511 results about "Excitation current" patented technology

The invention discloses a phase modifier unit state monitoring and load control method and system for reactive power compensation of a power grid, belongs to the technical field of automatic control of power systems, and mainly solves the problem that service life loss is aggravated or a control target is single due to the fact that the health state of equipment is not fully considered when an existing phase modifier unit responds to reactive power requirements of the power grid. The method comprises the following steps of: calculating reactive vacancy and extracting vibration frequency band energy characteristics by acquiring voltage and frequency of a power grid as well as vibration, temperature and exciting current signals of a unit in real time, and constructing a health state index HSI in combination with self-adaptive wavelet basis selection; taking minimum equipment life loss and optimal power grid voltage stability as multiple objectives, dynamically generating a load control instruction by adopting a particle swarm algorithm, realizing weight adaptive adjustment based on HSI, and introducing an online life loss model as a constraint condition; finally, reactive power output is adjusted through an excitation system, and cooperative control of power grid stability and equipment life extension is achieved.

The present invention provides a topology, method and system for bi-directional power conversion of excitation power supply for power battery testing, wherein the topology comprises a three-phase PWM (pulse width modulation) converter, a high-frequency isolation three-level LLC (logical link control) resonant converter and a DC-DC (direct current) converter forming a topology structure for a three-stage power conversion; an input end of the three-phase PWM converter is connected to a power grid side; the high-frequency isolation three-level LLC resonant converter is connected between the three-phase PWM converter and the DC-DC converter in series and is configured for realizing bi-directional DC voltage conversion and isolation, and to raise a busbar voltage between the high-frequency isolation three-level LLC resonant converter and the DC-DC converter; and, the DC-DC converter is configured to generate charging and discharging excitation currents for a power battery testing.

The invention discloses a magnetic adjustment water lubricated bearing and a bearing support control method, which are applied to a large ship propulsion shaft system, and comprise a bearing shell, an electromagnetic excitation module, a batten, a sensor module, a power supply driving module and a control system, a plurality of mounting grooves are formed in the bearing shell; an electromagnetic excitation module is arranged in each mounting groove and generates a variable magnetic field with set intensity; a plurality of magnetically soft alloy segments are arranged on the batten, the magnetically soft alloy segments correspond to the electromagnetic excitation modules one to one, and a magnetic field acts on the magnetically soft alloy segments to generate electromagnetic attraction force; the control system independently controls the excitation current of each electromagnetic excitation module according to data of the sensor module, and generates magnetic fields with different intensities to act on soft magnetic alloy areas at corresponding positions, so that precise control of local supporting rigidity and lubricating gaps of the water-lubricated bearing is realized, unbalance loading and abnormal wear risks are effectively reduced, and the service life of the water-lubricated bearing is prolonged. And the adaptive capacity of the bearing under low-speed heavy load and dynamic disturbance is improved.

The invention belongs to the technical field of power system operation and motors, and particularly relates to an energy storage type phase modifier control method which comprises the steps that a rotating shaft of a double-fed motor is connected with a flywheel to serve as an energy storage type phase modifier; the rotor winding is connected to a power grid through an excitation system and a transformer in sequence, and the excitation system is electrically connected by a reactor, a back-to-back converter and a filter in sequence; the stator winding is directly connected to a power grid; the control system decouples reactive power and active power, vector control is carried out on exciting current to absorb or release power, and reactive power-voltage support and active power-frequency support of the power grid are completed. The method overcomes the defects that a traditional direct-current excitation phase modulation mode can only modulate phase and cannot modulate frequency, or is cumbersome and slow in response. The system can meet the requirement of wide-range variable-speed operation, quickly store / release a large amount of rotor kinetic energy, inhibit the voltage and frequency fluctuation of a power grid, and is especially suitable for stations with high new energy occupation ratio. The invention also provides a non-transitory readable recording medium storing the program of the method and a system comprising the medium, and the program can be called through a processing circuit to execute the method.

