676 results about "Reverse current" patented technology

The invention relates to the technical field of countercurrent prevention, in particular to a photovoltaic system countercurrent prevention method, which comprises the following steps of: periodically sampling the voltage of a grid-connected point where a photovoltaic system is connected with a power grid, continuously obtaining an instantaneous measurement value of the voltage, and establishing and updating an instantaneous voltage data cache; and based on the instant voltage data cache, extracting voltage data in the latest fixed time window, calculating the maximum change rate of the voltage amplitude in the time window, and judging and generating a voltage transient trigger signal. According to the invention, on the basis of continuous and periodic sampling of the grid-connected point voltage, an instant voltage data cache is established, and accurate capture of voltage disturbance is realized; by calculating the change rate of the voltage amplitude in the specific time window, the accurate moment when the voltage transient event occurs can be identified, and the real-time performance and accuracy of voltage transient detection are improved.

A circuit may comprise an electronic switch with a load current path, which is switched between an output node and a supply node and is designed to connect or disconnect the output node to or from the supply node in accordance with a control signal. The circuit further comprises a control circuit which is designed to generate the control signal based on an input signal, and a current monitoring circuit which is designed to receive a current measurement signal that represents the load current flowing through the load current path, and to generate a protective signal, based on the current measurement signal, which indicates whether the output node should be disconnected from the supply node. The circuit further comprises a reverse current detection circuit, which is designed to detect that the load current is flowing in the reverse direction, namely from the output node to the supply node.

The invention discloses a low-cost high reactive overload energy storage converter topology and a modulation strategy thereof, is used for improving the reactive overload capacity of an energy storage converter, and belongs to the technical field of alternating current-direct current converters. According to the invention, the auxiliary diode is additionally arranged on the traditional ANPC bridge arm, so that the reverse current of the IGBT module is shared during high-proportion reactive output of the converter, and the reactive overload capacity of the converter can be efficiently improved with low cost on the basis of fully utilizing the existing equipment. Besides, a reactive overload capacity enhancement modulation strategy based on third harmonic injection is provided for the topology, and third harmonics are injected into modulation waves, so that the utilization rate of an auxiliary diode is improved, and the output capacity of reactive current is further enhanced. According to the method, a 100kVA prototype is tested and verified in Simulink / Plecs, the device cost of the proposed topology is only increased by 5.45% on the basis of a traditional ANPC, the reactive overload capacity is increased by 22%, and the power grid voltage supporting capacity of the energy storage converter can be effectively enhanced.

A power supply control device includes: an output stage circuit having a high-side transistor provided between an application terminal of an input voltage and a switch terminal, and a low-side transistor provided between the switch terminal and a ground terminal; a high-side driver; a low-side driver; a switching control circuit for controlling on / off state of the high-side and low-side transistors using the low-side and high-side drivers; a boot terminal for applying a boot voltage; a rectifying element for supplying a charging current to a boot capacitor during an on period of the low-side transistor; a reverse current detection circuit for detecting a specific reverse current state in which a reverse current flows from an output terminal to which the output voltage is applied, toward the low-side transistor via the coil and the switch terminal; and a monitor circuit for monitoring a height of the boot voltage.

Unidirectional hybrid switch. At least one example is a method operating a hybrid switch, the method comprising: sensing a voltage across an upper terminal and a lower terminal of the hybrid switch, the hybrid switch is forward biased when the upper terminal has higher voltage, and the hybrid switch is reverse biased when the lower terminal has higher voltage; when the hybrid switch is forward biased, selectively conducting a forward current from the upper terminal to the lower terminal by sharing the forward current between a FET switch and a BJT switch, the selectively conducting when a control terminal is asserted; and when the hybrid switch is reversed biased, non-selectively conducting a reverse current from the lower terminal to the upper terminal.

