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140 results about "Third harmonic" patented technology

Harmonics are multiple of fundamental frequency. So 3rd multiple of fundamental frequency is known as 3rd harmonic. Generally depending on the country fundamental frequency is 50hz or 60 hz. Non linear loads like electronics, some large induction motor with improper winding, generators etc generate this third harmonics.

Harmonic suppression power amplifier combining matching network and feed network

The invention relates to the technical field of radio frequency integrated circuits, in particular to a harmonic suppression power amplifier combining a matching network and a feed network, which comprises a transistor, an input matching module, an output matching module, a stabilizing module and a bias module, the input matching module comprises a first parallel resonance unit, the first parallel resonance unit is used for second harmonic suppression, the output matching module comprises a series resonance unit and a second parallel resonance unit, the series resonance unit is used for resonating at a second harmonic frequency and performing low-impedance grounding on the second harmonic, and the second parallel resonance unit is used for resonating at a second harmonic frequency and performing low-impedance grounding on the second harmonic. The second parallel resonance unit is used for resonating at a third harmonic frequency and forms a high-impedance open circuit for the third harmonic, the output matching module is coupled to a drain electrode of the transistor, and the bias module comprises a grid bias sub-module and a drain bias sub-module. The grid bias sub-module is coupled to a connection node of the input matching module and the grid of the transistor, the drain bias sub-module is coupled to the output matching module, and the bias voltage of the transistor is jointly determined by the grid bias sub-module and the drain bias sub-module. The power amplifier has the effect of improving the efficiency level of the power amplifier while realizing harmonic suppression optimization.
Owner:INNOVATIVE MICRO-IC TECH(FOSHAN) CO LTD

On-line monitoring method for insulation state of stator winding of full-power variable-speed pumped storage unit

The invention discloses a full-power variable-speed pumped storage unit stator winding insulation state online monitoring method, and provides a high-capacity generator unit stator winding insulation state online monitoring method which can be applied to a network side transformer neutral point ungrounded system. According to the method, an effective common-mode monitoring loop can be established, and monitoring is carried out by utilizing the third harmonic of the motor stator winding and is not interfered by the high-frequency switch harmonic of the frequency converter. In order to solve the problem that a full-power variable-speed pumped storage unit generally has large capacity and is not easy to realize online measurement, the invention provides a method for measuring on a neutral point outgoing line, which can realize online measurement of the insulation state of a stator winding when the load current is relatively large. The method is suitable for a full-power variable-speed pumped storage high-capacity unit, leakage current measurement can be carried out under the condition of large load current, and stator insulation information online monitoring is achieved.
Owner:TSINGHUA UNIVERSITY +1

Internet of Things flowmeter data compression sensing transmission optimization method and system

The invention discloses an Internet of Things flowmeter data compression sensing transmission optimization method and system, particularly relates to the field of low-power-consumption wireless communication networks, and is used for solving the problem of compressed sensing signal distortion caused by sampling time sequence misalignment in an LPWAN bandwidth limited environment. Constructing a local phase reference by extracting a pipeline vibration fundamental frequency component, and receiving a cloud synchronization reference timestamp alignment signal; fundamental frequency and third harmonic components are separated to calculate arrival time difference, and a phase-locked loop is triggered to dynamically adjust the phase of a sampling clock based on a pipeline material threshold value; after the stability of the zero crossing point time variance is verified, compressed sensing sampling is performed on the flow signal by adopting a phase synchronous clock, and an optimized compressed measurement value is generated and transmitted to the cloud through the LPWAN; through closed-loop cooperation of physical characteristics and a communication clock, complete capture of a signal sparse structure is guaranteed under a low-bandwidth condition, and cloud reconstruction precision is significantly improved.
Owner:JIANGSU HENGHE GRP

Apparatus, system and method of transmitting a wideband radio frequency (RF) transmit (TX) signal

For example, a transmitter, e.g., for a wireless communication device, may be configured to transmit a wideband Radio Frequency (RF) Transmit (Tx) signal having a wide bandwidth of at least 80 Megahertz (MHz). For example, the transmitter may be configured to generate the wideband RF Tx signal having the wide bandwidth based on a baseband signal. The transmitter may be configured to generate the wideband RF Tx signal including a suppressed third harmonic and a suppressed fifth harmonic.
Owner:INTEL CORP

Axial skewed pole motor eccentricity detection method based on asymmetric layered Hall

