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41 results about "Series impedance" patented technology

Method and system for analyzing transient stability in fault stage of tracking-constructing network type converter series-parallel system

The invention relates to the technical field of new energy grid-connected control, in particular to a fault stage transient stability analysis method and system for a following-constructed network type converter series-parallel system, and the method comprises the steps: enabling a constructed network type converter to be equivalent to a controlled voltage source series impedance, enabling a following network type converter to be equivalent to a controlled current source, and enabling the controlled current source to be equivalent to a controlled voltage source series impedance; the whole series-parallel system is equivalent to a scene in which double voltage sources and a single current source are jointly connected in parallel to a PCC point, and a series-parallel system model is constructed; according to the series-parallel system model, respectively representing an active power coupling term of the network-building type converter and a voltage coupling term of the network-following type converter under the condition of considering parallel connection of the network-following type converter and the network-building type converter; according to the coupling term, remodeling an active loop control structure of the network-constructing converter and a phase-locked loop synchronization structure of the network-following converter, and obtaining a transient analysis model of the series-parallel system considering the coupling term; the transient stability of the hybrid system in the power grid fault stage is analyzed through the transient analysis model, and the influence on the transient stability is effectively represented.
Owner:STATE GRID JIANGSU ELECTRIC POWER CO LTD RESEARCH INSTITUTE +3

Converter station AC filter group circuit breaker abnormal arcing modeling analysis method

A converter station AC filter group circuit breaker abnormal arcing modeling analysis method comprises the following steps: firstly, carrying out time mark alignment, amplitude calibration and filtering de-noising on wave recording signals such as AC bus voltage and filter branch current to obtain high-quality input data; then, combining a primary wiring diagram, enabling an alternating current system to be equivalent to an ideal power supply and series impedance, enabling circuit breaker arcing to be equivalent to arc resistance changing along with time, and constructing an equivalent circuit model comprising the power supply, the impedance, a capacitor, an electric reactor and dynamic arc resistance; establishing a state space equation according to a voltage and current constraint relation, and performing time domain solution by adopting a two-step two-order or three-order diagonal implicit Runge-Kutta method to obtain voltage and current responses of the whole process of the fault; on this basis, the arc resistance change is inversed according to the ratio of arc voltage to current, the current zero passage is identified through the resistance symbol change at adjacent moments, and the zero passage section is smoothed; and finally, the inversion result is verified again by means of the simplified equivalent model.
Owner:UHV CONVERTER STATION BRANCH OF STATE GRID SHANGHAI ELECTRIC POWER CO +1

Filter circuit, filter and communication device

A filter circuit, a filter and a communication device relate to the technical field of communication. The filter circuit includes a series branch connected between the first port and the second port and including a series resonance circuit and a series impedance element connected in series with each other, wherein the series resonance circuit includes a series resonator; and a parallel branch connected between a parallel node and a ground potential and including a parallel resonance circuit and a parallel impedance element connected in series with each other, wherein the parallel resonance circuit includes a parallel resonator, and the parallel node is located on a connection path of the first port and the second port; wherein the resonance frequency of the series resonator is less than the resonance frequency of the parallel resonator.
Owner:BOE TECHNOLOGY GROUP CO LTD

Novel matrix LLC secondary side resonant topology

The invention belongs to the technical field of key power supply conversion in an aviation airborne starting power converter, and discloses a novel matrix LLC secondary side resonant topology. On the basis of an LLC resonant topology circuit, a resonant cavity is placed on the secondary side of a transformer, a matrix transformer with the primary side connected in parallel and the secondary side connected in series is adopted, and the matrix transformer comprises n parallel H-bridge inversion units on the low-voltage side, a high-frequency matrix transformer, the LLC resonant cavity on the high-voltage side and a full-bridge uncontrollable rectification circuit. The matrix transformer is composed of n transformer units, primary sides of which are connected in parallel and secondary sides of which are connected in series. A primary winding of each transformer unit is connected with the H-bridge DC-AC inverter circuit. According to the matrix LLC secondary side resonant topology, by controlling the switching frequency of the H-bridge power MOS tube, square wave signals with different frequencies are obtained, the series impedance of the resonant capacitor and the resonant inductor is changed, the partial voltage at the two ends of the excitation inductor is adjusted, gain control over the resonant cavity is achieved, and the purpose of adjusting the output load voltage is achieved.
Owner:DALIAN UNIV OF TECH