The invention relates to a preparation method and application of an electrode, in particular to a preparation method and application of an anti-reverse current self-supporting electrode for anion exchange membrane water electrolysis hydrogen production. The self-supporting (NiCoFe) 9S8 electrode is constructed by adopting a directional solid-phase synthesis strategy to overcome the challenge of performance degradation of the electrolytic cell. The preparation method comprises the following steps: firstly, depositing a precursor solution of FeS2 and CoCl2 on a nickel felt substrate, and then carrying out annealing treatment to obtain uniformly grown (NiCoFe) 9S8; the method not only ensures uniform distribution of multiple metal components, but also constructs firm chemical bonding and efficient charge transfer between the catalyst layer and the conductive substrate through solid-phase interface reaction, and effectively avoids interface impedance caused by introduction of an additional binder. Therefore, high-current-density water electrolysis hydrogen production under intermittent fluctuation power supply is realized. In 1M KOH, the cell voltage is almost not attenuated when the electrode stably operates for 2000h at 500mAcm <-2 >.

The present invention relates to a manipulator control device and a robot based on kinetic energy recovery. The manipulator control device includes a motor, a motor drive module, a controller and an energy storage device; the motor drive module is connected to a power source, and controls the rotation of the motor through a control signal sent by the controller; the energy storage device is connected to the motor drive module, and receives the reverse current transmitted from the motor through the motor drive module and stores electric energy when the motor decelerates; and / or releases the stored electric energy to output a discharge current when the motor accelerates, and the discharge current is transmitted to the motor through the motor drive module. The manipulator control device based on kinetic energy recovery of the present invention, by providing an energy storage device, stores energy when the motor decelerates and releases energy when the motor accelerates, which can not only reduce the heating of the motor and improve the safety of equipment operation, but also save energy and reduce costs.

The invention relates to the technical field of electrochemical energy storage application, and discloses a load power prediction-based user side energy storage operation regulation method, which comprises the following steps of: acquiring load power and energy storage power in a sampling period, calculating a load prediction value at the end of a next period according to the initial load power and the end load power in the period, establishing a historical load extreme value database, and executing an asymmetric condition updating rule, namely, performing online correction on the database according to different comparison conditions in a charging mode and a discharging mode; an adjusting instruction is generated according to the capacity constraint of the transformer in the charging mode, and an adjusting instruction is generated according to the anti-countercurrent threshold constraint in the discharging mode. Preventive measures for two different operation risks of charging overload and discharging countercurrent are unified in a continuous control process with online self-learning capability according to system operation state switching adjustment reference and boundary conditions, and the economical efficiency and the safety of operation are both considered.

The invention discloses a full-working-condition driving force optimal distribution control method based on an HCU, and relates to the technical field of new energy automobile control, and the method comprises the following steps: building a long slope energy flux analysis model, generating a time sequence envelope curve of recovery power based on a slope, an automobile speed and a wheel end inertia, and extracting a local peak value interval in the time sequence envelope curve; and in the peak value interval, based on the open-circuit voltage, pulse current and impedance spectrum information of the power battery, online identifying the absorption capacity of the power battery, correcting the upper limit of the state of charge of the power battery, determining a rechargeable current threshold value, carrying out coupling analysis on the threshold value and the recovery power envelope curve, and identifying the reverse current risk time period of the inverter. According to the method, real-time constraint on the absorption capacity of the power battery under the long-slope deceleration working condition is achieved, the inverter reverse irrigation risk is recognized, a peak clipping track and a transient discharge channel are constructed, micro-pulse, accessory absorption and super-capacitor shunting are fused, energy closed-loop control is formed, and the safety of the whole vehicle and the energy utilization efficiency are improved.

The invention relates to an anti-countercurrent and anti-overload method, device and system for an optical storage power station. The method comprises the steps of obtaining a first power generation time period, a second power generation time period and photovoltaic output power based on meteorological data, a local electricity price scheme in each time period and preset intensity; load power and energy storage allowable charging power are predicted; controlling the power grid to charge the energy storage device in the first power generation period, and controlling the photovoltaic power generation device and the power grid to charge the energy storage device in the second power generation period; comparing the anti-countercurrent power threshold with the power grid output power, and adjusting the photovoltaic output power and the energy storage output power; and setting a maximum demand limit value, a demand control margin value and a power reduction margin value, and adjusting the energy storage allowable charging power of the energy storage device. According to the invention, countercurrent prevention and overload prevention are effectively ensured under the condition that the optical storage power station fully utilizes the electric energy of the photovoltaic power generation device, the operation cost of the power station is reduced, and stable circulation of self-generation and self-use of the electric energy of the power station is ensured.

