1247 results about "Grid connection" patented technology

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 grid-connected inverter control method based on second-order linear active disturbance rejection, and particularly relates to the field of grid-connected inverter control. Voltage and frequency error signals between the output side of the inverter and the power grid are obtained, a pre-synchronization control model is constructed, and voltage amplitude and frequency synchronization is achieved; a second-order linear active-disturbance-rejection controller is introduced in the frequency synchronization control process, an extended state observer is adopted to estimate the output frequency, the frequency change rate and a disturbance term, and a state error feedback control law is combined to generate a frequency regulation control quantity, so that accurate frequency control is realized; after grid connection, a dual-channel LADRC power regulation controller is constructed, and decoupling tracking control is carried out on active power and reactive power; meanwhile, on the basis of fast Fourier transform processing as a stable grid-connected state criterion, the method has the advantages of being high in control precision, high in anti-interference capability, good in current waveform quality, high in adaptability and the like, and is suitable for various grid-connected application scenes.

The invention discloses an electric power control method based on a diesel generator, commercial power and photovoltaic grid connection. The method comprises the following steps: acquiring operation data of commercial power, a diesel generator and photovoltaic-energy storage through an energy management system, constructing a multi-target dynamic optimization model, and distributing power by taking the lowest comprehensive operation cost, the highest power supply reliability and the minimum carbon emission as targets; the power analysis and regulation unit adopts a double-loop mechanism of outer-loop Kalman filtering prediction compensation and inner-loop model prediction control, synchronizes the voltage, frequency and phase of the side to be connected with the grid and the power grid side, and smoothly switches the power change rate of each energy source in the process through a self-adaptive sliding mode control strategy; and the grid-connected switching unit intelligently pre-judges the grid-connected switching opportunity by using a long short-term memory (LSTM) network and fuzzy logic fusion model. According to the invention, the energy utilization efficiency and the power supply stability are improved, multi-energy intelligent dynamic regulation and control are realized, the comprehensive operation cost of the system is effectively reduced, and reliable power supply under complex working conditions is ensured.

The invention relates to the technical field of boiler control, and discloses a gas-fired boiler starting control method and system. The method comprises the following steps: acquiring initial operation parameters such as hearth pressure, water inlet temperature, flue gas oxygen content and fuel valve opening of the gas-fired boiler, establishing a thermodynamic state model in a starting stage according to the initial operation parameters, and dividing dynamic response thresholds of different load intervals; and calculating a theoretical fuel supply rate of the combustor based on the model, generating and dynamically updating a fuel supply correction coefficient in combination with a threshold value, synchronously marking key nodes according to abnormal distribution of hearth temperature, and adjusting a spatial air distribution strategy of the combustor. And after the correction coefficient is subjected to multi-stage buffer smoothing, a fuel control instruction is output to an executing mechanism. And switching to steady state control after the boiler reaches the preset load. The method adapts to the characteristics of a power plant unit, so that the starting process is more stable, the damage to a heated surface and pollutant emission are reduced, and rapid grid connection is assisted.

The invention provides a coordination control method and device of a photovoltaic energy storage inverter for automobile charging based on artificial intelligence, and belongs to the technical field of automobile photovoltaic energy storage coordination control, and the method comprises the steps: monitoring the output power of a photovoltaic array, the state of charge (SOC) of an energy storage system, the state of a power grid and the power demand of a load in real time; a reinforcement learning algorithm is introduced, weather forecast and historical load data are combined, photovoltaic output and load demands in a future time period are predicted, and a power distribution instruction is generated; deciding a current operation mode and generating a mode switching instruction; seamless switching between grid connection and grid disconnection is controlled, and after switching is completed, the charging and discharging proportion of the lithium battery and the super capacitor is coordinated; integrating the energy storage real-time state and the power distribution instruction, and optimizing and adjusting the control parameters of the inverter in real time; continuously monitoring a running state and a switching process, and starting a standby mode when a fault is detected; and the data is uploaded to a monitoring platform. The system operation is efficiently optimized, the service life is prolonged, and stability is guaranteed.

