227 results about "Branch current" patented technology

The invention relates to the technical field of electric energy conversion control, and discloses a multi-source load auxiliary power supply power balance control system, which comprises a sampling module, a control module and a modulation module, the sampling module obtains parallel converter branch current and direct current bus voltage; the control module determines a weight by utilizing physical associated association of a bus voltage change gradient and branch current change polarity, corrects a dynamic slope factor determined by a current change rate according to the weight, and performs upper limit clamping on the dynamic slope factor according to a bus voltage margin; according to the invention, the rigid restriction of droop control logic is eliminated, the power deviation generated by asymmetry of feeder impedance is automatically offset while the bus voltage stabilization precision is maintained, and the convergence speed and the certainty of the system during violent load switching are improved.

The invention discloses a high-voltage discharge circuit suitable for a storage battery power supply and an electric flame stove. The high-voltage discharge circuit comprises an inversion driving module, a boosting transformer T1, at least three groups of active bridge rectifier modules and discharge modules corresponding to the active bridge rectifier modules. Through combination of driving of the active bridge rectifier module, voltage / current double-closed-loop feedback and real-time PWM signal output control of the control chip U1, current difference of each discharge branch is eliminated, the problem of uneven branch current is solved, and ring current and reactive power loss between branches are eliminated; a diode in a voltage doubling rectifying circuit and a bleeder resistor of a resonance circuit in the prior art are abandoned, an active bridge type rectifying module is adopted for driving, a PWM signal is dynamically adjusted through the low ESR characteristic of a capacitor C1 and closed-loop control, extra power loss is avoided, the working temperature of the circuit is controlled to be below 85 DEG C, and the service life of the circuit is prolonged. And the continuous service life of components in the circuit is prolonged.

The invention relates to a current switching-on and switching-off converter which comprises a shell barrel, a plurality of limiting rings and a plurality of wires, a shell cavity is formed in the shell barrel, the limiting rings are contained in the shell cavity, limiting holes and conductive springs are arranged in the limiting rings, the limiting holes are communicated with guide holes, the conductive springs surround the limiting holes, one ends of the wires are electrically connected with the conductive springs, and the other ends of the wires are electrically connected with the conductive springs. And the other end of the lead extends out of the shell cylinder. By adopting the technical scheme provided by the invention, when the number of branch currents is more, the wires are not limited to be arranged in the same plane any more, the reduction of the appearance size of the electric connector is facilitated, and the electric connector can be assembled and applied in a narrow space range; when the electric connector provided by the invention is plugged with other electric connectors, the rigid surfaces of the conductive parts are in contact with the flexible surfaces of the conductive springs, so that good electrical contact between the electric connectors can be ensured, and the reliability of electrical connection is ensured.

A converter station AC filter group circuit breaker abnormal arcing modeling analysis method comprises the following steps: firstly, carrying out time mark alignment, amplitude calibration and filtering de-noising on wave recording signals such as AC bus voltage and filter branch current to obtain high-quality input data; then, combining a primary wiring diagram, enabling an alternating current system to be equivalent to an ideal power supply and series impedance, enabling circuit breaker arcing to be equivalent to arc resistance changing along with time, and constructing an equivalent circuit model comprising the power supply, the impedance, a capacitor, an electric reactor and dynamic arc resistance; establishing a state space equation according to a voltage and current constraint relation, and performing time domain solution by adopting a two-step two-order or three-order diagonal implicit Runge-Kutta method to obtain voltage and current responses of the whole process of the fault; on this basis, the arc resistance change is inversed according to the ratio of arc voltage to current, the current zero passage is identified through the resistance symbol change at adjacent moments, and the zero passage section is smoothed; and finally, the inversion result is verified again by means of the simplified equivalent model.

