679 results about "Grid connected inverter" patented technology

Disclosed in the present invention are a grid-connect control method and apparatus for a grid-connect inverter. The method comprises: on the basis of a control structure of a grid-connect inverter in a dp domain, passing a deviation signal of a power outer loop through power outer loop controllers, so as to generate reference values of a current inner loop, and comparing the reference values of the current inner loop with an actual output current, so as to obtain error signals, wherein the control structure comprises a PQ power control outer loop and a current control inner loop, and the actual output current is obtained by means of performing phase tracking, on the basis of a synchronous reference frame phase-locked loop, on the voltage of a point of common coupling; and adjusting the error signals by means of a current inner loop controller, so as to generate modulation signals, performing pulse width modulation (PWM) on the modulation signals, so as to generate an on-off signal of an inverter bridge power semiconductor device, and controlling the state of connection and disconnection between the grid-connect inverter and a power grid on the basis of the on-off signal. In the present embodiment, the connection and disconnection between a grid-connect inverter and a power grid are controlled, so as to improve the stability of the grid-connect inverter in weak power grids.

Disclosed in the present invention are a voltage control method and system for clusters of a power distribution network having a high proportion of photovoltaics. The method comprises: acquiring parameters of a power distribution network, and constructing a comprehensive electrical distance by means of adjustable active power and reactive power reserves of each node in the parameters of the power distribution network; forming an improved weight matrix by means of distributed photovoltaic reactive power and active power supporting capacities, a reactive power sensitivity matrix and an active power sensitivity matrix, and obtaining an optimal reactive power cluster and active power cluster division result by a community algorithm by means of a node coupling degree index in each cluster and the comprehensive electrical distance; and selecting, by means of a clustering algorithm on the basis of the division result, a key node in each cluster to act, to improve the cluster voltage regulation and control capability. Starting from the relationship between active power sensitivity and reactive power sensitivity, and considering the impact of different changes on other nodes, efficient utilization of the reactive power regulation capability of a grid-connected PV inverter can be achieved, the complexity of control strategy computation is greatly reduced, and the situation where there are too many adjustable distributed photovoltaics in clusters is avoided.

A passivity-based dual-mode integrated control method for a grid-connected inverter (GCI) is provided. In view of the insufficient robustness of the conventional single-mode GCI in a high-impedance and low-inertia weak grid, and the problem of wideband oscillation of the grid voltage and grid current or even system instability in nonlinear application scenarios such as grid structure / parameter variation, and plug-and-play of the inverter, the dual-mode integrated control method performs modeling on the GCI based on a port-controlled Hamiltonian (PCH) model, thereby obtaining integrated control with a weighted passivity-based feedback control law for the GCI based on a grid-following (GFL) mode and a grid-forming (GFM) mode. Based on the dual-mode integrated control method, the stable operation of the GCI in severe grid conditions with large fluctuation of the impedance, and desirable robustness of the GCI in nonlinear working scenarios can be ensured.

The embodiment of the invention discloses a midpoint potential control method based on a diode clamping type three-level grid-connected inverter and a related device. The method comprises the following steps: generating an initial three-phase modulation wave through a current loop closed-loop control method according to a collected three-phase current value and a three-phase voltage value of a power grid side of the diode-clamped three-level grid-connected inverter; according to an initial modulation waveform generated by the initial three-phase modulation wave, a three-phase current value and an acquired voltage value of a voltage dividing capacitor at the direct current side of the diode clamping type three-level grid-connected inverter, calculating a zero-sequence component required by neutral-point potential balance; superposing a zero-sequence component required by neutral-point potential balance with the initial modulation waveform to obtain a final modulation wave; and generating a driving signal matched with each phase of bridge arm in the diode clamping type three-level grid-connected inverter according to the final modulation wave. By adopting the invention, the neutral-point voltage can be balanced, the distortion of the output waveform at the alternating current side is reduced, the voltage stress of the device is reduced, and the service life of the power device is prolonged.

