20 results about "Line current" patented technology

A voltage-controlled bridge is coupled to the line voltage and the transformer primary harmonic voltage, while a current-controlled bridge is coupled to the line current and the transformer secondary harmonic voltage. A synchronous average harmonic current compensator synchronously integrates the error between the measured bridge current and the command current every half-switch cycle and samples the compensator output to control the line current and linearize the harmonic coupling between the isolation bridges. A synchronous pulse-width modulation process tracks the commanded line voltage. One or more of the primary and secondary harmonic command circuits regulate the harmonic coupling voltages of the voltage-controlled and current-controlled bridges, respectively. The line voltage, line current, and primary and secondary harmonic commands provide generalized line and isolation voltage bus regulation freedom within a single stage.

This invention relates to a dual-loop converter for a linear-rotating switched reluctance generator and its control method. The drain of the positive switching transistor of each phase of the rotating generator unit is connected to a first positive circuit, and the source of the negative switching transistor of each phase of the rotating generator unit is connected to a first negative circuit. One end of a load resistor is connected to a first load circuit and a second load circuit connected in parallel, and the other end of the load resistor is connected to a third load circuit and a fourth load circuit connected in parallel. The cathode of the diode of each phase of the rotating generator unit is connected to the first load circuit, and the positive terminal of the winding of each phase of the rotating generator unit is directly connected to the third load circuit. The cathode of the diode of each phase of the DC generator unit is connected to the second load circuit, and the positive terminal of each phase of the DC generator unit is directly connected to the fourth load circuit. This invention solves the technical problems of existing converters using a large number of components and having high line current pressure.

Embodiments of the present disclosure relate to a current detection device for an electrical grid. A detection device for a DC electrical grid comprises: - a first detection module configured to detect a line current flowing along an electrical line and to provide a first detection signal indicative of the line current; - a second detection module configured to detect the line current along the electrical line and to provide a second detection signal indicative of a rate of change of the magnitude of the line current over time; - a plurality of signal processing modules for processing the first detection signal and the second detection signal and for providing a detection signal indicative of a behavior of the line current.

The application discloses a D-T hybrid multi-port DC fault current limiter topology structure and a control method thereof, and belongs to the technical field of DC power transmission and distribution. The fault current limiter is composed of a current limiting branch, an energy consumption branch and a control branch. The current limiting branch contains multiple current limiting inductors; the energy consumption branch includes two branches in which thyristor valve groups and energy consumption resistors are respectively connected in series, and one of the thyristors is replaced by an IGBT; and the control branch is composed of multiple groups of unidirectional diode valve groups. The control method comprehensively judges by monitoring the line current change in real time and combining the DC circuit breaker tripping signal to distinguish between real faults and system disturbances and control corresponding power electronic devices to act. The application adopts a mixed configuration of diode valve groups and thyristors, and is supplemented by key IGBTs, thereby significantly reducing the number of required fully controlled devices under the premise of guaranteeing the multi-port collaborative current limiting and reliable shutdown capability, and having the advantages of low cost, high reliability, and the like.

This invention relates to the field of motor control technology, particularly to applications requiring low vibration and high efficiency in underwater propulsion motors. Specifically, it provides a method for suppressing low-order harmonic torque and high-frequency harmonic current in underwater propulsion motors. This invention switches control modes according to changes in the motor's operating frequency, meeting not only the low-noise requirements for low-speed navigation but also improving controller efficiency for high-speed navigation. When the underwater propulsion motor operates at low speed, harmonic compensation of the line current suppresses low-order harmonics generated by the motor body and controller, thereby reducing electromagnetic force pulsation caused by harmonics. Furthermore, by significantly increasing the switching frequency using silicon carbide power devices, it suppresses phase voltage distortion caused by pulse width modulation technology, improves the sinusoidal nature of the output voltage, and reduces harmonic torque. When the underwater propulsion motor operates at high speed, the output current is large; by reducing the switching frequency, the switching losses of the power devices are reduced, improving the efficiency of the controller in the propulsion system.

