184 results about "Harmonic resonance" patented technology

A wind turbine may be controlled in a variety of manners to optimize operating parameters. In one arrangement, for example, the length or the pitch of a wind turbine rotor blade may be adjusted to avoid harmonic resonance frequencies. In another example, the length of a rotor blade may be modified to reduce noise or to optimize profits or both. The controls may be based on data from various types of sensors including accelerometers, sound meters, strain gauges and the like. Actuation of extendable rotor blades can rotate wind turbine rotors without wind or generator pulsing affording multiple advantages. A battery test control may also be used to determine the operational readiness of a battery useful for a variety of purposes in a turbine.

An amplifier circuit responsive to a power mode signal improves efficiency at low power levels without compromising efficiency at high power levels. At low power levels, high impedance is presented with suitable adjustment in the phase of the signal. Also, providing for predistortion linearization improves high power efficiency and switching the predistortion linearizer OFF at low power levels contributes little more than a small insertion loss. The power amplifier also uses a bias circuit incorporating a dual harmonic resonance filter to provide high impedance at a fundamental frequency and low impedance at a second harmonic. These properties are of particularly advantageous since amplifiers in cell-phones are used in low power modes most of the time although they are designed to be most efficient at primarily the highest power levels.

A radio frequency (“RF”) harmonic filter circuit as disclosed herein is fabricated using integrated passive device (“IPD”) technology. The RF harmonic filter circuit is configured to provide second, third, and fourth harmonic rejection while providing good input and output impedance matching. The RF harmonic filter circuit employs only one IPD loop inductance (preferably used for a second harmonic resonance circuit), which results in a significant die / package size reduction. The RF harmonic filter circuit also employs a combined circuit that performs input and / or output impedance matching and third harmonic rejection.

The invention discloses power transmission control device, power transmission device, non-contact power transmission system and secondary coil positioning method. The power transmission device (primary side device) can automatically detect relative position relation between the power transmission device (primary side device) and the power receiving side device (secondary side device) in high accuracy. The power transmission control device (20) includes a power-transmitting-side control circuit (22) that controls power transmission to a power receiving device (40), and a harmonic detection circuit (25) that detects a harmonic signal of a drive frequency of a primary coil. A resonant circuit (leakage inductance and resonant capacitor C2) that resonates with the harmonic of the drive frequency of the primary coil L1 is formed in the power receiving device (40) so that harmonic resonance occurs.

An amplifier circuit responsive to a power mode signal improves efficiency at low power levels without compromising efficiency at high power levels. At low power levels, high impedance is presented with suitable adjustment in the phase of the signal. Also, providing for predistortion linearization improves high power efficiency and switching the predistortion linearizer OFF at low power levels contributes little more than a small insertion loss. The power amplifier also uses a bias circuit incorporating a dual harmonic resonance filter to provide high impedance at a fundamental frequency and low impedance at a second harmonic. These properties are of particularly advantageous since amplifiers in cell-phones are used in low power modes most of the time although they are designed to be most efficient at primarily the highest power levels.

A method and apparatus for its practice are provided of differentiating at least one component of a heterogeneous sample from other component(s) using harmonic resonance imaging and of obtaining information regarding the sample from the differentiation. In a preferred embodiment, an image is created of a property of a harmonic or a combination of a harmonics producing a response having a contrast factor between the sample's constituent components. The desired harmonic(s) can be identified either in a preliminary data acquisition procedure on the sample or, if the sample's constituent components are known in advance, predetermined. The desired harnonic(s) may be identified directly by the user or automatically through, e.g., pattern recognition. A compositional map may then be generated and displayed and / or additional information about the sample may be obtained.