The embodiment of the invention provides a grid-connected inverter control mode switching method and device, equipment, a medium and a product, and is applied to the technical field of electrical control. The method comprises the following steps: acquiring a control mode switching signal of the grid-connected inverter, and determining a switching direction of a control mode based on the switching signal; when the switching direction indicates that the current control mode is switched from the GFL mode to the GFM mode, setting an initial value of an integrator of a power synchronization loop of the GFM mode as a phase angle value of a phase-locked loop corresponding to the GFL mode; switching the control mode from the GFL mode to the GFM mode based on a first preset path and a step-by-step switching mode; when the switching direction indicates that the current control mode is switched from the GFM mode to the GFL mode, acquiring a power steady-state output value of the GFM mode, and setting a power reference value of the GFL mode as the power steady-state output value; and switching the control mode from the GFM mode to the GFL mode based on the second preset path and the step-by-step switching mode. The technical effect of improving the control mode switching fluency is achieved.

The invention discloses a grid-connected inverter parameter optimization method based on an improved genetic particle swarm algorithm. The grid-connected inverter parameter optimization method comprises the following steps: constructing a target function; performing population position initialization; calculating a fitness value of each particle at an initial moment, recording an optimal solution, and storing initial global optimal particle and individual optimal particle information; random disturbance is added to the speed and the position of the particles; updating the speed and the position of the particle; performing multi-point crossover and mutation operation; according to the current optimal solution, carrying out local domain search by adopting a fine search mode based on Laplacian distribution and carrying out global neighborhood search by adopting a search mode based on Cauchy distribution; and checking convergence conditions, if convergence occurs, outputting an optimal solution, and obtaining optimal parameters of the grid-connected inverter system. The method has the remarkable effects that by optimizing three key parameters in a control system and utilizing a nonlinear dynamic strategy to enhance the global search capability and the convergence speed of the algorithm, various defects in the prior art can be overcome.

Aiming at the stability problem caused by harmonic resonance of multiple parallel photovoltaic inverters, the invention provides a parallel inverter micro-grid-oriented adaptive virtual impedance remodeling harmonic resonance suppression method, which comprises a virtual impedance remodeling unit of a grid-connected inverter, a parameter adaptive adjustment unit and a power grid impedance online detection unit. The virtual impedance remodeling unit can improve the output impedance characteristic of the grid-connected inverter and inject a certain damping component into the micro-grid; and the parameter adaptive adjustment unit adaptively adjusts control parameters in the virtual impedance remodeling unit and the current adjustment controller according to the impedance parameters of the power grid so as to maintain the stability of a system control loop. The power grid impedance online detection unit provides power grid equivalent impedance as the input of the parameter adaptive adjustment unit. The three units work cooperatively to form a self-adaptive virtual impedance remodeling multi-inverter micro-grid harmonic resonance suppression strategy, so that the characteristics of a current loop are improved, the inverters can be kept stable under various grid impedance conditions, and the reliability of a multi-inverter micro-grid system is improved.

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 a photovoltaic auxiliary greenhouse cultivation system which comprises a greenhouse body composed of a framework system and a photovoltaic ceiling, and the photovoltaic ceiling is laid on the top of the framework system, provided with a light splitting type solar thin film cell panel set with adjustable light transmittance and laid in a partitioned mode according to the illumination requirement. The dynamic light compensation system, the temperature balance system and the energy storage system are arranged at the top of the framework system, the energy storage system is used for storing energy and supplying power, the dynamic light compensation system is used for supplementing light for each indoor crop area according to photosynthetically active radiation and sun illumination conditions, and the temperature balance system is used for ventilating and humidifying the greenhouse; and the control machine is arranged on the greenhouse main body and is electrically connected with the dynamic light compensation system, the temperature balance system and the energy storage system so as to receive the monitoring data and control the operation of each electric appliance element. According to the system, lithium battery energy storage and a grid-connected inverter are integrated, the energy self-sufficiency rate is optimized, and the space utilization rate is increased through spectrum customization and three-dimensional planting; the method is suitable for tilled land shortage areas, and gives consideration to clean energy production and agricultural efficient output.