The present application relates to the technical field of wind power generation, and discloses a control method and apparatus for a grid-forming doubly-fed wind turbine generator, a generator, and a medium. In embodiments of the present application, a current reference value of a grid connection point is determined on the basis of measurement parameters of the grid connection point in combination with an internal potential parameter of a grid-forming doubly-fed wind turbine generator and a virtual impedance reference value, a voltage reference value of a grid-side converter is further determined on the basis of the current reference value of the grid connection point, and the grid-side converter is modulated on the basis of the voltage reference value, thereby implementing closed-loop control of the grid-side converter, such that a difference between an output voltage value and the voltage reference value of the grid-side converter is less than a preset threshold.

The invention relates to the technical field of power management, in particular to a multi-source data fusion photovoltaic power scheduling control system, which comprises a sensing extraction module, a disturbance identification module, an offset trend analysis module, a path switching module and a frequency band suppression module. According to the method, a disturbance pre-judgment interval is identified by constructing a time derivative sequence and combining illumination and wind speed trend change in a continuous period, a disturbance time period is accurately discriminated, the disturbance interval is confirmed and disturbance characteristics are extracted through conjoint analysis of photovoltaic and energy storage current change trend and grid-connected point fluctuation amplitude, and the disturbance accuracy is improved. An offset trend curve is formed by calculating photovoltaic and energy storage current change differences, the energy supply offset degree is judged in real time to trigger scheduling conditions, dynamic suppression adjustment is performed on regulation and control signal parameters according to spectrum energy distribution, the accuracy and timeliness of disturbance recognition, energy supply offset judgment and frequency band regulation and control are improved from multiple levels, and the energy storage and energy supply efficiency is improved. And more stable and efficient optical storage combined scheduling control is realized.

The invention belongs to the field of stability analysis of a grid-connected system of a grid-building converter, and particularly relates to a grid-building converter grid-connected resonance risk analysis method considering virtual impedance, which comprises the following steps: S1, establishing a three-phase time domain differential equation and simplifying the equation into a single-phase equivalent time domain model; converting into a harmonic state space model of the main circuit; s2, constructing a harmonic state space model of a control system comprising an active power control loop and a reactive power control loop; s3, introducing a virtual impedance control link, and correcting the voltage amplitude reference phasor output by the reactive power control loop; deriving an expression of a modulation signal disturbance phasor; s4, obtaining a complete frequency domain admittance model YGSC of the network construction converter considering the influence of the virtual impedance; an open loop gain TGFM of the grid converter grid-connected system is constructed; and S5, drawing a Nyquist curve based on TGFM, and carrying out resonance risk determination. According to the method, the interaction dynamic characteristics of the network building converter and the power grid under the influence of the virtual impedance can be accurately represented, and the resonance risk of the grid-connected system is evaluated.

The invention relates to the technical field of new energy grid connection, in particular to a new energy grid-connected inverter system based on a double-stator synchronous motor interface, which comprises a three-phase inverter and a double-stator synchronous motor, the double-stator synchronous motor comprises a first stator, a rotor and a second stator. Planar air gaps exist between the rotor and the first stator and between the rotor and the second stator. The rotor comprises a first rotor and a second rotor which are rigidly connected, the first rotor is axially adjacent to the first stator, the second rotor is axially adjacent to the second stator, and a magnetic isolation ring is arranged between the first rotor and the second rotor; each of the first stator and the second stator comprises a stator core and an armature winding, the first rotor comprises a first rotor core, an excitation winding and a starting winding, and the second rotor comprises a second rotor core and a permanent magnet. According to the invention, the double-stator configuration can realize voltage transformation and frequency conversion functions, and can solve the problems of reduced power grid inertia, insufficient short-circuit capacity, aggravated broadband oscillation risk and the like caused by grid connection of large-scale new energy through power electronic equipment.