Wearable device and method for non-invasive measurement of glymphatic flow

A computer-implemented method and system includes a head-mounted wearable device having two current electrodes that delivers an input alternating current over a range of frequencies to a subject during at least one intervention. The head-mounted wearable device includes at least two sense electrodes that collect voltage difference measurements in response to the input alternating current. A measurement validation module applies a Hilbert transform or a Cramer-Kronig test to the voltage difference measurements to generate a validated time-series impedance spectrum. A head fluid dynamics module fits the validated time-series impedance spectrum to an electrical circuit model to determine a glymphatic flow response to the at least one intervention.
Owner:アプライド·コグニション·インコーポレーテッド

Harmonic interaction characteristic analysis method, device and equipment based on chaotic characteristic, storage medium and program product

The invention discloses a harmonic interaction characteristic analysis method and device based on chaotic characteristics, equipment, a storage medium and a program product. The method comprises the following steps: obtaining harmonic impedance corresponding to a plurality of harmonic sources respectively; determining series impedance and parallel admittance of the power transmission line between the first harmonic source and the second harmonic source based on a pre-constructed equivalent circuit model of the power transmission line between the multiple harmonic sources, and determining equivalent connection impedance between the first harmonic source and the second harmonic source based on the series impedance and the parallel admittance; inputting the first harmonic impedance corresponding to the first harmonic source, the second harmonic impedance corresponding to the second harmonic source, the equivalent connection impedance and the Lyapunov exponent into a preset chaotic interaction factor calculation model to obtain a chaotic interaction factor between the first harmonic source and the second harmonic source; and determining an interaction characteristic analysis result between the first harmonic source and the second harmonic source based on the chaos interaction factor. Therefore, the stability of the multi-harmonic source system is improved.
Owner:HUIZHOU POWER SUPPLY BUREAU OF GUANGDONG POWER GRID CO LTD +1

Calculation method for steady-state voltage and loop current of sheath based on multi-loop land cable distributed model

This invention discloses a method for calculating the steady-state voltage and circulating current of the sheath based on a distributed model of a multi-loop terrestrial cable. The method includes: 1. Obtaining the factors affecting the steady-state induced voltage and circulating current of the sheath of a multi-loop single-core terrestrial cable; 2. Establishing a distributed parameter model per unit length of the multi-loop single-core terrestrial cable, thereby obtaining the linear equation matrix describing the entire multi-loop terrestrial cable system; 3. Calculating the series impedance of the multi-loop single-core terrestrial cable lines in the system's linear equation matrix; 4. Calculating the parallel admittance between the multi-loop single-core terrestrial cable lines in the system's linear equation matrix; 5. Constructing the impedance matrix and admittance matrix to complete the system's linear equation matrix; 6. Determining the boundary conditions of the system's linear equation matrix; 7. Solving the system's linear equation matrix to obtain the values ​​of the steady-state induced voltage and circulating current; 8. Calculating the steady-state induced voltage and circulating current of the sheath of a multi-loop single-core terrestrial cable with the same arrangement. This invention eliminates repetitive modeling and simulation calculations, improves the model's adaptability, and has significant engineering value.
Owner:XI AN JIAOTONG UNIV

Calculation Method for Sheath Induced Voltage and Circulating Current of a Multi-Circuit Cable System