The invention relates to the technical field of power grid safety evaluation, in particular to a power system short-circuit parameter prediction method, system and device based on time-space relevance and a storage medium. A multi-dimensional state vector including a node voltage vector, a branch current vector, a short-circuit impedance matrix, spatial position information and a time feature vector is constructed, and a space-time correlation feature vector including a time-dimensional feature, a spatial-dimensional feature, a space-time coupling feature and a state feature is extracted. Wavelet transform, Fourier analysis and graph theory analysis are adopted to identify a parameter change rule and a propagation effect. A multi-level prediction model of a statistical prediction layer, a deep learning layer and a fusion layer is constructed, and comprehensive description of dynamic characteristics of short-circuit parameters is realized through spatio-temporal feature fusion. A staged training strategy is adopted, and comprises the steps of establishing a basic model through offline training, updating parameters in real time through online learning, and quantifying uncertainty through a probability prediction framework. And a prediction correction mechanism and a reliability evaluation system are established, and a complete prediction-evaluation-correction closed loop is formed.

The invention relates to the field of capacitor monitoring, and provides a capacitor quasi-online state monitoring method and system for a wind power converter, and the method comprises the steps: extracting a data slice comprising DC bus voltage, capacitor branch current, housing temperature and output power from a data buffer area; furthermore, output power data is utilized, intelligent screening is carried out through a quasi-steady-state slice trigger, and only effective data with the power average value large enough and the fluctuation small enough are reserved. And for the screened effective data slices, extracting the DC bus voltage and the capacitance branch current, and accurately identifying the voltage, current amplitude and phase information of the main harmonic through fast Fourier transform. Based on the key harmonic data, the complex impedance of the capacitor is calculated, and then the original ESR and capacitance estimation value are calculated. And finally, in combination with the capacitor shell temperature extracted from the same data slice, performing temperature compensation on the original parameters, and outputting a final result capable of truly reflecting the aging state of the capacitor.

The invention discloses an electric power system wiring detection method based on block parallel processing, and relates to the field of current detection, and the method comprises the steps: collecting real-time operation data through a sensor disposed at a key node, and constructing a basic data set after Kalman filtering denoising and normalization processing; establishing a sub-block identification system based on topological structure blocks, and extracting electrical and topological feature vectors; a master-slave parallel computing architecture is adopted, a master node allocates tasks according to priorities, and an improved random forest model is utilized to perform sub-block level anomaly preliminary screening; cross-sub-block collaborative verification is realized by verifying the boundary interconnection switch state, the branch current and the bus voltage; and finally, constructing a global wiring state map to perform difference analysis, accurately positioning abnormal equipment and types, and verifying a result through high-precision retest. The method has the advantages that the efficiency is improved through scientific partitioning and distributed parallel computing, the accuracy is guaranteed in combination with multi-dimensional detection, boundary verification and a retest mechanism, wiring abnormity is efficiently positioned, and reliable support is provided.

The invention belongs to the technical field of power protection, and particularly relates to a station transformer grounding current synchronous synthesis method and system, and the method comprises the steps: carrying out the grouping according to the number of a station transformer, synchronously collecting the grounding branch current of each station transformer to obtain an original signal, carrying out the double identification, and carrying out the homologous copying; generating two paths of independent signals of frequency detection and phase calibration; frequency detection signals are grouped according to double identifications, the independent actual frequency of each station transformer is obtained after frequency detection processing, and a same-frequency sine dynamic reference signal is generated based on the independent actual frequency; performing phase alignment and compensation on the phase calibration signal and the corresponding reference signal according to the double identifiers to obtain a calibrated signal; according to the method, the phase calibration reference of each station transformer is completely matched with the actual frequency of the station transformer, the reason of phase reference dislocation caused by frequency fluctuation is eliminated from the source, and the accuracy of synthesizing the total grounding current in the station is improved.