The utility model discloses a planar capacitance resonator and the related preparation method, comprising a resonance body, a sensor electrode, a driving electrode and a related supporting substrate. The resonator is a suspended structure, and is fixed on the substrate through an anchor point; each of the sensor electrode and the driving electrode comprises an electrode plate and a solder pad, the electrode plates of the sensor electrode and the driving electrode are arranged on the two side of the resonance body separately and keep a clearance from the resonance body, the clearance between the plates performs as the media to form the capacitor structure; the solder pads of the sensor electrode and the driving electrode are fixed on the insulating medium layer, and the solder pads are provided with metal electrodes; the insulating medium layer are fixed on the substrate. The clearance between the any two electrodes of the capacitors is narrower than 100nm. The utility model has the advantages of extremely high dynamic performance, the harmonic resonance frequency exceeding 100 MHz, and the Q factor up to 105.

A radio frequency (“RF”) harmonic filter circuit as disclosed herein is fabricated using integrated passive device (“IPD”) technology. The RF harmonic filter circuit is configured to provide second, third, and fourth harmonic rejection while providing good input and output impedance matching. The RF harmonic filter circuit employs only one IPD loop inductance (preferably used for a second harmonic resonance circuit), which results in a significant die / package size reduction. The RF harmonic filter circuit also employs a combined circuit that performs input and / or output impedance matching and third harmonic rejection.

A combined eyelid warming device, resonance frequency generator, coupling device, and tissue response sensor are disclosed in the field of use in dry eye treatment. These combined devices are used to ensure that the entire eyelid surface and periorbital structures receive defined therapeutic warmth and appropriately tuned harmonic resonance frequency for a required period of time to stimulate flow from the Meibomian glands. The combined elements of the invention include an easily moldable heating disc, targeted formulation of the heating material, miniaturized resonant frequency vibrating generator combined with a properly designed reusable mask, to ensure precise location of the heat. Vibration may be delivered continuously or intermittently, and may be delivered according to one or more patterns. A chemical sensor is included to characterize flow as vibration is varied. The external energy source allows for circuitry in the external power module to act as a sweep range device, targeting the specific optimally tuned point or sweep frequency the individual patients body reacts to during initial use. The initial testing device supplied to the Doctor for treatment would include sensing elements to determine the optimal harmonic resonance frequency. Once the frequency is defined, the patient would receive a kit with custom harmonic resonant frequency vibrating generators set to their optimum parameters. This configuration would be amenable to both single use and reusable heater approaches.

The invention relates to a phase angle margin compensation-based system impedance active control method of a grid-connected inverter. Because the changing impedance exists in a power grid, a dynamic interaction influence exists between the grid-connected inverter and the power grid and thus the grid-connected current waveform quality is influenced, so that the weakening of the impedance interaction influence is crucial to improvement of the grid-connected current quality. According to the invention, the impedance active control method is characterized in that real-time grid impedance information is obtained in real time and thus a phase angle margin at an inverter output impedance amplitude-frequency curve intersection point frequency is solved; a voltage feedforward control method is employed and a phase angle margin of the inverter impedance at the impedance intersection point frequency is compensated in real time; operation is carried out on a voltage feedforward link output and a current ring PI result so as to obtain an SPWM control signal. According to the invention, because the active impedance control method with the phase angle margin compensation function is used, the harmonic resonance generated by the dynamic interaction influence between the inverter and the power grid near the impedance intersection point frequency can be effectively suppressed, so that the rid-connected current waveform quality of the inverter is improved and the grid-connected stability is enhanced.

Systems and methods for harmonic resonance control are described. In some embodiments, a system comprises a first switch-controlled VAR source and a harmonic management block which may each be configured to be coupled to a distribution power network. The first switch-controlled VAR source may comprise a first processor, a voltage compensation component, and a switch. The first processor may be configured to enable the voltage compensation component after a delay by controlling the switch based on first proximate voltage after a duration associated with the delay to adjust voltage volt-ampere reactive. The harmonic management block may be configured to compare a second proximate voltage to at least one resonant threshold to detect potential resonance caused by enablement of the voltage compensation component and to engage based on the comparison the resonance compensation component to manage the potential resonance.

