19746 results about "Direct current" patented technology

A tracking and adaptive compensation method for power fluctuation of a pulse load of a ship is provided. The method includes: based on a microgrid topology model of the ship, a pulse load model of the pulse load, and an interharmonic power and pulse parameter relationship model, performing power fluctuation tracking, frequency selection and a power spectrum analysis to obtain filtering parameters of a low-pass filter and filtering parameters of a band-pass filter; performing waveform adaptation to eliminate a phase delay caused by the low-pass filter and the band-pass filter, and obtaining a control command for a power compensation strategy; and generating, by a power loop, a pulse width modulation (PWM) signal to control a switching tube in a bidirectional direct current (DC) / DC converter of each of an energy storage battery pack and a supercapacitor of a hybrid energy storage system.

The invention relates to the technical field of operation prediction, in particular to an optical storage flexible direct current operation prediction method based on deep learning, and the method achieves the precise evaluation of photovoltaic power fluctuation through the analysis of historical operation data and the combination of a power state conversion matrix, guarantees that the energy storage charging and discharging rate can be matched with the load demand distribution, and improves the prediction precision. Power scheduling is optimized, topology analysis and power flow path identification are carried out, topology weight calculation is carried out by using a graph convolutional network, power flow can be dynamically adjusted, the adaptability of an operation mode is improved, the influence of power fluctuation on system stability is reduced, power matching is carried out by adopting an adversarial generative network, photovoltaic output is optimized, and the system stability is improved. The energy storage release path is more reasonable, the power loss is reduced, the overall power distribution efficiency is improved, and the load compensation strategy is optimized through short-period fluctuation detection and long-period trend fitting. And variable correction is performed based on error calculation and anomaly detection, so that the reliability of regulation and control response is improved.

The invention discloses a direct-current arc fault diagnosis method and device with adaptive capacity. The method comprises the following steps: 1) collecting a current alternating-current component when a current direct-current system normally works; 2) extracting time-frequency domain characteristics of a current AC component, wherein the time-frequency domain characteristics comprise a current peak-to-peak value, a standard deviation and an amplitude reconstruction harmonic power sum; 3) performing multi-time-frequency-domain feature fusion based on mahalanobis distance to obtain arc detection features; 4) calculating an arc fault judgment threshold value based on a box plot method; 5) collecting a current AC component in real time to calculate a Mahalanobis distance, comparing the Mahalanobis distance with an arc fault determination threshold, and recording an arc event; the method has the advantages that the system adaptability is high, the detection rate is high, the false alarm rate is low, and the method can be widely applied to high-voltage and low-voltage direct-current power distribution systems such as airplanes, vehicles and ships.

The invention discloses an operation collaborative optimization method for an optical storage direct current flexible interaction system. Comprising the steps of collecting operation data such as photovoltaic output, an energy storage state, household load power and direct current bus transmission power, fusing power market price information, and constructing a multi-dimensional time series data set; then, predicting an adjustable load capacity interval of the system based on a coupled physical constraint neural network model embedded with DC bus power balance, voltage constraint and equipment operation limitation; further constructing a state-action space, solving a Pareto frontier by adopting a multi-objective optimization algorithm, and generating a light storage and home load collaborative scheduling strategy set; then combining the real-time operation state and the prediction deviation information, applying a voltage-power droop control mechanism to carry out strategy decoupling, and generating an energy storage power correction amount and a flexible load priority control instruction; and finally, a control instruction is issued to the optical storage direct flexible system, so that collaborative optimization operation with consideration of economical efficiency, safety and comfort of the system is realized.

