147 results about "Harmonic excitation" patented technology

A varying magnetic field excites slight vibrations in an object and a radar sensor detects the vibrations at a harmonic of the excitation frequency. The synergy of the magnetic excitation and radar detection provides increased detection range compared to conventional magnetic metal detectors. The radar rejects background clutter by responding only to reflecting objects that are vibrating at a harmonic excitation field, thereby significantly improving detection reliability. As an exemplary arrangement, an ultra-wideband micropower impulse radar (MIR) is capable of being employed to provide superior materials penetration while providing range information. The magneto-radar may be applied to pre-screening magnetic resonance imaging (MRI) patients, landmine detection and finding hidden treasures.

A speech coding system (10) and associated method relies on a speech encoder (15) and a speech decoder (20). The speech decoder (20) includes a harmonic generator (70) which modulates the phase of each generated harmonic with a low frequency, low bandwidth signal to remove the buzzy quality of the speech and to produce natural sounding speech. The amplitude of the phase modulating signal is adjusted in accordance with the harmonic magnitude. For harmonics residing in a spectral valley the amplitude of the modulating signal is relatively large and for harmonics residing near spectral peaks, the amplitude of the modulation signal is relatively small.

A 2.3 kb / s speech coding technique with harmonic excitation and linear prediction is disclosed. The speech signals are acquired by speech acquisition system and then inputted to the processor of computer. The fundational tone detecting method and voiced sound analysis method are used to split the LPC exciting signal into lower band associated with voised sound and higher band relative to voiceless sound. A united harmonic model with a fixed phase spectrum of voiced sound of man speech is used to express the harmonic component and pseudo-noise component. An interpolation method is used to reduce noise. A short-lag filter is used for high quality of synthetic speech.

A “harmonic force generator” (HFG) is provided which creates counter-acting forces to a harmonic excitation. The advantageous HFG devices of the present disclosure may be used in canceling the undesired vibrations on a structure under the influence of a harmonic excitation. There are critical aspects to be controlled in the output force: the amplitude, the frequency and the relative phase with respect to given harmonic signal. All three of these components are adjusted by a closed loop control structure according to the present disclosure. The controller determines the transition time of all three features. The disclosed HFG advantageously produces this harmonically varying force only along a determined axis, with no force component in transverse direction.

The invention discloses a hybrid excitation permanent magnet motor for wireless transmission and tooth harmonic excitation in the technical field of motors. A stator and a rotor are arranged in a shell; a rotating shaft passes through a central hole of a rotor core and is fixed with the rotor core; the rotating shaft is connected with the shell through a bearing; a stator winding corresponds to apermanent magnet and a rotor exciting winding to generate electromagnetic induction; a rotor tooth harmonic winding and the rotor exciting winding are connected with a chopper circuit through a dioderectifying circuit; a driving signal of a switching element in the chopper circuit is acquired through a wireless receiving module; an excitation control system outputs a pulse signal to a wireless transmitting module, transmits the pulse signal to the wireless receiving module on the rotor through the wireless transmitting module, controls the on / off of the switching element in the chopper circuit and provides the needed exciting current for the rotor exciting winding; therefore, an air-gap field and the output voltage of the stator winding are adjusted. Compared with the prior art, the hybrid excitation permanent magnet motor has no electric brush, collecting ring, additional air gap or axial magnetic circuit, is simple in structure, low in flux leakage, low in electric excitation loss and high in motor efficiency, and has high capacity of adjusting a main field.