The invention discloses a power load prediction and energy storage optimization control method and system, belongs to the technical field of power system energy storage optimization control, and aims to solve the problems that the reaction is slow, the charging and discharging mode is not optimized enough and the risk of countercurrent cannot be pre-judged in advance due to the fact that reverse power transmission to a power grid is prevented through detection of an anti-countercurrent electric meter in an existing anti-countercurrent method. Based on historical load data, environmental data and time features, a time sequence deep learning model fused with an attention mechanism is utilized to output a future multi-time-scale user net load prediction result in a rolling manner, and whether a grid-connected point power prediction value is smaller than a dynamic countercurrent threshold value or not is judged so as to identify a countercurrent risk. And if the risk exists, establishing a countercurrent avoidance optimization model, otherwise, establishing a conventional scheduling optimization model, performing rolling solution by adopting an efficient solution algorithm to obtain an optimal charging and discharging power instruction sequence, performing electric energy quality evaluation and correction, and then issuing the optimal charging and discharging power instruction sequence to the energy storage converter for execution, thereby realizing pre-judgment of the countercurrent risk in advance and optimization of energy storage charging and discharging behaviors.

The invention belongs to the field of power system control, and discloses a direct-driven wind turbine generator network type-following network type dual-mode switching control method and system based on network side-machine side converter control conversion. According to the method, on the basis that grid-connected stability of the direct-driven fan is maintained, the control capability of a grid-side converter and a machine-side converter is fully combined, and the control capability of the direct-driven fan as a voltage source and a current source is excavated, so that when a voltage short-circuit ratio is changed due to access of large-scale new energy, the voltage short-circuit ratio is changed. The grid-connected flexibility and control free undisturbed switching of the direct-driven fan can be realized, and the grid-connected stability and adaptive capacity of the direct-driven wind power plant are improved.

The invention relates to the technical field of power system grid connection, in particular to an AI-based distributed photovoltaic power station grid connection access capacity evaluation optimization method, system and device and a storage medium. The method comprises the following steps: acquiring topological structure parameters of a power grid, line parameters and historical operation data of a photovoltaic power station, identifying voltage out-of-limit nodes and line overload nodes by simulating the operation state of the power grid under multi-stage access capacity, and determining the bearing capacity boundary of the power grid; time sequence fluctuation characteristics of photovoltaic output are extracted, meteorological data of irradiation intensity, temperature and cloud cover are combined, a photovoltaic output fluctuation range is predicted through an AI algorithm, and an access capacity constraint condition is obtained; analyzing the matching relationship between the power grid regulation resource capacity and the photovoltaic output fluctuation amplitude, calculating the up-regulation margin and the down-regulation margin of the power grid, and determining a capacity safety margin threshold by combining the occupation degree of the photovoltaic access capacity on the regulation resource; and generating an optimal access capacity scheme by integrating a power grid operation state, photovoltaic output prediction and economic benefits through an AI intelligent algorithm.

The invention provides a system platform and method for checking adjustment characteristics of a control system based on semi-physical simulation, and belongs to the technical field of power system control equipment detection. The system comprises an all-digital real-time simulation system (ADPSS), a water turbine governor to be tested, a physical interface communication module, a wave recording device and a signal interaction module. A full-electromagnetic example model constructed based on PSASP is built in the ADPSS, a closed-loop detection environment is constructed through the physical interface communication module and a water turbine governor to be detected, bidirectional signal transmission is achieved through the signal interaction module, and key parameters are recorded through the wave recording device. The method comprises the steps of simulation environment establishment, signal interactive transmission, multi-dimensional detection and check and result judgment and output. According to the method, multi-dimensional checking of the speed regulator acquisition and display function, the transfer function consistency, the grid-connected performance and the like and power grid stability influence verification can be completed without field installation, the coverage scene is comprehensive, the checking precision is high, and the method is suitable for performance detection of different types of speed regulators and has remarkable practical value.

The invention discloses a configuration method and system for a network-constructing type energy storage system for suppressing broadband oscillation, and relates to the technical field of new energy power generation grid connection and power system stability control. The invention aims to solve the problems that broadband oscillation is easily caused when a new energy field station is connected into a weak power grid, an existing suppression method affects equipment characteristics or needs additional investment, and netting type energy storage locating and sizing lacks scientific guidance. The method comprises the following steps: firstly, simplifying a system comprising a new energy station, a constructed network type energy storage system and a power grid, then carrying out impedance modeling on the two systems (reserving complete impedance characteristics of energy storage), and judging the stability through an impedance analysis method; and the optimal capacity is determined at a single position, and then the global optimal capacity and the corresponding position are determined by traversing the positions, so that low-cost broadband oscillation suppression is realized.

