35results about How to "Reduce overcurrent" patented technology

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.

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.

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 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 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 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 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.