The utility model relates to the field of resonance eliminators, and discloses a protection element and a current limiting type resonance eliminator, the protection element comprises at least two groups of protection units, the two adjacent groups of protection units are connected in series, and each protection unit comprises a protection module; the current-limiting resonance eliminator based on the current-sensitive resistor made of the current-sensitive material is connected in series between the PT neutral point and the ground. Under the normal operation condition, the current-limiting resonance eliminator is in a low-resistance state, and system parameters and PT performance are not affected; when excitation energy is generated due to a system fault, the current-limiting resonance eliminator suddenly changes into a high resistance state, quickly absorbs resonance energy, destroys resonance parameters, suppresses PT excitation current below 200mA, and ensures that a voltage transformer is unsaturated and a PT fuse is not fused; and a built-in current sensor is connected, so that the running state of the current-limiting resonance eliminator can be monitored in real time.

The invention relates to a method. The invention discloses an ATE-based method for batch detection of pseudo soldering and sealing-off of chip packaging bonding, and belongs to the technical field of semiconductors. The method comprises the following steps: aiming at packaged and bonded chips, providing excitation current for each chip to be tested through an ATE test machine, and conducting an ESD (Electro-Static Discharge) diode connected with each pin of the chip; detecting the voltage drop between each pin and the pin GND; and calculating the equivalent resistance to determine whether pseudo soldering or unsoldering exists. The detection method has high practicability, is simple to operate, is very suitable for large-scale application and popularization, and has a certain promotion effect on improvement of a chip packaging test technology, improvement of chip performance reliability and chip packaging inspection.

The invention provides an electromagnetic quasi-zero stiffness vibration isolator and a control method, and belongs to the technical field of vibration isolation. The vibration isolator comprises a base, a positive stiffness mechanism, a negative stiffness mechanism, a positive and negative stiffness connecting mechanism and a dynamic control module. The positive stiffness mechanism adopts a hydraulic spring to provide basic positive stiffness; the negative stiffness mechanism comprises a plurality of stator units distributed on the base in an annular array and a rotor suspended in the center of a magnetic field of the stator units, and is used for generating nonlinear negative stiffness; the top end of the hydraulic spring supports a load through the bearing table and keeps a preset gap with the inner wall of the rotor; the positive and negative stiffness connecting mechanism realizes displacement transmission and cooperative adjustment; the dynamic control module comprises a displacement sensor and a controller, the sensor collects displacement signals, and the controller adjusts excitation currents of the stator units according to the signals and dynamically adjusts electromagnetic force, so that the vibration isolator is kept in a quasi-zero stiffness state. The quasi-zero stiffness state can be still kept when the load changes, load self-adaption low-frequency vibration isolation is achieved, and the system stability and the vibration isolation performance are improved.

The invention discloses an automobile generator self-adaptive excitation control method based on load prediction, and relates to the technical field of automobile electrical control, and the method comprises the following steps: injecting a micro-amplitude identification pulse into a whole vehicle electrical system, capturing the dynamic response of an electrical load, building a load transition curvature map, marking a high-risk time window, and generating a buffer time slot; and in the buffer time slot, constructing a prediction model fusing time domain extrapolation calculation and frequency domain envelope regression, and outputting collaborative confidence with credibility. A load transition curvature map is constructed to identify a high-risk window, a time domain and a frequency domain are fused to predict output confidence, excitation current is guided to form an anti-shake track, and a dynamic adjustment path is generated by combining start-stop broadening of high-power equipment and voltage second-order derivative identification. And finally, a slew rate self-adaptive strategy is introduced at a chip end to reduce peak impact, power supply and chip cooperative protection is realized, and system robustness and intelligent driving electrical safety are improved.