The invention provides an axial skewed pole motor eccentricity detection method based on asymmetric layered Hall, and the method comprises the following steps: respectively installing a first group of linear Hall sensors and a second group of linear Hall sensors on a first axial layer and a second axial layer of a stator notch of an axial skewed pole motor in an asymmetric manner; after analog-to-digital conversion is carried out on the voltage signals detected by the linear Hall sensor, a pair of orthogonal third harmonic sinusoidal signals is obtained through grouping signal superposition, and the eccentric direction is determined; and based on a complex factor filter and a synchronous reference system phase-locked loop, extracting amplitudes of a positive sequence signal, a negative sequence signal and a sideband signal from the third harmonic sinusoidal signal, and further calculating a static eccentricity rate and a dynamic eccentricity rate. According to the axial skewed pole motor eccentricity detection method, two groups of linear Hall sensors are mounted in a layered and asymmetric manner, so that the eccentricity detection sensitivity and precision are effectively improved, the eccentricity state change in the motor operation process can be quickly responded, and the dynamic and static eccentricity rates and the eccentricity direction are output.
Owner:ZHENGZHOU UNIV +1

Alternating-current side third harmonic weakening modulation method under condition that direct-current side of railway power regulator contains frequency doubled ripples

The invention provides an alternating-current side third harmonic weakening modulation method of a railway power regulator under the condition that direct-current bus voltage contains frequency doubling ripples. The method comprises the following steps: constructing a bus voltage state space model of the railway power regulator, and designing a non-delay adaptive state observer to extract direct current component information of bus voltage; separating information of a direct current component and a double frequency ripple component of the bus voltage through a self-adaptive state observer; introducing the direct-current component information into voltage and current double-closed-loop control; designing a secondary pulse modulation ratio opposite to a ripple voltage phase through the extracted ripple pulse parameters; the third harmonic on the alternating current side of the RPC is weakened by injecting an opposite pulsation modulation ratio into a modulation coefficient; according to the method, under the condition that circuit topology and control strategy complexity are not increased, output voltage third harmonics are effectively weakened, direct current side voltage double frequency fluctuation is reduced, meanwhile, power coupling between the alternating current side and the direct current side can be compensated, the requirement for the capacitance value of a bus capacitor is reduced, the total harmonic distortion rate is reduced, and the service life of the bus is prolonged. And long-term stable operation of the system is guaranteed.
Owner:XIANGTAN UNIV

Method and system for identifying early fault section of power distribution network based on multi-dimensional feature probability mapping

The invention provides a power distribution network early fault section identification method and system based on multi-dimensional feature probability mapping, and belongs to the technical field of power system power distribution network fault detection. The method comprises the following steps: collecting zero-sequence voltage of a power distribution network bus and zero-sequence current signals of head ends of all feeder lines, and obtaining derivative signals of the zero-sequence voltage and the zero-sequence current signals; calculating the third harmonic energy of the zero-sequence current of each feeder line, and when the third harmonic energy exceeds a set threshold value, judging that the feeder line has an early fault; processing the zero-sequence current signal, and extracting an IMF1 component; calculating a correlation characteristic quantity and a dot product characteristic quantity for each section formed by the current difference values of the adjacent measuring devices based on the IMF1 component; and respectively carrying out standardized transformation on the correlation characteristic quantity and the dot product characteristic quantity, substituting the correlation characteristic quantity and the dot product characteristic quantity into a Laplacian cumulative distribution function, calculating a probability value of a fault in each section, and judging a fault section according to a set probability threshold value. The method can effectively and reliably identify the early fault section of the power distribution network.
Owner:STATE GRID HENAN ELECTRIC POWER ELECTRIC POWER SCI RES INST +1

Grid-connected inverter and control method thereof

The invention discloses a grid-connected inverter and a control method thereof, and belongs to the technical field of power electronics and new energy grid-connected control, and the method comprises the steps: obtaining voltage and current signals of the grid-connected inverter and a grid-side three-phase voltage; performing coordinate transformation on the acquired voltage and current signals, and performing voltage and current double-closed-loop decoupling control to obtain a d-axis modulation signal and a q-axis modulation signal; generating a three-phase fundamental wave modulation signal according to the d-axis modulation signal and the q-axis modulation signal; calculating a fundamental wave modulation degree; calculating a zero-sequence current component of the grid-side three-phase current; taking the fundamental wave modulation degree and the zero-sequence current component as input quantities, and outputting a third harmonic injection proportionality coefficient through a fuzzy controller; generating a third harmonic injection amount according to the third harmonic injection proportionality coefficient; and subtracting the third harmonic injection amount from the three-phase fundamental wave modulation signal to generate a third harmonic injection type modulation signal. According to the invention, dynamic adjustment along with power grid disturbance, load change or modulation degree fluctuation can be realized.
Owner:CHANGZHOU HUIYUAN ELECTRIC TECHNOLOGY CO LTD