An offshore wind power plant composite ring current collection system topology planning method based on an N-1 safety criterion comprises the following steps that S1, wind power plant basic data including wind turbine and transformer substation node coordinates, wind turbine rated power, cable electrical parameters and the like are obtained; s2, generating a candidate cable set and a cable cross avoidance constraint pair set based on the basic data; s3, a scene set containing a normal scene and all single cable fault scenes is constructed, an optimization model with the minimum total cost of the whole life cycle as the target is established, and cable construction / operation variables and direct current power flow power balance, node degrees and cable cross avoidance constraints are integrated; s4, solving the model to obtain an initial topology scheme; and S5, carrying out full fault set N-1 security verification on the initial scheme, and bringing a violation scene into a fault set to resolve until the scheme meets an N-1 criterion. According to the method, through non-predefined topological optimization and planning, reliability and economical efficiency are taken into consideration, calculation complexity is reduced, and the method can be expanded to a cross-substation scene.

The invention relates to the technical field of hydrogen production, in particular to a micro-grid hydrogen production system based on dynamic optimization control and a multi-mode energy scheduling method. Comprising a renewable energy power generation unit which comprises at least two distributed power supplies with different power generation characteristics; the multi-stage hydrogen production device is configured to receive the electric energy output of the renewable energy power generation unit and perform proton exchange membrane water electrolysis hydrogen production; the hybrid energy storage system comprises a super capacitor bank and a lithium ion battery pack which are connected in parallel to the direct current bus through a bidirectional DC / DC converter; the dynamic optimization controller is internally provided with a multi-time-scale coordination algorithm and is used for acquiring meteorological prediction data, load demand data and an energy storage SOC state in real time; the multi-mode scheduling module comprises three working modes including an island operation mode, a grid-connected operation mode and an emergency standby mode; according to the scheme, hydrogen production economy, equipment durability and power supply reliability can be considered at the same time.

The invention relates to the technical field of circuit control, in particular to a control method and system of a bidirectional charging and discharging circuit. The method comprises the following steps: collecting current monitoring data and voltage monitoring data of a bidirectional charging and discharging circuit in real time; performing arc characteristic analysis on the current monitoring data and the voltage monitoring data to obtain arc characteristic data; analyzing a high-frequency harmonic component and a current ripple fluctuation amplitude of the bidirectional charging and discharging circuit based on the arc characteristic data; performing direct-current arc detection on the bidirectional charging and discharging circuit according to the high-frequency harmonic component and the current ripple fluctuation amplitude to generate a direct-current arc fault judgment result; and calculating the instantaneous current change rate of the current monitoring data, and carrying out short-circuit detection on the bidirectional charging and discharging circuit through the instantaneous current change rate. By monitoring current and voltage data in real time, arc and short circuit characteristics are accurately analyzed, relay control is optimized, an accurate control instruction is generated, and the safety and reliability of the two-way charging and discharging circuit are improved.

The invention discloses a low-voltage ride-through control method of a flywheel energy storage system, which is based on a low-voltage ride-through control strategy of model predictive current control (MPCC) so as to improve the low-voltage ride-through capability of the flywheel energy storage system when a power grid fails. A future current value is predicted through system modeling and a prediction algorithm, so that effective control is realized. The MPCC-based machine side-power grid side coordination control strategy can quickly respond to the voltage sag of the power grid, provide reactive power support, stabilize the voltage of the direct current bus, and ensure the safe and reliable operation of the flywheel energy storage system during the voltage sag period of the power grid. A traditional pulse width modulation (PWM) technology is abandoned, the optimal switching state is directly selected through a limited control set, and hardware implementation of a power grid side converter is simplified. A differential control strategy aiming at a power grid symmetric fault (three-phase voltage sudden drop) and an asymmetric fault (single-phase grounding) is provided, the method is suitable for a complex power grid fault scene, and the system universality is improved.