This invention discloses a method, equipment, and medium for differential protection of phase-to-phase faults on 10kV overhead lines, relating to the field of power protection technology. The method includes: quantifying the instantaneous waveforms of three-phase current and voltage to obtain discrete sequences; obtaining the line current and line voltage change waveforms through point-by-point differential analysis; detecting the power direction angle offset using cross-phase detection; determining the fault direction by combining the initial polarity of the current jump; latching the trigger differential judgment start signal for a positive-direction fault; nonlinearly mapping the fault phase current with the transient characteristic duration to obtain a fault level coefficient; performing interval matching of the fault level coefficient based on a preset action delay level library; starting a delay timer according to the matched delay level; and performing a tripping operation after the delay timer expires to disconnect the faulty section of the overhead line. This invention improves the efficiency of fault isolation and achieves accurate graded protection and rapid section clearing for phase-to-phase faults on 10kV overhead lines.

The application discloses a ring main unit current transformer secondary circuit disconnection detection method and system, and relates to the field of power distribution network system protection automation. The method comprises the following steps: obtaining a power balance imbalance starting threshold value according to a power sum, judging whether a bus is power imbalanced according to the power balance imbalance starting threshold value, obtaining three-phase currents of incoming lines and outgoing lines of the bus when the bus is power imbalanced, calculating current imbalance degrees of the incoming lines and the outgoing lines of the bus according to the three-phase currents, judging whether a current transformer secondary circuit is abnormal according to the current imbalance degrees, calculating phase sudden change currents according to the obtained three-phase currents of the incoming lines and the outgoing lines of the bus at the same moment when the current transformer secondary circuit is abnormal, judging whether the phase sudden change currents satisfy a third preset condition, and if yes, the current transformer secondary circuit is disconnected. According to the power node power conservation principle, the line current transformer secondary circuit disconnection discrimination accuracy and rapidity are improved under the condition that bus voltages are normal.

This invention discloses a method, system, medium, and device for detecting DC arc faults. The method includes: acquiring line current signals, performing feature processing to obtain feature values, and saving the average value of the features within a preset time period as initial feature values; filtering effective frequency bands whose noise floor values ​​meet set conditions based on the noise floor values ​​of each feature frequency band using a frequency band selection method; calculating arc energy values ​​to obtain dynamic arc energy and static arc energy; and detecting DC arc faults: when both dynamic arc energy and static arc energy exceed their respective thresholds, and the number of DC arc occurrences within a preset time period reaches a preset number, a DC fault arc is detected; otherwise, it is detected as normal. This invention is applied to DC fault arc circuit breakers, which can significantly improve the accuracy and reliability of DC arc detection and reduce the risk of false positives and false negatives in DC arc detection.

The utility model provides a kind of for the multi-source environment power taking device of railway additional line and sensing self-powered system.The multi-source environment power taking device includes flexible band material magnetic core magnetic field power taking module and auxiliary power supply module, and the output end of flexible band material magnetic core magnetic field power taking module is connected with anti-surge module in parallel, and the output end of anti-surge module is connected with magnetic core saturation suppression and filter reactive compensation module in parallel;The output end of magnetic core saturation suppression and filter reactive compensation module is connected with multi-modal rectifier module in parallel, and the output end of multi-modal rectifier module and the output end of auxiliary power supply module are connected with power conversion device.The utility model is by adopting laminated magnetic core and adding insulation film between magnetic core layer and layer to suppress eddy current loss, realize the promotion of magnetic field induction power taking device power taking power;On the basis of magnetic field induction power taking, simultaneously capture the rest field source energy in environment to realize auxiliary power supply, multi-source complement, solve the problem of insufficient energy of magnetic field induction power taking mode under railway additional line current intermittence.

