36results about How to "Reduce overcurrent" patented technology

The invention discloses a power flow controller with a failure current limiting function. When a power grid does not fail, the power flow controller controls current on a current limiting inductor by a current transformer and regulates equivalent impedance flowing into the power grid, thereby controlling the transmission power of the power grid, and compensates the harmonic waves and reactive power of transmission current by the current transformer; and when the power grid fails, the current limiting inductor is directly connected in series to the power grid to function in failure current limiting, and simultaneously, the power flow controller also can control the current transformer to discharge the current limiting inductor and control the current of the current limiting inductor to better current limiting effects, and can perform steady current limiting by a current limiting bypass, with the current limiting inductor, of a protective circuit to better failure current limiting effects.

The invention discloses an optical fiber trigger type high-voltage solid-state switch. The optical fiber trigger type high-voltage solid-state switch comprises a high-voltage direct-current power source, an FPGA control system, an optical fiber driving signal transmission part, an optical fiber fault signal transmission part, an IGBT series circuit, a plurality of IGBT driving modules and a plurality of IGBT voltage-sharing circuits; the optical fiber driving signal transmission part comprises a first optical fiber transmission module and a first optical fiber receiving module, the optical fiber fault signal transmission part comprises a second optical fiber transmission module and a second optical fiber receiving module, a plurality of series IGBT switches are arranged in the IGBT series circuit, and the number of the IGBT driving modules is the same as the number of the IGBT switches; the positive pole of the high-voltage direct-current power source is connected with the collector of the first IGBT switch in the IGBT series circuit through a load, and the negative pole of the high-voltage direct-current power source is connected with the emitter of the final IGBT switch in the IGBT series circuit. The optical fiber trigger type high-voltage solid-state switch is high in integration level, small in circuit board size and low in cost, effective electric isolation is provided, and the optical fiber trigger type high-voltage solid-state switch has the overcurrent and short circuit protection function and is flexible and convenient to use.

The invention discloses an LED light-emitting lamp filament and an LED bulb adopting the same. The LED light-emitting lamp filament comprises a strip-shaped substrate and multiple LED chips arranged on the strip-shaped substrate. The two ends of the strip-shaped substrate are each provided with a metal strip-shaped electrode. The multiple LED chips are connected in series to form an LED light source. Multiple electronic devices having one of the conductive function, the current-limiting function and the protection function are arranged at the position, close to one of the ends, on the strip-shaped substrate or the position, close to each of the ends, on the strip-shaped substrate. The metal strip-shaped electrodes, the electronic devices and the LED light source are connected through a wire. The periphery of the strip-shaped substrate, the periphery of the LED light source, the periphery of each electronic device and the periphery of the connection position between the strip-shaped substrate and each metal strip-shaped electrode are coated with fluorescent rubber. The LED light-emitting lamp filament and the LED bulb adopting the same have the beneficial effects that according to different properties of the electronic devices, the connection wire of the LED light source and the metal strip-shaped electrodes can be prevented from rupture; or a current of the LED light-emitting lamp filament can be prevented from overcurrent; or the LED light-emitting lamp filament can be free from influence of overvoltage and overcurrent; or when the LED light-emitting lamp filament is overheated, the heat emitting phenomenon is reduced.

A light emitting diode (LED) driving apparatus is disclosed. The LED driving apparatus includes a power converter, a voltage sample-and-hold and comparison circuit, and a pre-charge clock generator. The power converter has a power transistor switch for processing power conversion and outputs a driving voltage at an output terminal. The voltage sample-and-hold and comparison circuit enters a sample-and-hold mode or a comparing mode according to a dimming status signal. The voltage sample-and-hold and comparison circuit samples and holds a feedback voltage to obtain a pre-storage voltage during the sample-and-hold mode and compares the pre-storage voltage with the feedback voltage to obtain a comparison result during the comparing mode. The voltage sample-and-hold and comparison circuit generates a pre-charge enable signal according to the comparison result. The pre-charge clock generator generates a pre-charge clock signal to control the power transistor switch according to the pre-charge enable signal and a clock signal.