The present invention discloses a calculation method for sheath induced voltage and circulating current of a multi-circuit cable system. First, this method calculates the calculation models of the series impedance matrix and the shunt admittance matrix per unit length of the cable line; subsequently, according to the telegraph equation in the frequency domain, series approximation is performed on the multi-circuit micro-segment cable lines under different grounding methods to construct the node admittance matrix of the micro-segment cable lines; then, a variety of cascade formulas are derived to obtain the complete node admittance matrix of the multi-circuit full-line cable system; according to the boundary conditions and the complete node admittance matrix of the multi-circuit cable system, the cable line micro-segments are subdivided, and the calculation models of the induced voltage and circulating current of the metal sheath of the multi-circuit cable under different grounding methods are constructed segment by segment. The present invention can accurately describe the distribution of sheath induced voltage and circulating current in the multi-circuit cable system, laying a solid foundation for the subsequent research on cable loss reduction measures.
Owner:ZHEJIANG HUAYUN ELECTRIC POWER ENG DESIGN CONSULTATION CO LTD +1

Low-noise amplifier circuit for full-duplex transceiver

There is provided a low-noise amplifier circuit (200a:200g) for a full-duplex radio transceiver, the low-noise amplifier circuit (200a:200g) comprising: an input port (Vin) for receiving a signal from an antenna; a first signal path operatively connected to the input port (Vin) and comprising a series impedance (Z1) and a first transistor (M1) operatively connected in series with each other for providing a positive polarity of the received signal at a first differential output (+Vout) of the low-noise amplifier circuit (200a:200g); a second signal path operatively connected to the input port (Vin) and comprising a second transistor (M2) for providing a negative polarity of the received signal at a second differential output (-Vout) of the low-noise amplifier circuit (200a:200g); a cancellation circuit (iC1, iC2) operatively connected to the first signal path for injecting a cancellation current in the first signal path; and a Self- Interference-Signal control circuit configured to receive channel and cross- interference information and to control the cancellation circuit (ic1, ic2) based on the received channel and cross-interference information.
Owner:TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

A resonant shunt impedance measuring device and its control system

The present invention discloses a resonant shunt impedance measurement device and its control system. The resonant shunt impedance measurement device comprises an LC series resonant branch, a capacitor-coupled series impedance measurement device (SIMD), and a bypass switch. The LC series resonant branch, the SIMD, and the bypass switch are connected in parallel. The LC series resonant branch flows through the steady-state current of most of the system to be measured without affecting the injection of the disturbance voltage. The control of the resonant shunt impedance measurement device consists of three parts: signal processing, reference generation, and PR-based dual closed-loop control. This control can achieve the control objectives of controllable disturbance voltage output amplitude and minimizing the fundamental current flowing through the SIMD. The present invention can achieve the goal of almost no fundamental current flowing through the SIMD across the entire frequency band, increase the switching frequency of the impedance measurement device, and reduce the size, cost, and loss of the impedance measurement device.
Owner:SICHUAN UNIV

A method and device for selecting a low-voltage circuit grounding line and confirming a grounding point range

The present invention discloses a method for selecting a grounding line and confirming a grounding point range in a low-voltage circuit, which relates to the field of power grid protection technology and includes the following steps: obtaining impedance parameters of the circuit power supply, equipment, and cable; connecting impedances in series in the circuit according to the measured parameters to make the three-phase impedances equal; installing a high-frequency current generating module and a grounding capacitor at the end of the circuit; creating a grounding impedance matching table for each device and important node according to the measured impedance parameters; the high-frequency current generating module alternately generates AC and DC currents and measures the neutral point and capacitor currents; and determining the grounding phase and grounding range by calculating the impedance based on the measured values. The present invention installs a high-frequency current generating module and a grounding capacitor at the end of the circuit. The high-frequency current generating module is activated when a fault occurs. During phase selection, each module generates high-frequency current in a sequential cycle, enters the fault phase selection and fault location logic, and can achieve accurate fault location, quickly select the grounded phase, locate the grounding point range, and improve the operational reliability of the low-voltage system.
Owner:MAINTENANCE COMPANY OF STATE GRID XINJIANG ELECTRIC POWER COMPANY +1

Difference analysis method and system for dynamic characteristics of parallel networking type converter