The invention provides an underground pipe column detection method and system and a medium, and the underground pipe column detection system comprises detection equipment, an excitation signal generator and an underground detection device; the detection equipment is in communication connection with the excitation signal generator and the underground detection device; the underground detection device comprises a transmitting coil and a magnetic sensor array consisting of a plurality of receiving coils; the excitation signal generator is configured to apply transient excitation current to the transmitting coil; the transient excitation current enables the transmitting coil to generate an excitation magnetic field; the excitation magnetic field enables the sleeve layer to generate an induced magnetic field; the magnetic sensor array is configured to collect the magnetic field intensity of the induced magnetic field and generate a magnetic field intensity vector; the detection equipment is configured to perform sparse reconstruction solution on the target vector containing the wall thickness information of the casing layer according to the magnetic field intensity vector and the space observation matrix corresponding to the magnetic sensor array, and through the embodiment of the invention, the limitation of the number of array elements on the detection resolution can be broken through, and the detection precision of the wall thickness of the underground pipe column is improved.

The utility model discloses a soft start system based on excitation current reduction, which is characterized in that a time relay mainly controls the switching of a live wire between a power resistor and an alternating current contactor, the power resistor magnetizes a transformer at the moment of electrification, and the alternating current contactor is connected into a circuit by the time relay after the magnetization is completed; and after the power resistor is short-circuited, the circuit is cut out, so that the purpose of suppressing the excitation inrush current is finally achieved, the excitation effect caused by voltage abrupt change at the power-on moment of the isolation transformer can be avoided, and the excitation abrupt change of the isolation transformer during power-on is effectively reduced.

The invention discloses a synchronous motor modular excitation active vibration suppression method for eccentric vibration, and the method comprises the steps: dividing a rotor excitation winding into 2P independent current control excitation modules in the circumferential direction, and respectively arranging an X-direction displacement probe and a Y-direction displacement probe, obtaining a first displacement signal and a second displacement signal of the rotor mass center relative to the stator and a rotor mechanical angular speed; performing band-pass filtering on the first displacement signal and the second displacement signal, and extracting a first displacement first-order component and a second displacement first-order component; calculating the shortest air gap direction angle and the eccentricity amplitude under the stator coordinate system, calculating the eccentricity, and calculating a first-order eccentricity coefficient; calculating a shortest air gap direction angle under a rotor coordinate system, and calculating an equivalent correction coefficient; and according to the equivalent correction coefficient, the first-order eccentricity coefficient, and the shortest air gap direction angle and the mechanical position angle under the rotor coordinate system, the injection amount of each excitation module is calculated, an excitation current instruction is generated and output to the corresponding excitation module, and active suppression of the unbalanced magnetic pulling force is realized.

The invention discloses a measurement method for accelerated calorimeter test based on in-situ electrochemical impedance spectroscopy. The measurement method comprises the following steps: applying excitation current to a battery to be detected; measuring the battery to be detected under the current condition through the EIS module to obtain real part impedance and imaginary part impedance under different frequencies; determining phase angles and impedances under different frequencies according to the real part impedances and the imaginary part impedances under different frequencies; the voltage of the battery to be detected at different surface temperatures is collected through the ARC module, and the corresponding temperature rise rate is determined; determining an impedance modulus deviation, a phase deviation, a voltage sharp change deviation and a temperature rise rate deviation according to the phase angles and the impedances under the different frequencies, the voltages under the different surface temperatures and the corresponding temperature rise rates, and generating an error signal; generating a corresponding sampling rate control instruction according to the error signal based on dynamic PID control; and the ARC module adjusts the sampling frequency according to the sampling rate control instruction so as to perform high-precision measurement.

The invention discloses a current transformer based on decoupling compensation and an adjusting method thereof, and relates to the technical field of current measurement. The method comprises the following steps: establishing an error coupling matrix by data acquired by a current transformer; a decoupling compensation hardware module is designed, and decoupling compensation is carried out on the exciting current, the secondary load and the transient component; establishing a working condition parameter set, and constructing a training sample library by taking the working condition parameters as input and the compensation coefficients as output based on a BP neural network; through a clock synchronization module, it is ensured that output signals of the three compensation units and current signals of the secondary side of the mutual inductor are the same in frequency and phase; different working conditions are simulated through the standard current source, and the adjusted precision is recorded. According to the invention, through multi-dimensional error decoupling and combination of the BP neural network and the PID, hardware shunting and algorithm optimization are utilized to realize separated compensation of three errors, the method is adaptive to complex working conditions, and the adjustment precision of the compensation circuit is improved.