A low-pulsation inverse-cosine plus third-harmonic auxiliary salient pole type radial permanent magnet motor and a method for optimizing air gap harmonics

The application discloses a low-pulsation inverse-cosine plus third-harmonic auxiliary salient pole type radial permanent magnet motor and a method for optimizing air gap harmonics, and belongs to the technical field of motor manufacturing. A novel radial permanent magnet synchronous motor with inverse-cosine plus third-harmonic auxiliary salient poles is provided, and the method can suppress air gap flux density harmonics and reduce torque ripple and average torque loss. The specific process is as follows: the rotor air gap flux density is proportional to the rotor magnetomotive force, and the main air gap flux density harmonic order affecting the torque ripple is determined. The inverse-cosine plus third-harmonic method is used to modify the auxiliary salient poles, so as to reduce the air gap flux density harmonics, especially the 9th, 11th, 19th and 21st harmonics causing the first and second order torque ripples, thereby reducing the torque ripple; since the third harmonic is not the main air gap flux density harmonic causing the torque ripple, the injection of the third harmonic can reduce the average torque loss.
Owner:JIANGSU UNIV

Reconfigurable injection-locked local oscillator system

This invention discloses a reconfigurable injection-locked local oscillator system, comprising a voltage-controlled oscillator (VCO), an injection-locked frequency multiplier (ILL), and an injection-locked amplifier (ILA). The first output terminal of the VCO is connected to the first input terminal of the ILL, the second output terminal of the VCO is connected to the second input terminal of the ILL, the first output terminal of the ILL is connected to the first input terminal of the ILL, and the second output terminal of the ILL is connected to the second input terminal of the ILL. The VCO generates a low-frequency fundamental wave, the ILL multiplier performs frequency multiplication on the low-frequency fundamental wave to generate a second or third harmonic wave, and the ILL amplifies the power of the second or third harmonic wave, thereby improving the accuracy of the output millimeter-wave frequency.
Owner:ZHUOSHI TECHNOLOGY (SUZHOU) CO LTD

First-harmonic and third-harmonic shared cavity type impedance matching mechanism for high-frequency buncher

The invention discloses a first and third harmonic shared cavity type impedance matching mechanism for a high-frequency buncher, which is characterized in that the first and third harmonic shared cavity type impedance matching mechanism is connected with a bunching electrode to jointly form the first and third harmonic shared buncher; the shared buncher is arranged between an external ion source of the cyclotron and the cyclotron; the cavity type impedance matching mechanism shared by the first harmonic and the third harmonic comprises a cavity type matching circuit shared by the first harmonic and the third harmonic and a coupler shared by the first harmonic and the third harmonic. According to the invention, the groove which is folded for multiple times is innovatively processed in the lower cavity of the cavity, so that the integrated structure of the lower cavity and the outer conductor is ingeniously realized, and the risk of folding cracking is fundamentally eliminated. Through the first harmonic and third harmonic shared cavity design, the function of originally needing two independent bunchers is integrated into one shared cavity, the system cost is effectively reduced, meanwhile, the occupied space is remarkably reduced, and the requirement of a compact accelerator is perfectly met.
Owner:CHINA INSTITUTE OF ATOMIC ENERGY

Millimeter wave broadband high harmonic rejection tripler

This invention discloses a millimeter-wave broadband high harmonic suppression tripler, comprising an input matching network, a time-domain shaping tripler unit, and a differential common-source output stage. The proposed time-domain shaping tripler unit employs transistor pairs with different gate widths and bias voltages to superimpose two sets of voltage signals of different amplitudes in the time domain, thereby enhancing the inherent harmonic suppression of the tripler unit. Furthermore, by connecting a common-mode impedance control in series at the center tap of the primary inductor coil of the output transformer of the tripler unit, the output power of the third harmonic is further improved. The input matching network achieves single-ended to differential conversion, with its primary and secondary coil center taps grounded and open-circuited respectively in a counterintuitive manner, improving differential-mode balance and common-mode stability. Simultaneously, by using a series-coupled inductor, the quality factor of the transistor input impedance is reduced, improving the bandwidth performance of the tripler.
Owner:SOUTHEAST UNIV