The invention relates to the technical field of offshore wind power grid connection, in particular to a low-frequency oscillation suppression method for an offshore wind power synchronous machine grid connection system, which comprises the following steps: acquiring inherent parameters of the synchronous machine grid connection system and active power reference instructions of each fan of an offshore wind power plant; according to the inherent parameters, control parameters of a preset damping controller are determined, and the damping controller is configured based on the control parameters; acquiring an actual operation frequency signal of the offshore low-frequency power grid in real time, and comparing the actual operation frequency signal with a preset rated frequency of the offshore low-frequency power grid to obtain a frequency deviation signal; inputting the frequency deviation signal into a configured damping controller, and outputting a damping power instruction; and superposing the damping power instruction and the active power reference instruction to generate an active power control instruction. According to the invention, the low-frequency oscillation of the new energy synchronous machine grid-connected system can be effectively suppressed, and meanwhile, the situation that the grid-connected safety is threatened due to the great fluctuation of the terminal voltage of the motor caused by suppression measures is avoided.

The invention discloses an improved flexible direct current fault control method for improving current differential protection adaptability, and belongs to the technical field of power system relay protection and new energy power generation system grid-connected control. The method comprises the following steps: detecting a voltage drop abrupt change signal and a negative sequence voltage signal of a flexible DC output end, and starting a control strategy when the signals are satisfied; detecting a terminal voltage signal and active power of a new energy sending-out terminal, and calculating a new energy side current phase angle and a power angle; calculating a flexible DC side current phase angle control value and a negative sequence dq axis current reference value based on the parameters; and controlling the flexible DC side to output a negative-sequence current corresponding to the negative-sequence dq-axis current reference value, so as to actively adjust the current phase of the flexible DC side, reduce the phase angle difference between the fault current of the flexible DC side and the fault current of the new energy side, and discriminate the internal and external faults of the region through traditional current differential protection. According to the invention, the degree of freedom is controlled and the current phase is adjusted by using the flexible direct-current side negative-sequence current to reduce the phase angle difference of the two sides, so that the problem that the current differential protection adaptability in the double-end weak feedback system is reduced is solved, additional hardware is not needed, and the power grid safety and the new energy stable grid connection are ensured.

The invention discloses a wind power plant voltage and frequency cooperative tuning control method, and relates to the technical field of tuning control, and the method comprises the steps: obtaining the real-time operation data of a wind power plant, carrying out the preprocessing of the real-time operation data of the wind power plant, carrying out the voltage fluctuation and frequency disturbance prediction through a cellular automaton model in combination with the pre-obtained power grid data, and carrying out the voltage fluctuation and frequency disturbance prediction. Obtaining a prediction state matrix; carrying out multi-objective optimization solution in combination with a pre-constructed multi-objective optimization problem and constraint conditions, and obtaining an optimal droop coefficient vector in combination with a preset rule; and the optimal droop coefficient vector is used as a control reference, and voltage and frequency cooperative tuning is carried out in combination with grid-connected point voltage and frequency obtained in real time and communication network topology data. According to the method, prediction is carried out through the cellular automaton model, the rapid and cooperative regulation capability of the voltage and the frequency of the wind power plant is improved, and therefore the urgent demand of a power system for rapid, accurate and cooperative control under the access of high-proportion new energy is better met.

The invention provides an anti-countercurrent control system and method based on transformer area flexible direct current interconnection, belongs to the technical field of power distribution network and new energy fusion control, and is suitable for direct current flexible interconnection and green energy collaborative utilization of heterogeneous transformer areas such as expressways, parks and urban and rural fusion areas. The system comprises an energy route management module, a transformer area capacity marking module, an energy monitoring module, a flexible direct current interconnection scheduling module, an anti-countercurrent module and an intelligent scheduling strategy module, and the control method comprises the steps of initializing the state of a transformer area, collecting data in real time, judging redundant power and scheduling the redundant power to the transformer area without power generation / grid connection capacity, and executing an anti-countercurrent strategy. And parameters and strategies are optimized based on an intelligent self-learning mechanism. The method achieves the preferential local consumption of new energy, prevents power countercurrent, guarantees the safety of a power grid, improves the adaptability and economical efficiency of the system, and is adaptive to a complex multi-source distributed energy scene.