The invention relates to a dynamic characteristic difference analysis method and system for a parallel grid-forming converter, and belongs to the technical field of converter evaluation. The method comprises the following steps: establishing a mathematical model of a double-mechanism grid-type converter grid-connected system under a dq coordinate system taking a power grid as a reference system, solving the mathematical model to obtain a voltage steady-state value and a power angle steady-state value of the converter during steady-state operation of the system; the method comprises the following steps: for an actual model of a double-mechanism grid-type converter grid-connected system, enabling a converter and a power grid to be equivalent to a voltage source model with series impedance to obtain an equivalent circuit model, and transforming and analyzing the equivalent circuit model to obtain a relational expression of output active power of each converter about a power angle, impedance and voltage; and solving the instantaneous power synchronization coefficient difference, and evaluating the influence effect of different parameters on the dynamic characteristic difference of the converter by adopting the instantaneous power synchronization coefficient difference. According to the method, the dynamic characteristic difference detection efficiency of the system is improved.
Owner:CHINA ELECTRIC POWER RESEARCH INSTITUTE CO LTD +2

Parameter measurement method for four-circuit alternating-current transmission lines arranged on same tower in parallel and capable of inhibiting induced voltage

The invention discloses a same-tower parallel four-circuit alternating-current power transmission line parameter measurement method for inhibiting induced voltage. The method comprises the following steps: dividing a same-tower four-circuit power transmission line into five groups of wiring modes; measuring the short-circuit impedance in each wiring mode and the series impedance in a mode that the tail end of the line is grounded through impedance; calculating the characteristic impedance and the propagation coefficient in the corresponding wiring mode by using the impedance grounding series impedance measurement result and the line short-circuit impedance measurement result of the line in each wiring mode, and further calculating the distribution impedance and the distribution admittance in the corresponding mode; and finally, calculating the resistance, inductance and ground capacitance of each phase lead of the same-tower four-circuit line, the inter-phase coupling capacitance and inter-phase coupling inductance of the single-circuit line, and the coupling capacitance and coupling inductance between each phase lead of the four-circuit line through the distributed impedance and distributed admittance in each wiring mode and simultaneous equations. According to the method, the no-load power frequency induced voltage of the line can be effectively suppressed, and the line parameters can be accurately measured.
Owner:MAINTENANCE & TEST CENTRE CSG EHV POWER TRANSMISSION CO

Impedance measuring apparatus and impedance measuring method

The present invention measures the impedance of impedance elements in a state in which a measurement target, which is formed by connecting a plurality of impedance elements in series, and a non-measurement target are connected in parallel. The present invention comprises: a measurement current supply unit 2-1 which supplies a measurement AC current Im1 between both ends of electrochemical cells C2, C3; a measurement current supply unit 2-2 which supplies a measurement AC current Im2 between both ends of electrochemical cells C7-C10; a voltage detection unit 3-1 which detects a complex terminal voltage value V1 across the electrochemical cells C2, C3; and a processing unit 4 which calculates the impedance of the electrochemical cells C2, C3 on the basis of the complex terminal voltage value V1 detected by the voltage detection unit 3-1 and a complex current value IZ1 of an AC current Iac detected by a current sensor 7-1 in a state in which the measurement AC current Im2 and the measurement AC current Im1 flowing through a power supply device PD cancel each other.
Owner:HIOKI DENKI KK

Filter circuit, filter and communication device

A filter circuit, a filter and a communication device relate to the technical field of communication. The filter circuit includes a series branch connected between the first port and the second port and including a series resonance circuit and a series impedance element connected in series with each other, wherein the series resonance circuit includes a series resonator; and a parallel branch connected between a parallel node and a ground potential and including a parallel resonance circuit and a parallel impedance element connected in series with each other, wherein the parallel resonance circuit includes a parallel resonator, and the parallel node is located on a connection path of the first port and the second port; wherein the resonance frequency of the series resonator is less than the resonance frequency of the parallel resonator.
Owner:BOE TECHNOLOGY GROUP CO LTD

Cable electrical parameter calculation method, system and device considering influence of backflow cable and storage medium