A high-efficiency omni-directional rectenna based on class-f harmonic rejection structure

The application discloses a high-efficiency omnidirectional rectenna based on a class-F harmonic suppression structure and belongs to the rectenna field, comprising: a plurality of rectenna units which are arranged at equal intervals and rotate around the same center and are used for receiving radio frequency energy; the rectenna unit comprises a receiving antenna and a rectifier circuit; the receiving antenna comprises an antenna radiation structure, a metal floor and a feed microstrip line; a U-shaped groove is arranged on a region of the antenna radiation structure which is close to the metal floor, and a rectangular groove is arranged in the U-shaped groove; the U-shaped groove and the rectangular groove are used for suppressing the radiation of the second harmonic and the third harmonic; the rectifier circuit is arranged on the upper surface of a PCB and is used for rectifying the output signal of the antenna radiation structure by the microstrip line and electronic components; and the plurality of rectenna units are connected through a direct current synthesis network, so that the size of the rectenna can be reduced and the efficiency of the rectenna can be improved.
Owner:GUANGDONG UNIV OF TECH

Power amplifier with harmonic filtering circuit

An amplifier includes a signal input terminal for inputting an input signal; a voltage input terminal for inputting a power supply voltage; an amplification circuit for generating an amplified input signal based on the input signal, wherein the amplified input signal has a fundamental frequency, a first harmonic, and a second harmonic, wherein the first harmonic is the second harmonic of the fundamental frequency, and the second harmonic is the third harmonic of the fundamental frequency; a harmonic filter circuit coupled between the voltage input terminal and the amplification circuit for filtering the first harmonic and the second harmonic; and a signal output terminal coupled to the harmonic filter circuit for outputting an output signal based on the amplified input signal.
Owner:RICHWAVE TECH CORP

Low-phase noise signal source circuit and radar device

The invention relates to the field of integrated circuits, and discloses a low-phase noise signal source circuit and radar equipment, and the low-phase noise signal source circuit comprises a four-core F23 type voltage-controlled oscillator which is used for generating a fundamental frequency, a second harmonic and a third harmonic; the harmonic self-mixer is connected with the quad-core F23 type voltage-controlled oscillator, and is used for mixing the fundamental frequency and the third harmonic into a quadruplicated frequency signal and outputting the quadruplicated frequency signal, and mixing the fundamental frequency and the fundamental frequency into a secondary frequency multiplication signal and outputting the secondary frequency multiplication signal; and the amplifier is connected with the harmonic self-mixer and is used for amplifying the quadruplicated frequency signal and outputting the amplified quadruplicated frequency signal. The signal source circuit can generate quadruplicated frequency signals.
Owner:SOUTHERN UNIVERSITY OF SCIENCE AND TECHNOLOGY

An ultra-wideband high harmonic rejection power amplifier

The application discloses a kind of ultra-wideband high harmonic suppression power amplifier, including low-frequency power amplification branch, high-frequency power amplification branch, harmonic suppression matching network, the harmonic suppression matching network includes low-frequency harmonic suppression matching network, high-frequency harmonic suppression matching network and common output end;The low-frequency power amplification branch, high-frequency power amplification branch respectively to the frequency different low-frequency band signal, high-frequency band signal in work wideband is carried out power amplification, the low-frequency harmonic suppression matching network, high-frequency harmonic suppression matching network respectively to the impedance matching of fundamental wave in low-frequency band signal, high-frequency band signal after power amplification, while inhibiting second and third harmonic signals.The application solves the problem of low power efficiency and poor high-order harmonic suppression in the prior art.
Owner:NO 55 INST CHINA ELECTRONIC SCI & TECHNOLOGYGROUP CO LTD

