a second pattern, the second pattern different from the first pattern. Finally, a simulated spectrum is provided based on the second truncated set of spatial harmonics orders.

The invention concerns a method for determining the running condition of a member rotating on a surface, said method comprising the initial process which consists in performing a spatial frequency analysis of the rotational speed of the member so as to identify at least one frequency window not including a harmonic of the revolution of the member wherein a law determining the running condition is established, and an iterative process for determining the running condition comprising steps which consists in: measuring the rotational speed V of said member; spatially sampling said speed with a constant spatial sampling period Delta d; analyzing the sampled signal in the frequency window identified so as to determine the running condition on the basis of the established law.

The invention discloses an axisymmetric periodic permanent magnet focusing system with a prominent third spatial harmonics. The system comprises a plurality of permanent magnet focusing units with thelengths of L, each permanent magnet focusing unit comprises in order from left to right: a first magnetic pole (1); a first permanent magnet (2) having an N pole connected to the first magnetic pole(1); a second magnetic pole (3) connected to the S pole of the first permanent magnet (2); and a second permanent magnet (4) having an S pole connected to the second magnetic pole (3). The axisymmetric periodic permanent magnet focusing system with a prominent third spatial harmonics achieves the required peak axial magnetic field intensity Bm under the condition that the period L of the periodicpermanent magnet focusing system is not reduced, and simultaneously suppresses the fluctuation of the radius of an electron beam by utilizing the third spatial harmonics of the magnetic field distribution of the periodic permanent magnet focusing system on the axis, so that the aim of maintaining the stable passing of the electron beam is achieved.

The invention discloses a motor equivalent air gap model. The equivalent air gap model is established on the basis of a unified air gap magnetic field modulation theory, and a typical induction motorand synchronous motor structure is divided into initial excitation magnetomotive unit, a modulator and a filter which are cascaded. An initial excitation source establishes initial magnetomotive distribution in the physical air gap; the modulator modulates the initial magnetomotive distribution to generate a series of magnetomotive harmonic components, and all the magnetomotive harmonic componentsgenerate corresponding magnetic flux density harmonic components in the air gap; and an armature winding, as the spatial harmonic filter, extracts the effective air-gap magnetic flux density harmoniccomponents to generate a magnetic link or an electromotive force and further to supply power to a load or receive synchronous current, so that corresponding mechanical output is generated. Mathematical expression of the equivalent air gap model is clear and concise, an air gap magnetic field modulation behavior can be described clearly, effectively and qualitatively, an operation characteristic of the motor is reflected, internal connection as well as difference between inductive motor and the synchronous motor is verified and sensed visually, and theoretical understanding is deepened.

The invention belongs to the technical field of motor analysis design, and discloses a method for analyzing magnetic potential of a non-sine power supply multiphase motor. The method includes the steps that the concepts of equivalent positive sequence currents and equivalent inverted sequence currents are imported, a synthetic forward circular rotating field and a synthetic inverted circular rotating field are seen as being generated by the equivalent positive sequence currents and the equivalent inverted sequence currents respectively, subharmonic currents are indicated as current phasors in an index mode, on the basis of magnetic potential equivalence, harmonic equivalent sequence currents corresponding to the subharmonic magnetic potential are acquired, and then corresponding space harmonic forward magnetic potential and inverted magnetic potential are directly solved. The method is based on the electro mechanics fundamental principles, the concept is clear, complex calculation of superposing the subharmonic magnetic potential of all phases in a traditional method is avoided, the method is suitable for analyzing the magnetic potentials of the multiphase motor under multiple working conditions, and when default phases or asymmetrical windings or asymmetrical currents or other failures occur, only corresponding elements in a current matrix or a winding spatial position matrix need to be changed.

A rotating induction machine, containing five or more different phases, having windings distributed according to a sinc function with a cutoff frequency allowing low-order spatial harmonics but preventing higher order spatial harnomics from flowing. In a preferred embodiment, the machine is connected to drive means capable of injecting third harmonic into the machine. In a further preferred embodiment, the windings are connected to the drive means with a mesh connection and the machine has five phases.

The invention provides a method for computing a double absorption layer alternating phase shift mask diffraction field. The method comprises the following specific steps; 1, setting the number n of spatial harmonics when an electromagnetic field is expanded; 2, performing Fourier series expansion on the dielectric constant of each grating layer, wherein, performing Fourier series expansion on TM polarized light by computing the reciprocal of the dielectric constant; and 3, for TE polarized light and the TM polarized light, solving the characteristic matrix of each grating layer, and obtaining a diffraction field corresponding to the TE polarized light by using continuous boundary conditions in the tangent direction of the electromagnetic field. Through the Fourier series expansion on the TM polarized light by computing the reciprocal of the dielectric constant, the convergence of the TM polarized light while entering a damaged mask grating can be improved, so that the calculated diffraction field has a higher accuracy.

