372 results about "Harmonic filtering" patented technology

A method for padding, filtering, denoising, image enhancing and increased time-frequency acquisition is described for digitized data of a data set where unknown data is estimated using real data by adding unknown data points in a manner that the padding routine can estimate the interior data set including known and unknown data to a given accuracy on the known data points. The method also provides filtering using non-interpolating, well-tempered distributed approximating functional (NIDAF)-low-band-pass filters. The method also provides for symmetric and/or anti-symmetric extension of the data set so that the data set may be better refined and can be filtered by Fourier and other type of low frequency or harmonic filters.

The method of the invention in one aspect involves electronic power control by varying the amplitude of an electrical power supply voltage, independent of frequency, whereby the output frequency will always be the same as the input frequency. An electrical circuit apparatus for accomplishing this function in a specific embodiment is also disclosed herein. The specific circuitry of this aspect of the invention uses eight solid state switches, such as IGBT's, eight diodes, an inductor, input and output filters and novel controlling circuitry. The controller apparatus and methods of the invention may be used to implement all otherwise conventional converter types, buck, boost, and inverting (and duals of these) versions to obtain different regulating characteristics, including galvanic isolation of the output from the input. Indeed, the eight-switch controller can act to either buck or boost the input voltage, and can switch between bucking and boosting during a cycle, thus providing more control of the regulated output voltage. The inventive methods and devices may be used in power factor correction, voltage and/or current harmonic filtering and neutralization, line and load conditioning, control of power transfer between two power grids, and programmable control of surges, sags, dropouts and most other voltage regulation problems.

The method of the invention in one aspect involves electronic power control by varying the amplitude of an electrical power supply voltage, independent of frequency, whereby the output frequency will always be the same as the input frequency. An electrical circuit apparatus for accomplishing this function in a preferred embodiment is also disclosed herein. The preferred circuitry of this aspect of the invention uses four solid state switches, such as IGBT's, four diodes, an inductor, input and output filters and novel controlling circuitry. The controller apparatus and methods of the invention may be used to implement all otherwise conventional converter types, buck, boost, and inverting (and duals of these) versions to obtain different regulating characteristics, including galvanic isolation of the output from the input. The inventive methods and devices may be used in power factor correction, voltage and/or current harmonic filtering and neutralization, line and load conditioning, control of power transfer between two power grids, and programmable control of surges, sags, dropouts and most other voltage regulation problems.

A power supply including an inverter receiving a DC input signal from a DC input source (11). The inverter is implemented as a single-ended inverter. Each inverter is driven by a signal source (13A, 13B), which outputs an AC signal. The output from each inverter is input to a first stage harmonic filter. The power supply includes an output circuit that includes a rectifier (D1) arranged about a point so that if the inverter attempts to drive the point beyond a predetermined voltage, the rectifier conducts in order to return at least one of power and current to the DC input source. The output from the first harmonic filter (L1A, C1; L1B, C1) is output to a second harmonic filter (L2, C2) and is then output from the power supply.

A driving apparatus is provided and configured to suit driving at least a string of light emitting diodes (LEDs). The driving apparatus includes a flyback power factor correction (PFC) converter, a harmonics-filtering unit and a control unit. The flyback PFC converter works in an operation mode according to a pulse-width modulation (PWM) signal and receives an AC power so as to convert the AC power into a pulsating current. The harmonics-filtering unit is coupled to the flyback PFC converter and the string of LEDs, for receiving the pulsating current and filtering out the high-frequency harmonic components in the pulsating current so as to drive the string of LEDs. The control unit is coupled to the flyback PFC converter and the harmonics-filtering unit, for producing the PWM signal according to the AC power and the pulsating current, and reducing the peak-to-average ratio (PAR) of the pulsating current.

The invention provides a dynamic harmonic filter, mainly comprising a variable reactor (4), an anti-parallel thyristor trigger circuit (5), a control coil (6) and a capacitor group (7), wherein, one end of the variable reactor is in parallel connection with the capacitor group; two terminals of the anti-parallel thyristor trigger circuit are respectively connected with the both ends of the control coil to form a circuit; multiple groups of quick fuses (8) and a capacitor contactor (9) are in parallel connection with a series circuit of a capacitor (10) to form the capacitor group; when capacitive reactance of the capacitor group changes, the control coil is started under the action of the anti-parallel thyristor trigger circuit, and dynamically adjusts the inductance of the variable reactor. The dynamic harmonic filter of the invention forms a low-impedance loop to absorb the harmonic wave under harmonic frequency of f0; besides, the dynamic harmonic filter provides reactive current to improve power factor under the fundamental harmonic frequency. The dynamic harmonic filter creates conditions for reduction of harm of the harmonic wave to a transformer, a power cable, a motor, a control system, a communication system and the capacitor and the like.

