77results about "Voltage polarity indication" patented technology

A power semiconductor circuit includes: a power semiconductor element having a gate electrode configured to actuate the power semiconductor element, a collector electrode, and an emitter electrode electrically connected to a first emitter terminal; and a temperature sensor having a first measurement point with a measurement terminal and a second measurement point electrically connected to the emitter electrode, so that a voltage which drops over the temperature sensor is measurable between the measurement terminal and the first emitter terminal for the temperature measurement. Corresponding methods for determining a temperature of a power semiconductor element and for determining a sign of a load current in a bridge circuit are also described.

A semiconductor device includes a first and a second output transistor on a high and a low side respectively, a first terminal connected to the connection node between the first and second output transistors, and a second terminal configured to be connected via a bootstrap capacitor to the first terminal. The first output transistor is driven based on a voltage between the first and second terminals. A switching circuit is provided between a terminal fed with a predetermined control supply voltage and the second terminal. The switching circuit includes a first and a second switching element, which are N-channel MOSFETs connected in series. According to the voltage at the first terminal, the first and second switching elements are turned on or off.

A flux switch system is disclosed. The system (50) includes an input stage (52) configured to provide an interrogation pulse. The system also includes a plurality of flux loops (62, 64) configured to receive an input current (IIN). Each of the flux loops includes a Josephson junction (J1, J2) configured to trigger to generate an output pulse in response to a first polarity of the input current and to not trigger to generate no output pulse in response to a second polarity of the input current opposite the first polarity. The system further includes an output stage (54) configured to propagate the output pulse to an output (INTout) of the flux switch system.

The application discloses a voltage acquisition circuit, a bipolar direct-current power supply and a voltage acquisition method. A voltage difference between a near-end voltage and a far-end voltage is calculated by a subtracter. First, second and third switch switching units combine the positive and negative states of a power supply output voltage to switch the connection relationship between the voltage difference output by a positive voltage compensation voltage unit, a negative voltage compensation voltage unit and the subtracter and two input ends of a comparator. When a positive voltage is output, the positive voltage compensation voltage unit is connected to the inverting input end of the comparator, and the output end of the subtracter is connected to the non-inverting input end of the comparator; when a negative voltage is output by the power supply, the negative voltage compensation voltage unit is connected to the non-inverting input end of the comparator, and the output end of the subtracter is connected to the inverting input end of the comparator. A control unit determines whether far-end sensing sampling is normal according to the high and low levels of an abnormal comparison voltage output by the comparator. The application can identify the situations of disconnection and reverse connection when the bipolar direct-current power supply outputs a negative voltage.

For a DC-overcurrent detector (1) comprising an electric line (2), a first current sensor (3), a current flow direction sensor (4) and a comparator unit (5) it is suggested, that the detector (1) further comprises a threshold criterion unit (6), with an input of the threshold criterion unit (6) being connected to the current flow direction sensor (4) for receiving an actual current flow direction, and with an output of the threshold criterion unit (6) being connected to the comparator unit (5), proving the comparator unit (5) with the threshold criterion, and that the threshold criterion unit (6) is adapted to determine a first threshold criterion in case the actual current flows in the first direction (14), and a second threshold criterion in case the actual current flows in the second direction (15).

This application relates to the field of generator testing technology, and particularly to a method, apparatus, and equipment for determining the power direction of a generator's current transformer. The method includes: short-circuiting the target side of a transformer to construct a short-circuit closed loop, wherein the short-circuit closed loop includes a generator, a current transformer, and a transformer, and a waveform recorder is connected to the loop; injecting current into the short-circuit closed loop through a zero-start current from the generator until the generator terminal current rises to a first target current; using the waveform recorder to acquire the secondary voltage at the generator terminals and the secondary current of the current transformer, calculating the actual reactive power at the generator terminals based on the secondary voltage and secondary current; and determining the power direction of the generator's current transformer based on the reference reactive power and the actual reactive power at the generator terminals. This solves the problem that the power direction of the generator's current transformer secondary current and terminal secondary voltage, as well as the limitation of impedance components, can only be tested and verified after grid connection.