Hybrid coupler for magnetic resonance imaging

A transmit / receive switch for magnetic resonance imaging (MRI) of a 1H atomic nucleus at 3T (tesla) and 7T magnetic field strengths includes a first and second dielectric substrate and a first and a second microstripline hybrid coupler formed on the first and second dielectric substrates respectively. A first port and a second port are connected to a first junction and a second junction respectively of the first microstripline hybrid coupler, a third port and a fourth port are connected to a third junction and a fourth junction of the second microstripline hybrid coupler respectively. Each port is connected by a matching network embodied by a microstripline wire to a pair of parallel resonant circuits. The transmit / receive switch is configured to operate at a fundamental frequency of about 127.8 MHz at 3T and at a third harmonic frequency of about 298 MHz at 7T.
Owner:IMAM ABDULRAHMAN BIN FAISAL UNIV

Third harmonic suppression film microstrip filter based on mixed structure

The invention provides a third harmonic suppression film microstrip filter based on a mixed structure. Comprising a substrate, a pair of coplanar waveguide feeder lines used for being connected with an external circuit and playing a role in impedance matching, and a plurality of interdigital resonators used for generating passband characteristics of the filter, the hairpin resonator is used for generating a transmission zero point at the low end of the filter to improve low-end stop-band suppression, the 1 / 4 wavelength open-circuit lines are used for suppressing third harmonics of the filter, and the pair of coplanar waveguide feeder lines, the interdigital resonators, the hairpin resonator and the 1 / 4 wavelength open-circuit lines are all laid on the substrate. The plurality of interdigital resonators are located between the pair of coplanar waveguide feeders, the hairpin resonator is located between the plurality of interdigital resonators, the pair of coplanar waveguide feeders is connected with the interdigital resonators at two sides of the plurality of interdigital resonators, and the plurality of 1 / 4 wavelength open-circuit lines are connected with the pair of coplanar waveguide feeders in parallel.
Owner:北京航天微电科技有限公司

Single-stage multi-port motor driver power distribution control method based on modulation wave splitting

The invention discloses a single-stage multi-port motor driver power distribution control method based on modulation wave splitting. The method comprises the following steps: firstly, obtaining a three-phase reference voltage of a single-stage multi-port motor driver under a natural coordinate system; under a virtual two-level framework, carrier pulse width modulation of third harmonic injection is used to generate a three-phase duty ratio; according to the first direct current source port reference power, a zero-sequence component is obtained through calculation; injecting the calculated zero-sequence component into a three-phase duty ratio of the motor, obtaining three-phase duty ratios of a first switch tube and a second switch tube under a virtual two-level frame based on modulation wave splitting, and obtaining three-phase duty ratios of the first switch tube and the second switch tube under an actual three-level frame through normalization; and finally, comparing the three-phase duty ratio of the motor under the actual three-level framework with a carrier wave to generate a driving signal to control each bridge arm switch tube.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Method and system for adjusting number of sub-modules in modular multilevel converter, and electronic equipment

The invention relates to the technical field of current converters, in particular to a method and system for adjusting the number of sub-modules in a modular multilevel current converter and electronic equipment. The method comprises the steps that target third harmonic zero-sequence voltage corresponding to each operation point in the operation range of the modular multilevel converter to be adjusted is determined, and the target third harmonic zero-sequence voltage is the third harmonic zero-sequence voltage enabling the bridge arm output voltage peak value of the modular multilevel converter to be adjusted to be minimum; under the condition that the modular multilevel converter to be adjusted is in a running state, determining a bridge arm voltage reference value of the modular multilevel converter to be adjusted under the current running point according to the target third harmonic zero sequence voltage corresponding to the current running point, and adjusting the number of sub-modules adopted in the modular multilevel converter to be adjusted according to the bridge arm voltage reference value. By adopting the scheme, the compactness and low cost of the modular multilevel converter can be realized.
Owner:GUANGDONG YANGJIANG CHUANGYUAN OFFSHORE WIND POWER COMPREHENSIVE INVESTMENT CO LTD +5

Motor stator winding fault diagnosis method based on quadrature-axis current second harmonic component

The invention discloses a motor stator winding fault diagnosis method based on quadrature-axis current second harmonic components, belongs to the field of motors, and aims to solve the problems of low open-circuit fault diagnosis speed and low accuracy of a part of conductors of a five-phase permanent magnet synchronous motor. The method comprises the following steps: step 1, collecting a five-phase current signal of a motor, and separating quadrature-direct axis current of a fundamental wave space and quadrature-direct axis current of a third harmonic space through Clark transformation and Park transformation; step 2, Fourier decomposition is carried out on the quadrature-axis current of the fundamental wave space, a second harmonic component is extracted, and Fourier decomposition is carried out on the five-phase current to obtain a fundamental wave component; 3, calculating the change rate delta of a second harmonic component, and judging the number of fault strands according to a preset segmentation threshold value; and step 4, positioning a fault phase through the amplitude drop amplitude of the fundamental current amplitude of the five-phase current.
Owner:HARBIN INST OF TECH +1