The invention relates to the technical field of wireless communication, and provides a radio frequency power amplifier and a radio frequency chip, the radio frequency power amplifier comprises an input matching circuit, a first-stage amplifier, a first inter-stage matching circuit, a second-stage amplifier, a second inter-stage matching circuit, a third-stage amplifier and an output matching circuit which are electrically connected in sequence; the radio frequency power amplifier further comprises a control module, a direct current power supply module, a first bias circuit, a second bias circuit and a third bias circuit. The first biasing circuit comprises a power detection network and a switch control circuit; the first input end of the power detection network serves as the first input end of the first bias circuit, the second input end of the power detection network serves as the second input end of the first bias circuit, and the power detection network is used for receiving a radio frequency signal, converting the radio frequency signal into a control voltage in a detection mode and outputting the control voltage to the input end of the switch control circuit. The control switch controls connection or disconnection of the circuit. According to the invention, the robustness of power can be improved.

The invention relates to the technical field of hybrid inverters, and discloses a hybrid inverter supporting reactive compensation and a control method thereof, and the hybrid inverter comprises a DC input unit, a three-phase full-bridge inversion unit, a grid-connected switching unit, a signal acquisition unit and a digital control unit. The direct current input unit comprises a photovoltaic interface, a battery interface and a direct current bus and is used for converging photovoltaic and energy storage electric energy; the three-phase full-bridge inversion unit is composed of a power device and an LCL filter and converts direct current into alternating current. The grid-connected switching unit comprises a static switch and an isolation transformer and is used for controlling power grid connection; the signal acquisition unit detects voltage and current signals; and the digital control unit judges a grid-connected mode or an off-grid mode according to the signal, calculates a reactive current reference value and generates a PWM (Pulse Width Modulation) control signal so as to realize reactive compensation control in the grid-connected mode and the off-grid mode. According to the invention, reactive power compensation capability is provided in both grid-connected and off-grid operation modes, and stable operation of the inverter in various working conditions is ensured.

The invention discloses a power matching-based current limiting method, system and equipment for a network construction type flexible direct current system. Relates to flexible direct current transmission. An existing current limiting method affects system stability and control accuracy. The current limiting condition is equivalently converted into the power limiting condition under the characteristic that the output voltage of the grid-forming converter is stable, the power limiting condition is converted into the angular frequency judgment condition under the characteristic of droop control, and when the angular frequency of the system is smaller than the lower limit of the angular frequency threshold value, it is judged that the system has overcurrent under large disturbance, and then the system is controlled. And the power matching module is connected, the output power of the converter is limited to be the maximum value, and then the current is limited to be the maximum value allowed to be output by the converter. According to the technical scheme, the current limiting effect of the converter can be achieved on the premise of not changing the network construction type frequency modulation control characteristics, complex parameter measurement and setting are not needed, the potential operation scene of the flexible direct current system can be effectively dealt with, and safe and reliable operation of the network construction type flexible direct current system is ensured.

The invention provides a split type direct current charging multi-split group charging and group control control system, and belongs to the technical field of split type direct current charging piles. The split type direct current charging system comprising a main control cabinet, a power distribution unit, a charging pile terminal and other hardware architectures is constructed; a voltage monitoring unit, a current sensor module, a harmonic filter and other multi-dimensional sensor networks are integrated to acquire power grid state data in real time, and a sliding time window method is used to carry out segmented analysis on the data to extract power grid characteristic parameters; establishing a multi-objective optimization model comprising a power balance equation and a power grid stability equation to calculate an optimal power distribution matrix, adopting a neural network to realize intelligent distribution and dynamic balance adjustment of the power of each charging pile terminal, and starting an emergency power redistribution mechanism to ensure stable operation of the system when the power grid is detected to be abnormal. The technical problem of unbalanced power distribution of the multi-pile charging system caused by power grid voltage fluctuation and harmonic pollution is solved.

