427 results about "Higher order harmonics" patented technology

In an operation range of an actuator subjected to quick acceleration and deceleration, a motor drive apparatus, an electric actuator and an electric power steering apparatus capable of continuous torque control up to the high drive speed and high torque area. A controller comprises a voltage saturation detecting means for detecting the voltage saturation of the output voltage of an inverter circuit, based on the battery voltage, and a waveform controller that converts the drive waveform of the inverter circuit into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWN carrier wave; and continuously changes the ratio of superimposing the high-order harmonics in response to the voltage saturation detected by a voltage saturation detecting means. This arrangement allows the controller to continuously change the drive waveform of the inverter circuit.

The disclosure concerns a a motor drive apparatus, an electric actuator and an electric power steering apparatus capable of continuous torque control up to the high drive speed and high torque area, in order to enable quick acceleration and deceleration. A controller comprises a voltage saturation detecting apparatus for detecting the voltage saturation of the output voltage of an inverter circuit, based on the battery voltage, and a waveform controller that converts the drive waveform of the inverter circuit into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWN carrier wave; and continuously changes the ratio of superimposing the high-order harmonics in response to the voltage saturation detected by a voltage saturation detecting means. This arrangement allows the controller to continuously change the drive waveform of the inverter circuit.

A method of seismic surveying using one or more vibrational seismic energy sources activated by sweep signals. The highest order harmonic that has sufficient strength to cause significant harmonic distortion of a sweep segment is determined. A number of sweep segments in excess of the number of sources is selected. Initial phase angles are selected for each sweep segment of each seismic energy source so that substantially all harmonics up to and including the highest order harmonic are suppressed. Using cascaded sweeps, seismic data are acquired and processed to substantially attenuate harmonics upto the selected order.

An acoustic-based system, such as a touchscreen system, is provided. The system comprises an acoustic substrate and an acoustic transducer operably coupled to the substrate. The transducer exhibits a higher order odd resonant frequency that is equal to the operating frequency of the system. As a result of using the higher resonant frequency that is substantially equal to the operating frequency, the thickness of the transducer can be increased, and thus made more durable.

A phase-based TOF system preferably generates an optical waveform with fast rise and fall times, to enhance modulation contrast, notwithstanding there will be many high order harmonics. The system is preferably operated with an odd number of phases, to reduce system bias error due to the higher order harmonics, while maintaining good modulation contrast, without unduly increasing system memory requirements. Preferably the system can dynamically calibrate (and compensate for) higher order harmonics in the TOF generated optical energy waveform, over time and temperature. Within the optical energy transmission channel, or within the optical energy detection channel, detection amplifier gain may be modified, and / or detector signal integration time may be varied, and / or digital values may be employed to implement calibration and error reduction The resultant TOF system can operate with improved phase-vs-distance characteristics, with reduced calibration requirements.

Light load efficiency of a power factor correction circuit is improved by adaptive on-time control and providing for selection between a continuous conduction mode and a discontinuous conduction mode wherein the discontinuous conduction mode increases time between switching pulses controlling connection of a cyclically varying voltage to a filter / inductor that delivers a desired DC voltage and thus can greatly reduce the switching frequency at light loads where switching frequency related losses dominate efficiency. The mode for controlling switching is preferably selected for each switching pulse within a half cycle of the cyclically varying input voltage. A multi-phase embodiment allows cancellation of EMI noise at harmonics of the switching frequency and adaptive change of phase angle allows for cancellation of dominant higher order harmonics as switching frequency is reduced.

A method and apparatus for manipulating ions using a two-dimensional substantially quadrupole field, and a method of manufacturing an apparatus for manipulating ions using a two-dimensional substantially quadrupole field are described. The field has a quadrupole harmonic with amplitude A2, an octopole harmonic with amplitude A4, and higher order harmonics with amplitudes A6 and A8. The amplitude A8 is less than A4. The A4 component of the field is selected to improve the performance of the field with respect to ion selection and ion fragmentation. The selected A4 component can be added by selecting a degree of asymmetry under a 90° rotation about a central axis of the quadrupole. The degree of asymmetry is selected to be sufficient to provide the selected A4 component.

A new generation polarimetry apparatus and methodology is disclosed, which involve passing polarized light through a sample including a chiral analyte, where the analyte is under the influence of a periodically varying magnetic field. The apparatus also utilizes optical heterodyne detection and lock-in detection at higher order harmonics of the magnetic field modulation frequency to improve sensitivity and detection limits of optical properties of chiral analytes.

