422 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.

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.

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.

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 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 1^st 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.

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.

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.

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.