The invention discloses a quantum double-ring cooperative current measurement device and method, and belongs to the technical field of electric measurement. The device comprises an outer ring unit used for measuring a high-frequency signal in current; the inner ring unit is used for measuring a low-frequency signal in the current; the digital signal processing unit is used for carrying out synchronous high-speed ADC sampling on the high-frequency signal measured by the outer ring unit and the low-frequency signal measured by the inner ring unit, carrying out fast Fourier transform on the sampled signal and converting the sampled signal into a frequency domain to obtain a VTMR (f) signal and a delta fNV (f) signal, and calculating the VTMR (f) signal and the delta fNV (f) signal to obtain the VTMR (f) signal and the delta fNV (f) signal. And reconstructing the full-band current waveform of the time domain. According to the invention, the measurement accuracy and reliability of the current sensor in broadband, high harmonic and strong interference scenes can be significantly improved, and the method is suitable for the fields of new energy grid connection, flexible direct current transmission, power grid protection, high-precision measurement and the like.

The invention is applicable to the technical field of electrical systems, and provides a new energy access-oriented real-time power grid dynamic constant value checking method, which comprises the following steps of: constructing a full model by acquiring multi-aspect data of a power grid, generating various research state operation modes, and calculating setting parameters by adopting an iterative algorithm considering a new energy short-circuit characteristic, so that the real-time dynamic constant value checking of the power grid is realized. The sensitivity and selectivity of the protection setting value can be accurately checked in real time. Compared with an existing static checking mode, the implementation mode of the invention can adapt to dynamic changes of a power grid operation mode after new energy access, timely discover potential problems of a protection constant value in a new energy environment, generate early warning information and a constant value recommendation interval, effectively avoid failure of the protection constant value, improve reliability and safety of a power grid protection system, and improve the safety of the power grid protection system. Stable operation of the power grid under the condition of new energy high-permeability grid connection is guaranteed, the problem that the prior art cannot adapt to new energy dynamic changes, and consequently a protection constant value may fail is solved, and powerful support is provided for safe operation of the power grid.

The embodiment of the invention discloses a negative damping elimination method, device and equipment based on SVG and a storage medium, and the method comprises the steps: carrying out the impedance scanning of the SVG in a range of 1-3000Hz, obtaining the positive-sequence impedance and negative-sequence impedance of the SVG under different operation conditions, and determining the leading operation condition of the SVG impedance; determining the positive sequence equivalent impedance and the negative sequence equivalent impedance of the SVG grid-connected point according to the positive sequence dominant impedance and the negative sequence dominant impedance of the SVG under the dominant operation condition; determining the value ranges of the positive sequence damping correction value and the negative sequence damping correction value of the SVG; the maximum value of the intersection of the two value ranges is determined as SVG compensation damping, and the SVG compensation damping is merged into an SVG grid-connected point port; according to the scheme, only two unknown parameters including the positive sequence damping correction value and the negative sequence damping correction value are involved, the parameters can be calculated based on an analytic formula pure algebraic equation, the calculation mode is simple, the port impedance characteristic negative damping of the SVG in the full frequency band within the range of 1-3000 Hz can be eliminated, and the problem of high-frequency oscillation is thoroughly solved.

The invention relates to the technical field of distributed energy grid-connected control, in particular to an intelligent monitoring ball enhanced distributed power supply coordination pre-synchronization control method and system, and the method comprises the steps: deploying a master intelligent monitoring ball at a grid-connected point, deploying slave intelligent monitoring balls at the output ends of all distributed power supplies, and forming a star-shaped sensing network; based on a multi-objective optimization algorithm, calculating a pre-synchronization target parameter and an adjustment weight of each distributed power supply, and generating a coordination control instruction; the virtual synchronous motor module receives the coordination control instruction, dynamically adjusts a virtual inertia and a damping coefficient, and adjusts output voltage, frequency and phase through a pre-synchronization execution unit; and after the synchronization reaches the standard, sequentially closing the grid-connected switches according to a preset power supply response priority sequence to complete the grid-connected action. According to the invention, a technical architecture of global monitoring-coordinated decision-precise execution-closed loop optimization is constructed, so that the stability and precise control problem during high-permeability distributed energy grid connection is solved.

