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725 results about "Angular frequency" patented technology

In physics, angular frequency ω (also referred to by the terms angular speed, radial frequency, circular frequency, orbital frequency, radian frequency, and pulsatance) is a scalar measure of rotation rate. It refers to the angular displacement per unit time (e.g., in rotation) or the rate of change of the phase of a sinusoidal waveform (e.g., in oscillations and waves), or as the rate of change of the argument of the sine function. Angular frequency (or angular speed) is the magnitude of the vector quantity angular velocity. The term angular frequency vector is sometimes used as a synonym for the vector quantity angular velocity.

High-efficiency measurement method for sinusoidal signal frequency in undersampling and implementation device

The invention belongs to the technical field of digital signal processing, and provides a high-efficiency measurement method of a sinusoidal signal frequency in undersampling and an implementation device which can estimate parameters such as frequency and the like under the condition of undersampling and can finish precise frequency measurement. The invention adopts the technical scheme that traditional FFT spectrum analysis and all phase FFT spectrum analysis are adopted to obtain a peak value spectrum G (q) and a peak value spectrum Ga (q); a phase value is directly read from the peak valuespectrum to take the square of a G (q) modulus to obtain a power spectrum value Pg (q); after performing modulus division on Pg (q) and Ga (q), amplitude estimation is obtained to take the differenceof the phase value of G (q) and the phase value of g(q), and the difference divided by tau=(N-1) / 2 to obtain frequency offset estimation delta k; and finally delta k delta omega and q delta omega aresuperposed to obtain digital angular frequency estimation which directly serves as the phase estimation and the amplitude estimation of the measured signal. The invention is mainly used for undersampling measurement in digital signal processing.
Owner:LIANYUNGANG RES INST NANJING UNIV OF SCI & TECH

Current type wireless power supply system load self-adapting control method

The invention discloses a current type wireless power supply system load self-adapting control method. The method comprises steps of measuring the current value Idc of a direct current power supply of a current type wireless power supply system; calculating the load value RL of a load circuit in accordance with the current value Idc of the direct current power supply; calculating a minimum angle frequency value omega meeting the preset transmission efficiency eta in accordance with the load value RL of the load circuit; and adjusting a variable component of a primary side resonant network, and enabling the resonance angular frequency omega 0 of the primary side resonant network to be equal to omega. The method the advantages that a wireless communication module is not used, the design cost is low, only a parameter is measured, the detection error is little, the accuracy is high, the circuit design is simple, the implementation is easy, the system determines the variation condition of the load circuit in accordance with the real-time detected current value of the direct current power supply, the parameter of the primary side resonant network is changed in accordance with the change of the load circuit, the working efficiency of the system is improved and the system has high working efficiency when the load is changed dynamically.
Owner:重庆前卫无线电能传输研究院有限公司

Space rotating magnetic field generating apparatus and control method thereof

The present invention provides a space rotating magnetic field generating device of random rotating axle, the coil part (2) is three groups pairwise orthogonal Helmholtz coils, every group coil is made up of three groups winding Helmholtz coils, and three groups coil connect each phase of three-phase current respectively. According to parameter of rotating magnetic field (1) required by user, rotating axle direction angle Theta, Phi determines initial position of rotating magnetic field Gamma, angular frequency of rotating magnetic field Omega and amplitude of rotating magnetic field B0, CPU (311) obtains variation magnetic field produced by three groups coils: BX,BYand BZ, and obtains impulse width and frequency of corresponding modulating signal, three groups waveform generators (312) of control power source part (3) inversion produce three groups three-phase current, supply for three groups coils, and produces three direction variation magnetic field. The required rotating magnetic field (1) is obtained after the three variation magnetic fields are overlapped in space. Impulse width and frequency of every waveform generator (312) modulating signal can be adjusted for changing rotating axle of rotating magnetic field, amplitude, frequency and initial position.
Owner:INST OF ELECTRICAL ENG CHINESE ACAD OF SCI