The invention discloses a method for carrying out dynamic and real-time shimming on any multi-order harmonic component in a selected area for magnetic resonance imaging, and the method can be used for improving the uniformity degree of a main magnetic field in an imaging area through cancelling out non-uniform harmonic items. According to the method provided by the invention, the weight distribution of any-order harmonic of the main magnetic field in the selected area can be analyzed once through phase information of images which are acquired by a three-dimensional gradient echo sequence twice, wherein a series of technical means of carrying out water-fat phase synchronization, eliminating low-signal noise pollution by virtue of an amplitude template and unwinding a three-dimensional phase are adopted, so that the weight component coefficient of any-order harmonic in the selected imaging area can be accurately and rapidly analyzed; a reversed compensating current is added into a corresponding harmonic shimming coil so as to accurately cancel out non-uniform high-order harmonics and only reserve zero-order harmonics, namely a uniform field; and the method provided by the invention has the advantage of maximally improving the uniformity degree of the main magnetic field by combining owned hardware conditions.

A hybrid conditioner for filtering harmonics in a power system that includes a non-linear load. The hybrid conditioner includes an active filter structured and controlled to filter one or more high-order harmonic currents of the fundamental frequency, and a passive filter structured to filter one or more low-order harmonic currents of the fundamental frequency. The active filter and the passive filter are electrically connected in parallel with one another. The hybrid conditioner may also be for providing reactive power compensation for the power system, wherein the active filter is further controlled to provide a compensatory reactive power for compensating for the reactive power that is consumed by the load. The hybrid conditioner may also provide oscillation dampening for the power system, wherein the active filter is further controlled to damp oscillating currents that exist between the passive filter and the AC source.

A mixer produces an improved output signal during frequency translation of an input signal using a local oscillator (LO) signal. The mixer includes five component mixers connected in parallel. Each component mixer uses a phase-shifted version of the LO signal for frequency translation to produce a component output signal from the input signal. The component output signals are scaled according to corresponding gain factors and combined to form the output signal. When the mixer is used in a receiver, the phases of the component LO signals and the gain factors are configured to substantially cancel overlapping baseband versions of component input signals located at the third, fifth, seventh and ninth harmonics of the LO frequency. When used in a transmitter, the same phase and gain factor configurations substantially cancel third, fifth, seventh and ninth harmonics within the output signal.

The invention relates to the nuclear reactor core power monitoring field and discloses a method for online monitoring the neutron flux distribution of the reactor core. The method bases on M1 internal neutron detectors and M2 external neutron detectors which are arranged on the reactor. According to a reference reactor core model of a renewal reactor that MPhi is equal to (1 / k) FPhi, higher order harmonics are solved. Then, reading data of the internal neutron detectors and the external neutron detectors are combined. The neutron flux distribution in the core of a real reactor is reconstructed online.

A method of determining an overlay error in which asymmetry of a first order of a diffraction pattern is modeled as being a weighted sum of harmonics. Both the first order harmonic and higher order harmonics are non-negligible and weights for both are calculated. The weights are calculated using three or more of sets of superimposed patterns using a least mean square method.

The invention discloses an air conditioner and a harmonic torque compensation method and control method and device of a compressor. The harmonic torque compensation method comprises the following steps of obtaining a load torque harmonic of the compressor and a motor output electromagnetic torque harmonic of the compressor under any operating condition of the compressor, and determining a harmonic compensation order according to the load torque harmonic and the electromagnetic torque harmonic; obtaining a harmonic frequency corresponding to the harmonic compensation order and determining a harmonic compensation mode according to a frequency interval in which the corresponding harmonic frequency is located; adjusting compensation parameters of the harmonic compensation mode for multiple times according to a default rule and carrying out harmonic torque compensation control on the compressor according to the adjusted compensation parameters in sequence; and determining the final harmonic torque compensation parameters according to the harmonic torque compensation result of the compressor during each operation. Therefore, full-band harmonic torque control of low-order harmonics and high-order harmonics cannot be achieved, and the motor output torque of the compressor better tracks the load torque of the compressor.

Various embodiments of the present invention provide systems and methods for determining fly height. For example, a system for fly height determination is disclosed that includes a head assembly disposed in relation to a storage medium, a write channel, and a read circuit. The read circuit is operable to receive information from both the head assembly and the write channel. A frequency determination circuit is included that is operable to receive a first signal from the read circuit corresponding to information received from the write channel and to provide a first fundamental frequency and a first higher order frequency based on the first signal, and the frequency determination circuit is operable to receive a second signal from the read circuit corresponding to information received from the head assembly channel and to provide a second fundamental frequency and a second higher order frequency based on the second signal. A compensation variable calculation module is included that is operable to divide the first fundamental frequency by the first higher order harmonic to yield a compensation variable. A fly height calculation module is included that is operable to divide the second fundamental frequency by the second higher order harmonic and the compensation variable to yield an indication of a distance between the head assembly and the storage medium.