On the basis of the inverter-side current feedback control strategy, the invention presents a multi-inverter micro-grid harmonic resonance suppression method based on adaptive virtual impedance remodeling. The method includes a virtual impedance remodeling unit, a parameter adaptive adjustment unit and a grid impedance online detection unit. The virtual impedance remodeling unit can improve the output impedance characteristics of grid-connected inverters and inject certain damping components into a micro-grid. The parameter adaptive adjustment unit adaptively adjusts the control parameters ofthe virtual impedance remodeling unit and a current regulating controller according to the impedance parameters of the grid to maintain the stability of the system. The grid impedance online detectionunit provides the equivalent impedance of the grid as the input of the parameter adaptive adjustment unit. The method improves the characteristics of the current loop, and enables inverters to maintain stability under various grid impedance conditions. The method can solve the problems of complex control system, fixed control parameters and low efficiency of the regulation process in the existingmulti-inverter micro-grid system.

A tool holder and rotating spindle of a milling machine is provided. A dampening member may be disposed on an outer surface of the tool holder or spindle or between the tool and tool holder or tool holder and spindle to mitigate harmonic resonance attributable to the use of the tool holder with the cutting tool.

The invention discloses an encapsulation fixing structure device of a piezoelectric stack actuator, belongs to the technical field of precision machinery and equipment, and relates to nanometer driving and precision positioning. The encapsulation fixing structure device of the piezoelectric stack actuator comprises an encapsulation structure main body, a pre-load nut, and the piezoelectric stack actuator. In the encapsulation structure main body, the shape formed by a fixed plate and two wings is is an inverted U; the two sides of a piezoelectric stack cavity are connected with the two wings through a linear spring beam in a flexible way, thereby being easy for the installation and down-lead of a piezoelectric stack; a piezoelectric stack mounting hole is processed on the fixed plate; the mounting hole is communicated with a hollow cavity of the piezoelectric stack cavity; a wiring trough is processed on the two sides of an inner wall of a connecting cavity; an inner screwed hole is opened on one end of the piezoelectric stack cavity apart from the fixed plate. The invention is applied to high-precision nanometer driving, high-frequency harmonic resonance driving and a high-precision locating system.

The invention relates to an identifying method of dragging power supply system harmonic wave resonant frequency. The method includes the steps of collecting net voltages, used for dragging or baking a running train, in a dragging power supplying system and all four-quadrant converter alternating current side voltages of the train; after the collected data are preprocessed, using an FTF method to calculate the net voltages, all the four-quadrant converter alternating current side voltages and each sub-harmonic component amplitude; for odd sub-harmonics, calculating a harmonic gain coefficient, and according to a relation curve of the harmonic gain coefficient and frequency, identifying the harmonic resonance frequency. The method not only can be used for guiding model selection of a train which is newly input in a railway and avoid occurrence of highly-harmful resonance, but also can be used for testing and detecting the train and identifying the harmonic resonant frequency of a newly-built railway.

A tool holder for use in a rotating spindle of a milling machine. The tool holder comprises a conically tapered shank portion for insertion into the spindle and a cutting tool mounting portion. Disposed between the shank and mounting portions is a flange portion. The flange portion includes a continuous channel formed therein which circumvents the shank portion and is adapted to accommodate a dampening member. The dampening member is compressable between the flange portion and the spindle when the tool holder is inserted into the spindle, and is adapted to eliminate harmonic resonance attributable to the use of the tool holder with a cutting tool.

An antenna system suitable for a mobile device is disclosed. The mobile device includes a display casing with a conductive region and a non-conductive region. The antenna system includes a driven element having an inverted-F antenna arranged in the non-conductive region of the display casing. The display casing is also provided with an electrostatic discharge (ESD) conductor as a countermeasure against ESD. The ESD conductor is connected to the conductive region of the casing. The ESD conductor causes static charges in the air to be discharged to the conductive region of the casing. The ESD conductor also produces harmonic resonance and exchanges electromagnetic energy with the driven element to improve the gain of the driven element.