Online recognition method for asynchronous electromotor rotor resistance

The invention relates to an online identification method on the rotor resistance of an asynchronous motor, and the method is used for optimizing resistance parameters in the vector control with a speed transducer. The invention includes the following procedures of collecting the electromagnetic torque Te and the psi 2parameter of the flux linkage of a rotor, identifying the rotor resistance according to the electromagnetic torque Te and the psi 2 parameter of the flux linkage of the rotor by the formula that r2 is equals to 3 / 2Pn omegas psi <2>2 / Te, among which the p n is the number of the pole-pair of the motor, and the omega s is the slip angular frequency, taking the identified rotor resistance as the parameter to implement the vector control of the motor. The online identification method of the invention can identify the rotor resistance of the asynchronous motor on line on the vector control of the motor with the speed transducer by a voltage model method, thereby being simple and practical, and having higher precision. The invention can identify the resistance parameter of the rotor on line accurately under any condition that load exists, and the resistance parameter is stable. Experiments prove that the invention can obtain right resistance parameter of the motor rotor accurately whether the motor is in cold state or in hot state.
Owner:EMERSON NETWORK POWER CO LTD

Method for measuring electrical conductivity of solution

The invention discloses a method for measuring the electrical conductivity of solution, comprising the following steps of: exciting electrodes by adopting a sinusoidal signal with stable voltage amplitude and fixed frequency; carrying out two-channel high-speed A/D transformation on an excitation voltage signal and a current signal of electrode response at the same time; computing voltage effective value U, current effective value I and active power P; dividing the current effective value I by the voltage effective value U to obtain an apparent resistance m, computing a power factor cosine theta and tangent absolute value n of a power factor angle theta, and computing the resistance value Rx between the electrodes by utilizing the following formula, wherein the omega in the formula is angular frequency of the excitation signal and Cp expresses the sum of distributed capacitances between the electrodes and electrode leads; and obtaining the electrical conductivity by utilizing the formula G=K/Rx, wherein the K is an electrode constant. By adopting the invention, adverse effects of electrode polarization, electrode interelectrode and electrode lead distributed capacitances to the measurement of electrical conductivity of the solution can be completely eliminated, and the electrical conductivity of the solution can accurately measured.
Owner:FUJIAN NORMAL UNIV

Method for determining initial position angle of rotor of permanent-magnetic synchronous motor

The invention discloses a method for determining an initial position angle of a rotor of a permanent-magnetic synchronous motor. The method comprises the steps of: inputting a high-frequency rotary voltage vector signal with an amplitude value as U, an angular frequency as omega and an initial phase position as thetaci to obtain an alpha-axis current ialpha and a beta-axis current ibeta; converting the ialpha and the ibeta into a coordinate which rotates synchronously for the angular frequency omega to obtain a d-axis current id and a q-axis iq; performing low-pass filtering on the id and iq to obtain Idf and Iqf; calculating a predicted value thetari of the initial position angle of the rotor by utilizing a formula; inputting a pulse voltage vector in the stator winding, wherein the angle is equal to thetari; obtaining the d-axis current and an integral under the action of the pulse voltage vector, thereby obtaining sigmaI0; after 3 ms-10 ms, inputting another pulse voltage vector to the stator winding, wherein the angle is equal to thetari plus 180 degrees; obtaining the d-axis current and an integral under the action of the other pulse voltage vector, thereby obtaining sigmaIpi; and comparing the absolute values of the sigmaI0 and the sigmaIpi, wherein if the absolute value of the sigmaIpi is greater than the absolute value of the sigmaIpi, the initial position angle of the rotor is equal to thetari; otherwise, the initial position angle of the rotor is equal to thetari plus 180 degrees. The method for determining the initial position angle of the rotor of the permanent-magnetic synchronous motor, disclosed by the invention, has the advantages of simple treatment process and high detection precision.
Owner:SHANGHAI STEP ELECTRIC +1

Reversing rotatory shaker movement

A shaker movement permits an arbitrary path of motion in a shaker's shaking action. The shaker movement comprises independent control over the "X" and "Y" directions of the shaking actions by a pair of track assemblies, each track assembly comprising a pair of fixed rods and a pair of sliding rods that are interconnected with each other in a rectangular, grid-like pattern. Motion in both directions can be driven by a single motor utilizing independent pulley-and-belt systems or by two synchronized motors which are connected to a sliding rod of each track assembly. By altering the relative amplitude, phase angle, and frequency between the "X" and "Y" directions, the shaking action can follow a desired path. The shaker path can be varied from the traditional circular orbital motion or linear motion, to a new group of shaking patterns in which the direction of the shaking movement can reverse. The new patterns of shaker movement cause the liquid being shaken to be more thoroughly mixed, with less power input, and at a lower angular frequency than is practical with traditional paths of motion. This results in higher rates of gas transfer to and from the liquid, resulting in greater growth of a bacterial culture, and for higher rates of mass transfer at equivalent levels of energy input.
Owner:BULL DANIEL