A system for controlling a permanent magnet synchronous motor calculates fundamental a d-axis (or q-axis) voltage command based on a difference between a d-axis (or q-axis) current command and a d-axis (or q-axis) current feedback signal, calculates a harmonic suppression d-axis (or q-axis) voltage command used to suppress at least one higher-order harmonic current component included in a harmonic current component which is calculated based on the differences between the current feedback signals and the current commands, and calculates a d-axis (or q-axis) voltage command by adding the fundamental d-axis (or q-axis) voltage command and the harmonic suppression d-axis (or q-axis) voltage command. The d-axis and q-axis voltage commands are transformed into three-phase voltage commands, which are converted into a drive voltage for driving the permanent magnet synchronous motor. As a result, the harmonic current components are significantly suppressed and the motor's overall performance is improved.

The invention relates to a multi-mode non-linear optical microscopy imaging method and device. The multi-mode non-linear optical microscopy imaging device mainly comprises a laser system, an optical scanning microscope and a non-linear optical signal detecting and acquiring system. The multi-mode non-linear optical microscopy imaging device can work in a single-laser-beam mode and a dual-laser-beam mode and can realize multi-mode non-linear optical microscopy imaging such as two-photon excited Fluorescence (TPEF) imaging, multiphoton high-order harmonic (such as second harmonic generation SHG, and third harmonic generation THG) scattering imaging, coherent Raman scattering (such as anti-Stokes CARS) microscopy imaging) on isolated biological tissues and living cells, so that various non-linear specific optical signals of biological tissue samples can be obtained in situ, so that the important basis is provided for the optical diagnosis and deep analysis of the samples. Besides, a reflection measurement manner disclosed by the invention can be further directly applied to the acquiring of various non-linear specific optical signals of live animals and the microscopy imaging.

A pre-ionized medium created by a capillary discharge results in more efficient use of laser energy in high-order harmonic generation (HHG) from ions. It extends the cutoff photon energy, and reduces the distortion of the laser pulse as it propagates down the waveguide. The observed enhancements result from a combination of reduced ionization energy loss and reduced ionization-induced defocusing of the driving laser as well as waveguiding of the driving laser pulse. The discharge plasma also provides a means to spectrally tune the harmonics by tailoring the initial level of ionization of the medium.

The invention provides a method for detecting distortion degree of inrush current of a transformer, which adopts abundant high order harmonic resulting in inrush current distortion in inrush current to comprehensively reflect the distortion degree of the inrush current so as to judge whether fault current or magnetizing inrush current leads the current of the transformer to be abnormal according to the distortion degree. Therefore, the distortion degree Q is defined and the calculation method of Q is declared as follows: filtering out direct current components by a difference algorithm; and filtering out fundamental components by a cosine filter. When the judgment result is the fault current, the numerical values of a front sequence and a rear sequence of the cosine filtering are basicallyconsistent, so the Q value is small; when the judgment result is the magnetizing inrush current, the numerical values of the front sequence and the rear sequence of the cosine filtering have big discrepancy, so the Q value is big. The fault current and the magnetizing inrush current can be strictly distinguished by selecting a valve value properly. The method has higher redundancy on the criterion and can use braking with a logic product door, therefore, differential protection can not act in a delaying manner when being dropped into a transformer in fault. The invention has the advantage ofimproving the condition of low long-term correct action rate of the differential protection of the transformer.

A method, device, and plurality of circuit enhancements for a rectifier system that enable reduction in lower order and higher order harmonics, without substantially reducing the rectifier's direct current output voltage. The rectifier system comprises a phase shifting primary transformer subsystem and a multi-pulse rectifier. At least one series impedance path is coupled to one of three input terminals / leads of the transformer subsystem and conducts one phase of three phase currents from a power supply to the transformer subsystem. The series impedance path provides low impedance to the 1st harmonic and substantially higher, inductive impedance to higher harmonics of the power supply frequency. The impedance of the series impedance path at a selected frequency above a third harmonic of the power supply's fundamental frequency divided by the impedance at the fundamental frequency of the three phase power supply is substantially greater than the selected frequency divided by the fundamental frequency of the power supply.

A harmonics attenuator employing a combination controller that incorporates features of a classic controller and a state space controller to function as a hybrid controller unit. The PID portion of the classic controller regulates the steady state error and is separated from the pulse width modulated constant frequency signal generator that also comprises part of the classic controller. The PID portion is coupled with a state space controller such that the output of the PID controller, i.e., the steady state error correction, is input to the state space controller. The state space controller further receives as input variables a reference sinusoidal signal, the load current, the current across a pre-load filter capacitor, and the output voltage. From these inputs, the state space controller generates a transient error correction that is fed to a PWM signal generator for generating a sinusoidal output voltage signal with both steady state and transient error correction. The combination controller is thusly incorporated into an electrical feedback system referred to as a harmonics eater to attenuate higher order harmonics in an AC driven system.