The invention provides a method for eliminating vibration of a PWM powered brushless direct current motor through frequency calculation. For the motor preliminarily designed in a electromagnetic scheme, spatial harmonic distribution of air gap flux density is firstly calculated, then the time harmonic wave change of the air gap flux density is calculated within a commutation period and is compared with the inherent vibration frequency of a motor iron core, and if the frequencies are similar, resonance is produced, the electromagnetic design scheme of the motor is needed to be optimized, and the frequencies are re-calculated till the vibrations produced by spatial harmonic flux density and harmonic wave flux density are not resonant with the iron core. The space and time changes of flux density causing motor vibration under the operating working condition of the motor are fully considered in the method, the accuracy of motor vibration calculation in a motor product development phase is improved, accordingly the success rate of motor design is improved, a development and trial-manufacturing period of the motor is shortened, and non-renewable resources including copper, iron, aluminum and the like are effectively saved.

The invention belongs to the technical field of acceleration tests, and particularly relates to a space driving mechanism harmonic reducer multi-performance parameter accelerated degradation test evaluation method, which comprises the steps of obtaining a performance degradation value of each tested sample at each degradation detection moment under each acceleration stress; carrying out normalization processing on each performance degradation value; carrying out uncertain process modeling on the performance degradation process under the acceleration stress level, and constructing a system degradation equation; establishing a relationship between the normalized performance degradation data and the reliability; performing comprehensive trade-off optimization on all unknown parameters of the system degradation equation by using an uncertainty statistical analysis method; and solving a system margin equation, an unreliability distribution function and a reliability measurement equation of a corresponding space harmonic reducer product by combining the threshold values of the performance parameters. According to the method, the problem of cognitive uncertainty quantification caused by a small number of test samples and limited performance detection times in a multi-performance parameter accelerated degradation test of the harmonic reducer is solved.

A rotor structure (24) for a fault-tolerant permanent magnet electromotive machine (10) is provided. A back-core lamination (28) is disposed around a plurality of permanent magnets (30). The back-core lamination (28) comprises a plurality of high-reluctance regions (50) arranged to attenuate asynchronous magnetic flux components while avoiding synchronous magnetic flux components. The asynchronous and synchronous magnetic flux components result from spatial harmonic components of a plurality of fractional-slot concentrated windings (18) of a stator (12) of the machine.

The invention concerns a method for determining the running condition of a member rotating on a surface. The method includes an initial process of performing a spatial frequency analysis of the rotational speed of the member to identify at least one frequency window not including a harmonic of the revolution of the member wherein a law determining the running condition is established, and thereafter, an iterative process for determining the running condition including measuring the rotational speed V of the member; spatially sampling the speed with a constant spatial sampling period Δd; and analyzing the sampled signal in the frequency window identified so as to determine the running condition on the basis of the established law.

The present invention is a reluctance motor (10) that rotates as a result of the magnetic flux generated at the drive coil (14) of a stator (11) being interlinked with the rotor teeth (22) of a rotor (21). In the rotor, the key protrusion (119) of a rotor base material section (111) and the key protrusion (129) of a ring-shaped section (121) are fitted / affixed to a key groove (109) of a shaft (101), a core material section (112) that is integral to the rotor base material section is caused to be the rotor teeth provided with an electromagnet pole coil (28), the core material (25) is protected by a protruding piece (123) integral to the ring-shaped section, resulting in an inductor pole coil (27). By means of arranging in the direction of rotation in such an easy structure, it is possible to generate an induced current using the induction pole coil by means of the spatial harmonic component of the interlinked magnetic flux, and by supplying the result to the electromagnet pole coil as field magnet current, electromagnetic force is generated that assists in primary rotational force.

A reluctance motor has: a stator provided with drive coils to which multiphase drive currents are inputted; and a rotor provided with a plurality of salient poles which receive primary rotating force when magnetic fluxes generated in the drive coils are interlinked with the rotor, and the rotor has: inductor pole coils which are placed on magnetic paths on which spatial harmonic components superimposed on the magnetic fluxes generated in the drive coils are interlinked with the rotor side so that induced currents can be generated in the inductor pole coils due to the spatial harmonic components of the magnetic fluxes; rectifier elements which rectify the induced currents generated in the inductor pole coils; and electromagnet coils as defined herein, and the inductor pole coils and the electromagnet coils do not serve for each other's purposes but are placed on the rotor individually.

The invention discloses a multi-phase cage type induction motor magnetic field calculation method and system, and the method comprises the steps: dividing a motor solving region according to the type of an excitation source, thereby obtaining a motor model, and obtaining a distribution function of the current density of a stator winding based on the motor model; aiming at the influence of the k current density harmonics, taking the vector magnetic potential in each sub-domain as a solving object of a control equation, respectively establishing a Laplace's equation, a Poisson equation and a Helmholtz equation, and solving a general solution of the vector magnetic potential according to boundary conditions among interfaces; based on the general solution of the vector magnetic potential of each sub-domain, solving the harmonic coefficient of each sub-domain; and based on the harmonic coefficient of each sub-domain, solving the radial and tangential components of the air gap flux density according to the vector magnetic potential expression of the air gap sub-domain, and solving the torque caused by the k space harmonics of the magnetomotive force and the total electromagnetic torque according to the radial and tangential components of the air gap flux density and the Maxwell tensor method.