The invention provides a multi-dimensional electrical equipment insulation analysis and evaluation method, and relates to the technical field of electrical equipment insulation online detection and intelligent diagnosis. According to the method, an electrically isolated direct current detection channel is constructed in a neutral point small resistance grounding system, controllable direct current detection signals are injected, micro direct current leakage response signals are collected, and after zero drift correction, temperature compensation and power frequency ripple suppression are carried out, layered attribution is carried out in combination with primary system topology and an equipment ledger, and a multi-dimensional response matrix is formed. According to the method, environment and working condition normalization is realized through factor rejection and robust pull-back, a mechanism model containing leakage channel equivalent parameters and path constraints is established, multi-working-condition data is fused to calculate equivalent insulation parameters and credibility indication quantity, and a multi-dimensional insulation representation vector is generated. And performing time sequence analysis on the representation vector, extracting degradation and abrupt change characteristics, outputting a health index and a risk level, and realizing quantitative evaluation and intelligent early warning of the insulation state.

The present invention relates to the technical field of power source power allocation. Disclosed are a direct current power source power allocation method and system for a generator status monitoring apparatus. The method comprises the following steps: by means of system data, constructing a variational problem model; solving the constructed variational problem model, and using a particle swarm optimization algorithm to optimize computing parameters of the variational problem model; and, on the basis of a computing result of the variational problem model, allocating the total output power of a hybrid energy storage system to an energy-type storage device and a power-type storage device according to a ratio. By means of using the convergence-guaranteed particle swarm optimization algorithm, the present invention not only excels in the solving speed but also shows significant advantages in computational accuracy; furthermore, by means of solving the variational problem model, more accurate allocation ratios are obtained; variational mode decomposition can achieve adaptive matching of the optimal center frequency and bandwidth for each mode, thus effectively separating intrinsic mode components and achieving frequency domain partitioning of signals.

The invention provides a fault detection method, device and equipment for a direct current transformer with variable magnetic flux density, and the method comprises the steps: obtaining a magnetic field recovery curve family through gradient pulse excitation, and extracting a characteristic spectrum which reflects the fatigue degree of an iron core; separating fast and slow recovery components by using a time scale decomposition technology, calculating a scale coupling factor and establishing a dynamic health reference; a hysteresis critical point is positioned by adopting a bidirectional approximation test, and a fault precursor is identified from hysteresis width parameters; extracting an intersection point position through curve family cross analysis, constructing an angle field, calculating an angle sequence, and quantifying a fault development speed; designing a self-adaptive excitation scheme based on the development speed, and identifying a fault resonance mode from the chaotic transition features; a multi-resolution space fault distribution diagram is generated through phase space trajectory deviation degree analysis; spatial distribution and time sequence evolution information are fused to calculate a comprehensive fault index, four-stage classification diagnosis is realized, and a complete mutual inductor fault detection technical scheme from early warning to accurate positioning is formed.

The invention discloses an IGBT junction temperature real-time decoupling modeling method and system based on dynamic electric heating compensation, and relates to the technical field of state monitoring of power electronic devices. At present, junction temperature estimation is not accurate due to IGBT on-state voltage drop measurement distortion and chip internal thermal gradient in a high-voltage environment. The method comprises the following steps: in an offline stage, constructing an ideal electrothermal characteristic database of an IGBT, a dynamic temperature gradient compensation database in a chip and Foster thermal network model parameters; in the on-line stage, synchronous sampling and preprocessing are carried out on IGBT module operation parameters; combining online real-time parameters with an offline database by using an adaptive Kalman filter, and iteratively and cooperatively estimating the real-time junction temperature and loss of the IGBT; and finally, outputting and applying the estimated accurate junction temperature and loss data. According to the technical scheme, the hot spot effect in the chip is accurately decoupled, the junction temperature estimation precision and the robustness of online monitoring are improved, and core data support is provided for fine thermal management and early fault early warning of the flexible direct current converter valve.

There is provided an apparatus for an enclosure of a direct current connection of a photovoltaic solar panel, the apparatus comprising: a housing comprising at least two parts that, when joined together, form a chamber for surrounding mating direct current connectors with an air gap, the housing comprising at least one support structure for positioning the direct current connectors in a central part of the chamber.