The invention provides a millisecond rapid reconstruction method and system for a power supply network after power network failure. A rapid network reconstruction master station collects power networkstate information from a transformer substation or a substation of a power plant, and compares the power network state information with a control strategy table containing possible failures; when itis monitored that an anticipated power network splitting failure occurs, switch-on pre-starting signals are sent to sub-stations corresponding to a plurality of network connection recovery circuit breakers; after the failure is cleared, the substations are used for identifying a clearing moment according to in-place information, and sending synchronous check switch-on signals to the correspondingin-place network connection recovery circuit breakers; and meanwhile, the master station independently monitors the clearing of the failure, sends backup synchronous check switch-on signals to the corresponding network connection recovery circuit breakers, and realizes the network reconnection of the split power network within 150ms after splitting on the basis of the above mechanism. The circuitbreaker which forms an electromagnetic loop network is disconnected after the interconnection of the power network is recovered.

The invention relates to a SiC MOSFETE open-loop active driving circuit, and belongs to the technical field of circuit control. The circuit comprises a traditional driving circuit and an auxiliary circuit, the auxiliary circuit comprises a di / dt detection circuit and a shunting circuit, the di / dt detection circuit is used to determine ON and OFF states of a SiC MOSFETE, and transmits the signal obtained by determining to the shunting circuit, and the shunting circuit is used to shunt gate current of the SiC MOSFET via the signal of the di / dt detection circuit. According to the provided SiC MOSFETE open-loop active driving circuit, the shunting circuit and the di / dt detection circuit are added to the traditional SiC MOSFET driving circuit, the ON / OFF delay time is shortened, the switching loss is reduced, the active driving circuit is of open-loop operation, and the system cost and complexity are reduced.

The invention provides a protection system of a wind turbine. The wind turbine includes a generator having a stator and a rotor, a rotor side converter, a grid side converter and a direct current link located between the rotor side converter and the grid side converter, and the protection system includes a first switch element, one or more side resistor elements and a controller. The one or more side resistor elements are electrically coupled with the direct current link or a plurality of windings of the stator through one or more side switch elements. The controller is used for controlling the first switch element to disconnect the grid side converter and the plurality of windings of the stator with a public power grid in response to an electromagnetic torque loss event, and controlling the one or more side switch elements to switch on electrical connection between the one or more side resistor elements and the direct current link or electrical connection between the one or more side switch elements and the plurality of windings of the stator so as to generate electromagnetic torque in the generator. The invention also provides a wind turbine.

Provided is a fault protection applied to a wind power plant and an energy stabilization circuit. A power converter is composed of a voltage source converter and a chopper or a current source converter. A direct current end of a rectifier is connected with a switch provided with an antiparallel diode and a buffer absorption circuit in parallel. A primary side of a single-phase transformer is connected with a switch and a resistor in parallel, and a secondary side of the single-phase transformer is connected with an alternative current output end of the rectifier. The primary side of the single-phase transformer is respectively connected with a power grid and a switching-in end of the wind power plant. A three-phase alternative current end of a power converter is connected with the power grid and a switching-in end of the wind power plant through a three-phase filter circuit and a three-phase transformer. A direct current end of the power converter is connected with a direct current end of the rectifier in series and then connected with an energy storage inductor in series. Under a normal condition, power output of the wind power plant is smoothed through charging and discharging of the energy storage inductor. Under a fault condition, the energy storage inductor is firstly utilized to limit current, then a thyristor of the rectifier is turned off, and the energy storage inductor is disengaged from the power grid. Current is limited through the resistor connected with the primary side of the transformer in parallel.

An object of the present invention is to reduce an overcurrent of an inverter and a motor. A control device for an electric motor in which windings of respective phases are independently connected, the control device for the electric motor uses a zero-phase current calculation means for calculating a zero-phase current based on detection values of currents of the respective phases flowing in the electric motor and a position of a rotor of the electric motor to control a current flowing in the electric motor such that a vector sum of a drive current and the zero-phase current is equal to or lower than a predetermined current.