The present invention relates to a fluxgate type leakage current detection device, characterized by including: an oscillator unit that generates a pulse current having a predetermined frequency; at least one first core wound with at least one first coil having one end connected to the oscillator unit and magnetized by the pulse current; a second core wound with a second coil having one end grounded; and a core unit that supplies a third coil wound around the first core and the second core and supplied with a compensation current; and a control unit that determines the frequency of the pulse current in accordance with at least one feature of the at least one first core, filters out a frequency component from a voltage signal of a current induced in the at least one first core, detects a DC component leakage current of a conductor to be measured, and supplies a reverse current corresponding to the detected DC component leakage current to the third coil as the compensation current.

Disclosed in the present application are a load control circuit, a chip, a communication circuit and an interactive control method. The load control circuit comprises a rectifier bridge circuit, a modulation circuit, an energy control module, and a first controller, wherein the rectifier bridge circuit is connected to the modulation circuit; the rectifier bridge circuit is connected to the energy control module; the first controller is connected to both the modulation circuit and the energy control module; the rectifier bridge circuit is used for rectifying an input signal and outputting a rectification result; an input signal port in the rectifier bridge circuit is used for connecting in parallel to a load element external to the load control circuit; the first controller is used for causing a current change in the rectifier bridge circuit by means of controlling the modulation circuit, so as to drive a current change in the load element to perform modulation; and the energy control module is used for charging, by means of the rectification result, a capacitor externally connected to the load control circuit, and for gating the capacitor externally connected to the load control circuit to supply power to the modulation circuit.

The application provides a kind of airborne high-voltage direct current system protection method and device, the system includes DC bus, protection controller and the distribution function unit connected between DC bus and each function unit branch, distribution function unit at least includes series connection's explosive fuse, contactor and current sensor;Including the following steps: each function unit branch is defined as power supply branch or load branch, and forward action logic and reverse action logic based on current flow direction are set for power supply branch and load branch respectively;System operation, current amplitude and direction signal flowing through each function unit branch are collected in real time using current sensor, and current amplitude and direction signal are transmitted to protection controller;Protection controller selects corresponding action logic according to the direction signal detected currently, and compares current amplitude with action threshold in selected action logic, when current amplitude exceeds action threshold, explosive fuse or contactor is triggered to execute protection action.

A safety module for an inverter of a motor vehicle. The inverter including at least two power circuits. The safety module including a control unit and at least two safety switches, each safety switch being associated with a power circuit and being connected between the power circuit and a point referred to as the “measurement” point. The control unit being capable of controlling each safety switch and being configured to detect a closing malfunction of a safety switch if: a) a closing command has been sent to the safety switch, the other safety switches being open, b) and the voltage at the measurement point is negative.

The application discloses a kind of open-winding photovoltaic energy storage converter system fault diagnosis method, device, equipment and storage medium, it is related to power electronic converter fault diagnosis technical field, the method comprises: obtaining the photovoltaic side DC bus current, energy storage side DC bus current and three-phase AC output current of open-winding photovoltaic energy storage converter system;According to three-phase AC output current, photovoltaic side DC bus current, energy storage side DC bus current obtains the current residual of photovoltaic side fault phase and the current residual of energy storage side fault phase;The current residual of photovoltaic side fault phase and the current residual of energy storage side fault phase are processed, and first diagnostic variable and second diagnostic variable are obtained;Detect the current flow direction of fault phase in open-winding photovoltaic energy storage converter system;According to the current flow direction of fault phase, first diagnostic variable and second diagnostic variable, determine fault location.The method can realize accurate fault positioning of open-winding photovoltaic energy storage converter system.

The invention relates to the field of power grid monitoring, and discloses a fault studying and judging method, device and system for a self-adaptive standing book and an adaptive pole-mounted switch. The method comprises the following steps: determining a first transient zero-sequence current frequency and a second transient zero-sequence current frequency corresponding to each pole-mounted switch point, and determining machine account information corresponding to each pole-mounted switch point according to a current frequency ratio between the first transient zero-sequence current frequency and the second transient zero-sequence current frequency; then determining the polarity of the transient zero-sequence current between the switch point positions on every two adjacent columns; determining a power supply direction between every two adjacent pole switch points according to the polarity of the transient zero sequence current; performing fault study and judgment on the line according to the standing book information and the power supply direction; therefore, the self-adaptive standing book identification and the power supply direction are used as preconditions of fault research and judgment, the accuracy of fault research and judgment can be improved, and fault misjudgment and missed judgment are reduced.