Inverse Q filtering method for seismic wave signal

InactiveCN102053273AOvercoming the defect of suppressing high frequencyHigh-resolutionSeismic signal processingFrequency spectrumOmega
The invention provides an inverse Q filtering method for a seismic wave signal. The method comprises the following steps: extracting a quality factor Q value from the seismic wave signal collected from a seismic channel; performing time-frequency transformation on the collected seismic wave signal so as to acquire a seismic wave frequency spectrum shown in the specification, wherein tau is a travel-time and omega is an angular frequency; and performing inverse Q filtering on the seismic wave frequency spectrum by utilizing the following formula shown in the specification, so as to acquire the seismic wave frequency spectrum U (tau, omega) after inverse Q filtering, wherein gamma is equal to 1 / (phiQ); omega h is the highest frequency within the seismic bandwidth; sigma 2 is a stable factor; i is an imaginary part unit; tau' in exponential terms is an integration variable, and the value range of the integration variable is within an integrating range from omicron to tau; and the quality factor Q is related to the integration variable tau'. The high-frequency component is not pressed in the stabilizing treatment process in the inverse Q filtering method provided by the invention, so the inverse Q filtering method has the advantages that the resolution ratio is increased but the high-frequency noise is not increased, and the signal to noise ratio (SNR) is increased.
Owner:CHINA PETROLEUM & CHEM CORP

Three-phase alternating current phase sequence detection apparatus and method

ActiveCN101320063AAccurate detectionTimely and effective phase sequence judgmentPhase sequence/synchronism indicationTime conditionThree-phase
The invention discloses a three-phase alternating current phase sequence detecting device and a method thereof. The detecting device comprises a three-phase alternating current sampling module, a coordinate system transformation module, an angular frequency signal acquirement module and a phase sequence direction judgment module. The detecting device includes the following detecting method: A. the three-phase alternating current sampling module samples the instantaneous values of current three-phase alternating current to obtain a sampling instantaneous value; B. the coordinate system transformation module converts the sampling instantaneous value into a two-phase synchronous rotating coordinate system from a three-phase static coordinate system, and q axis component xq can be worked out; C. the angular frequency signal acquirement module receives xq and obtains an error signal; the error signal can be adjusted to change the value of the xq; the acquired value of the angular frequency Omega 0 can be output to a feedback channel module thereof and the phase sequence direction judgment module; the feedback channel module outputs Omega 0 to the coordinate system transformation module; D. the phase sequence direction judgment module distinguishes the mark of Omega 0 and determines the phase sequence direction. The device provided by the invention can detect the real-time condition of the phase sequence. The device provided by the invention is simple and practical and has excellent capacity of resisting disturbance.
Owner:ZTE CORP

Micro power grid frequency control method and system

A micro power grid frequency control method and a system are provided, wherein the method comprises the steps of obtaining d-axis and q-axis components of an output voltage, an output current and a filtering inductance current of an LC filter at the grid side of an inversion power supply; obtaining the output reactive power, the output active power and an output voltage amplitude of the LC filter in combination with the d-axis and the q-axis components of the output voltage and the output current; obtaining a virtual excitation electromotive force by taking the output reactive power and the output voltage amplitude as the input of a virtual excitation controller; obtaining an active power increment by inputting an output angular frequency of a virtual synchronous generator controller into a frequency controller; and obtaining a d-axis and a q-axis reference instruction value and an output angular frequency of the inverter output voltage by taking the output active power, the virtual excitation electromotive force, the active power increment and the d-axis component and the q-axis component of the filtering inductance current as the input of the virtual synchronous generator controller. According to the invention, the micro power grid frequency change caused by load disturbance can be effectively inhibited; and the island micro power grid can be operated stably.
Owner:ELECTRIC POWER RES INST OF GUANGDONG POWER GRID
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