The invention discloses an anti-countercurrent control method and system for an energy storage transformer driven by bidirectional power regulation, and relates to the technical field of anti-countercurrent control of transformers, and the method comprises the steps: collecting the active power of a gateway ammeter, the active power of a load, the capacity of a transformer and a power factor of a power grid power supply grid-connected point in real time, and constructing a real-time operation data set; energy storage discharge countercurrent risk identification is carried out, segmented discharge is triggered to reduce protection, and segmented power adjustment is carried out in the discharge direction; according to the real-time operation data set, overload risk identification of the energy storage charging transformer is carried out, segmented charging demand reduction protection is triggered, and segmented power adjustment is executed in the charging direction. The technical problems that in the prior art, countercurrent is likely to happen during discharging of the energy storage transformer, overload is likely to happen during charging, and consequently equipment operation is not safe and a power grid is not stable are solved, and the technical effect that the operation safety of the energy storage transformer and the stability of the power grid are improved through the segmented power adjustment and power slow rising strategy is achieved.

The invention relates to the technical field of fault detection, in particular to an electronic component fault management method and system. The method comprises the following steps: collecting real-time data and constructing a real-time fault monitoring data set; reading historical data and constructing a historical reference data set; comparing the real-time fault monitoring data set with the historical reference data set item by item in a corresponding time window to obtain a drift amplitude, and mapping according to the drift amplitude to generate a reverse excitation amplitude instruction; a reverse current signal according to the reverse excitation amplitude instruction is injected into the loop node to be measured, and a Hall null drift amount is determined according to Hall output; outputting an electronic disturbance quantity based on the Hall null drift quantity; therefore, through dynamic data cooperation and an active excitation response mechanism, the problems of missing detection recessive degradation, misjudgment transient interference and single diagnosis dimension of traditional fault management are solved, and the hidden danger recognition precision and the protection reliability are remarkably improved.

The invention discloses a micro-copper pillar bump interconnection resistor electromigration degradation prediction method. The method comprises the following steps: obtaining the net flux of Cu atoms in a Cu6Sn5 layer and a Cu3Sn layer and the net flux of Ni atoms in a Ni-Cu-Sn compound layer under forward current and reverse current; establishing a relationship between the net flux of Ni atoms and the thickness change of the Ni-Cu-Sn compound layer and a relationship between the net flux of Cu atoms and the thickness change of the Cu6Sn5 layer and the Cu3Sn layer; establishing a thickness polarity growth model of the Ni-Cu-Sn compound, the Cu6Sn5 layer and the Cu3Sn layer; establishing a thickness polarity consumption model of the Cu bonding pad, the Sn solder and the Ni layer; and establishing a resistance electromigration degradation model of micro-copper pillar bump interconnection. According to the method, the electromigration degradation prediction of the interconnection resistor of the copper pillar bump plated with the Ni layer can be realized, and a large amount of service life and time and economic cost generated by a failure analysis test are greatly reduced or avoided.

The invention discloses a composite voltage generation device and a cable insulation performance evaluation system and method, and relates to the technical field of high-voltage insulation testing. The composite voltage generating device comprises a synchronous controller, a direct current source, an impact source, an IGBT active protection unit and a magnetic isolation coupler, and by means of the excellent characteristics of the IGBT and the magnetic isolation coupler, the superposition time sequence accuracy of direct current and impact voltage is improved, and waveform distortion is reduced. The IGBT active protection unit comprises a first IGBT and a second IGBT, and direct-current voltage polarity switching can be realized through selective conduction of the IGBTs; the RC circuit is connected in parallel between the collector electrode of the first IGBT and the emitter electrode of the second IGBT, reverse current flowing back to the direct current source direction can be discharged through the RC circuit, the risk of energy flowing back is reduced, meanwhile, the magnetic isolation coupler can completely block direct current, and an impact source is protected against the influence of direct current voltage; according to the invention, the authenticity and reliability of cable insulation performance evaluation can be effectively improved.