This application provides a bioelectrical impedance measurement method, circuit, chip, and electronic device. The method includes: obtaining a first contact impedance value corresponding to a first excitation electrode and a second contact impedance value corresponding to a second excitation electrode through a preset method; determining the transmission direction of an excitation current between the first and second excitation electrodes based on the first and second contact impedance values; controlling the excitation current to transmit between the first and second excitation electrodes according to the transmission direction; determining a target voltage value between a first and second measuring electrode, and calculating the impedance of the measured object based on the target voltage value; wherein the first and second contact impedance values ​​are different. This application can reduce the influence of contact impedance on the bioelectrical impedance measurement results, reduce the measurement error of bioelectrical impedance, and improve the accuracy of bioelectrical impedance measurement.

The invention provides an active and reactive decoupling control method for a double-shaft excitation synchronous generator, and the method comprises the steps: building a mathematical model of the double-shaft excitation synchronous generator in a dq0 coordinate system, and determining the corresponding control relation between active power and q-axis excitation current, and between reactive power and d-axis excitation current; active power adjustment: keeping the d-axis exciting current constant, adjusting the magnitude of the q-axis exciting current, realizing continuous adjustment of the active power, and controlling the reactive power to fluctuate within a preset range; adjusting reactive power, keeping q-axis exciting current constant, adjusting d-axis exciting current, adjusting reactive power between an absorption state and an emission state, and controlling active power to fluctuate within a preset range; performing dynamic compensation adjustment; according to the method, the dq0 coordinate system mathematical model is established, the active-q-axis current and reactive-d-axis current incidence relation is defined, active / reactive precise decoupling adjustment is achieved, the output voltage is kept stable when the load changes, and the requirement of a complex power grid for power control is met.

The invention discloses a signal reading system and method for superconducting microwave multiplexing device detection, and belongs to the field of superconducting microwave multiplexing device detection, and the system comprises a server which can issue a detection configuration instruction to a signal board, receive and return detection data, operate detection software, execute spectrum analysis and data analysis, and generate a detection result; the signal board is provided with a circuit containing a programmable logic device, and the circuit can output accurate intermediate frequency signals and excitation current signals according to instructions of the server, processes output signals of the detected superconducting microwave multiplexing devices mixed by the frequency mixing board through a critical sampling filter bank algorithm to obtain detection data, and transmits the detection data back to the server; and the frequency mixing plate can perform up-conversion on the intermediate frequency signal generated by the signal plate to radio frequency to form a radio frequency detection signal, output the radio frequency detection signal to each detected superconducting microwave multiplexing device, perform down-conversion on the radio frequency response signal returned from each superconducting microwave multiplexing device to intermediate frequency, and output the radio frequency response signal to the signal plate. The system can detect the quality of the device with low computing resources.

The invention belongs to the field of battery thermal runaway early warning, and particularly relates to an early warning method and device for thermal runaway of a lithium ion battery pack, and the method comprises the steps: firstly collecting the voltage, temperature and current data of a battery cell, and judging the grade of a current working condition according to a preset rule; self-adaptively matching a corresponding alternating current excitation strategy according to the working condition grade and applying excitation; synchronously acquiring the compensated excitation current and the voltage response of each battery cell through a sampling chip configured with a compensation strategy; based on the response information, a multi-dimensional impedance anomaly judgment strategy is combined, and a judgment parameter set containing impedance deviation, thermal runaway risk, voltage and temperature deviation flag bits is calculated and generated; and finally, determining the thermal runaway risk level of the battery pack through an evaluation algorithm according to the parameter set, and packaging and reporting the thermal runaway risk level through CAN communication. According to the invention, on-line and accurate sensing and early warning of the internal state of the battery under various working conditions such as standing and dynamic operation are realized.