The invention discloses a cable electrical parameter calculation method, system and device considering the influence of a backflow cable and a storage medium. The cable electrical parameter calculation method adopted by the invention comprises the following steps: obtaining structure parameters and material parameters of a cable and a backflow cable; calculating a series impedance matrix including the cable and the backflow cable according to the structure parameters and the material parameters of the cable and the backflow cable; obtaining a voltage drop equation according to the series impedance matrix; and in combination with the installation condition of double-end grounding of the on-site backflow cable, a voltage drop equation is simplified, and cable electrical parameters including positive-sequence resistance, positive-sequence reactance, zero-sequence resistance and zero-sequence reactance are obtained. According to the method, the current coupling influence of the backflow cable and each phase cable is considered, accurate calculation of the electrical parameters of the cable with the backflow cable is realized, and the universality is high.
Owner:ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY

A method for constructing a traction network simulation model based on current distribution characteristics

This invention relates to the field of power systems and their automation technology. It provides a method for constructing a traction network simulation model based on current distribution characteristics. The method includes: establishing multi-conductor transmission line equations based on Maxwell's equations, including Gauss's law and Faraday's law; deriving a chain-like network model of the traction network based on the multi-conductor transmission line equations and a chain circuit model with multi-conductor transmission lines as the backbone and randomly connected transverse elements; simplifying the chain-like network model to obtain a simplified series impedance matrix equation and a parallel admittance parameter matrix after conductor merging; and calculating the series impedance and parallel admittance values ​​using the simplified series impedance matrix equation and the parallel admittance parameter matrix after conductor merging. This invention improves the accuracy and applicability of traction network electrical simulation and signal analysis.
Owner:CHINA RAILWAY CONSTR ELECTRIFICATION BUREAU GRP RALL TRANSIT EQUIP CO LTD +1

Spiral Inductor and Passive Integrated Circuit

ActiveCN113013332BSpiral inductorSkin effect
The spiral inductor of the present invention includes a substrate and a spiral wiring disposed on the substrate. A part of the spiral wiring includes a divided wiring portion, and the divided wiring portion is divided into a plurality of mutually parallel wirings when viewed from a top-down perspective. The divided wiring portion is disposed inside the spiral wiring. In the circuit of the divided wiring portion, the wirings inside and outside the divided wiring portion are alternately arranged with a second insulating layer in between, such that the wiring inside the divided wiring portion becomes the wiring on the outside after being staggered, and the wiring on the outside of the divided wiring portion becomes the wiring on the inside after being staggered. The spiral inductor can suppress the skin effect and the proximity effect, and can improve the area utilization efficiency and reduce the series impedance. In addition, the divided wiring portion is alternately arranged through the insulating layer, which can improve the Q value.
Owner:SANAN JAPAN TECH CORP

Circuit structure in electric connector, electric connector and phased array antenna

The utility model discloses a circuit structure in an electric connector, the electric connector and a phased-array antenna, which are applied to the field of electric connectors, and comprise a first circuit end connected with a first external end in a conducting manner and a second circuit end connected with a second external end in a conducting manner, a multi-section impedance matcher is arranged between the first circuit end and the second circuit end; the impedance matcher comprises at least one series impedance matcher connected in series in the circuit structure, and at least one impedance matching branch; one end of the impedance matching branch is connected between the first circuit end and the second circuit end; the impedance matching branch comprises a short-circuit impedance matching branch and / or an open-circuit impedance matching branch. According to the utility model, the multi-section impedance matchers are arranged in the circuit structure of the electric connector, the impedance matching branch sections are additionally arranged in the circuit structure of the electric connector, and reflected waves generated by the impedance matching branch sections are subtracted from reflected waves on a main circuit, so that the bandwidth range of matched radio-frequency signals can be widened, and the signal transmission bandwidth of the electric connector is improved.
Owner:INFINERA (CHENGDU) MICROSYSTEM TECH CO LTD

Circuit arrangement for operating at least a first and a second LED string from an AC or DC voltage source

