36results about How to "Reduce overcurrent" patented technology

A rotor (4, 4A) for a rotary electric machine (1), the rotor being arranged to face a stator (3) and being roratably attached to a housing (2), the rotor includes a core body (41) formed by a plurality of core sheets (42) laminated in a direction of a rotational axis (C) of the rotor, first and second end plates (43,44,47) arranged at both end surfaces of the core body in a direction where the core sheets are laminated, and a fixing member (45) fixing the first and second end plates to the core body (41) to hold the core body by the first and second end plates, wherein at least one of the first and second end plates is formed by a plurality of composition members (43a, 43b, 44a, 44b, 47a, 47b) overlapping in a thickness direction of the first end plate and the second end plate.

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 a double-main-filament primary-assistant triple-helix energy-saving lamp filament and a manufacturing method thereof, which is spirally wound by a filament secondary winding body (4), and the filament secondary winding body (4) consists of The filament primary winding body (3) is helically wound; the filament primary winding body (3) is composed of two main tungsten wires (1) and molybdenum wire (7) and two main tungsten wires (1) ) and one or more auxiliary tungsten wires (2) on the molybdenum wire (7). The invention has the characteristics of higher reserves of electronic powder, stronger bombardment resistance, high thermal effect, faster temperature rise and long service life, and the winding speed is faster during production, the winding efficiency is higher, and the winding is not easy to cause broken wires. The product qualification rate is high.

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 method for calculating a single-phase voltage phase, in particular to a method for obtaining the single-phase voltage phase of a power grid, and solves a problem that a conventional technical scheme for obtaining the single-phase voltage phase of the power grid is low in accuracy of phase acquisition, slow in response, and sensitive to changes in system frequency, and isnot suitable for applications with high dynamic performance requirements. The method is realized by the following steps: 1) collecting the grid voltage Us and obtaining DC components vd and vq in a rotating coordinate system; 2) obtaining the DC components vd<-> and vq<-> with the second harmonic components eliminated; 3) using the vq<-> and a value of zero as inputs to form a PI closed loop controller; 4) introducing angular velocity [omega] into the output of the PI closed-loop controller to form a feedforward disturbance, comparing the feedforward disturbance with the output of the PI controller and then inputting a compared result to an integration link. The method uses a software-implemented closed-loop phase-locked loop, and is particularly suitable for the control of a PWM rectifier in an electric locomotive, and can also be used for obtaining the single-phase voltage phases in other environments.

The invention discloses a phase sequence change control method and system. The method comprises: obtaining a power angle of a power generator in real time; if the power angle is greater than a presetthreshold, controlling the connection line of a corresponding current zero-crossing phase to disconnect to realize opening when the current of a certain phase, in a connected state, of the power generator and a power system passes zero; and after connection of phases between the power generator and the power system is disconnected, when the voltage of a certain phase in a disconnected state at thepower generator side is equal to the voltage of a certain phase in a disconnected state at the power system side, connecting the line of the phase in the disconnected state at the power generator side with the line of the phase in the disconnected state at the power system side, wherein the voltages of the phases are equal, until lines of all phases at the power generator side and the power system side are connected. When opening is realized at the current zero crossing point, the produced surge voltage is minimum, and when closing is realized when the voltage is equal, the produced surge current is minimum, thereby reducing impact on the power system during phase sequence change process, and improving safety and stability of the power system.

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.