Fault-tolerant sensorless control method for double three-phase synchronous reluctance motors

The invention discloses a fault-tolerant sensorless control method for a dual three-phase synchronous reluctance motor, and the method carries out the filtering of an observation flux linkage after an open-circuit fault based on a second-order generalized integrator with a frequency-locked loop, and achieves the purpose of improving the position-less control performance of the dual three-phase synchronous reluctance motor after the open-circuit fault. According to the invention, the hybrid flux linkage observer based on SOGI-FLL is adopted to carry out adaptive compensation on harmonic distortion under a single-phase open-circuit fault condition, so that the precision of flux linkage observation and rotor position estimation is improved. Compared with a traditional position-free control method, the three-time flux linkage harmonic caused by an open-circuit fault can be effectively inhibited, and the position observation precision and stability are remarkably improved. Meanwhile, high-precision position estimation can still be kept under the low-speed and zero-speed working conditions, the position-free stable operation speed range of the dual three-phase synchronous reluctance motor is expanded, and the method is suitable for high-reliability position-sensorless control application under various operation conditions such as the healthy working condition and the single-phase open-circuit fault.
Owner:HARBIN INST OF TECH

Methods and systems for speed and torque control of permanent magnet synchronous motors

PendingCN122316158AMotor speedVoltage amplitude
This invention discloses a speed and torque control method and system for a permanent magnet synchronous motor. The system includes a voltage frequency domain information calculation module, a third harmonic generation module, a current generation module, a motor transfer function module, and a load torque adaptive control module. It calculates and outputs the fundamental voltage amplitude and frequency based on the motor's mathematical model; outputs the third harmonic amplitude through adjustable coefficients; outputs the dq-axis current, electromagnetic torque, and motor speed using the SHEPWM mathematical model; adjusts the load torque by regulating parameters, outputting an adaptive load torque based on speed feedback; and adjusts the motor speed output by the motor transfer function module according to the adaptive load torque. This invention significantly improves the maximum output torque of the permanent magnet synchronous motor; achieves stable speed control without complex parameter tuning, reducing the difficulty of implementing the control system; and effectively suppresses speed fluctuations introduced by the third harmonic, achieving synergistic optimization between torque enhancement and speed stability.
Owner:CHANGCHUN UNIV OF TECH

Interference suppression method for GPS L1, GPS L2 and GPS L5 and radio frequency circuit

The invention discloses an interference suppression method for a GPS L1, a GPS L2 and a GPS L5 and a radio frequency circuit. The method comprises the following steps: acquiring a first trap circuit, a second trap circuit, a third trap circuit, a fourth trap circuit and a low-pass filter circuit; circuit structures of the first trap circuit, the second trap circuit, the third trap circuit, the fourth trap circuit and the low-pass filter circuit are configured, and circuit parameters of one or more of the first trap circuit, the second trap circuit, the third trap circuit and the fourth trap circuit are configured; the low-pass filter circuit is used for suppressing one or more of a GPS L1 frequency signal, a GPS L2 frequency signal and a GPS L5 frequency signal, and the low-pass filter circuit is used for suppressing second harmonics and third harmonics generated by the Bluetooth module. The interference signal suppression intensity can be freely combined according to requirements, and the precision of the suppression frequency is improved through parameter configuration, so that the cost is saved, and the application scene is wider.
Owner:SHENZHEN FENDA SMART TECH LTD

A method for improving reliability of double-winding motor control based on current spectrum sensing

The application relates to a method for improving the reliability of double-winding motor control based on current spectrum sensing, and the control steps are as follows: a) a main controller receives instructions from a host computer through a bus, controls a main winding, a slave controller receives instructions from the bus, controls a slave winding, and the slave controller receives a main winding current feedback signal; b) the slave controller performs fast Fourier transform (FFT) on the main winding current feedback signal, extracts a fundamental wave, a third harmonic, a fifth harmonic and an even harmonic of the current, judges the running state of the main controller through real-time analysis of the current harmonic in the main winding current feedback signal, and when the current harmonic in the main winding current feedback signal is abnormal and no start instruction is obtained within a set time, the slave controller autonomously starts and controls the slave winding. The method can accurately and timely sense the abnormal condition of the high-voltage side, avoids false detection and missed detection, and greatly improves the reliability of double-winding operation.
Owner:LISHUI FOUNDER INTELLIGENT DRIVE INST CO LTD +1