The invention discloses a synchronous generator rotor turn-to-turn fault online monitoring method and system, and the method comprises the steps: building a time-varying parameter mathematical model which comprises a stator branch, a normal excitation loop, an excitation fault additional loop, a damping loop and a load based on a multi-loop theory, and collecting the current signals and key-phase signals of all parallel branches of a stator in real time; the fractional harmonic characteristic quantity representing the fault is extracted through analysis, and whether turn-to-turn short circuit occurs or not is judged according to a preset criterion; and if the fault is determined, determining the position of the fault magnetic pole by adopting a phase matching algorithm in combination with the key-phase signal and the magnetic pole fault characteristic angle database. According to the method, the primary side of the generator does not need to be transformed, high-sensitivity online monitoring and accurate positioning of rotor turn-to-turn faults in operation can be achieved, and the method is suitable for safety guarantee of an active-service unit.

The invention discloses a direct-current system ground fault real-time monitoring method and system, and relates to the field of intelligent power distribution, and the method comprises the steps: collecting the bus voltage, branch current and disturbance response signals of each branch, constructing a fusion abnormal factor in a fixed monitoring window, comprehensively reflecting the voltage change rate, disturbance amplitude response and current vector offset characteristics, and carrying out the real-time monitoring of the ground fault of a direct-current system. And inputting the factor and a disturbance parameter into a nonlinear scoring function together, and outputting a grounding probability confidence score. And for the branch with the scoring result exceeding a set threshold value, the system executes bypass closing and main branch opening operation, voltage and current derivative data are collected in a recovery window, the voltage drop recovery rate is calculated, and whether an actual grounding point is formed or not is judged. And if the fault is confirmed to be true, the isolation state is maintained, and branch reset operation is completed through a recovery criterion and a manual permission mechanism in a subsequent period. The method has better effects in real-time performance, accuracy and safety.

The invention belongs to the technical field of metallurgical equipment, and particularly relates to a method for transforming a direct-current submerged arc furnace based on a traditional three-phase alternating-current submerged arc furnace and the direct-current submerged arc furnace. The direct-current submerged arc furnace comprises a submerged arc furnace body, three cathodes, three anodes and a direct-current power source, the three cathodes are arranged on the furnace top at equal intervals of 120 degrees, and the three anodes and the three cathodes are arranged at the furnace bottom in an aligned mode; the three anodes are respectively connected with the positive electrode of a direct-current power supply, the three cathodes are respectively connected with the negative electrode of the power supply, direct current is respectively input into the furnace through the three anodes and forms three groups of stable electric arcs with the three corresponding cathodes, so that the magnetic induction force of an external magnetic field can be reduced, the problem of arc deflection is solved, and the energy consumption of metallurgy is reduced; the insulating layer can cut off branch currents distributed in the hearth of the direct-current submerged arc furnace, interference of the branch currents on electric arcs is avoided, the electric arcs are prevented from deviating, the length of the electric arcs is shortened, heat efficiency is improved, and energy consumption of metallurgy is reduced.

The invention relates to the technical field of electromagnetic transient simulation, in particular to an electromagnetic transient simulation decoupling method, system and device based on a single-impedance branch and a medium, and the method comprises the steps: dividing a system to be simulated into two subsystems which are connected through the single-impedance branch, and carrying out the equivalent reconstruction to form a reconstructed branch model; establishing a discrete state space equation based on the reconstructed branch model; according to the main step length, the number of sub-steps meeting the stability condition is determined based on a small-step synthesis algorithm, and the main step length is equally divided into differential step lengths; in each main step length interval, performing iterative calculation on the state-space equation by using a differential step length to obtain a branch current and a capacitor voltage at the next moment; and injecting the calculated branch current serving as a known current source into an original network equation, solving in parallel to obtain the port voltage of the subsystem, and completing decoupling calculation and promoting simulation. According to the method, effective decoupling of the universal single-impedance branch can be realized, and the applicability, the numerical stability and the calculation efficiency of parallel simulation are improved.

The invention relates to the technical field of fault detection, in particular to a generator stator winding turn-to-turn short circuit detection method and system, and the method comprises the steps: synchronously collecting stator branch current, an air-gap magnetic field and an engine base vibration signal; preprocessing the signal and standardizing the working condition; extracting and adaptively fusing three types of feature vectors of branch current circulation, magnetic field asymmetry and vibration feature spectrum correlation to generate a comprehensive fault feature vector; inputting the short-circuit fault into a trained turn-to-turn short-circuit intelligent classifier, and outputting a fault judgment result and a continuous short-circuit fault confidence coefficient index; and finally, combining a confidence index trend and a feature contribution degree backtracking analysis result to generate a comprehensive state evaluation report. According to the invention, high-sensitivity and high-reliability online detection and early warning of early weak turn-to-turn short circuit are realized.

