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55results about How to "Limit current" patented technology

Power fluctuation and malfunction control system and method of direct-current-transmission double-fed wind turbine set

The invention relates to a power fluctuation and malfunction control system and method of a direct-current-transmission double-fed wind turbine set, and belongs to the field of wind power. The system includes a double-fed power generator, a stator-side converter, a rotor-side converter, a net-side direct-current converter and an energy storage system. According to the method, firstly, the energy storage system supplies power to the rotator-side converter to achieve inverse conversion; secondly, after a draught fan is enabled, the stator-side converter conducts rectification boosting, the net-side direct-current converter conducts constant power control and controls the energy storage system to charge and discharge electricity to achieve power fluctuation suppression; if voltage drop occurs to a power network, the net-side direct-current converter conducts constant direct voltage control, and the rotator-side converter and the energy storage system run in a voltage drop malfunction control mode; if overvoltage occurs to the power network, the energy storage system conducts voltage clamp on the power network; if the network is disconnected, the net-side direct-current converter conducts constant direct voltage control, the rotator-side converter makes the output power of the power generator turn to zero; and finally, the net-side direct-current converter is switched off. The power fluctuation and malfunction control system and method of the direct-current-transmission double-fed wind turbine set are conducive to usage of the double-fed wind turbine set in a flexible direct current transmission system.
Owner:QUFU NORMAL UNIV

Emitting laser for etching top end non-doping intrinsic layer asymmetric metal membrane vertical cavity surface

The invention relates to an etching apex non-doped intrinsic layer asymmetrical metal film vertical cavity surface emitting laser and a preparation method thereof. The invention comprises a Bragg reflector, a high resistive layer, an electrode, a substrate and a quantum well active region. The upper surface is etched with a round metal reflection film, a metal film lead, a contact layer of the metal film and an upper electrode and the upper electrode; the lower surface of the substrate is provided with the round metal reflection film, a lower surface metal film lead and a lower surface electrode. By introducing the non-doped intrinsic layer to etch the current aperture and combining the upper surface with the substrate surface to etch a metal film asymmetrical structure in order to implement the restriction to current and optical field, the invention has the efficacies of the electrode and the reflector of the metal film, simplifies a vertical cavity emitting laser array integration process, reduces the logarithm of distributed Bragg reflector, restricts the diffusion area of the current, improves the photoelectric coupling efficiency of injected current, avoids proton bombardment or respective oxidation process and is beneficial for integration as the intrinsic high-resistive layer and a chip implement the grown in one operation.
Owner:HEBEI UNIV OF TECH

Hollow cathode power converter and control system thereof

The invention provides a hollow cathode power converter and a control system thereof. The hollow cathode power converter comprises a main transformer primary side circuit and a main transformer auxiliary side rectifying and wave-filtering circuit; the output voltage of the main transformer auxiliary side rectifying and wave-filtering circuit is sampled to form voltage closed-loop control, and the output current of the main transformer auxiliary side rectifying and wave-filtering circuit is sampled to form output current closed-loop control; before the ignition of a hollow cathode is successful, a holding electrode and reference ground present high impedance, and a current closed-loop does not work; when the ignition of the hollow cathode is successful, the impedance of the holding electrode is decreased until the output voltage of the main transformer auxiliary side rectifying and wave-filtering circuit is dragged to be lower than a second set value so as to judge that the ignition of the hollow cathode is successful; and when the voltage of the holding electrode is decreased to be lower than the maximum limiting voltage of a holding power supply, closed-loop control is carried out on the output current of the main transformer auxiliary side rectifying and wave-filtering circuit. A heating power supply, an ignition power supply and the holding power supply are coupled to obtain a main converter, so that the power density is high, and the dynamic response is improved.
Owner:SHENZHEN ACAD OF AEROSPACE TECH

Superconductivity flat wave current limiting reactor applicable to high-voltage direct-current transmission

Provided is a superconductivity flat wave current limiting reactor applicable to high-voltage direct-current transmission. A superconducting magnet composed of a superconducting coil (1), a coil frame (2), a coil upper supporting plate (3), a coil lower supporting plate (4) and a coil fastening screw (5) is arranged inside a low-temperature dewar device composed of a low-temperature dewar drum (7) and a low-temperature dewar upper cover plate (8). The superconducting magnet is cooled through direct evaporating of liquid nitrogen or cooled through the liquid nitrogen added into a refrigerator. The superconducting magnet is installed with the low-temperature dewar upper cover plate (8) through a pull rod (6). The superconducting magnet and a transition line (10) are connected with a direct current power grid through a current lead wire (9). A sleeve heat preservation layer (11), a sleeve low-temperature insulation layer (12) and a sleeve normal-temperature insulation layer (13) are arranged outside the current lead wire (9), good insulation is guaranteed, and heat leakage is reduced. The superconductivity flat wave current limiting reactor has no loss and only a flat wave effect is obtained when the direct current power grid works normally. When the direct current power grid is short-circuited, resistance of the reactor is increased fast, and short-circuit current is restrained to certain level.
Owner:INST OF ELECTRICAL ENG CHINESE ACAD OF SCI