The invention relates to a deep sea ore lifting pump structure and a control method thereof, and belongs to the technical field of ore lifting pumps. The structure comprises an ore lifting pump shell;a high-speed shaft is arranged in the ore lifting pump shell; a flow separation driving mechanism is arranged between the high-speed shaft and the ore lifting pump shell; and a fine particle fluid channel is formed between the flow separation driving mechanism and the high-speed shaft, and is provided with multiple guide rotating impellers in limiting fixed sleeving with the high-speed shaft. Theflow separation driving mechanism comprises a low-speed rotating hub; a spiral blade disc is arranged on the outer wall of the low-speed rotating hub; and a speed reducer in limiting embedded fixation with the low-speed rotating hub is arranged in the low-speed rotating hub. The structure has the advantages of compact structure, good flow separation effect, good pulp passing performance, enough conveying power and long service life, can improve the conveying efficiency, can save axial space, realizes separate flowing of high-concentration large-particle pulp and fine-particle seawater to prevent the runner blockage phenomenon, and achieves the purposes of low wear of the pump by pulp in a runner and efficient flow passing.

The invention provides a drum type washing machine suppressing electric current flowing through a motor when the number of poles of the motor is switched in spin-drying. When the number of poles of the motor is switched to change its rotational frequency, application of the electric current is started from a minimum conduction angle for driving the motor to suppress the electric current flowing through the motor as well as a rise in temperature of the motor, a power switching means, or the like.

A light emitting diode (LED) driving apparatus is disclosed. The LED driving apparatus includes a power converter, a voltage sample-and-hold and comparison circuit, and a pre-charge clock generator. The power converter has a power transistor switch for processing power conversion and outputs a driving voltage at an output terminal. The voltage sample-and-hold and comparison circuit enters a sample-and-hold mode or a comparing mode according to a dimming status signal. The voltage sample-and-hold and comparison circuit samples and holds a feedback voltage to obtain a pre-storage voltage during the sample-and-hold mode and compares the pre-storage voltage with the feedback voltage to obtain a comparison result during the comparing mode. The voltage sample-and-hold and comparison circuit generates a pre-charge enable signal according to the comparison result. The pre-charge clock generator generates a pre-charge clock signal to control the power transistor switch according to the pre-charge enable signal and a clock signal.

The invention relates to a prefabricated bin for a high-voltage SF6 phase angle control switching breaker. A box is divided into a plurality of compartments, namely an incoming line compartment, a PT (potential transformer) compartment, at least one capacitor compartment, at least one inductor compartment, a transformer compartment and a control chamber. The prefabricated bin is simple in structure, small in occupied area, capable of realizing workshop assembly, low in cost, and convenient to use, maintain and overhaul.

An object of the present invention is to reduce an overcurrent of an inverter and a motor. A control device for an electric motor in which windings of respective phases are independently connected, the control device for the electric motor uses a zero-phase current calculation means for calculating a zero-phase current based on detection values of currents of the respective phases flowing in the electric motor and a position of a rotor of the electric motor to control a current flowing in the electric motor such that a vector sum of a drive current and the zero-phase current is equal to or lower than a predetermined current.

A current converter control method for improving the low-voltage ride-through capability of a doubly-fed fan comprises the steps that after the voltage drops suddenly, the voltage of a direct-currentcapacitor and the current ir of a rotor are monitored constantly, and whether the voltage of the direct-current capacitor or the current of the rotor exceeds a limit value or not is judged; when the direct-current capacitor voltage or the rotor current ir exceeds a limit value, an active Crowbar protection circuit is triggered; when the direct current capacitor voltage and the rotor current are both lower than the limit value and no out-of-limit is kept in the two cycles, the active Crowbar protection circuit is exited, and PI control of the rotor side converter and the network side converterare switched into comprehensive interference suppression control at the same time; and after voltage drop is recovered, PI control is switched back, and the purpose of low-voltage ride through of thewind power plant under sudden power grid fault drop is achieved. Compared with a PI control strategy, the comprehensive LVRT control strategy designed by the invention can make full use of the outputcapability of the converter, has the better transient control performance in the voltage drop period, and can effectively meet the low-voltage ride-through requirement of the doubly-fed fan.