The invention discloses an improved modal analysis method of power distribution network harmonic resonance. The improved modal analysis method comprises the following steps that: a resonant frequency is determined through using a spectrum analysis method; the eigenvalue matrix of a node admittance matrix under the resonant frequency is obtained; the eigenvalues of the node admittance matrix are sequenced according to an ascending order, and the locations of the eigenvalues are recorded; and the first m minimum eigenvalues are selected as the feasible solutions of critical modes under the resonant frequency, critical right eigenvectors corresponding to each feasible solution are determined, the maximum right eigenvalues and the positions thereof of the critical right eigenvector feasible solutions can be obtained, and the positions are the feasible solutions of a highest excitation node. The improved modal analysis method of the invention has the advantages of high computational efficiency and accurate positioning of the highest excitation node, and the like, and is more suitable for the harmonic resonance analysis of a power distribution network.

Described herein are contactors comprising one or more split or otherwise sectionalized contacts. By comprising split contacts, contactors incorporating features of the present invention increase the number of electrical contact sites between the split contactor and another contactor, allowing current to flow through multiple sites and preventing or mitigating the formation of magnetic fields, harmonic resonance and resulting vibration and noise production. In some embodiments, the contactors comprise at least one bifurcated (split in two) moveable contact and at least one fixed contact. The bifurcated contact can be configured such that it can be easily manipulated as if it were a singular contact, while simultaneously providing the advantages of a bifurcated one.

A wind turbine may be controlled in a variety of manners to optimize operating parameters. In one arrangement, for example, the length or the pitch of a wind turbine rotor blade may be adjusted to avoid harmonic resonance frequencies. In another example, the length of a rotor blade may be modified to reduce noise or to optimize profits or both. The controls may be based on data from various types of sensors including accelerometers, sound meters, strain gauges and the like. Actuation of extendable rotor blades can rotate wind turbine rotors without wind or generator pulsing affording multiple advantages. A battery test control may also be used to determine the operational readiness of a battery useful for a variety of purposes in a turbine.

The embodiment of the invention discloses a shale oil and gas microwave resonance impact collaborative production-increasing technical method. The shale oil and gas microwave resonance impact collaborative production-increasing technical method comprises the following steps that S100, a shale bed is subjected to inherent frequency detection and vibration and temperature detection; S200, an electric pulse excitation source is controlled to emit a high-energy pulse wave band to be subjected to harmonic resonance with shale, and thus the shale cracks to form a crack; S300, the microwave frequency, the penetration depth and the microwave absorbent delivery quantity are determined; S400, variable-power electromagnetic waves are superimposed on the basis of high-energy electric pulse waves, an oil reservoir is heated through a variable-power high-frequency medium polarization heat-generation mechanism, the viscosity of shale oil and the plasticity and toughness of the reservoir are lowered,and the reservoir brittle rupture tendency is enlarged; and S500, the reservoir is improved, and collaborative production-increasing is realized. The advantages of an electromagnetic wave heating production-increasing technology and a frequency spectrum resonance impact production-increasing technology are combined, the high-energy impact waves with the inherent frequency of the target reservoir are superimposed on the electromagnetic wave heating basis, and the characteristics of low pollution, low energy consumption and the like are realized.

The utility model discloses an ultra high voltage frequency modulation harmonic resonance testing power supply based on a high power IGBT, which comprising a rectification circuit, a controller, a high power IGBT inverter, an LC filter circuit, an ultra high voltage generating circuit and a detection circuit. The input terminal of the rectification circuit is connected with a three-phase AC input, the output terminal of the rectifier circuit supplies current toward the high power IGBT, the controller generates a PWM control signal for the high power IGBT inverter, the output signal of the high power IGBT inverter changes to a smooth sine signal through the LC filter, and then be sent to the input terminal of the ultra high voltage generating circuit, which generates high voltage, the detection circuit detects the output of the ultra high voltage generating circuit, transferring the detection signal to the controller via the optical fiber in high speed. The utility model has advantages of simple structure, light weight, low cost, high reliability and capability of graded outputting ultra high voltage.