A power supply including an inverter receiving a DC input signal from a DC input source (11). The inverter is comprised of two half bridges (S1 A, S2A and S1B, S2B). Each inverter is driven by a signal source (13A, 13B), which outputs an AC signal. The output from each inverter is input to a first stage harmonic filter. The power supply includes an output circuit that includes first and second rectifiers (D1, D2) arranged about a point so that if the inverter attempts to drive the point beyond a predetermined first and second voltage, the respective rectifier conducts in order to return at least one of power and current to the DC input source. The output from the first harmonic filter (L1A, C1; L1B, C1) is output to a second harmonic filter (L2, C2) and is then output from the power supply.

A doubly balanced transceiver system having a transmit terminal (TX), a receive terminal (RX), and an an antenna terminal (ANTENNA), 180° hybrids (201, 240), 90° hybrids (204, 304, 235 and 335), a power amplifier (230, 330) and a RX/TX switch (220) for disabling the power amplifier so that signals received at the transmitter are reflected to the receive terminal (RX). The 180° hybrids (201, 240) preferably split and re-combine signals into parallel paths. A loopback test mode is preferably provided by use of an antenna isolation switch (302) to enable a power detect terminal (POWER_DETECT). This eliminates pricey and problematic GaAs switches, and allows the use of low cost silicon for the power amplifier. The doubly balance architecture also has the advantage of eliminating common-mode noise, and reflection problems with the PA gain stages. Additionally, greater power can be extracted from the power amplifier. Further the arrangement has less insertion loss compared to a GaAs switch. Also, dependant upon system specifications, it may be possible to eliminate harmonic filtering at the power amplifier output.

A broad-spectrum harmonic filter is developed. This filter is to be connected in series ahead of the load which generates harmonics. This filter basically consists of 3 fixed elements, i.e. a series reactor and a shunt reactor in series with a capacitor. It can function to completely filter out 5th harmonic current in 3 phase systems (or 3rd harmonic current in single phase systems) and to reduce other harmonic components by high percentages say, typically close to 70%. Thus the portions of various harmonics flowing toward the electrical power source can be held within acceptable limits.

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 a cluster communication power amplifier. The cluster communication power amplifier comprises an input impedance matching circuit, a controllable attenuation network circuit, a power amplifier, a directional coupling and output power detection circuit, an isolator, a harmonic filter and an output micro-strip impedance matching circuit, which are sequentially connected. The cluster communication power amplifier also comprises a digital signal processor (DSP) circuit. The power amplifier comprises a pre-amplifier and a final amplifier, which are in front-back connection; input and output impedance matching circuits are connected in series and in parallel to form micro-strip mixed matching circuits of a trapezoid connection capacitor; the output power detection circuit is connected to the DSP circuit; the output of the DSP circuit is connected with a control end of the controllable attenuation network circuit; and the input and output impedance matching circuits are micro-strip mixed matching circuits. The cluster communication power amplifier performs control and management in an intelligent automatic gain control (AGC) mode, is applicable to temperature compensation, temperature detection, power and voltage standing wave ratio (VSWR) detection and the like, and has the characteristics of low gain flatness, convenience for gain control, high stability and the like based on a mature power backing-off linear technology.

A drive system for driving large capacity motors includes a motor and a variable frequency drive which accepts input from a three-phase power source. The drive system includes a step-up transformer, preferably of a high-capacity three-phase type, positioned between and electrically connected to the motor and the variable frequency drive to thereby step-up voltage received from the variable frequency drive to be supplied to the motor. The transformer includes a transformer chamber formed in the transformer tank containing a cooling fluid for cooling transformer internal components. A plurality of inductors forming part of a harmonic filter are positioned within the transformer chamber such that they can be protected from the environment and simultaneously cooled with other transformer internal components by the dielectric fluid. The filter includes capacitors that are preferably mounted outside of the tank.