The invention discloses a mixed excitation magnetoelectric machine adopting harmonic excitation, comprising a machine shell (1), a stator core (2), a stator winding (3), a permanent magnet pole (4), aferromagnetic pole (5), a rotating shaft (6), a rotor core (7) and a rotor winding (8), wherein, a rotor magnet pole is composed of the permanent magnet pole (4) and the ferromagnetic pole (5) whichis provided with the rotor winding (8); the rotor winding (8) consists of a harmonic winding (14) and an excitation winding (13); the stator winding (3) comprises a main winding (11) and a harmonic excitation winding (12), and is distributed in a stator groove; the pole distance of the main winding and the pole distance of the rotor excitation winding are identical; the pole distance of the harmonic excitation winding and the pole distance of the rotor harmonic winding are identical; the harmonic excitation winding is connected with an excitation controller; when the motor runs, the current inthe harmonic excitation winding can be controlled to achieve the functions of adjusting magnetic field and voltage. Compared with the prior art, the invention has no electric brush, collecting electric ring, additional air gap, axial magnetic circuit, has simple structure, little magnetic-flux leakage, less excitation loss, high efficiency of the motor and strong ability of adjusting the main magnetic field.

The invention discloses a wind vibration realizing method for a double coupled system with consideration a high-frequency base force balance test. With a second-order blind identification technology based on a complex mode theory, decoupling of a coupled measurement signal is realized; and reliable parameter recognition is carried out on a separated signal by using a Bayesian spectral density method based on all-aerodynamic force simulation, so that a separation / mixing matrix, an inherent frequency and a damping ratio of a BMS and thus correction of a distorted aerodynamic signal is realized.On the basis of power calibration, a wind effect and equivalent static wind load calculation method considering the influence of a three-dimensional coupling effect of a super high-rise building structure is established by using a harmonic excitation method, so that defects of the HFFB are overcome to a certain extent and the result becomes real and accurate.

The invention relates to a fatigue testing device for lateral dynamic bending of a piston rod of a vibration damper, which is provided with a simple harmonic motion mechanism driven by a driving device to be used for providing simple harmonic excitation; a spring support is sleeved outside an output component of the simple harmonic motion mechanism; two pressure springs which are arranged from top to bottom are arranged in the spring support; the output component of the simple harmonic motion mechanism is clamped between the two pressure springs; the upper end of the spring support is connected with a force sensor; the upper end of the force sensor is connected with a universal connector; and the device is also provided with a fixing clamp and a data acquiring and processing system, wherein the signal output end of the force sensor is connected with the data acquiring and processing system. The invention has the advantage that bidirectional symmetric exciting force with the same maximum value can be applied to piston rods of various specifications to enable each piston rod to complete excitation for the set times under a certain excitation frequency, thus the fatigue strength of lateral dynamic bending of the piston rod of the vibration damper can be detected to ensure the product quality.

The invention discloses a micro-crack nondestructive detection system and a detection method thereof. The micro-crack nondestructive detection system comprises a signal generator, a low frequency vibration exciter, a high frequency exciter, a detected member, a piezoelectric sensor, a preamplifier and a signal acquisition and analysis system; the signal generator is electrically connected with the detected member through the low frequency vibration exciter and the high frequency exciter, the piezoelectric sensor is fixed on the detected member through an adhesive, and the signal acquisition and analysis system is electrically connected with the piezoelectric sensor through the preamplifier; and the signal-generator can simultaneously output two paths of simple harmonic excitation signals with different frequencies. Defect detection is carried out by using the non-linear modulation effect of a crack structure under multi-frequency excitation, and whether the existence or not of the micro-crack and the micro-crack damage of the detected member are directly determined according to the quantity and amplitude of side frequencies in a response spectrum without complex signal processing, so the system and the method have the advantages of use convenience, sensitive detection and high detection efficiency.

The invention discloses a hybrid excitation fault-tolerant motor system based on brushless harmonic excitation. In the system, a harmonic winding (8) is added; an excitation winding and the harmonic winding are mounted in a rotor slot in a sleeve manner, and both are concentrated windings; excitation winding coils are orderly connected end to end in series, and form an electric excitation magnetic field; the harmonic windings in two rotor slots which are opposite in radial direction are connected in series to form one phase; and the harmonic windings of each phase are connected in parallel and then connected with the excitation windings through a rectifying circuit, and provide power for the excitation windings. For the motor system provided by the invention, on the rotor structure, the excitation windings, the harmonic windings and a rectifier are added, and an electric brush and a slip ring are omitted, thus, further improvement of reliability and power density of the motor is facilitated. Meanwhile, a permanent magnet in the rotor is set in a V form, the permanent magnet has both radial magnetization and tangential magnetization, magnetic flux is concentrated effectively, output power of the motor is improved, and the system has the advantages, such as wide range of speed regulation, high power density and high efficiency.