To provide a power monitoring device and a monitoring method thereof.SOLUTION: A power monitoring device includes a power detection module and a processor. The power detection module converts a forward power into a forward signal, and converts a reverse power into a reverse signal. The processor is configured to determine whether the forward signal and the reverse signal meet a first judgment condition at a first time to generate a first result, and to determine whether the forward signal and the reverse signal meet a second judgment condition at a second time to generate a second result. The processor determines whether to send a warning signal based on the first result and the second result.SELECTED DRAWING: Figure 1

The invention discloses a three-phase circuit lightning stroke identification method and device, relates to the technical field of power system positioning, and aims to accurately judge the lightning stroke type and the lightning stroke position, conveniently identify the line accident reason and quickly position the line fault caused by the lightning stroke. The method comprises the following steps: fitting a relationship between a lightning peak value on a line and a transmission distance according to a finite difference time domain method; a transient magnetic field generated by lightning stroke is induced through a PCB differential ring, and induced electromotive forces generated at the two ends of the transient magnetic field are sampled; when the induced electromotive force is greater than a set threshold value, recording current waveform data of a three-phase line; and judging an output lightning stroke type according to the current waveform data and whether the polarities of the three-phase current head waves are the same or not, and judging a lightning stroke position in combination with a relationship between a lightning peak value and a transmission distance. The lightning stroke type and the lightning stroke position can be accurately judged, and line accident reasons can be conveniently identified and line faults caused by lightning stroke can be rapidly positioned.

The invention relates to a three-core cable zero-sequence current direction checking device and method, and belongs to the technical field of power system relay protection, and the checking device comprises a coupling unit which is provided with a three-core cable connector and is used for injecting a transient excitation signal into a zero-sequence loop, acquiring an injection signal reference quantity corresponding to the transient excitation signal; the acquisition unit is provided with a mutual inductor connector, and the acquisition unit is used for acquiring transient response current caused by the transient excitation signal in a zero sequence loop; and the host is connected with the coupling unit and the acquisition unit, and the host judges the direction of the zero-sequence current according to the reference quantity of the injection signal and the transient response current. The coupling unit and the acquisition unit detect the transient response current on the zero-sequence loop through non-probing contact, the direction of the zero-sequence current is judged by comparing the injection signal reference quantity and the transient response current, and power failure is not needed in the whole process.

The present application relates to the technical field of power generation motor, and discloses a power generation motor insulation state prediction method and system. The method collects three-phase stator current signals and operation mode identification signals of the power generation motor, and constructs an insulation degradation characteristic vector. The power generation mode and the motor mode are distinguished based on window average active power, and an operation mode variable and a mode change indicator are constructed. The basic coupling coefficient between the degradation characteristics is calculated, the coupling weight is adjusted by introducing a mode sensitivity function, an adaptive adjacency matrix driven by the operation mode is constructed, and the event-driven update of the graph structure is realized. Based on the adaptive graph structure, spatial feature extraction and time dimension fusion are carried out, and a normalized insulation health index is output for state evaluation and trend analysis. The method can weaken the influence of the difference between the two working conditions on the coupling relationship of the characteristics, improve the stability and reliability of the insulation degradation evaluation, and is suitable for online monitoring and early warning of the power generation motor of the pumped storage unit.

A balance characteristic test device for a zero-phase current transformer, which can perform a balance characteristic test using a small output current source. The device includes: an electric wire (1) disposed so as to penetrate a through-hole of a zero-phase current transformer (100) in a plurality of round trips; a current source (2) that causes a direct current to flow through the electric wire (1); and an ammeter (3) that measures the magnitude of a secondary current of the zero-phase current transformer (100).