A switching modulation circuit generates a first control signal with a duty ratio. A delay circuit delays the first control signal to generate a second control signal. A zero crossing detector detects whether an output current of a DC / DC converter is smaller than a threshold in a rectification interval, and generates a third control signal. A monitoring circuit detects a reverse-flow possibility of the output current, and generates a fourth control signal. A delay time of the delay circuit is set shorter than the delay time of the zero crossing detector. When the reverse-flow possibility does not exist, and the third control signal has transitioned to indicate that the output current is smaller than the threshold, a driver circuit turns off both first and second switching elements. When the reverse-flow possibility exists, and the second control signal has transitioned from an ON state to an OFF state, the driver circuit turns off both the first and second switching elements.

The invention discloses an uninterrupted calibration method and device for a medium and low voltage current transformer and a medium. The method comprises the following steps: measuring a primary side original current signal of a to-be-measured current transformer by using a pre-prepared mobile calibration platform; injecting a reverse current with the same frequency as the injection current source of the current transformer to be detected into the current transformer to be detected, and counteracting a primary side original current signal of the current transformer to be detected; generating a pilot frequency current according to a pre-selected pilot frequency signal by using an injection current source, inputting the pilot frequency current to a primary side of the current transformer to be detected for pilot frequency current calibration, and collecting a secondary side output signal; performing error analysis on the to-be-detected current transformer based on the secondary side output signal, and determining an error analysis result; and adjusting the calibration parameters of the to-be-detected current transformer based on the error analysis result to perform pilot frequency current calibration again until the error analysis result meets a preset requirement, and completing calibration of the to-be-detected current transformer.

Circuits and methods are provided that more effectively and efficiently implement multi-level converter circuits. In some embodiments an integrated circuit comprises a switching network that when connected to one or more capacitors causes said switching network to form a capacitor arrangement dependent on a state of the switching network. A controller may be configured to control the state of the switching network to cycle between a set of states maintaining each state for a predefined amount of time according to a timing pattern to convert a first voltage to a second voltage. The controller may be further configured to maintain a particular state of the switching network for longer than the predefined amount of time in response to a determination that a current flow to a source of the first voltage may occur.

The invention relates to the technical field of photovoltaic power generation, in particular to a photovoltaic charging and discharging control method and system based on a direct-current coupling optical storage all-in-one machine, and the method comprises the steps: monitoring system operation parameters in real time; after the countercurrent risk is judged, energy storage is preferentially utilized to absorb redundant electric energy; when the stored energy is saturated, the photovoltaic output is dynamically adjusted instead of shutdown; when photovoltaic power generation is insufficient, the gap is supplemented through energy storage discharge. By monitoring system operation parameters in real time and dynamically coordinating photovoltaic power generation, energy storage charging and discharging and load requirements, photovoltaic energy is utilized to the maximum extent while reverse current of a power grid is avoided, redundant electric energy is preferentially stored in a battery, and photovoltaic output is intelligently adjusted instead of direct shutdown after energy storage is saturated; and when the load demand is higher than that of photovoltaic power generation, a gap is supplemented through energy storage discharge, so that energy waste is remarkably reduced, the system operation time is prolonged, the overall power generation income and economy are improved, and safe and stable operation of a power grid is ensured.

Bidirectional isolated universal topology (BIUT) high power DC-DC converter assemblies and systems balance voltages and control currents between high power DC sources and high power DC loads where at least some of the high power DC sources are alternative energy or renewable energy power supplies and high power DC loads associated with alternative energy or renewable energy. The BIUT high power DC-DC converter assemblies and systems are capable of reversing current flow direction where loads become the sources and sources become the load in DC power systems where the supplies and loads are all connected to a common DC voltage bus.

The application discloses a GaN HEMT device integrated with a reverse diode and a preparation method thereof. The GaN HEMT device comprises a two-dimensional electron gas structure, a source electrode, a drain electrode, a P-GaN gate electrode, a passivation layer, a source field plate structure, a Schottky contact metal, an ohmic contact metal and a P-GaN layer. The Schottky contact metal and the surrounding structure thereof constitute a Schottky diode, and the P-GaN layer and the surrounding structure thereof constitute a P-i-N diode. The application integrates the parallel Schottky diode and P-i-N diode, and provides a new path for the reverse current of the GaN HEMT device. In the reverse conduction, the low reverse conduction voltage of the Schottky diode can be utilized, and the strong overcurrent capacity of the P-i-N diode can be exerted. The source field plate structure is utilized to build a reverse conduction loop, and the reverse conduction part is formed with the aid of the potential barrier layer. The reverse conduction part and the forward conduction part share the drain region, and the area is reduced.