The invention provides a power transformer-used silicon steel sheet iron core magnetic performance detection system and a detection method. The system comprises a to-be-detected excitation iron core, a compressive stress loading and measuring module arranged on the to-be-detected excitation iron core, a variable-frequency excitation power unit, an iron core magnetic performance measurement unit and a DC bias unit. The method comprises steps: the magnetic performance detection type of the to-be-detected excitation iron core is judged; the relationship between each item of magnetic performance and other detection items of the to-be-detected excitation iron core in different conditions is detected; and a detection report is issued. The system and the method provided by the invention is low in cost, flexible in arrangement and simple in structure and realization process; simulation on harmonic excitation conditions of the engineering-used large power transformer iron core, DC magnetic bias operation conditions and iron core compressive stress conditions is effectively and accurately realized; and a reliable and accurate basis is provided for evaluating the no-load excitation performance of the engineering-used large power transformer in different operation working conditions.

A process to fracture connecting rods and the like, that are made of high strength materials, comprises of the following mechanisms:(a) Fatigue: fluctuation of stresses in a pre-notched connecting rod due to the use of harmonic excitation will extend the notch tip in the connecting rod and will weaken the predetermined fracture plane by creating micro-cracks,(b) Resonance: resonance occurs when the frequency of the used harmonic excitation matches a natural frequency of the connecting rod, idealized as a structural system,(c) Pre-stressing forces: by applying pre-stressing forces acting in the same loading mode, the stresses in the connecting rod due to several force components can be superimposed,(d) Dynamic force: applying a dynamic force will raise the stress intensity factor, exceeding the fracture toughness of the material.

The invention discloses a series composite structure double-frequency and multi-amplitude piezoelectric ultrasonic transducer applied to a thermal ultrasonic wire bonding and sealing process of an integrated circuit chip. The transducer is composed of two sets of double-ended radiating piezoelectric oscillators and two two-stage mechanical variable-amplitude poles with different amplification factors. The transducer can work at the frequency near the frequency of 60 kHz or 120 kHz and has three driving modes. Under simple harmonic excitation signals with the same frequency, the transducer canobtain multiple amplitude outputs to meet the different requirements of the wire bonding process of the integrated circuit chip and improve the bonding connection efficiency and reliability. Meanwhile, clamping mechanisms of the composite structure ultrasonic transducer adopt flexible flange clamping mechanisms formed by circular arc hinges, the influence of the clamping rack disturbance torque onthe ultrasonic transmission efficiency in the axial ultrasonic transmission process of the variable-amplitude pole can be effectively lowered, and the utilization rate of ultrasonic energy is increased.

The invention relates to the field of harmonic identification methods, in particular to a harmonic identification method used for harmonic identification in power systems or control systems. The method comprises the following steps: creating response signal non-linear state space model; and extracting state vector estimated value, harmonic amplitude and phase at k moment. The method for harmonic identification based on generalized Kalman filter can obtain accurate information of harmonic component in excitation response signal of simple harmonic wave in a fast and real-time manner, and can be applied to harmonic identification in power systems or control systems conveniently.

The invention discloses an acceleration noise filtering and integration method combined with spectrum energy shape fitting. The spectral curve in the close region of the peak dominant frequency is assumed to conform to the Gaussian function distribution. According to the cumulative energy variation of the noisy signal in the region, the parameters of the correlation Gaussian function are fitted, and the distribution range of the effective information of the dominant frequency is determined according to the principle of triple radius, and then the corresponding velocity and displacement signalare obtained through the frequency domain integration and inverse Fourier transform in the effective frequency band. Compared with the traditional frequency domain integration method, the method of the invention can realize automatic determination of the integration frequency band, can obtain higher integration precision under harmonic excitation and stable and good integration precision under random excitation, and has stronger anti-noise performance.