Circuit arrangement (10) for operating at least a first and a second LED string, comprising: - a rectifier (14) having a first (14a) and a second rectifier terminal (14b) for coupling to an AC voltage source (12) or a DC voltage source (11), and a third (14c) and a fourth rectifier terminal (14d) for providing a rectifier output voltage (Urect); - a voltage equalisation longitudinal impedance (24); - at least one first (100) and one second load subgroup (200), each having a first (102, 202) and a second terminal (104, 204), wherein a bridging element (120, 220) is connected between the first and the second terminal, and each having a coupling element (110, 210) designed as a four-pole with a first (106, 206) and a second primary terminal (108, 208), as well as with a first (112, 212) and a second secondary terminal (114, 214), wherein the first primary terminal (106, 206) is electrically connected to the first terminal (102, 202) and the second primary terminal (108, 208) is electrically connected to the second terminal (104, 204), wherein the first LED string (D100 to D155), which has a first number of LEDs connected in series, between the secondary terminals (112,114) of the coupling element (110) of the first load subgroup (100) and the second LED string (D200 to D227), which has a second number of LEDs connected in series,is connected between the secondary terminals (212,214) of the coupling element (210) of the second load subgroup (200); , - a control device (20) which is designed to control the bridging elements (120, 220) as a function of a voltage difference between the respectively associated first terminal (102, 202) and an auxiliary DC voltage source (22) related to the third rectifier terminal (14c), and as a function of a respective LED string voltage which is applied between the first (102, 202) and the second terminal (104, 204) when the respectively associated bridging element (120, 220) blocks a short-circuit current flow between the two terminals (102, 104, 202, 204); - wherein the second terminal of a higher load subgroup, which is not a lowest load subgroup, is electrically connected to the first terminal of a next lower load subgroup, wherein the first terminal of a highest load subgroup is electrically coupled to the fourth rectifier terminal (14d) and the voltage compensation longitudinal impedance (24) is connected between the second terminal of a lowest load subgroup and the third rectifier terminal (14c); - a voltage divider device (26) connected between the third (14c) and the fourth (14d) rectifier terminal for providing a control signal (28) to the voltage compensation series impedance (24), wherein the voltage divider device (26) is designed to control a current with a current value (Ireg) as a function of an instantaneous value of the rectifier output voltage (Urect) through the series-coupled load subgroups (100, 200) by means of the control signal (28);characterized in that the control device (20) is designed, when the circuit arrangement (10) is operated on a DC voltage source (11), to permanently control at least a first bridging element of the bridging elements of the load subgroups into a short-circuit state and to permanently control at least a second bridging element of the bridging elements of the load subgroups into a state in which the second bridging element blocks a short-circuit current flow between the first and the second terminal of the associated load subgroup.;
Owner:INVENTRONICS GMBH

Interpolation-free hybrid line simulation model with accurate zero-sequence impedance and construction method of interpolation-free hybrid line simulation model

The invention belongs to the technical field of power system simulation, and discloses an interpolation-free hybrid line simulation model of accurate zero sequence impedance and a construction method thereof, the model comprises a decoupling module, a parallel compensation module and a series synthesis module; the decoupling module is used for enabling the electromagnetic propagation delay time to be equal to the simulation step length of a simulation program and realizing interpolation-free calculation decoupling at the two ends of the line; the parallel compensation module is used for compensating introduced additional parallel susceptance and inter-phase capacitance in an original physical model of the introduced line; and the series synthesis module is used for synthesizing the residual series impedance of the line, so that the total series positive-sequence impedance and zero-sequence impedance of the equivalent model are matched with a preset target value under the fundamental frequency. According to the method, calculation decoupling without interpolation can be provided for a short line, and full-sequence network parameters including zero-sequence components can be accurately simulated, so that the requirement of modern power distribution network high-fidelity parallel simulation can be well met.
Owner:JIANGSU KUNYOU ENERGY TECH CO LTD +1

Series virtual impedance method for improving grid-connected current quality of static synchronous compensator under weak grid