The invention discloses an open circuit diagnosis method, an open circuit diagnosis device, an energy storage system and a vehicle, and belongs to the technical field of energy storage. The open circuit diagnosis method comprises the following steps: judging whether an open circuit fault occurs in n branches or not; and when the open circuit fault occurs in the n branches, determining the shunt current in each branch, and if the shunt current is less than or equal to the first target current, judging that the corresponding branch is open circuit. According to the open circuit diagnosis method provided by the invention, the problems of fault false alarm and the like caused by circulation between the branches due to the differential pressure can be effectively solved, the open circuit state of each branch can be diagnosed, and the after-sales maintenance efficiency can be improved.

The invention discloses a distributed photovoltaic-containing power distribution network planning layer multi-objective optimization method, which comprises the following steps of: constructing a multi-objective optimization model taking investment cost, network loss and voltage deviation as sub-objectives, and integrating the sub-objectives into a unified optimization function through a weight coefficient method; multi-dimensional constraint conditions such as node voltage safety, power balance, capacity upper limit, branch current and whole network permeability are established in combination with load flow calculation, photovoltaic optimal point distribution and capacity configuration are solved by adopting an improved flower pollination algorithm, and the convergence speed and optimization precision are improved. The improved dynamic projection primal-dual distributed algorithm is adopted, and local information exchange and a self-adaptive step length mechanism are utilized, so that the real-time network loss minimization and voltage stability control of the high photovoltaic penetration power distribution network are realized, and the safety and economy of the system are ensured.

The invention provides a power distribution network node harmonic exceeding main cause identification method, device and system and a medium, and the method comprises the steps: building a node admittance matrix based on the node harmonic voltage and branch current monitoring data of a power distribution network, building a related equation of the harmonic voltage and an injection current, and employing a compressed sampling matching pursuit algorithm to identify the harmonic exceeding main cause of the power distribution network; solving a sparse harmonic injection current vector, and calculating a node harmonic voltage distortion rate according to a harmonic current injection value so as to judge a standard exceeding condition; through a modal analysis method, harmonic current threshold comparison and multi-frequency superposition effect analysis, identifying main factors exceeding the standard, including harmonic injection standard exceeding, multi-frequency superposition and resonance phenomena; and quantizing contribution degrees of resonance and harmonic injection, and distinguishing composite causes of harmonic exceeding. According to the method, the problem that the harmonic cause is unknown in the harmonic exceeding scene is solved, and the accuracy of the harmonic exceeding cause is remarkably improved. Through simulation and actual measurement verification, the accuracy of the method provided by the invention is verified.

The invention discloses a cable branch box power supply system and a method thereof, the cable branch box power supply system comprises a three-section surge protection device, an integrated trigger type discharge gap unit, an MOV clamping unit and a residual voltage shaping network, and is cooperated with a follow-up cut-off mechanism to inhibit surge and optimize residual voltage in stages, cut off current at a voltage zero point when the surge is attenuated and a power frequency current exists, and improve the reliability of the power supply system. Electric arc and operation overvoltage are reduced; the on-line health diagnosis module analyzes the deterioration trend of a key element through equivalent parameter injection measurement and an NTC temperature probe, and uploads data through an RS-485 / Modbus bus; the dynamic load distribution module adjusts branch current in real time; the intelligent cooperative control module integrates multiple modules to realize self-adaptive linkage; the fault isolation unit is linked with the follow-up cutoff mechanism, and triggers cutoff and sends an opening signal to an upper level when the fault isolation unit is abnormal; and the event recording module is used for storing related data and supporting USB on-site calling. According to the invention, the surge resistance, the cutoff reliability and the operation stability of the system are enhanced, and the preventive maintenance capability is improved.