The invention discloses a loop resistance measuring method, system and device, and relates to the technical field of electrical measurement. The method comprises the following steps of: performing loop data acquisition at each interface of the disconnecting switch adopting a three-channel wiring mode, injecting excitation current by an excitation source, and acquiring three-channel voltage original signals and initial sampling flow by a differential isolation amplifier to obtain the initial sampling flow; time sequence identification is carried out on the initial sampling flow to complete sample starting and ending point identification, inter-channel time alignment is completed, and a synchronous voltage sample set is output. According to the invention, by constructing a complete data chain covering high-precision synchronous sampling, adaptive signal processing, phase compensation calculation and intelligent statistical diagnosis, the problems of low measurement precision and insufficient anomaly identification capability caused by poor synchronism, phase error and lack of deep analysis in a traditional method are solved; the accuracy and anti-interference performance of loop resistance measurement and the intelligent level of state diagnosis are improved.

The application discloses a superconducting synchronous phase modifier excitation power supply device, which comprises a three-phase rectifying device, an adjusting module, a protection module and a digital control module, wherein the three-phase rectifying device is used for providing a bus side DC voltage; the adjusting module is used for adjusting an excitation total current; the protection module is used for ensuring safe operation of the device; and the digital control module is used for realizing high-precision continuous adjustment of excitation winding voltage and current. The superconducting synchronous phase modifier excitation power supply device solves the problem of unbalanced reactive output of the superconducting synchronous phase modifier caused by large excitation current ripple, and improves the reliability of the superconducting synchronous phase modifier.

A stator permanent magnet motor with reduced air gap magnetic reluctance includes: a stator assembly comprising an annular stator core and a plurality of stator teeth evenly distributed along its circumference, wherein the outer surface of the plurality of stator teeth is provided with axially extending permanent magnet mounting slots, and permanent magnets are embedded in the slots to form a multi-pole magnetic field; a rotor assembly comprising a coaxially arranged rotor core, wherein the outer circumferential surface of the rotor core is provided with rotor teeth that are staggered with the stator teeth to form an asymmetrical tooth groove structure; the permanent magnet mounting slots are formed at the top of the stator teeth and are T-shaped; the rotor teeth adopt a stepped profile structure and mesh with the T-shaped permanent magnet mounting slots. The stepped profile rotor teeth and the T-shaped permanent magnet mounting slots mesh tightly, and their sidewalls are in contact with each other, which strengthens the structural connection between the permanent magnet mounting slots and the rotor teeth, optimizes the air gap magnetic flux density distribution, reduces air gap magnetic reluctance, and avoids the occurrence of increased excitation current and decreased power factor due to increased magnetic reluctance.

The application provides an ultra-short beam current homogenization transmission line system and method based on a four-octupole composite magnet, which comprises the four-octupole composite magnet and a system, a linear type and a bending type beam homogenization structure, and a two-stage iron for the beam homogenization transmission line; further comprises an ultra-short linear type beam homogenization transmission line, an ultra-short bending type beam homogenization transmission line, an ultra-short linear-bending composite type beam homogenization transmission line and an ultra-short symmetric bending type beam homogenization transmission line based on the homogenization structure and / or the two-stage iron; the method comprises a four-octupole composite iron-based excitation current debugging method and a linear type and a bending type beam debugging method; the application solves the problems that the place with the largest envelope on the transmission line is occupied and the eight-pole iron cannot fully play a role, solves the problem that the beam envelope at the position of the eight-pole iron is small and the field intensity requirement of the eight-stage magnet is high, and solves the problem that the length of the transmission line is too long, which leads to the increasing cost of the surrounding shielding civil engineering.