A filter uses a special autotransformer that has a ferromagnetic core with a plurality of legs and flux return bars. A first coil is located on one leg, and a second coil is located on the same leg, but spaced from the first coil. The first coil and at least part of the second coil are connected in series to receive distorted alternating current and at least that part of the second coil is connected to an output terminal. Between the coils and extending at least part of the way from the first leg to an adjacent leg is a magnetic shunt assembly to divert part of the flux generated in the first coil by the alternating current so that that part does not link with the second coil. An air gap is located to link with the second coil to create an inductor in that coil by flux in the second coil, and a capacitor is connected across the second coil to tune it to the fundamental frequency of the alternating current and substantially reduce harmonics in that current.

The present invention relates to a wind turbine facility comprising a power generator operationally connected to an AC/AC converter adapted to receive variable frequency AC-power from the power generator, and adapted to generate substantially fixed frequency AC-power. The wind turbine facility further comprises a harmonic filter system, and a grid transformer comprising a primary winding being operationally connected to the AC/AC converter, and a secondary winding adapted to be operationally connected to an associated, substantially fixed frequency AC-power supply grid. The grid transformer further comprises a tertiary winding being operationally connected to the harmonic filter in order to suppress unwanted harmonics, such as selected harmonics generated by the AC/AC converter. The turn ratio between the primary and tertiary windings is selected in such a manner that a voltage of the tertiary winding is lower than a nominal voltage level of the associated AC-power supply grid voltage.

The invention relates to a method for controlling three-phase four-leg converter, belonging to the field of power electronics converter. The method is that: the idea of generating switch tube control pulses of the four legs is that: the front three of the four legs adopt SPWM control or harmonic filtering technique to eliminate the 6k+/-1th harmonics (wherein, k is a natural number 1, 2, 3, 4,í¡), the control pulse for the fourth leg eliminates the phase voltage zero-sequence harmonics generated by the front three ones, by the SPWM control or harmonic filtering technique, i.e. by the mutually or approximately counteraction of the 3kth harmonics generated by the fourth leg and the 3kth harmonics generated by the front three ones. The invention eliminates all the low-order harmonics to ensure the quality of the output waveforms of the converter, applied to the application occasions of medium-high frequency output. The method makes the converter possess the advantages of low switching frequency, small total harmonic distortion (THD) of output voltage, etc.

A front end circuit and a wireless communication device capable of achieving matching with an antenna across a wide frequency band and capable of suppressing degradation in high-frequency characteristics caused by the influence of transmission signal harmonics is provided. A front end circuit includes a variable matching circuit connected to a low-frequency band transmission port side of a diplexer and a harmonic filter connected between the variable matching circuit and the diplexer. The harmonic filter has a pass band that overlaps with a low-frequency band-side communication band and a stop band that overlaps with a harmonic frequency of the low-frequency band-side communication band.

The invention provides a second-order generalized integrator structure based on a frequency locking loop and a phase-locked loop synchronization method. The structure comprises a second-order generalized integrator, a frequency locking loop based on the second-order generalized integrator and a feedback loop; the second-order generalized integrator is used for receiving a voltage input signal of asingle-phase power grid and outputting a first orthogonal output signal and a second orthogonal output signal, wherein the voltage input signal comprises an input voltage signal and input frequency;the frequency locking loop based on the second-order generalized integrator is used for obtaining adjustment frequency and a third orthogonal output signal and a fourth orthogonal output signal according to the first orthogonal output signal; and the feedback loop is used for feeding back the adjustment frequency to the second-order generalized integrator to serve as new input frequency. The second-order generalized integrator structure based on the frequency locking loop provided by the invention improves the filtering ability of the DC components in the voltage signal, meanwhile improves the phase locking accuracy when the input signal contains the DC components and has better harmonic filtering ability.

A system for detecting both forward and reverse power of a power amplifier in the presence of harmonics created by the power amplifier is provided. A forward power detection system receives detection signals from an in-phase amplifier leg and a quadrature-phase amplifier leg of the power amplifier. The forward power detection system applies a phase shift to the detection signals such that forward components of the detection signals are essentially in-phase, and reverse components of the detection signals are essentially 180 degrees out-of-phase. The phase shifted detection signals are then combined and filtered to provide a signal indicative of forward power. In a similar fashion, a reverse power detection system applies a phase shift to the detection signals to provide a signal indicative of reverse power.