The invention discloses an optical storage integrated micro-grid management system and method, particularly relates to the technical field of hybrid energy storage power distribution control, and is used for solving the problem of high-frequency circulating current caused by dynamic response mismatch of a lithium battery and a super capacitor in the prior art. The method comprises the following steps: acquiring a micro-grid power instruction change rate and branch currents of a lithium battery and a super capacitor in real time; when the power instruction change rate exceeds a threshold value, determining a mismatch risk level according to the current internal resistance ratio; if a high risk is reached, synchronously extracting high-frequency components of two paths of current, and calculating a cross-correlation entropy of the high-frequency components through phase-space reconstruction to quantify a dynamic mismatch degree; constructing a dynamic circulating current suppression compensation function containing a cross-correlation entropy derivative damping term and an internal resistance ratio nonlinear proportional term based on the mismatch degree and the internal resistance ratio; superposing the function with an original power distribution instruction to generate a correction instruction; finally, the output of the hybrid energy storage unit is controlled through the bidirectional DC / DC converter, real-time active suppression of the dynamic circulating current is realized, the system efficiency is improved, and the service life of equipment is prolonged.

The invention discloses an IGBT parallel current balancing method and device based on real-time feedback control, and relates to the technical field of power electronic conversion, and the method comprises the steps: activating a double-pulse test device to carry out the transient test of an IGBT, and obtaining the test information; performing simulation analysis by taking the multiple physical parameters as constraints to obtain simulation information; performing collaborative analysis on the test information and the simulation information to obtain a parallel current prediction function; introducing an equalization control coefficient to obtain an equalization control quantity; and activating a grid charge regulator to control and regulate the balance control quantity of the IGBT. According to the invention, the technical problems that the existing control and adjustment technology of conversion equipment between alternating current and direct current lacks an accurate feedback and dynamic adaptation mechanism, parallel branch parameters are difficult to control in a balanced manner, and the requirements of efficient and stable electric energy conversion under complex working conditions cannot be met are solved; the technical effects of accurately controlling the parallel branch current of the alternating current and direct current conversion equipment in a balanced manner and improving the electric energy conversion efficiency and the system stability under complex working conditions are achieved.

The invention relates to a cable insulation state monitoring method and system, electronic equipment and a medium. The method comprises the following steps: acquiring an insulation state parameter of a main line and leakage current and electric field intensity of a branch contact; calculating branch current fluctuation and insulation resistance, and positioning an initial contact; extrapolating from a starting contact along a trunk line, and calculating section insulation degradation probability by combining current fluctuation and insulation state parameters; dynamically adjusting the acquisition frequency according to the probability and updating the electric field intensity; and generating a fault propagation path diagram according to the initial position and the gradient, simulating multi-scene operation data, and outputting a global insulation state monitoring result. Therefore, according to the method, the collection frequency is updated in real time along the main line section, the section degradation probability is calculated by integrating the insulation state parameters, then the fault propagation path diagram is generated, multiple operation scenes are simulated, early recognition and global evaluation of cable insulation degradation are achieved, and the monitoring precision and the early warning reliability are improved.

The invention provides a low-voltage cabinet overload early warning method and device based on current harmonic recognition, and relates to the technical field of power supply, and the method comprises the steps: carrying out the current double-side real-time monitoring of a low-voltage cabinet, and generating an input side current harmonic feature vector and N output branch current harmonic feature vectors; performing overload main cause positioning analysis, and outputting real-time overload early warning; if the main factor is the input side overload main factor, branch overload contribution degree quantification is carried out, and N overload risk weight factors are output; global collaborative load reduction of the N output side devices is carried out; and if the main factor is the output side overload main factor, analyzing and generating an output side load reduction strategy based on harmonic-load coupling disturbance characteristics of the real-time main factor branch equipment on N-1 output side equipment after isolation. The technical problem that the load adjustment of the whole system is unbalanced due to the fact that the load adjustment method mostly depends on manual judgment and lacks dynamic adjustment and optimization of the whole load condition of the power supply system in the prior art is solved.