The application belongs to the field of power systems and relates to a series virtual impedance method for improving grid-connected current quality of a static synchronous reactive compensator under a weak power grid. In view of the problems that the existing methods cannot simultaneously achieve stability and harmonic suppression and the THD of grid-connected current increases and the quality of grid-connected current decreases due to harmonics in a weak power grid, the application constructs a grid-connected system with a three-level diode clamped STATCOM as a core, designs a harmonic suppression module containing a multi-resonant controller and a series virtual inductor, superimposes the harmonic suppression module and an original virtual series impedance to form a composite series virtual impedance, injects the composite series virtual impedance into a shunt impedance correction feedforward path, and realizes closed-loop control of grid-connected current. The method can effectively suppress characteristic harmonics, reduce THD, ensure stable operation of the system under a weak power grid, and has good dynamic performance and is easy to implement.
Owner:HARBIN INST OF TECH

SVG virtual impedance adaptive switching control method and system

The invention discloses an SVG virtual impedance adaptive switching control method and system. The method mainly comprises a virtual series impedance control link, a virtual parallel impedance control link and an SVG double-closed-loop control link. The oscillation frequency of a new energy station is monitored through VMD and HT conversion, an optimal virtual impedance control loop is put into use, and the output of a virtual impedance control link is used as a compensation amount to be compensated to an original double-closed-loop control structure of the SVG, so that the SVG obtains a more excellent oscillation suppression effect in a broadband range. And the limitation that a single virtual impedance control method is difficult to adapt to the multi-band oscillation suppression requirement is overcome. The method can be widely applied to wind power, photovoltaic and other new energy grid-connected systems containing the SVG, and an effective solution is provided for broadband oscillation suppression and safe and stable operation of the new energy grid-connected systems.
Owner:HUNAN UNIV

Plasma radio frequency power source and radio frequency system

The invention relates to a plasma radio frequency power source and a radio frequency system. The plasma radio frequency power source comprises a radio frequency power amplifier module; the impedance compression unit comprises at least one impedance compression network, and the impedance compression network is provided with a series branch circuit or a parallel branch circuit, or both of the series branch circuit and the parallel branch circuit. The radio frequency power amplifier module, the matcher and the impedance compression unit are sequentially connected in series, the output end of the impedance compression unit is used as a load cavity connecting port, and the impedance compression unit is used for compressing impedance of a load cavity to be within a matchable impedance range of the matcher. According to the invention, the impedance compression unit is arranged between the matcher and the cavity, so that different and large-range changing load impedances of a plurality of cavities can be compressed to a narrow range, the design requirement on the matcher is reduced, and the requirements on larger-range impedance matching capability and higher matching speed of a radio frequency system in different processes can be met; and the product cost is reduced and the product structure is miniaturized.
Owner:MORNSUN GUANGZHOU SCI & TECH

Method for measuring parameters of single-loop three-phase alternating-current transmission line in high induced voltage environment

The invention discloses a method for measuring parameters of a single-loop three-phase alternating current transmission line in a high induced voltage environment. The three-phase wire at the tail end of the line is grounded through the impedance Z and directly grounded, zero-sequence voltage or positive-sequence voltage is applied to the head end, sequence component series impedance and sequence component short-circuit impedance of the measured line when the measured line is grounded through the impedance Z are obtained, induced voltage on the measured line can be effectively reduced, and the measurement accuracy of the measured line is improved. And meanwhile, each parameter of the single-circuit alternating-current power transmission line can be accurately measured.
Owner:MAINTENANCE & TEST CENTRE CSG EHV POWER TRANSMISSION CO