A method for evaluating harmonic resonance risk of flexible DC converter station, a device and storage medium are provided. By scanning the harmonic impedance of each maintenance mode in the frequencyband of interest, the harmonic impedance amplitude and phase angle of each overhaul mode at each scanning frequency point are obtained, and the maximum and minimum harmonic impedance amplitudes and phase angles of each scanning frequency point and the maximum and minimum harmonic impedance amplitudes and phase angles of each scanning frequency point are calculated, and the harmonic impedance amplitude characteristic region and phase angle characteristic region of the system side are obtained. The harmonic impedance characteristics of flexible DC converter station are calculated, and the amplitude characteristic curve and phase angle characteristic curve of harmonic impedance at converter station side are obtained. Judging the harmonic impedance amplitude characteristic curve of the converter station side and the harmonic impedance amplitude characteristic region of the system side, whether the phase angle characteristic curve of harmonic impedance of converter side coincides with thephase angle characteristic region of harmonic impedance of system side at the same frequency point, in order to determine whether there is harmonic resonance risk at the frequency point, and to realize harmonic resonance risk assessment of flexible DC converter station.

The invention discloses an ultraharmonic resonance signal frequency amplifying device which realizes treble signal frequency amplifying by utilizing an ultraharmonic resonance principle. For a cubic nonlinear flexible body structure, when exciting force frequency is approximate to one third of linear inherent frequency of the structure, free vibration frequency is adjusted for a nonlinear item, a free vibration item is not attenuated to be zero but is precisely equal to treble of exciting frequency, and an ultraharmonic resonance phenomenon is generated. A low-frequency signal source excites a micro beam to generate ultraharmonic resonance; a current signal generated by the micro beam for vibrating and cutting a magnetic induction line is identical with vibration frequency of the micro beam; the current signal generated by the micro beam for vibrating and cutting the magnetic induction line is coupled by a transformer primary coil and transferred to a transformer secondary coil; a treble frequency signal is outputted by a high- and low-pass filter circuit; and an nth treble frequency amplifying signal can be obtained by cascading n treble frequency amplifying devices.

The invention discloses a combined compensation system of an injection-type hybrid active power filter and a static var compensator. The combined compensation system is composed of the injection-type hybrid active power filter and the static var compensator, wherein, the injection-type hybrid active power filter is composed of an uncontrollable rectifier bridge, an inverter, an output filter reactor, a coupling transformer, an injection branch and a high-pass filter, a first capacitor (C1) and a first inductor (L1) in the injection branch form a first harmonic resonance circuit, and forms a triple resonance injection branch with an injection capacitor (C[F]), and a second capacitor (C[G]), a second inductor (L[G]) and a resistor (R[G]) form a second order damped high-pass filter; the static var compensator is a thyristor controlled reactor; and an output terminal of the injection capacitor (C[F]) is connected with the high-pass filter, the static var compensator and electric grids. In the combined compensation system, one compensation system is respectively arranged at two feeding sections of an electric traction system, which can realize comprehensive control on reactive, harmonics and negative sequence compensation in electric railways.

The invention discloses a harmonic impedance measuring device of a tractive power supply system and a test method of the device. The device can obtain relatively complete voltage and current harmonic characteristics of the tractive power supply system by carrying out disturbance test on the tractive power supply system only once, and further obtain accurate harmonic impedance characteristic of the tractive power supply system; the characteristics can be displayed in a display screen in real time; and data and technology support is provided for harmonic resonance and stability analysis of the tractive power supply system on the basis of an impedance analysis method.