The invention relates to the technical field of sensors, in particular to a transformer dynamic magnetic bias current detection method and device based on magnetoelectric coupling sensing, and the detection device composed of a magnetoelectric coupling sensing element, an exciting coil and a rear-end processing circuit is used for measuring direct current magnetic bias current. The working principle of the magnetoelectric coupling sensing element is based on stress coupling between the magnetostrictive material and the piezoelectric material, then an output signal is generated on the piezoelectric material, and the sensitivity is remarkably improved by using the resonance amplification effect of the magnetoelectric coupling sensing element. Non-contact current detection can be realized by detecting the magnetic field generated by the magnetic bias current of the neutral point grounding wire of the transformer, and direct physical contact with power equipment is not needed, so that the safety of the system is improved, and the problem of high installation difficulty of a contact sensor is avoided; high-sensitivity, high-precision, anti-interference and real-time transformer direct-current magnetic bias current monitoring is achieved, and the transformer direct-current magnetic bias current monitoring device has the advantages of being easy to install and deploy and small in size.

The invention discloses a power-on reset circuit, and relates to the technical field of integrated circuits, in order to eliminate static power consumption of the power-on reset circuit and reduce power consumption of the power-on reset circuit, the power-on reset circuit comprises a discharge delay circuit, a current mirror circuit and a buffer circuit; the discharge delay circuit comprises a capacitor and an NMOS (N-channel Metal Oxide Semiconductor) tube M4, and the NMOS tube M4 is used for discharging the capacitor; the current mirror image circuit comprises an NMOS tube M2, an NMOS tube M3 and a PMOS tube M9. The grid electrode of the NMOS tube M2 and the grid electrode of the PMOS tube M9 are respectively connected with the output end of the buffer circuit; the grid electrode of the NMOS tube M3 is respectively connected with the source electrode of the PMOS tube M9, the drain electrode of the NMOS tube M2 and the grid electrode of the NMOS tube M4; the current mirror image circuit is used for turning off the NMOS tube M2 after the reset signal is ended, and pulling up the drain electrode voltage of the NMOS tube M3 to the power supply voltage through the PMOS tube M9, so that the NMOS tube M3 enters a deep linear region, and a direct current path from the power supply to the ground in the current mirror image circuit is cut off; and the buffer circuit is used for outputting a reset signal according to the voltage change of the capacitor in the discharge delay circuit.

A plasma processing system includes a pulsed voltage source configured to generate a pulsed voltage waveform having a first frequency. The plasma processing system includes a radio frequency source configured to generate a radio frequency waveform having a second frequency that is higher than the first frequency. The plasma processing system includes a junction box enclosure electrically coupling the pulsed voltage source to a direct current conductor coupled to a substrate support and further electrically coupling the pulsed voltage source to a radio frequency conductor coupled to a radio frequency baseplate. The junction box enclosure includes a pulsed voltage filter circuit coupled between the radio frequency source and the radio frequency conductor and operable to filter the pulsed voltage waveform. The junction box enclosure further includes a radio frequency filter circuit coupled between the pulsed voltage source and the direct current conductor and operable to filter the radio frequency waveform.

A simulation system of a railway system for a Medium-Voltage Direct Current (MVDC) distribution network includes: a computing device which stores a simulation program including a converter station model configured to simulate a converter station included in the MVDC distribution network and a train operation model configured to simulate an operation state of a train that is supplied with power from the converter station and runs; a converter controller which controls a DC / DC converter included in the converter station model; and a Hardware In the Loop Simulation (HILS) device which performs a simulation based on the converter station model, the train operation model, and the converter controller. Herein, the converter station model and the train operation model are executed in software by the HILS device, and the converter controller is connected to the HILS device and driven to control the converter station model.