Light load efficiency of a power factor correction circuit is improved by adaptive on-time control and providing for selection between a continuous conduction mode and a discontinuous conduction mode wherein the discontinuous conduction mode increases time between switching pulses controlling connection of a cyclically varying voltage to a filter / inductor that delivers a desired DC voltage and thus can greatly reduce the switching frequency at light loads where switching frequency related losses dominate efficiency. The mode for controlling switching is preferably selected for each switching pulse within a half cycle of the cyclically varying input voltage. A multi-phase embodiment allows cancellation of EMI noise at harmonics of the switching frequency and adaptive change of phase angle allows for cancellation of dominant higher order harmonics as switching frequency is reduced.

The invention provides a high-speed railway electric energy quality and traction network voltage comprehensive compensation system. The comprehensive compensation system comprises a single-phase back-to-back STATCOM installed on the traction side of a traction substation and thyristor switched high-pass filters installed in section posts. The single-phase back-to-back STATCOM is used for negative sequence compensation, lower-order harmonic filtration within the range of 2-11 order and power factor and traction network bus voltage control. The thyristor switched high-pass filters are used for absorbing high-order harmonic with the order of 11 or above and stabilizing the traction network terminal voltage. The single-phase back-to-back STATCOM can detect the power factor of the traction substation in real time, carry out dynamic stepless regulation on reactive output and maintain the power factor of the system to be 0.9 or above. The thyristor switched high-pass filters arranged in the section posts are used for absorbing harmonic currents with the order of 11 or above and improving the traction network voltage. The whole high-speed railway electric energy quality and traction network voltage comprehensive compensation system has the advantages of being small in occupies area, low in operation loss, low in construction cost, high in reliability, simple in technology implementation, prominent in comprehensive benefit and the like.

A mixer includes, an input current generation unit generating an input current; a first path circuit unit including n number of transistors having sources connected in common to an output node of the input current generation unit; and a second path circuit unit including n number of transistors having sources connected in common to the output node of the input current generation unit, and respectively corresponding to the n number of transistors included in the first path circuit unit. Local oscillator signals sequentially phase-shifted by 180° / n are individually input to gates of the n number of transistors included in the first path circuit unit, and local oscillator signals having opposite phases to the local oscillator signals input to the gates of the corresponding transistors included in the first path circuit unit are individually input to gates of the n number of transistors included in the second path circuit unit.

A light emitting element emits a modulated light modulated in a pattern having a repetitive period toward a space. A driving unit drives the light emitting element. A light receiving element distributes charges corresponding to an incident light containing a reflected light obtained by reflecting the modulated light on an object to storage capacitors and stores the distributed charges. A control unit controls an exposure of the light receiving element. A signal processing unit measures a distance to the object by using a value sampled by the light receiving element. The control unit controls the exposure of the light receiving element to give a sensitivity to at least one high-order harmonic. The signal processing unit linearly combines a component of a fundamental wave with a component of the at least one high-order harmonic to measure the distance to the object.

The invention discloses an electric-vibration model-based power transformer failure diagnosis method, which comprises the following steps of: training to establish an electric-vibration model by acquiring a voltage signal, a current signal, an oil temperature signal and a plurality of vibration measuring points of a transformer; and performing failure diagnosis on the transformer by comparing measured data of vibration with predicted data obtained through the model. According to the method, both input and output of the vibration model are related with actual vibration, and signal, transformer parameters and the like can be measured or acquired; the method has extremely high practicability; a fundamental frequency component of the vibration of the transformer is considered by the model, and high order harmonic is also included, and some failures which cannot be reflected by the fundamental frequency vibration can be discovered; and the vibration of a plurality of measuring points of the oil tank wall of the transformer is considered by the model, the possibility that the internal vibration of the transformer is not inflexibility or incompletely reflected by single-point vibration is eliminated, and the accuracy for performing monitoring diagnosis of the transformer by using the electric-vibration model is improved.

A new generation polarimetry apparatus and methodology is disclosed, which involve passing polarized light through a sample including a chiral analyte, where the analyte is under the influence of a periodically varying magnetic field. The apparatus also utilizes optical heterodyne detection and lock-in detection at higher order harmonics of the magnetic field modulation frequency to improve sensitivity and detection limits of optical properties of chiral analytes.

All-optical quasi-phase matching (QPM) uses a train of counterpropagating pulses to enhance high-order harmonic generation (HHG) in a hollow waveguide. A pump pulse enters one end of the waveguide, and causes HHG in the waveguide. The counterpropagation pulses enter the other end of the waveguide and interact with the pump pulses to cause QPM within the waveguide, enhancing the HHG.