The invention relates to a combined contra-rotating propeller electric propulsion system. The combined contra-rotating propeller electric propulsion system comprises a first motor, a shafting system,a first screw propeller and a rim type propeller. Propulsion efficiency is improved, the power of a large diesel engine which is high in price and limited in model selection range is delegated to a plurality of small-power generator sets through the mode of the electric propulsion system, so that a model selection range is expanded, and the initial installation cost of a power system is reduced. Arudder and propeller integrated type is adopted, the maneuverability of a ship is improved. The system is particularly suitable for medium and large ships.

Provided is a fault protection applied to a wind power plant and an energy stabilization circuit. A power converter is composed of a voltage source converter and a chopper or a current source converter. A direct current end of a rectifier is connected with a switch provided with an antiparallel diode and a buffer absorption circuit in parallel. A primary side of a single-phase transformer is connected with a switch and a resistor in parallel, and a secondary side of the single-phase transformer is connected with an alternative current output end of the rectifier. The primary side of the single-phase transformer is respectively connected with a power grid and a switching-in end of the wind power plant. A three-phase alternative current end of a power converter is connected with the power grid and a switching-in end of the wind power plant through a three-phase filter circuit and a three-phase transformer. A direct current end of the power converter is connected with a direct current end of the rectifier in series and then connected with an energy storage inductor in series. Under a normal condition, power output of the wind power plant is smoothed through charging and discharging of the energy storage inductor. Under a fault condition, the energy storage inductor is firstly utilized to limit current, then a thyristor of the rectifier is turned off, and the energy storage inductor is disengaged from the power grid. Current is limited through the resistor connected with the primary side of the transformer in parallel.

The invention discloses an intelligent control device of a direct current motor. The intelligent control device of a direct current motor is formed by two parts: an intelligent controller and a PID controller, wherein the intelligent controller is used for intelligently giving PID parameters and transmitting variables to the PID controller; and the PID controller is used for applying the adjustedPID parameters to a control object. By giving PID parameters to the control object, the intelligent control device of a direct current motor enables a separate excitation-type DC motor to respond quickly and accurately to the speed regulation requirement without the phenomenon of speed overshoot. The invention also discloses an intelligent control method of a direct current motor. The intelligentcontrol method is self-adapted to different motor characteristic curves, and enables the DC motor to quickly and accurately respond to the speed regulation requirement without the phenomenon of speedovershoot by intelligently giving 3 parameters: armature voltage armature current and field current.

The invention relates to a surge protector in which a semiconductor chip and electrodes are electrically connected by full area. In an insulation casing, a wiring terminal, a conductive connecting line, an electrode, a semiconductor chip, an electrode, a mechanical thermal trip device, an indication window mechanism, a conductive connecting line and a wiring terminal are electrically connected sequentially. Conductive solidification liquid is injected and filled into cracks and clearances generated after conductive faces at both sides of the semiconductor chip and the planes of the two electrodes of the surge protector are welded and connected electrically, and becomes a conductive body in the cracks and the clearances of the semiconductor chip and the electrodes after being solidified, so that the aim that the conductive full section of the semiconductor chip in the surge protector participates in electrical connection is achieved.

The invention discloses a method and a device for determining effective torque, a robot and a household appliance. The method comprises the following steps: a torque curve of the motor is obtained; The torque curve is discretized to obtain a discrete torque curve; The area under the line of torque curve in discrete form is calculated, and the actual torque of the motor is obtained. The invention solves the technical problem that a constant is needed in an actual torque formula in the prior art, and the torque of the actual motor is a variable, so that the actual torque formula can not be directly used for calculating the actual torque.

The invention provides a millisecond-level fast reconfiguration method and system for a power supply network after a power grid fault. Fast network reconfiguration The main station collects grid status information from substations or substations of power plants, and compares it with the built-in control strategy table that may fail; The corresponding sub-station sends a closing pre-start signal; when the fault is cleared, the sub-station identifies the clearing time according to the local information, and sends a detection synchronous closing signal to the corresponding local recovery network circuit breaker; at the same time, the main station independently monitors To clear the fault, send a backup inspection synchronous closing signal to the corresponding recovery network circuit breaker, based on the above mechanism, the disconnected power grid will be re-connected to the grid within 150ms after decommissioning. After the power grid is restored to interconnection, the circuit breakers forming the electromagnetic ring network are opened.