Discontinuous modulation method and device for converter device

The invention discloses a discontinuous modulation method and device for a converter device. The discontinuous modulation method for the converter device comprises the following steps: injecting third harmonics into a three-phase voltage instruction to improve the voltage utilization rate; based on the corrected voltage instruction, a target phase with the highest voltage and a reference phase with the lowest voltage are identified, and the output current direction of the target phase is obtained in real time; obtaining and judging the offset state of the neutral-point voltage of the bus through a double-hysteresis model; finally, in combination with the state and the current direction of the target phase, corresponding zero-sequence voltage is selected and injected according to a preset rule, and a final modulation wave is generated to drive a switching device. By dynamically associating the control decision of the neutral-point voltage with the physical characteristics of the load current, the technical problem that the neutral-point voltage of traditional discontinuous modulation is out of control under the severe working conditions of high modulation ratio, low power factor and the like is effectively solved.
Owner:SHENZHEN HEWANG ENERGY CO LTD

A contact contact state on-line monitoring and early warning method of a power distribution room switch cabinet

PendingCN122449343APhase currentsMagnetic field amplitude
The application relates to the technical field of power distribution network electrical equipment state monitoring, and discloses a contact contact state online monitoring and early warning method for a switch cabinet in a power distribution room. The method synchronously collects spatial magnetic field instantaneous signals and busbar phase current instantaneous signals through an annular magnetic field sensing array and a current transformer; the fundamental wave magnetic field amplitude, the third harmonic magnetic field amplitude and the busbar phase current amplitude are extracted by using a digital phase-locked demodulation algorithm; the spatial distribution gradients of the fundamental wave magnetic field amplitude and the third harmonic magnetic field amplitude are subjected to first-order and third-order normalization processing by using the busbar phase current amplitude, so that the spatial magnetic field asymmetry index and the spatial gradient modulation degree are obtained; the spatial magnetic field asymmetry index and the spatial gradient modulation degree are compared with preset confidence threshold values respectively, and a contact state early warning result is output by combining two-dimensional phase diagram judgment logic. The application realizes decoupling and online independent evaluation of static electric contact degradation and dynamic mechanical fatigue.
Owner:HUADIAN POWER INTERNATIONAL CORPORATION LTD

Fault-tolerant control method for open-circuit fault of single switch tube of five-phase permanent magnet synchronous motor

The invention provides a fault-tolerant control method for an open-circuit fault of a single switch tube of a five-phase permanent magnet synchronous motor. The method comprises the following steps: deducing each phase voltage according to a fault position and reconstructing a space voltage vector; then a virtual voltage vector is generated by applying a discrete space vector modulation technology so as to expand a candidate vector set, and optimization is carried out through sector division; a third harmonic current is reduced by setting a specific segmented given current; and finally, by constructing a voltage error value function, a current prediction step in traditional model prediction is omitted, and an optimal voltage vector is directly selected to generate a PWM signal. According to the method, the torque ripple and the current harmonic can be effectively suppressed without modifying a motor mathematical model and a reduced-order transformation matrix, and the method has high dynamic performance and good universality.
Owner:JIANGSU UNIV

Small size high efficiency wideband class-f amplifier based on harmonic stretching

The application discloses a small-size high-efficiency wideband class-F amplifier based on harmonic stretching, and solves the problem that the existing class-F amplifier is difficult to realize second harmonic impedance short circuit and third harmonic impedance open circuit at the current source end face in a wideband range. DS , a power amplifier tube V GS , a first microstrip TL1, a second microstrip TL2, one end of the first microstrip TL1 and one end of the second microstrip TL2 being connected to a first node A, the other end of the second microstrip TL2 being connected to a second node B, the other end of the first microstrip TL1 and the drain of the power amplifier tube V GS being connected to a third node C; the power supply V DS is connected to the second node B; and the first microstrip TL1 and / or the second microstrip TL2 is a variable cross-section microstrip.
Owner:SHAANXI REACTOR MICROELECTRONICS