The invention belongs to the field of geophysical exploration, and particularly relates to a very-low-frequency three-component coil calibration method based on frequency sweep excitation, which comprises the following steps: acquiring an alternating-current excitation current and a time domain signal of a three-component coil, and performing frequency domain transformation on the time domain signal to obtain a plurality of frequency domain response vectors covering a frequency sweep range; constructing a linear equation set for describing a coil system error based on a plurality of frequency domain response vectors measured under each attitude and the calculated excitation magnetic field reference vector, and solving the linear equation set by using a least square method to obtain a calibration matrix for correcting measurement data; and the calibration matrix is adopted to correct the measurement data of the three-component coil in the use state, so that systematic errors of the very-low-frequency three-component coil can be accurately calibrated and calibrated, and the measurement precision and data reliability of a very-low-frequency electromagnetic method are effectively improved.

This invention relates to the field of shaking table testing technology and discloses an electromagnetic shock protection device suitable for large-scale shaking table tests. It includes multiple support columns spaced along the outer perimeter of the shaking table and a surrounding arresting cable net assembly. The support columns are equipped with pulley assemblies. The surrounding arresting cable net assembly includes steel cables and at least one set of electromagnetic arresting assemblies. The steel cables are wound around the pulley assemblies, and the ends of the steel cables are connected to the electromagnetic arresting assemblies. The electromagnetic arresting assemblies include a spool and a generator connected to the spool. The steel cables are connected to the spool, and the generator is electrically connected to a control device. The control device controls the damping force on the steel cables by adjusting the excitation current of the generator. This invention aims to solve the problems of existing mechanical or hydraulic arresting systems, which suffer from slow response and inability to adjust damping force in real time, resulting in a harsh shock protection process, high peak force, and potential secondary damage.

The invention discloses a rotor position detection method for multiplexing a synchronous motor body as a rotary transformer, and the method comprises the following core steps: a, independent detection windings (2) are embedded in grooves of a stator (3), the number of detection coils contained in each phase of independent detection winding (2) is equal to 1 / 2n of the number of rotor salient poles (4), and n is a natural number smaller than 10; b, detection coil parameters of all the independent detection windings (2) are completely consistent, the electrical phase difference between the independent detection windings (2) of each phase is equal to 360-degree electrical angle divided by the phase number of the independent detection windings, and the independent detection windings (2) are uniformly distributed on the inner circumference of a stator slot; c, the independent detection windings (2) of all phases are sequentially connected in series end to end and then connected into a carrier signal generated by a carrier generator, and the real-time angle position of the rotor salient pole (4) is calculated through a precise full-wave rectifier, a potential translation circuit and a position conversion module. A solid rotor position sensor is abandoned, a synchronous motor body is reused as a core component of a rotary transformer, and sensorless rotor position detection is achieved; the device adapts to special working conditions such as high temperature, strong electromagnetic interference and full sealing; according to the invention, excitation current interference is eliminated, the detection precision is improved, position closed-loop control in a zero-speed-full-speed range is realized, the response speed is high, the control precision is high, the production cost is low, and the synchronous motor is suitable for various synchronous motors with rotor magnetic resistance anisotropy and circumferential uniform distribution, such as a new energy automobile dragging motor, a linear motor and a household appliance totally-enclosed compressor.

A power converter includes a transformer, a main switch, an active clamp switch, and a primary side controller circuit. The primary side controller circuit is configured to indirectly measure a magnetizing current through the transformer during a first switching cycle of the power converter and estimate a zero-crossing point of the magnetizing current for a second switching cycle based on the indirect primary side measurement of the magnetizing current. Based on the estimated zero-crossing point, the primary side controller circuit generates an auto-tuned delay, for the second switching cycle, between disabling the main switch and enabling the active clamp switch before the zero-crossing of the magnetizing current occurs. The active clamp switch is enabled during the second switching cycle in accordance with the auto-tuned delay.