The invention discloses a method for measuring vibration performance of the tool nose of a micro-milling tool, which belongs to the field of micro processing. The method is characterized in that the micro-milling tool is clamped in the tool nose of a spindle, one end of a piezoelectric actuator is pasted on the tool handle of the micro-milling tool, and the other end of the piezoelectric actuator is connected with a high frequency force sensor pasted on a machine tool motion platform; a machine tool drives the micro-milling tool to conduct micro feeding to the piezoelectric actuator, certain precompression is applied between the piezoelectric actuator and the tool handle of the micro-milling tool, and the piezoelectric actuator generates shock excitation under the action of excitation of an externally-connected signal generator; and a laser Doppler vibrometer is adopted to measure the vibration performance of the tool nose of the micro-milling tool. The method provided by the invention has the advantages that harmonic excitation is only applied on the tool handle of the micro-milling tool, so that damage of the tool nose is avoided, the micro-milling tool with small diameter can be measured, the frequency is high, the vibration performance can be on-line measured, and the method is simple, easy and convenient to implement.

The invention discloses a method for exciting a rotary ultrasonic motor and relates to the field of the ultrasonic motors. The method comprises the following steps of determining the number of piezoelectric slices in each group, the group number of the piezoelectric slices, the number of operating waves and a physical included angle between adjacent groups of piezoelectric slices when the total number of the piezoelectric slices is fixed; for the rotary ultrasonic motor which is uniformly provided with the piezoelectric slices, estimating a first exciting effect by using a first formula so as to obtain a first basic parameter combination for ensuring the first exciting effect to be maximized; for the rotary ultrasonic motor with the grouped piezoelectric slices, estimating a second exciting effect by a second formula and a third formula so as to obtain a second basic parameter combination for ensuring the second exciting effect to be maximized; calculating an excitation response generated by harmonic excitation; and if standing waves or backward waves do not exist near a working point, using the first basic parameter combination or the second basic parameter combination as a final scheme. The method helps to improve the operation stability and the efficiency of the ultrasonic motor.

The invention relates to a method for measuring the hysteresis loop of a transformer core material under harmonic excitation. Because the method gives consideration to the operation condition of a power transformer under the working condition of non-sine excitation, compared with the measurement data obtained by a conventional single-chip measurement system and an Epstein square measurement device under the standard sine excitation, the magnetic flux and hysteresis loop obtained in the mode of harmonic excitation are closer to the magnetic characteristics of the transformer core material under the harmonic excitation during working. The method is more accurate in calculation of three-dimensional finite element simulation analysis of the core material, and has the guide significance for the optimization and design of the structure of the transformer core.

The invention provides an optimizing and designing system for dynamic property of a fluidic-resistance suspension of an automobile powertrain. The optimizing and designing system is characterized in that firstly, the mechanical principle is utilized to determine relative structural parameters of the fluidic-resistance suspension, and the relative structure parameters include relative parameters of a rubber main spring, relative parameters of an upper liquid chamber and a lower liquid chamber, relative parameters of a runner and relative parameters of hydraulic oil; then, the actual working principle of the fluidic-resistance suspension is deep understood to construct a mechanical model of the fluidic-resistance suspension, and a functional structure can be abstracted into that the lower liquid chamber, a liquid chamber separating layer and the upper liquid chamber are sequentially arranged in a cavity from bottom to top; a runner liquid column is further arranged in the middle of the liquid chamber separating layer, and the runner liquid column can move along with harmonic excitation exerted at the top of the suspension; due to the fact of the changeable characteristic of the rubber liquid chamber, the upper liquid chamber above the runner liquid column can be simplified into an equivalent piston; and an elastic body of the upper liquid chamber can be simplified into the changeable volume with the rigidity to be shown through a left spring and a right spring. A correlation formula of representation property of the fluidic-resistance suspension is induced; the dynamic property, with the parameters optimized, of the fluidic-resistance suspension is achieved; and an optimized sample is obtained based on the dynamic property with the parameters optimized to obtain the optimal dynamic property.