Synchronous quadrature current compensators and synchronous average harmonic current compensators effectively control the harmonic current flow between the isolation bridges of a clock bidirectional resonant power converter. The synchronous average harmonic current compensator controls the superposition of low-frequency and switching currents across the nodes of the current control bridge to track the commanded line current and harmonic linearizes the dynamic coupling admittance of the voltage control bridge. A differential amplifier attenuates the low-frequency and reactive components of the bridge current signal from the quadrature current compensator. An error amplifier sums the synchronously modulated quadrature current signal used to estimate the transmitted harmonic current to track the safety-limited quadrature current command reference by generating a duty cycle. The line is inductively connected to either the voltage control bridge or the current control bridge, where the other bridge is driven by a duty cycle to command the harmonic current flow between the bridges.

The application discloses a bridge arm current distribution method and system for reducing M3C bridge arm current peak value, comprising the following steps: constructing a current distribution model based on the relationship between the power frequency side line current, the frequency division side line current and the bridge arm current; optimizing the current distribution model based on the concept of sub-converter upper limit current; obtaining the selection principle of positive sequence current distribution coefficient based on the optimized current distribution model; proposing a solving method of the positive sequence current distribution coefficient with the minimum sub-converter upper limit current as the target based on the selection principle of the positive sequence current distribution coefficient; designing the solving process of the positive sequence current distribution coefficient in actual application based on the solving method of the positive sequence current distribution coefficient with the minimum sub-converter upper limit current as the target, obtaining the positive sequence current distribution coefficient, and determining the distribution scheme of each bridge arm current. The application can effectively reduce the bridge arm current peak value, significantly improve the overload capacity of the M3C converter station, reduce the investment and construction cost of the M3C converter station, and improve the economy of the whole system.

The application belongs to the technical field of fault line selection, and particularly relates to a small current secondary grounding fault line selection method and system based on mathematical morphology. Bus zero sequence voltage and each feeder zero sequence current are collected. The voltage signal is decomposed by using a mathematical morphology OCCO algorithm to extract transient and steady components. If the transient component exceeds a threshold value, voltage disturbance is determined and the fault time is recorded. If the effective value of the steady component exceeds the threshold value after the fault time, it is confirmed that a single-phase grounding fault occurs. According to the zero sequence current of each feeder after the voltage disturbance occurs, the transient component is obtained by using the OCCO algorithm, and the transient energy value of each feeder is calculated accordingly. The feeder with the maximum energy is selected as the suspected fault line. The instantaneous transient power of the transient component of the current and the transient component of the voltage of the line is calculated, and the fault type is determined according to the polarity. The OCCO algorithm adaptively extracts fault features, and the double criteria of transient energy and instantaneous power polarity can accurately identify single-phase grounding and secondary grounding fault lines.

A power flow controller includes a voltage source converter including an alternating current (AC) voltage output configured to be simultaneously coupled to a first power transmission line and a second power transmission line. The voltage source converter is configured to generate, at the AC voltage output, AC voltage to be injected into the first power transmission line with additive polarity and into the second power transmission line with subtractive polarity to perform complementary compensation on the first and second power transmission lines. The power flow controller may further include a controller coupled to the voltage source converter and configured to control the phase angle of the AC voltage relative to at least one of the phase angles of the first and second power transmission line currents.

The present application belongs to the technical field of power electronic component manufacturing, and particularly relates to a pole-mounted circuit breaker overcurrent protection control method and system. The method comprises: collecting line current instantaneous value and constructing an analysis window; calculating waveform polarity index based on positive and negative half-wave current integration and duration difference to identify the asymmetric characteristics of magnetizing inrush current; combining current decay intensity and second-order difference value to calculate transient fluctuation reliability to distinguish cold load start-up and fault arc characteristics; using waveform polarity index and transient fluctuation reliability to construct comprehensive confidence weight, and then calculating fault degree; and only when the average value of fault degree in the analysis window exceeds the preset threshold, overcurrent protection is executed. The present application solves the problem that traditional protection cannot distinguish between non-fault transient impact and real fault, and realizes reliable locking under large current interference and precise action under real fault.