The invention relates to the technical field of direct-current transformers, in particular to a direct-current transformer for a power distribution network, which comprises an iron core, a coil and insulating oil, an insulating assembly is arranged between the coil and the iron core, and the insulating assembly comprises an insulating paperboard, an insulating cushion block, an insulating contour semi-ring and a semi-ring groove, the insulating paper board is of a structure with a round inner wall and an octagonal outer wall. Through the unique design of the insulating paperboards, the insulating partition strips and the insulating partition blocks, the longitudinal oil ducts and the transverse oil ducts are effectively reserved, the oil flow path of the transformer is optimized, the cooling efficiency is improved, and stable operation of the transformer is ensured; through the bisection splicing structure of the insulating cardboard and the overturning action of the insulating parting strip, the quick clamping assembly of the insulating cardboard and the iron core is realized, the time for adapting the winding on site is saved, the tightness and uniformity of the winding are improved, and the reliability and safety of the transformer are enhanced.

The invention provides a clock signal generating circuit, a wired communication transceiver and electronic equipment, and the circuit outputs a first DC voltage comprising phase difference information and frequency difference information of a reference clock signal and a feedback clock signal through a phase frequency detection module. The pulse generator generates a narrow pulse signal based on the DC voltage and a reference clock signal, the oscillation frequency of each secondary ring oscillator in the cross-coupled ring oscillator is controlled by the first DC voltage, and the cross-coupled loop performs synchronous coupling and phase sequence adjustment processing on each secondary ring oscillator. One output node in the cross coupling ring oscillator receives the narrow pulse signal, frequency and phase locking is completed in an injection locking mode, and the frequency divider is used for conducting frequency division processing on any high-frequency clock signal and outputting a feedback clock signal. Therefore, a high-frequency multi-phase clock signal with low phase noise and high phase precision can be generated by using the low-frequency reference clock signal.

The present invention discloses a transformer fault diagnosis technology based on knowledge mapping, which relates to the field of fault diagnosis technology and includes the following steps: S1, obtaining transformer multimodal data and performing data preprocessing; S2, establishing a memory-enhanced early warning model to predict transformer operation data; S3, transformer fault diagnosis. The present invention comprehensively considers online monitoring data or offline test data such as transformer oil dissolved gas data, oil temperature, partial discharge signal, core or clamp grounding current, DC current, infrared spectrum, winding deformation curve, ambient temperature and humidity, etc., performs fault diagnosis on the predicted multimodal data, and predicts possible future transformer faults.

The invention provides an arc discharge detection method and device for a photovoltaic inverter and electronic equipment, and the method comprises the steps: collecting sample current data corresponding to the photovoltaic inverter, and classifying and marking the sample current data as arc data and arc-free data; taking the sample current data as a data sample, taking the arc data and the arc-free data as sample labels corresponding to the data sample, and training a preset neural network model; converting the trained neural network model into an algorithm program, deploying the algorithm program to a preset micro-control unit, inputting real-time current data collected by the micro-control unit into the neural network model, and determining a data type to which the real-time current data belongs; and when the data type is the electric arc data, determining that the photovoltaic inverter has a direct current arc discharge phenomenon. And low-cost and high-precision intelligent arc discharge detection can be realized.

The invention relates to a simple and reliable touch control switch. The simple and reliable touch control switch consists of a 12-V direct-current power supply, a one-way silicon controlled rectifier 1 (SCR1) trigger circuit, a one-way silicon controlled rectifier 2 (SCR2) trigger circuit, a relay control circuit and a load RL circuit. A conventional mechanical self-locking rocker switch or a toggle switch has the defects that actions are mechanical, operating actions are different because of persons, a contact is easy to jitter, a contact is easy to ablate, abrade and the like. The touch control switch is realized by only using a small number of common components and two touch metal pieces, namely an on-load circuit is switched on by touching a touch electrode once, and an off-load circuit is switched off by touching the touch electrode once. The overall touch control switch is made of discrete components, and strong electricity can be effectively isolated from weak electricity through a relay, so that the power supply of a load can use alternating current and also can use direct current. Therefore, the touch control switch has a certain function in the field of household appliances, industrial automation, and optical, mechanical and electrical integration.