The invention discloses a power flow controller with a failure current limiting function. When a power grid does not fail, the power flow controller controls current on a current limiting inductor by a current transformer and regulates equivalent impedance flowing into the power grid, thereby controlling the transmission power of the power grid, and compensates the harmonic waves and reactive power of transmission current by the current transformer; and when the power grid fails, the current limiting inductor is directly connected in series to the power grid to function in failure current limiting, and simultaneously, the power flow controller also can control the current transformer to discharge the current limiting inductor and control the current of the current limiting inductor to better current limiting effects, and can perform steady current limiting by a current limiting bypass, with the current limiting inductor, of a protective circuit to better failure current limiting effects.

The invention relates to a deep sea ore lifting pump structure and a control method thereof, and belongs to the technical field of ore lifting pumps. The structure comprises an ore lifting pump shell;a high-speed shaft is arranged in the ore lifting pump shell; a flow separation driving mechanism is arranged between the high-speed shaft and the ore lifting pump shell; and a fine particle fluid channel is formed between the flow separation driving mechanism and the high-speed shaft, and is provided with multiple guide rotating impellers in limiting fixed sleeving with the high-speed shaft. Theflow separation driving mechanism comprises a low-speed rotating hub; a spiral blade disc is arranged on the outer wall of the low-speed rotating hub; and a speed reducer in limiting embedded fixation with the low-speed rotating hub is arranged in the low-speed rotating hub. The structure has the advantages of compact structure, good flow separation effect, good pulp passing performance, enough conveying power and long service life, can improve the conveying efficiency, can save axial space, realizes separate flowing of high-concentration large-particle pulp and fine-particle seawater to prevent the runner blockage phenomenon, and achieves the purposes of low wear of the pump by pulp in a runner and efficient flow passing.

The invention belongs to the technical field of circuit control, in particular to a SiC MOSFET open-loop active drive circuit. The circuit includes a traditional drive circuit, and also includes an auxiliary circuit, the auxiliary circuit includes a di / dt detection circuit and a shunt circuit; the di / dt detection circuit is used to judge the turn-on and turn-off phases of the SiC MOSFET, and judge the obtained The signal is transmitted to the shunt circuit; the shunt circuit shunts the gate current of the SiC MOSFET through the signal of the di / dt detection circuit. The present invention provides a SiC MOSFET open-loop active drive circuit, which adds a shunt circuit and a di / dt detection circuit after the traditional SiC MOSFET drive circuit, shortens the switching delay time, reduces the switching loss, and the active drive circuit is Open-loop operation reduces system cost and complexity.

The invention discloses a filament of a main-auxiliary type triple-helix energy-saving lamp with a plurality of main wires; the filament is formed by winding a quadric winding body (4) of the filament in a spiral shape, the quadric winding body (4) of the filament is formed by winding a once winding body (3) of the filament in a spiral shape, and the once winding body (3) of the filament is formed by winding three or more main tungsten filaments (1), three or more molybdenum filaments (7) and one or more auxiliary tungsten filament(s) (2) which is / are wound on the three or more main tungsten filaments (1) and molybdenum filaments (7) in a spiral shape. The filament of the invention has the characteristics of higher storage quantity of electronic powder, stronger bombardment resistant capacity, high pyrometric effect, more rapid temperature raise and long service life; furthermore, when in production, the winding speed is higher, and the wire winding efficiency is also higher; therefore, filament breakage hardly occurs when winding, and the qualification rate of products is improved.

A radio-frequency heating apparatus with a range hood includes: a radio-frequency heating device having a range hood; a plurality of lighting lamps (41 42) for lighting under the radio-frequency heating device; and dimming device (49) provided with TRIAC (44) for controlling luminance of lighting lamps (41, 42), wherein the plurality of lighting lamps (41, 42) are connected in series. With this arrangement, even if a short-circuiting failure occurs in one of the lamps, the inside resistance of the other lamp can restrict a short-circuiting current, thereby preventing an overcurrent from flowing in dimming device (49) during short-circuit.