The application discloses a two-stage parallel high-power hydrogen production power supply system and a non-contact line current sharing control method thereof in the technical field of power supply or distribution circuit, which comprises a three-phase power supply, the three-phase power supply is connected with input ends of two PWM rectifiers respectively, output ends of each PWM rectifier are connected with input ends of two DC / DC converters, and output ends of the two DC / DC converters are connected with a hydrogen production PEM device, wherein the three-phase power supply, the PWM rectifier DC output end and the DC / DC output end are parallel operation; the conventional topology is improved, high reliability and low cost are considered, the application proposes a non-isolated three-phase power supply, PWM rectifier output end and DC / DC converter output end "three-end direct parallel" system architecture. The architecture effectively breaks the bottleneck that single-stage failure leads to the failure of the whole module, higher system-level reliability can be provided through fewer redundant devices; reasonable distribution and loop current suppression of the parallel system power are realized.

An input line-connected current-controlled bridge is dynamically coupled to an output line-connected voltage-controlled bridge of a single-stage bi-directional isolated resonant power supply using a synchronous average harmonic current controller. A bridge current sensor measures low frequencies and switching currents across nodes of the current controlled bridge. Synchronized average harmonic bridge current is controlled using superimposed non-modulated and modulated feedback, respectively, to track line current commands and linearize the coupling to the voltage controlled bridge. The power factor correction signal drives the line current command to regulate the DC voltage bus. The feed-forward and feedback trim circuits generate commands to the voltage-controlled bridge to track the input line voltage with attenuated harmonics. A single stage power supply has a defined interface for synchronizing and regulating power sharing of one or more modules.

This application provides a dual-power switch switching device, comprising a main contact branch and a main thyristor branch. A main magnetic switch and a thyristor QN1 are respectively installed on the main contact branch and the main thyristor branch. A main current transformer CTN1 is installed on either the main contact branch or the main thyristor branch. A spare contact branch and a spare thyristor branch are also provided, each equipped with a spare magnetic switch and a thyristor QN2. A spare current transformer CTN2 is installed on either the spare contact branch or the spare thyristor branch. Both the main current transformer CTN1 and the spare current transformer CTN2 are connected to a contact break detection circuit. A current detection device is installed on the output side of the main power switch circuit and the spare power switch circuit. This application directly detects the line current using the current transformer in conjunction with the contact break detection circuit, accurately determining whether a break has occurred.

This invention discloses a testing system and method for the power system of flapping-wing aircraft, belonging to the field of flapping-wing aircraft testing. In this system, a wind tunnel experimental platform is used to install the power system under test and provide test conditions; a signal measurement module is used to synchronously acquire electrical power, motor current and voltage, motor speed, rocker arm angle, rocker arm torque, lift, and net thrust; a motor characteristic testing platform is independently set up to establish the correspondence between motor output torque and line current and line voltage offline; a data acquisition and analysis module receives the above signals and correspondences, calculates the actual output torque of the motor, and thus obtains the efficiency of the electronic speed controller, motor, flapping-wing mechanism, as well as the overall efficiency and force efficiency of the power system. This invention can comprehensively reveal the energy flow and loss of each component within the power system of a flapping-wing aircraft, providing a quantitative basis for power system design verification and optimization, and is applicable to various types of motor-driven pure flapping-wing mechanisms.

This invention provides a DC power supply output positive and negative line current balancing circuit, belonging to the technical field of balanced circuits. The invention includes an output positive line current sampling amplifier circuit whose input terminal is connected to the positive terminal of the DC power supply, and whose output terminal is connected to the input terminal of a positive and negative current signal error comparator amplifier and the positive terminal of the power supply output interface. The output ground line current sampling amplifier circuit has its input terminal connected to the negative terminal of the power supply output interface, and its output terminal is connected to the input terminal of the positive and negative current signal error comparator amplifier and the input terminal of a variable impedance adjustment circuit. The output terminal of the variable impedance adjustment circuit is connected to the negative terminal of the DC power supply, and its input terminal is connected to the output terminal of the positive and negative current signal error comparator amplifier. The advantages of this invention are: it can adjust the output ground line current in real time to maintain a balanced state with the output positive line current, resulting in high safety and strong stability.