The invention provides an optical storage parallel network control method, which comprises the following steps: calculating the current load rate percentage of each residual unit according to the connection relation and electrical path information of the residual units after isolation; evaluating the available margin capacity and the frequency regulation bearing capacity of the remaining units, matching the available margin capacity and the frequency regulation bearing capacity with a specific power value and a frequency regulation requirement which need to be compensated, and determining a feasible unit combination scheme for fault recovery; generating a power redistribution list and a frequency adjustment responsibility distribution table according to the direct current bus connection mode of the optimal unit recombination, and obtaining an output power set value and a frequency adjustment parameter of each unit after adjustment; and extracting the continuous power supply time value of the optical storage parallel network, updating the total power supply capacity value of the optical storage parallel network, and maintaining the continuous power output and frequency stability after the fault of the optical storage parallel network.

The invention relates to the technical field of information, and discloses a fault current suppression method and system for a direct-current deicing device, fault current data of the direct-current deicing device are analyzed through fast Fourier transform, and direct-current bus voltage drop data are obtained based on an analysis result and are processed through a support vector regression algorithm, so that a fault current suppression result is obtained. Obtaining a voltage stress sudden increase trend and further determining stress distribution data of a switching device in the device; processing the stress distribution data by a Kalman filtering algorithm to obtain a processing result so as to determine a dynamic correction coefficient of a bridge arm switching time sequence, and processing the dynamic correction coefficient and element response delay data of the device by a particle swarm optimization algorithm to generate a bridge arm switching time sequence so as to determine a real-time adjustment parameter influencing the discharge rate of a buffer capacitor in the device; and comparing voltage oscillation characteristics before and after matching to determine an impedance compensation value of a commutation path for execution, thereby realizing effective suppression of current oscillation in the DC deicing device.

The invention discloses a hybrid hydrogen production system coupled with photovoltaic renewable energy and an optimal configuration method, and relates to the technical field of new energy utilization and energy storage control, and the hybrid hydrogen production system comprises a photovoltaic power generation unit, an alkaline water electrolytic tank unit, a proton exchange membrane electrolytic tank unit, a hydrogen storage unit, a control unit and the like. Photovoltaic electric energy is directly supplied to the two types of electrolytic cell stacks through the direct current bus, a traditional DC-DC power converter is omitted, and loss in the energy transmission process is reduced; and through a dynamic electrolytic cell switching algorithm configured by the control unit, the input proportion and the number of operation units of the two stacks are changed and adjusted in real time, and the quick response capability and the long-term stability are both considered. The system can stably produce hydrogen under the condition of renewable energy fluctuation, can dynamically adapt to input power change, can realize maximum power point tracking control on the premise of not using extra power conversion equipment, and remarkably reduces initial investment cost and operation energy consumption while ensuring hydrogen production efficiency.

The invention belongs to the technical field of ceramic preparation, and particularly relates to silicon nitride ceramic and a preparation method thereof. The silicon nitride ceramic is prepared from the following raw materials in parts by weight: 80-99.5 parts of silicon nitride powder and 0.5-20 parts of a sintering aid, the silicon nitride powder is alpha-Si3N4 powder; the sintering aid comprises at least two of CaF2, Y2O3, MgO, Mg (OH) 2, Al (OH) 3, Al2O3, AlN, MgCO3, Mg (NO3) 2, Y (NO3) 3 and Al (NO3) 3. On the basis of an existing silicon nitride dissolution-precipitation sintering mechanism, by adding sintering aids such as low-cost calcium fluoride, introducing a gas-phase mass transfer mechanism and combining a low-cost direct-current electric field assisted sintering technology, low-cost and rapid preparation of the high-performance silicon nitride ceramic is achieved, the process is simple and efficient, and operation is easy to control.