The invention discloses an energy storage type phase modifier with a damping structure and a system, and belongs to the technical field of electric power equipment. The brush doubly-fed motor comprises a stator and a rotor. An air gap is formed between the stator and the rotor; three-phase symmetrical windings are arranged in the stator and the rotor; the damping structure is made of an electric conductor material and is arranged along the circumference of the notch of the rotor; the damping structure can be equivalent to a three-phase winding, and in the equivalent three-phase winding of the damping structure, each phase is self-short-circuited. The damping structure optionally comprises at least one of the following structures: a slot wedge made of an electric conductor, a cage bar and an end ring. According to the invention, the energy storage type phase modifier has the capabilities of suppressing the excitation current peak value and improving the short-circuit current on the premise of ensuring the high inertia supporting function, so that an excitation system is effectively protected, and the short-circuit voltage supporting capability of the motor is enhanced.

Embodiments of the present application provide an antenna assembly and an electronic device. The antenna assembly comprises a near field communication chip and a first conductive structure; the first conductive structure is electrically connected to the near field communication chip to transmit near field communication excitation current supplied by the near field communication chip; the first conductive structure is provided with one or more first gaps; when the first conductive structure transmits the near field communication excitation current, the first conductive structure can generate a magnetic field, and the magnetic field generated by the first conductive structure can radiate to the outside by means of the first gaps.

The invention discloses an array coil excitation coupling eddy current detection probe, system and method and a related device, and relates to the technical field of nondestructive testing. The probe comprises a double-coil excitation module and a sensing module; the double-coil excitation module comprises two semicircular Helmholtz coils; the two semicircular Helmholtz coils are symmetrically arranged, are parallel and coaxial, and are electrified with alternating-current excitation current with the same direction, the same frequency and the same phase; the distance between the two semicircular Helmholtz coils is adjustable; and the sensing module is arranged in the central area of the two semicircular Helmholtz coils and is used for detecting the magnetic field change caused by the eddy current field at the defect. According to the invention, the detection precision of pipeline corrosion, cracks and composite defects can be improved.

The embodiment of the invention provides a unit excitation de-excitation system and method, and the system comprises a controller which is used for controlling the trigger angle of a three-phase full-control bridge to be switched from a rectification state to an inversion state during normal shutdown so as to achieve inversion de-excitation, and recognizing a fault signal and triggering a de-excitation switch during accidental shutdown; the three-phase full-control bridge is electrically connected to an excitation winding of the generator and is configured to provide rectification or inversion voltage under the control of the controller; the field suppression switch is connected in series in the excitation loop and is configured to respond to a signal of the controller to disconnect the excitation loop during accidental shutdown; the non-linear resistor is connected to the excitation winding in parallel and is configured to absorb residual energy in the rotor when the field suppression switch is switched off; and the protection device is configured to monitor the excitation current and voltage in real time and trigger a protection action when an abnormality is detected. Energy waste of traditional resistor de-excitation is avoided, reliable de-excitation can still be ensured under the extreme fault condition, and the rotor is prevented from being damaged due to overheating.

This application relates to a self-starting control method for a variable-speed pumped-storage unit and the variable-speed pumped-storage unit itself. The self-starting control method, when the stator is not connected to the grid, controls each power branch to pre-charge to establish the DC bus voltage; connects a portion of the power branches to the rotor and another portion to the stator; based on the rotor position relative to the stator, modulates the excitation current of each power branch to drive the rotor to smoothly increase speed; when the rotor reaches a preset speed, the power branches are connected to the rotor. The self-starting control method for a variable-speed pumped-storage unit provided in this application, by omitting the SFC (Self-Fuel Collector) and reusing the advantages of a multi-branch parallel converter topology, achieves SFC-less starting, solving the problems of high cost, low utilization, and complex excitation systems caused by the requirement of a separate SFC for traditional pumped-storage units. This simplifies the system structure, reduces costs, and improves operational reliability.