The invention discloses a current injection type SiC MOSFET parallel current-sharing driving circuit, which detects the voltage difference between two ends of a current sampling resistor through an isolation amplifier and a differential amplification circuit, indirectly measures the current value of each parallel branch, and determines the current difference value of the parallel branches through the differential amplification circuit. And when the current of the SiC MOSFET parallel circuit is unbalanced, a control signal is output to the forward current injection circuit or the reverse current injection circuit. Through a forward current injection circuit and a reverse current injection circuit, forward current or reverse current is injected into a grid electrode under the action of a control signal, the change rate of grid-source voltage is changed, the switching-on and switching-off speed of SiC MOSFETs is dynamically adjusted, the phenomenon of non-uniform parallel current of the SiC MOSFETs caused by inconsistent device parameters or asymmetric circuit layout in the circuit is effectively inhibited, and the switching-on and switching-off speed of the SiC MOSFETs is improved. The active current sharing circuit has the advantages of being good in adjusting performance and high in response speed.

The invention relates to automatic reverse current regulation in an active clamped flyback converter. According to one embodiment, a method is presented that includes sensing a reverse current through a main switch of an active clamped flyback (ACF) converter. The ACF converter includes a flyback transformer and an auxiliary switch. The method further includes determining whether a sensed voltage corresponding to the reverse current exceeds a threshold; reducing a duration of the reverse current by an incremental time interval, the duration of the reverse current including a first incremental time interval, the duration of the reverse current corresponding to a duration in which the auxiliary switch is activated; increasing the duration by a second incremental time interval greater than the first incremental time interval, the increasing in response to the reverse current not exceeding the threshold; and activating the auxiliary switch for the duration to achieve zero voltage switching (ZVS).

The invention provides a driving circuit of a high-side switching tube, and the driving circuit of the high-side switching tube comprises a pull-up unit which carries out the pull-up of a grid potential of the high-side switching tube through a first current when a control signal is effective; the second pull-down unit is used for carrying out pull-down on the grid potential of the high-side switching tube by utilizing second current when the control signal is invalid; the pull-up unit further adjusts the first current according to the first current adjusting signal so as to adjust the starting speed of the high-side switching tube, and therefore slow starting of the high-side switching tube is achieved. According to the driving scheme of the high-side switching tube, the structure is simple, slow switching-on and switching-off of the high-side switching tube can be achieved, mistaken switching-on of the high-side switching tube can be avoided when the voltage of the input end is subjected to rapid step, and it can be ensured that no reverse current flows back to a driving circuit power source when the voltage of the output end is higher than the voltage of the input end.

The invention relates to the technical field of electric power, in particular to a vacuum circuit breaker and a phase selection closing control method, and the vacuum circuit breaker comprises a hybrid electromagnetic mechanism and a vacuum arc-extinguishing chamber; the hybrid electromagnetic mechanism comprises a permanent magnet closing assembly and an electromagnetic repulsion opening assembly, the permanent magnet closing assembly comprises double coils and a T-shaped movable iron core which are arranged in parallel, and a discharge loop is formed to drive a movable contact of the vacuum arc-extinguishing chamber to complete a closing action and maintain a closing state; the electromagnetic repulsion opening assembly comprises a static coil panel and a moving coil panel which are coaxially and oppositely arranged to form a reverse current repulsion loop so as to drive a moving contact of the vacuum arc-extinguishing chamber to complete an opening action and maintain an opening state, and the moving coil panel is connected with a T-shaped moving iron core of the permanent magnet closing assembly through an insulating guide rod; the vacuum arc-extinguishing chamber comprises a driving connecting rod, a moving contact and a static contact, one end of the driving connecting rod is connected with the moving contact, and the other end of the driving connecting rod is connected with the insulating guide rod. Therefore, the opening and closing speed of the vacuum circuit breaker is improved.