The invention advances a new tooth electro time-grating displacement sensor able to make both dynamic and static measurement, making two groups of teeth on both stator / scale and rotor / slide, selecting two groups of teeth on the stator / scale or rotor / slide and staggering by half tooth to form orthogonal, not staggering the other two groups of teeth, forward and backward winding coils on the stator / scale and rotor / slide at regular tooth intervals, using two groups of coils as excitation coils and exciting by two orthogonal simple harmonic waves so as to obtain standing wave responses in the other two groups of coils as standing response coils, superposing the two standing waves and obtaining electric travelling wave whose phase shift directly reflects angular or linear displacement. And its stator / scale and rotor / slide framework can be machined by any common- precision machining device to assure uniform coil distribution, and it can replace any present static and dynamic measuring means to implement high-precision measurement.

Methods and systems for simulating acoustic field resulted from particular excitations by performing vibro-acoustic analysis of a structure are disclosed. According to one aspect of the present invention, vibro-acoustic analysis of a structure is performed in two stages. First, steady state dynamic (SSD) responses are obtained using a finite element analysis model of a structure subject to harmonic excitations (e.g., external nodal loads, pressures, or enforced motions (e.g., ground motions), etc.). The steady state responses are the results (e.g., nodal velocities at desired locations of the structure) obtained in a finite element analysis in frequency-domain. Second, an acoustic analysis is conducted according to Helmholtz equation using the nodal velocities obtained at desired locations on the structure as a boundary condition. The acoustic analysis can be performed in a number of procedures (e.g., boundary element method, Rayleigh approximation method, etc.).

The invention provides a method for measuring the radial dynamic flexibility of a rolling bearing. A vibration table applies a dynamic load to an inner ring of the bearing directly through a switching section, a force sensor and an acceleration sensor are connected between the vibration table and the switching section, the vibration table applies simple harmonic excitation, data collected by the acceleration sensor and data collected by the force sensor are recorded, and a real load applied to the inner ring of the bearing is acquired by using a switching section influence eliminating technology; and a real displacement is acquired by using a multi-section displacement correcting technology, then a force-displacement hysteresis loop is drawn according to the synchronous real load and real displacement acquired by direct loading, and finally, the radial dynamic flexibility of the rolling bearing under parameters of different excitation frequencies, different force amplitudes and the like is acquired. The method provided by the invention is easy to implement and simple to operate, and can acquire a high-precision dynamic flexibility test value under the parameters of different excitation frequencies, different excitation force amplitudes and the like very conveniently.

The invention discloses a method for controlling a cascaded multi-cell high-power high-frequency ice melting power supply, which includes the following steps: S1, an input side implements input-side power factor rectification through instantaneous direct current control to suppress the input-side harmonic, wherein the direct current control is composed of current inner loop control and voltage outer loop control; S2, SPWM inversion control is carried out on a combined inverter, and multiple combined phase shifting H-bridge inverter structure control is adopted; and S3, the combined inverter adopts input voltage sharing and output current sharing control. The technical problems in the prior art are solved, for example: there is high harmonic in the ice melting excitation input power supply,and the input current is of low quality; and the output harmonic at the output side is high, and loop current is generated, which reduces the safety of the ice melting power supply.

The invention discloses a large mass method based structural topology optimization design method under the simple harmonic accelerated speed excitation and is used for solving the technical problem of poor practicability of a structural topology optimization method under current harmonic force excitation. According to the technical scheme, multipoint accelerated speed excitation is converted into force excitation with a large mass method, the force excitation is applied to a structure, structural displacement response is calculated with a modal acceleration method, and design is implemented with the minimum structural displacement response in a specified position as a target and with structural mass as constraint. By means of the method, simple harmonic excitation of multipoint accelerated speeds is realized, a clear and effective structure configuration is obtained, and the design demand of multipoint accelerated speed loading in engineering is met. An optimization design result is obtained after 203 times of iteration during implementation. The displacement response amplitude value of an initiating structure under the designed degree of freedom r=204 is 1.8215 m, the displacement response amplitude value of the optimized structure under the designed degree of freedom r=204 is 0.4138 m, and the displacement response amplitude value is reduced by 77.28%.