The invention discloses a hard strap voltage monitoring device and method, and relates to the field of power grid hard strap voltage monitoring, the device is provided with a first metal plate, a second metal plate and a third metal plate which are arranged in parallel in principle, the first metal plate is connected with an object to be measured or the object to be measured is regarded as the first metal plate in actual use; the second metal plate is grounded; the other end of the capacitor is connected with one end of the first resistor and the grid electrode of the field effect transistor. The drain electrode of the field effect transistor is connected with one end of the second resistor, and the source electrode and the other end of the first resistor are grounded together. The device drives the second metal plate to do sine regular motion along the vertical direction through a sine signal, thereby changing the voltage of the third metal plate, calculating the amplitude of the voltage to be measured by using the peak-to-peak value of the voltage, judging the polarity of the voltage by combining the phase difference, being only used for accurate measurement of the voltage, not needing gear switching, and avoiding tripping accidents caused by wrong gear selection of a universal meter. And the non-contact design is adopted, so that the voltage measurement safety is improved.

An artificial nociceptor may include a sensor configured to convert a damaging force into electric energy, a conversion circuit configured to generate an input voltage having a form of a cycle signal having a frequency and amplitude changed, based on the electric energy, and a storage circuit including a plurality of memory cells and configured to provide the input voltage to first memory cells included in a selected area, among the plurality of memory cells.

The present application discloses a combiner device, a photovoltaic power generation system, and a fault detection method, the combiner device including at least two photovoltaic power generation strings connected in parallel, further including a current detection circuit for detecting the current of each photovoltaic power generation string, a voltage detection circuit for detecting the voltage of the photovoltaic power generation strings connected in parallel, an insulation impedance detection circuit for detecting the insulation impedance of the photovoltaic power generation strings connected in parallel, and a controller for determining whether a reverse connection fault occurs in the photovoltaic power generation string based on the current, voltage, and insulation impedance. When determining the photovoltaic power generation string, the three parameters of the current, voltage, and insulation impedance are comprehensively determined to accurately determine whether a reverse connection fault actually occurs in the photovoltaic power generation string, thereby reducing the impact of erroneous determination on the power generation amount, and the current alone cannot accurately determine whether a reverse connection fault occurs, and the current may be reversed due to other faults.

An apparatus for testing an image sensor includes a load resistor, a first switch configured to be electrically connected to a first signal line of a device under test and a first end of the load resistor, a second switch configured to be electrically connected to a second signal line of the device under test and a second end of the load resistor, a first parametric measuring unit electrically connected to the first switch, and a second parametric measuring unit electrically connected to the second switch. At least one of the first parametric measuring unit and the second parametric unit is configured to correct an error of the load resistor during a testing operation of an output voltage of the device under test.

To provide an electronic circuit, a drive circuit, and a determination method for determining the current polarity of a switching element included in a half-bridge circuit with a simple configuration.SOLUTION: The electronic circuit of the present embodiment includes a determination processing unit that determines a current polarity of at least one of a first switching device and a second switching device based on a first voltage between a first electrode and a second electrode of the first switching device during a dead time of a half-bridge circuit including the first switching device and the second switching device.SELECTED DRAWING: Figure 1

The application relates to the technical field of intelligent substation power supply monitoring, in particular to a high-voltage-grade intelligent substation AC / DC integrated power supply monitoring system. The system comprises an equipment abnormality reason analysis unit, an abnormality reason classification unit and a parameter data information comparison unit. In the application, the parameter data information comparison unit extracts fault reason parameter data information, compares each parameter data information, classifies fault reasons with the same parameter data information, shows that the two parameter data that are compared and coincided belong to the same data type and correspond to the same fault reason, merges the fault reasons corresponding to the parameter data that are compared and coincided, only retains the parameter data corresponding to one fault reason in the later period, and the remaining same parameter data is eliminated, so that the control system can avoid storing too much redundant data, system storage overload is avoided, and the normal operation of the system is affected.

An electrical apparatus forming part of an AC power supply network comprises a conductor, sensors for measuring current and voltage on the conductor and a control unit. The control unit receives, from the sensors, measurements of the current and the voltage at the conductor and calculates a phase angle between them. Whether a short circuit current is occurring in the conductor is determined and a set of predetermined phase angle ranges is selected depending on whether a fault is present. Which of the ranges contains the calculated phase angle is used to determine if the power flow is incoming or outgoing. First and second phase angle ranges are used when no short circuit fault is present; third and fourth ranges are used when a fault is present. The directions of power flow may be measured at different points in the network and the location of a fault determined as lying between two of these points.