Power distribution control circuit of vehicle-mounted motor controller of electric vehicle and control method of control circuit

ActiveCN106004495ATroubleshooting Power-Up Current Pulse IssuesSolving Current Pulse ProblemsElectric devicesElectric vehicle charging technologyDistribution controlElectrical battery
The invention discloses a power distribution control circuit of a vehicle-mounted motor controller of an electric vehicle and a control method of the control circuit. The control circuit comprises a power battery, a complete vehicle logic unit, the vehicle-mounted motor controller, a drive motor controller, a power-on buffer circuit, a CAN bus and a vehicle-mounted electric control switch, wherein the complete vehicle logic unit is connected with the power battery, the vehicle-mounted motor controller and the drive motor controller, connected with a first electric control switch and a second electric control switch through low-tension control wires and then grounded; a negative electrode of the battery is connected to the vehicle-mounted motor controller and the drive motor controller; a positive electrode of the battery is connected with a parallel circuit formed by the power-on buffer circuit and the second electrical control switch and then connected to the drive motor controller and the vehicle-mounted motor controller. Multiple motor controllers share one power-on buffer circuit through specific control logic, a relay is used among the motor controllers for power distribution control, normal demands are met, and electrical safety can also be guaranteed.
Owner:CHENGDU RAJA NEW ENERGY AUTOMOTIVE TECH CO LTD

Current increasing and voltage stabilizing circuit with current limiting function

The invention relates to a current increasing and voltage stabilizing circuit with a current limiting function, comprising a current increasing unit used for increasing and outputting a current, a current limiting unit used for limiting overlarge current output by the current increasing unit and a voltage stabilizing unit used for supplying stable output voltage to voltage output by the current increasing unit and the current limiting unit, wherein the input end of the current increasing unit is electrically connected with a power input end of the current increasing and voltage stabilizing circuit, the output end of the current increasing unit is connected with the input end of the current limiting unit, the output end of the current limiting unit is electrically connected with the output end of the voltage stabilizing unit, and the point in which the output end of the current limiting unit is electrically connected with the output end of the voltage stabilizing unit is electrically connected with the power input end of the current increasing and voltage stabilizing circuit. The current increasing and voltage stabilizing circuit with the current limiting function limits the current of the current increasing and voltage stabilizing circuit by adopting the current limiting unit and the voltage stabilizing unit, thereby avoiding that the current is too large to damage the voltage stabilizing unit.
Owner:OCEANS KING LIGHTING SCI&TECH CO LTD +1

MOSFET chip manufacturing process for improving grid characteristics

The invention discloses an MOSFET chip manufacturing process for improving grid characteristics, which comprises the following steps: removing an isolation oxide layer in a groove region, obtaining first lightly-doped polycrystalline silicon and second lightly-doped polycrystalline silicon on the peripheral side of a groove, heavily doping the lightly-doped polycrystalline silicon in the groove, obtaining first heavily-doped polycrystalline silicon, and removing the residual isolation oxide layer in a body forming region and a source region, close to the groove, of the epitaxial layer; carrying out heavy doping on part of the region of the first lightly-doped polycrystalline silicon, and obtaining second heavy-doped polycrystalline silicon; forming a dielectric layer upwards, wherein the type of the second heavy-doped polycrystalline silicon is opposite to that of the first lightly-doped polycrystalline silicon; and forming a diode by the first lightly doped polycrystalline silicon and the second heavily doped polycrystalline silicon, forming a resistor by two ends of the second lightly doped polycrystalline silicon, and connecting the diode with the resistor in parallel to be connected to the grid electrode in series. The polycrystalline silicon resistor and the polycrystalline silicon diode are integrated in the chip, so that the current flowing through the grid electrode is effectively limited, and the protection on the grid electrode is realized.
Owner:深圳市芯电元科技有限公司

Surge protection device comprising Y-shaped pressure-sensitive chip, and distribution box

The invention provides a surge protection device comprising a Y-shaped pressure-sensitive chip, and a distribution box. The surge protection device comprising the Y-shaped pressure-sensitive chip comprises an insulated fixing seat, the Y-shaped pressure-sensitive chip, a first electrode and a second electrode, wherein the first electrode and the second electrode are used for being connected with an external circuit, the Y-shaped pressure-sensitive chip is fixed on the fixing seat, the Y-shaped pressure-sensitive chip comprises an electrode A, an electrode B, an electrode C, a first piezoresistor chip and a second piezoresistor chip, the first piezoresistor chip is located between the electrode A and the electrode B, the second piezoresistor chip is located between the electrode A and the electrode C, the electrode B is electrically connected with the second electrode, and the electrode C is electrically connected with the first electrode. The surge protection device comprising the Y-shaped pressure-sensitive chip, and the distribution box can be used in a direct current system and an unconventional 690 VAC and above power system, and the safety performance is higher.
Owner:广东立信防雷科技有限公司
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