The present application relates to the field of motor winding parts arranged in slots, in particular to a six-pole fifty-four-slot flat copper wire motor three-branch balanced winding and a using method thereof. The six-pole fifty-four-slot flat copper wire motor three-branch balanced winding comprises three-phase flat copper wire windings symmetrically distributed in the circumferential direction of the core slot, characterized in that: the span of the welding end (1) is equal, and the height of the welding end (1) lead-out wire is equal; the power lead-out wire end (3) is composed of four U-pin wire types and one I-pin wire type; the first layer of the power lead-out wire end (3) is composed of one I-pin wire (4) and one equal-span U-pin wire (5); the second layer and the third layer are both composed of one equal-span U-pin wire (6); the fourth layer and the fifth layer are both composed of one equal-span U-pin wire (7); and the sixth layer is composed of one equal-span U-pin wire (8). The present application has compact structure, balanced three-phase current, and balanced branch current of each phase.

The application discloses a fault current analysis method and system of a multi-terminal flexible DC circuit, wherein the method comprises the following steps: analyzing fault current data when a modular multilevel converter DC side is short-circuited to obtain time sequence segmentation rule data; performing equivalent processing on the modular multilevel converter based on the segmentation rule data to obtain an equivalent circuit model comprising an RLC series circuit and a time-varying current source; constructing a second-order differential equation describing the fault current according to the equivalent circuit model, and solving the second-order differential equation to obtain a fault current expression containing dynamic AC feed-in; constructing a fault equivalent network of the multi-terminal flexible DC circuit; constructing a state space equation of the fault equivalent network based on a branch current method and the fault current expression, and solving the state space equation to obtain fault current data of the multi-terminal flexible DC circuit. The method improves the accuracy of fault analysis.

The invention discloses a method, a device and equipment for determining the inductance of a filter inductor and a medium, and relates to the technical field of inverters. By establishing a target state equation, the dynamic change of the output voltage under different bridge arms of the inverter system and the current of the filter inductor can be known subsequently. And according to the target state equation, determining a branch current of a coupling inductance winding of each bridge arm and a target current corresponding to filtering, so that the branch current and the target current are abstracted into a mathematical expression in a circuit operation process, and the branch current and the target current are deduced and determined through a mathematical mode. And determining the ripple current variation of the filter inductor by taking the determined branch current and the target current as subsequent constraint parameters. Furthermore, the inductance value of the filter inductor is determined based on the ripple current variable quantity of the filter inductor, and is used as an important basis for selecting the filter inductor, so that the specific inductance value is determined on the basis of reducing the inductance value of the filter inductor, and the selection accuracy is improved.

The application provides a phase-shift PWM modulation control method based on duty cycle scaling, which realizes real-time dynamic adjustment of output duty cycle by introducing a duty cycle scaling mechanism, can be used for active equalization control of branch currents in a multiple interleaved topology, makes the current and thermal stress distribution of each branch device more consistent, and thus significantly improves the overall operation stability and long-term reliability of the system. The application supports a large range of phase shift and is suitable for various high-power multiple interleaved topology structures. The application does not require an external synchronization signal and can generate double-bridge-arm driving signals only by relying on a single PWM input, which significantly reduces the system implementation complexity, simplifies the control interface and saves control resources.

The invention discloses a battery management system, a battery pack and an electric device. The battery management system comprises a first switch, a second switch, a third switch, a voltage sampling module, a first current sampling module, a second current sampling module and a processor. The first switch is electrically connected between the first sampling point and the second sampling point; the second switch is electrically connected between the anode of the first battery and the cathode of the second battery, and the anode of the second battery is electrically connected with the first sampling point; the third switch is electrically connected between the negative electrode of the second battery and the reference point; the voltage sampling module collects the voltage of the first sampling point, the voltage of the second sampling point, the voltage of the first battery and the voltage of the second battery; the first current sampling module collects main loop current; the second current sampling module collects current of a branch where the first battery is located; and the processor is used for determining whether each switch has a fault according to the sampled voltage and current. According to the embodiment of the invention, the accuracy of switch diagnosis can be improved.