The invention provides a low-voltage servo motor current sampling method, and relates to the technical field of motor control. The method is based on an H-bridge driving circuit, V1 and V4 as well as V2 and V3 in four switching devices V1-V4 are respectively controlled by PWM1 and PWM2 with opposite levels; the voltage Ur is measured through the sampling resistor R1 connected in series, and Ucur is obtained through the RC low-pass filter; ucur is sampled at a digital triangular wave peak value moment by utilizing the characteristic that Ur polarity corresponds to motor current polarity during a PWM1 high level period and combining the matching design of a motor electromagnetic time constant and a switching period, and the current magnitude and polarity are obtained. According to the method, the polarity of the motor current can be easily obtained by analyzing the current flow direction of the H-bridge control pulse when the PWM1 is in the high-level period. Compared with a traditional scheme, the problem of polarity misjudgment caused by phase deviation and Hall sensor signal delay possibly occurring in current reconstruction is solved.

The invention discloses an active power distribution network fault identification method and apparatus, and an electronic device. The method comprises the following steps: generating a fault information coding vector based on fault information respectively collected by a plurality of feeder terminal units included in the power distribution network; dividing a power supply area of the power distribution network by taking the T-shaped interval as a boundary to obtain a plurality of power supply areas; based on the fault information coding vector, determining a target fault area from the plurality of power supply areas, and determining a fault type of the target fault area; based on the fault type, determining fault research and judgment indexes respectively corresponding to a plurality of intervals included in the target fault area; and determining a candidate fault scene of the target fault area based on the fault research and judgment indexes corresponding to the plurality of intervals. According to the invention, the technical problems of high fault positioning complexity and low identification accuracy caused by the introduction of the distributed power supply in the active power distribution network are solved.

A bidirectional current sense circuit allowing for sensing of power current passing through a power field-effect transistor, regardless of the direction of the power current. The bidirectional current sense circuit outputs a current sense signal representing the power current onto a current sense output node. The bidirectional current sense circuit includes the power field-effect transistor, and two current sense circuits. One of the current sense circuits senses the power current when the power current flows in the positive direction. The other current sense circuit senses the power current when the power current flows in the negative direction.

An electronic circuit according to an embodiment of the present invention is provided with a determination processing unit for determining a first voltage between a first electrode and a second electrode of a first switching element in a dead time of a half-bridge circuit including the first switching element and the second switching element. The current polarity of at least one of the first switching element and the second switching element is determined.

This zero current sensor (1) for detecting the timing at which a current flowing through a current path (CP) becomes zero comprises: a saturable inductor (Lsat) connected on the current path (CP); and a transformer (T) in which a primary winding (Np) is connected in parallel to the saturable inductor (Lsat). The zero current sensor (1) is provided with an output circuit (10) that is connected to a secondary winding (Ns) of the transformer (T) and outputs an induced current of the secondary winding (Ns) as a detection signal (Vsen). The output circuit (10) outputs, as a detection signal (Vsen), a positive pulse or a negative pulse corresponding to the direction of the induced current of the secondary winding (Ns).

The invention relates to a bidirectional current isolation sampling device and method and a direct current charging pile, and the device is connected with a direct current bus through a signal collection module, and converts the collected bus current into a first voltage signal; the voltage boosting module is connected with the signal acquisition module and is used for boosting the first voltage signal to a positive value and outputting a second voltage signal; the isolation conversion module is connected with the voltage lifting module, electrically isolates the second voltage signal and outputs a third voltage signal; the signal processing module is connected with the isolation conversion module and converts the third voltage signal into a single-ended signal adaptive to sampling of the analog-to-digital converter; the controller is connected with the signal processing module and used for obtaining the voltage value of the single-end signal and calculating the current value and the transmission direction of the bus current according to the voltage value, the problem that bidirectional current sampling is high in cost or unstable is solved, bidirectional current detection can be independently carried out with lower-cost structural design, and the reliability of the system is improved. And the accuracy of bus current monitoring is improved.