A power converter incorporating a synchronous rectifier implements adaptive turn-off voltage control for fast turn-off of the synchronous rectifier in the continuous conduction mode. In some embodiments, the synchronous rectifier turn off detection threshold is adaptively changed as a function of the detected operation mode of the power converter. In response to detecting the power converter being operated in the continuous conduction mode, the synchronous rectifier turn off detection threshold is set to a voltage value farther away from zero volt as compared to the nominal turn off detection threshold. In this manner, the synchronous rectifier can be turned off earlier while in the continuous conduction mode. When the synchronous rectifier can be turned off quickly, large reverse current or negative current as well as large drain voltage spike at the synchronous rectifier can be avoided. The reliability of the synchronous rectifier and the power converter is improved.

An example apparatus includes a first transistor having a control terminal and first and second terminals. The apparatus includes a second transistor having a control terminal and first and second terminals, the second terminal of the second transistor coupled to the second terminal of the first transistor. The apparatus includes a first amplifier having a first input, a reference input, and an output, the first input of the first amplifier coupled to the first terminal of the first transistor, the output of the first amplifier coupled to the control terminal of the first transistor. The apparatus includes a second amplifier having first and second inputs and an output, the first input of the second amplifier coupled to the first terminal of the first transistor, the second input of the second amplifier coupled to the first terminal of the second transistor, and the output of the second amplifier coupled to the control terminal of the second transistor. The apparatus includes a control circuit coupled to the control terminal and the second terminal of the second transistor and coupled to the first transistor, the control circuit capable of adjusting a voltage at the control terminal of the second transistor responsive to a current through the first transistor.

This cathode for water electrolysis includes a catalyst part and a reverse current absorber that is electrically connected to the catalyst part, wherein the reverse current absorber contains a hydrogen storage alloy, and the hydrogen storage alloy contains Al.

An intelligent motor control system based on an integrated circuit is characterized in that an MCU microcontroller is arranged, the motor driving end of the MCU microcontroller is connected with a driving circuit, and the driving circuit drives a motor to work; the current / position detection end of the MCU microcontroller is connected with a first motor detection circuit, and the first motor detection circuit is provided with a current detection circuit and a position detection circuit; the over-temperature / over-voltage detection end of the MCU microcontroller is connected with a second motor detection circuit. The second motor detection circuit is provided with a voltage detection circuit and a temperature detection circuit. The data transmission end of the MCU microcontroller is connected with a CAN network interface circuit, and the CAN network interface circuit is connected with the motor. The motor controller has the advantages that the motor controller has the functions of motor driving, forward and reverse current differential detection, driving voltage detection, over-temperature detection and position detection and is integrated with the CAN network interface and the MCU debugging interface, and efficient, accurate and safe motor control is achieved.

The invention discloses an inverter circuit topological structure for driving double three-phase motors, and belongs to the technical field of power generation, power transformation or power distribution. The topology comprises a six-phase bridge arm, a switching tube in the bridge arm is connected in series with a diode, and a branch after the switching tube is connected in series with the diode is inversely connected in parallel with a diode. A plurality of switching tubes and diodes of the topology are connected according to a specific rule, a reverse current path is blocked by serially connecting the diodes, and current mutation in the switching process is reduced; and meanwhile, an anti-parallel diode is used for maintaining a continuous current path, normal work of the circuit is ensured, and the circuit has the advantages of simple circuit design, low control cost, high efficiency and the like, and is widely applicable to low-voltage and high-current dual-three-phase motor driving scenes.

The invention belongs to the field of semiconductor devices, provides a gallium nitride high-electron-mobility transistor integrated with a Schottky diode and a preparation method of the gallium nitride high-electron-mobility transistor, and aims to solve the problem that a conventional gallium nitride high-electron-mobility transistor (GaN HEMT) lacks a body diode. According to the invention, monolithic integration of the SBD and the GaN HEMT is realized through structural design, a low-impedance path is provided for reverse current, and the integration mode not only retains the original high performance characteristic of a GaN device, but also additionally endows the GaN device with reverse conduction and reverse recovery capabilities; moreover, through the structural design, the SBD can be synchronously completed on the basis of the existing GaN HEMT process, a special process or new equipment is not needed, and the cost is effectively controlled while the performance improvement is ensured; compared with an external interconnection diode scheme, parasitic inductance caused by lead bonding is eliminated, the voltage overshoot and ringing phenomena in the switching process are remarkably reduced, high-frequency switching application is facilitated, and switching loss can be greatly reduced.