The application discloses a double feedback branch current compensation type charge pump circuit, which comprises a core circuit, a double feedback branch and a bias circuit connected in sequence, wherein the input node of the double feedback branch is connected with the core circuit for detecting the potential change of the output voltage, the first output node of the first feedback branch in the double feedback branch is connected with the gate of the bias circuit, the second output node of the second feedback branch is connected with the bias circuit, and the up and down charging and discharging currents are carried out phased current compensation through the bias circuit according to the degree of the output voltage deviating from the center potential. The application solves the mismatching problem of the up and down charging and discharging currents when the output voltage deviates from the center potential through the double feedback branch, can convert the phase error output by the frequency discriminator into the difference between the charging and discharging currents, charges and discharges the loop filter to generate the control voltage of the voltage controlled oscillator, thereby realizing the lower charging and discharging current mismatching in the wider control voltage range, the smaller ripple on the output voltage, and the optimization of the jitter performance of the output clock of the phase-locked loop.

The invention relates to the technical field of energy storage configuration, in particular to a network construction type SVG super capacitor configuration method, system and device based on a direct current side direct-hanging super capacitor and a storage medium. Acquiring grid-connected voltage, target instantaneous active power and continuous discharge time; selecting the specification of a super capacitor monomer, determining a single cluster rated voltage and setting a branch current-limiting threshold value; establishing a single-cluster supercapacitor discharge model, simulating a process from constant-power discharge to a current-limiting threshold value, considering the influence of internal resistance voltage division, calculating single-cluster release energy through power-time integration, and obtaining single-cluster constant discharge power; calculating the number of super capacitor clusters; the number of parallel branches and the number of series clusters are determined by combining the topological direct-current side voltage range of the MMC, and the direct-current side rated voltage is set. By establishing a discharge model considering internal resistance voltage division, accurately calculating the actual discharge capacity of a single cluster, and systematically planning super capacitor configuration in combination with MMC topological characteristics, the problems that an existing method is insufficient in configuration precision and lack of topological adaptability are solved, and the reliability of a network-forming SVG is improved.

The application discloses a sub-threshold CMOS reference source with high power voltage rejection ratio, and relates to the field of integrated circuits.The reference source is composed of a first-stage starting circuit, a pre-stabilization circuit, a second-stage starting circuit and a core voltage reference circuit.The first-stage starting circuit and the second-stage starting circuit ensure that the circuit enters a normal working state, and the pre-stabilization circuit provides a stable and small-ripple secondary power voltage VDDs for the core voltage reference circuit.The core voltage reference circuit adopts a multi-branch current source to improve the loop phase margin, and the combination of the two can improve the low-frequency PSRR degradation problem of the sub-threshold CMOS reference source.

The invention provides a controllable zero-crossing direct-current circuit breaker and a control method thereof, and belongs to the technical field of power electronics. The controllable zero-crossing direct-current circuit breaker comprises a through-flow branch, a current transfer branch and an energy dissipation branch, adopts semi-control and full-control devices, and is simple in logic, economical and reliable. According to the circuit breaker, the thyristors and the IGBTs are matched to input the pre-charging capacitors, the bidirectional breaking capacity is achieved, and the short-circuit current of a direct-current power grid can be effectively broken; meanwhile, the number of current zero crossing points of a mechanical switch branch during a fault is greatly increased, and the reliability of the direct-current circuit breaker is enhanced. The invention provides a control method of a controllable zero-crossing direct-current circuit breaker. The controllable zero-crossing type direct-current circuit breaker is controlled under the two conditions that the direct-current line where the circuit breaker is located operates normally or before the fault of the direct-current line where the circuit breaker is located is detected and after the fault of the direct-current line where the controllable zero-crossing type direct-current circuit breaker is detected.