The invention discloses a distributed photovoltaic grid-connected and off-grid coordination control method. The method comprises the following steps: a photovoltaic data acquisition terminal acquires an operation state data set of a photovoltaic array, an inverter and the like through each node sensor and intelligent equipment; the photovoltaic data preprocessing terminal performs denoising, normalization and the like on the original data to form a standardized data set; the data analysis terminal calculates a power balance equal coefficient, inputs the power balance equal coefficient into the decision model and outputs a grid-connected and off-grid coordination index; the coordination control terminal judges a grid-connected operation mode or an off-grid operation mode according to the index; the energy management terminal coordinates the power output of each unit during grid connection, and optimizes an energy storage charging and discharging strategy during off-grid; the state monitoring terminal performs real-time monitoring, discovers abnormal early warning and triggers fault processing; according to the method, the operation stability and the energy utilization efficiency of the photovoltaic system are improved.

The invention discloses a grid-connected control method and system based on a three-port energy router. The grid-connected control system comprises a photovoltaic power generation system, an energy storage system and a grid-connected inverter system, the photovoltaic power generation system adopts a perturbation and observation method and is used for performing photovoltaic maximum power generation; the energy storage system comprises a storage battery, adopts direct current bus voltage stabilization control, and is used for performing peak load shifting of energy and maintaining the direct current bus voltage; the preceding stage of the grid-connected inverter system adopts fuzzy VSG + pre-synchronization control so as to realize grid-connected and off-grid seamless following and provide voltage support; the post-stage of the grid-connected inverter system adopts double closed-loop + optimization compensation control, performs power regulation and control through weighted cooperation with a VSG double closed-loop system, and is responsible for long-term energy balance. According to the invention, photovoltaic maximum power tracking, energy storage charging and discharging coordination and grid-connected and off-grid seamless switching are realized, and the method is suitable for distributed power supply grid connection, a DC micro-grid and a novel power distribution system.

The invention discloses a pre-synchronization control method for a network-building converter based on a virtual synchronous generator, and the method comprises the steps: collecting the three-phase voltage of the output end of the virtual synchronous generator VSG and the three-phase voltage of a power grid side, converting the three-phase voltage into a voltage component in a two-phase static coordinate system through Clark conversion, and extracting a positive-sequence component; calculating a phase difference compensation coefficient based on the positive sequence component; based on the phase difference compensation coefficient, adaptively setting a PI parameter; and calculating and adjusting the amplitude of the internal potential to finish pre-synchronization. In the working process, through self-adaptive PI parameter setting and amplitude accurate judgment, the pre-synchronization time is shortened, the grid-connected impact current is reduced, and the grid-connected success rate of the micro-grid in a weak grid scene is improved.

The invention relates to the technical field of photovoltaic inverter grid connection, and discloses a photovoltaic panel assembly insulation impedance fault positioning method, a storage medium and a system. Comprising the steps of collecting voltage between positive and negative electrodes of an inverter under first voltage, voltage to ground of the negative electrode of the inverter and a direct-current component of leakage current of an output end, close to a power grid side, of the inverter; collecting the voltage between the positive electrode and the negative electrode of the inverter under the second voltage after voltage disturbance, the voltage to ground of the negative electrode of the inverter and the direct-current component of the leakage current of the output end, close to the power grid side, of the inverter; calculating a first insulation resistance value corresponding to the plurality of photovoltaic panel assemblies under the first voltage, and calculating a second insulation resistance value of the plurality of photovoltaic panel assemblies under the second voltage; and according to the first insulation resistance value and the second insulation resistance value, positioning the photovoltaic panel assembly with the insulation resistance abnormity. According to the invention, the accurate positioning of the insulation fault of the photovoltaic panel assembly level is realized, and the specific photovoltaic panel assembly with the insulation abnormity can be accurately identified from the series photovoltaic string.