SVG virtual impedance adaptive switching control method and system

The application discloses an SVG virtual impedance adaptive switching control method and system, mainly including a virtual series impedance control link, a virtual parallel impedance control link and an SVG double closed loop control link; the oscillation frequency of a new energy station is monitored through VMD and HT transformation, the optimal virtual impedance control loop is put into operation, and the output of the virtual impedance control link is compensated to the original double closed loop control structure of the SVG as a compensation amount, so that the SVG obtains more superior oscillation suppression effect in a wide frequency range, and the limitation that a single virtual impedance control method is difficult to adapt to multi-frequency band oscillation suppression demand is overcome. The application can be widely applied to wind power, photovoltaic and other new energy grid-connected systems containing SVG, and provides an effective solution for wide frequency oscillation suppression and safe and stable operation of the new energy grid-connected systems.
Owner:HUNAN UNIV

Computing method for full-band full-dimensional series impedance matrix of submarine cable

The invention discloses a submarine cable full-band full-dimensional series impedance matrix calculation method. The method comprises the following steps: (1) constructing a submarine cable full-band full-dimensional series impedance matrix; (2) calculating relative position parameters of the cable conductor; (3) calculating internal self-impedance provided by a conductor material, external impedance provided by a conductor geometrical shape and impedance provided by a seawater loop according to the relative position parameters of the cable conductor; and (4) calculating and determining diagonal elements and non-diagonal elements of the full-dimensional series impedance matrix according to the internal self-impedance and the external impedance of the cable conductor and the impedance provided by the seawater loop. According to the method, the full-dimensional series impedance matrix is calculated based on the original structure parameters and the position parameters of the cable, and full-band coverage is achieved through calculation; and meanwhile, full-dimensional series impedance matrix calculation is divided into three parts of calculation of internal self-impedance provided by a conductor material, external impedance provided by a conductor geometrical shape and impedance provided by a seawater loop, the calculation logic is clear, and the calculation accuracy is high.
Owner:ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY +1

A low-loss start-up surge suppression method

This invention relates to the field of startup surge suppression technology. Specifically, it relates to a low-loss startup surge suppression method. The method includes the following steps: S1, collecting the equipment load status and current-limiting device temperature before startup, and simultaneously acquiring historical startup data of the electrical equipment. Based on the equipment load status and the current-limiting device temperature, the historical startup data is classified into different status types. This invention uses a dual-loop architecture of current-limiting circuit and bypass circuit. Immediately after startup, the main circuit is switched to the pure copper bypass circuit, and the current-limiting circuit completely exits operation. There is no additional power loss caused by any series impedance, completely solving the problem of continuous heating and low energy efficiency caused by long-term series connection of traditional current-limiting components. Simultaneously, a standard startup current curve is generated based on historical successful startup data to accurately locate the optimal switching time and minimize the operating time of the current-limiting circuit.
Owner:SHAANXI STARS ELECTRONICS TECH CO LTD

Voltage regulator and power supply system using same

The voltage regulator is arranged between a power supply and a pulsator of a plasma chamber and comprises an impedance element and a switch, and the impedance element is connected with the switch in series. One end, far away from the switch, of the impedance element is connected to a circuit between the first output end of the power supply and the first input end of the pulsator; one end, far away from the impedance element, of the switch is connected to a circuit between the second output end of the power supply and the second input end of the pulsator. Through the scheme provided by the invention, the function of quickly changing the voltage can be effectively realized.
Owner:TRUMPF HUETTINGER SP ZOO

Self-adaptive series impedance compensation method considering bidirectional power flow characteristics

The invention discloses a self-adaptive series impedance compensation method considering bidirectional power flow characteristics, which belongs to the technical field of power distribution network voltage control, and comprises the following steps: acquiring a voltage signal and a current signal of a common connection point in a line in real time, and calculating active power and reactive power of the line; according to the active power and the reactive power, virtual impedance compensation quantity needing to be connected in series is calculated; judging the power flow direction according to the flow direction of the active power, and determining the positive and negative polarities of the virtual impedance compensation amount according to the power flow direction; and determining a drop voltage based on the virtual impedance compensation amount, and performing voltage compensation. According to the method, the problem of bidirectional out-of-limit of the steady-state voltage caused by reverse power transmission of the distributed power supply is solved, and the accuracy and stability of the terminal voltage of the power distribution network are ensured.
Owner:CHANGAN UNIV