The invention provides a dual three-phase synchronous motor and a harmonic magnetic field oriented brushless excitation method thereof in allusion to problems of motor starting and low harmonic excitation utilization ratio, and belongs to the field of permanent magnet synchronous motors. According to the invention, a motor rotor is provided with a rotor DC excitation winding F and a rotor harmonicinduction winding H, the pitch of the rotor DC excitation winding is 1, the pitch of the rotor harmonic induction winding is 1 / 3, a motor stator winding is two sets of stator windings in star connection, the phase shift is 30 degrees, and neural points are connected together. The current waveform of the two sets of stator windings is controlled, the current of each three-phase stator winding is enabled to contain an alternating zero-sequence current component, the alternating zero-sequence current components of the two sets of stator windings are orthogonal in phase, harmonic magnetic field oriented control is performed according to the rotor position so as to enable the alternating harmonic magnetic field to induce the harmonic electromotive force in the rotor harmonic induction windingH, and thus a rotor main magnetic field is established through rotating, rectifying and supplying the rotor DC excitation winding F, so that brushless electrical excitation of the synchronous motor isrealized.

The invention relates to a large difference protection method based on second harmonic excitation surge current of a converter transformer. When a single-phase earth fault is generated in a valve side area of the converter transformer, second harmonic content in differential current in large difference protection, differential current in differential protection of a Yn / Y converter transformer and differential current in differential protection of a Yn / D converter transformer is adopted for comprehensive recognition to recognize excitation surge current, so that the resulting protection maloperation is effectively avoided. The method is simple and reliable to realize and lower in realization threshold, can be realized on the original protection device platform, and has a very high popularization value.

The invention discloses a harmonic excitation imaging system for a tapping-mode atomic force microscopy. The harmonic excitation imaging system comprises a function generator, a low-pass filter and a phase lock amplifier added to the prior tapping-mode atomic force microscopy, wherein the function generator is connected with the excitation signal input end of an AFM probe exciter; the phase lock amplifier is connected between a photoelectric four quadrant receiver and an AFM controller; and the low-pass filter is connected in series between the function generator and the phase lock amplifier. The harmonic excitation imaging system is imaging technology which adopts a harmonic superposed signal as an excitation source in a tapping mode and the phase lock amplifier to obtain the high-order harmonic components of probe motion and makes use of the amplitudes and phases of the high-order harmonic components to acquire more information and higher resolution.

A brushless harmonic excitation synchronous motor belongs to the field of electro-magnetic synchronous motors. The brushless harmonic excitation synchronous motor aims at solving the problems that an existing permanent magnet motor depends on an expensive permanent magnet material, and a separate exciter is required by an electro-magnetic motor. According to the brushless harmonic excitation synchronous motor, a winding groove is formed in the middle position of a pole shoe of each pole, the winding grooves divide the pole shoes into rotor sub-teeth, a harmonic winding is embedded in each rotor sub-tooth, a harmonic magnetic field is generated in a motor air gas by means of a third harmonic current, a higher harmonic current or a dc component current in a stator, a sensing current generated in the harmonic windings provides an exciting current for an exciting windings, and brushless excitation is achieved. The brushless harmonic excitation synchronous motor is completely based on electric excitation, does not depend on the permanent magnet material and the exciter, overcomes the shortcoming that a motor system is complex and huge in structure in an exciting mode of the independent exciter, and is simple in structure, convenient to manufacture, good in performance and suitable for being applied to wind-driven generation and mixed hybrid electric vehicles.