The invention discloses a dispatching method and system based on a distributed diesel generator and a virtual power plant, and relates to the technical field of power systems and energy internet. Comprising the steps that a local control unit establishes an operation constraint model containing a nonlinear fuel efficiency and carbon deposition risk model, and generates a health recommendation domain; the cloud end generates a triple scheduling instruction packet containing reference power, offset bandwidth and weight vectors in combination with power grid constraints; identifying the impedance of a grid-connected point on line at the edge side, and carrying out asymmetric compression correction on the bandwidth based on the voltage sensitivity under a weak grid; and the local unit performs rolling optimization solution under the double constraints of the corrected instruction and the local model, and switches to the anti-carbon deposition autonomous mode containing dummy load input when the communication is interrupted and the carbon deposition risk is high. According to the invention, through cloud-side-end cooperation and hierarchical closed-loop correction, the conflict between the weak network voltage out-of-limit risk and the low-load carbon deposition of the unit is effectively solved, and the safety and the performability of scheduling are improved.

The invention provides a data-driven multi-target control method, device and system based on model prediction, is applied to a three-phase three-level neutral point clamped converter, and aims to realize dual accurate control of switching frequency and neutral point voltage. According to the method, a switch weight factor and a neutral point voltage weight factor are used as inputs, and an average switch frequency in a fixed sliding window time and a neutral point voltage maximum value in another fixed sliding window time are used as outputs; and constructing an equivalent dynamic linearization data model under each dynamic working point of the closed-loop system by adopting a tight-format dynamic linearization method. Based on the data model, a data driving controller is elaborately designed to realize accurate regulation and control of the switching frequency and the maximum value of the neutral point voltage. The method has a high practical value and a wide application prospect in typical application scenes of power electronics and power transmission, such as grid connection and motor driving.

The invention relates to a frequency domain modeling method, device and equipment for a serial DR-MMC port and a medium, and the method comprises the steps: injecting current disturbance at the serial DR-MMC port, carrying out the measurement equivalence of a response quantity at a grid-connected point according to a preset grid-connected interface equivalent parameter set, and obtaining low-voltage side current small signals of a DR and an MMC; according to the low-voltage side current small signal, performing dual frequency domain transformation on a DR time domain switching function, establishing a DR switching function frequency domain model, and further deriving a DR AC side small signal relationship according to the switching function frequency domain model; constructing a DR frequency domain sub-model, an MMC frequency domain sub-model and a direct current frequency domain sub-model based on the relationship between the low-voltage side current small signal and the alternating current side small signal and in combination with device alternating current and direct current constraints, MMC loop control constraints and direct current network equivalent constraints; and assembling the DR frequency domain sub-model, the MMC frequency domain sub-model and the DC frequency domain sub-model at the grid connection point to obtain a frequency domain model of the AC port. The method has the effect of improving the characterization accuracy of the frequency domain characteristic of the grid-connected point port in the broadband range.

The invention discloses a vehicle-mounted charging and discharging system and method based on a V2G technology, and relates to the technical field of electric vehicle charging and discharging. The system comprises a power grid interaction module used for performing power grid connection confirmation, overcurrent protection, leakage protection and grid-connected synchronous detection; the man-machine interaction module is used for displaying a charging and discharging setting interface and battery state information and supporting remote operation of a user; the communication module is used for realizing information interaction with an external power grid dispatching center and a cloud management platform; the vehicle-mounted charging and discharging module is used for adjusting charging and discharging voltage and current of a vehicle power battery; the battery management module is used for collecting state parameters of a vehicle power battery and controlling and protecting the charging and discharging process. The control center module is used for monitoring battery parameters, receiving a user instruction and an external power grid dispatching signal, predicting the power of a vehicle power battery and generating a charging and discharging plan. The method can improve the flexibility and economy of the electric vehicle participating in the power grid interaction, guarantees the safety of the battery, and prolongs the service life of the battery.