The invention provides a power grid connection disturbance observer feedback control method, which belongs to the technical field of power grid connection, and comprises the following steps: detecting power grid impedance parameters by using a multi-frequency harmonic injection technology, designing a disturbance observer algorithm to establish a state equation set, and constructing a nominal inverter model by using a low-pass filter; the total disturbance amount is estimated in real time by comparing the difference value between the actual current output and the nominal model output, a feedback control strategy is constructed, the disturbance estimation value serves as a feedforward compensation signal to be superposed to the current controller output, and disturbance components in different frequency ranges are processed in a classified mode according to disturbance types. A disturbance observer bandwidth parameter and a filter cut-off frequency are set, a disturbance estimation value is compensated to a current control loop in real time through a feedforward compensation signal to suppress the influence of power grid disturbance on the grid-connected current, and the technical problem that it is difficult to accurately estimate and compensate the influence of power grid disturbance on the grid-connected inverter in real time is solved.

The invention relates to a design and parameter setting method for an active power controller of a network construction type converter. The method comprises the following steps: determining performance index requirements of the active power controller of the network construction type converter; according to performance index requirements and an automatic control principle, a mathematical model of an active power loop of a grid-connected inverter is used as a to-be-corrected object, proper rotational inertia and damping coefficient are selected to calculate steady-state gain, and then a controller is designed; according to a Bode diagram of a system open-loop transfer function after the controller is added, verifying whether the controller meets performance index requirements or not; the controller is corrected, a system open-loop transfer function at the moment is regarded as a new object to be corrected, and a correction network is designed according to frequency domain characteristics of the new object to be corrected; and correcting the new to-be-corrected object by adopting the correction network to obtain the final active power controller of the network construction type converter. According to the method, the active power controller meeting the performance index requirements is efficiently designed, and a theoretical basis is provided for the design of a control loop of a network-forming converter.

The invention provides a strong series compensation grid-connected stability regulation and control method of a grid-forming type energy storage converter and a related device, and belongs to the technical field of grid connection of a power grid. According to the method, a three-phase grid-connected inverter complete sequence impedance model controlled by the virtual synchronous generator is established by using a harmonic linearization method, and reasons for causing subsynchronous oscillation by using a double-closed-loop control strategy are analyzed. In order to improve the grid-connected stability of a strong series compensation power grid of a grid-forming type energy storage converter, a PI-LADRC control strategy is provided, a sequence impedance model under the control mode is established, and grid-connected stability margin information under the PI-LADRC control strategy is obtained by comparing output impedance characteristics of a grid-connected inverter under a double closed-loop control mode and a PI-LADRC control mode. According to the invention, the PI-LADRC control strategy is adopted, so that the grid-connected stability can be effectively regulated and controlled.

The invention discloses an impedance remodeling method for suppressing harmonic oscillation based on a superconducting magnetic energy storage system, and belongs to the technical field of power generation, power transformation or power distribution. The method comprises the following steps: analyzing theoretical characteristics of the superconducting magnetic energy storage system, analyzing mathematical models and working characteristics of an SMES and a storage battery, and carrying out theoretical modeling on the hybrid energy storage system; the method comprises the following steps: performing small signal modeling on a grid-connected converter control system under voltage control type virtual synchronous control, and establishing a grid-connected converter small signal sequence impedance model; a sequence impedance remodeling model is introduced, the influence of the sequence impedance remodeling model on the low-frequency impedance of the virtual synchronous control system is revealed, in order to obtain the optimal sequence impedance of the grid-connected converter, real-time and accurate power grid impedance information is obtained by injecting a multi-harmonic disturbance signal into the grid-connected inverter, and a traditional impedance remodeling strategy is dynamically adjusted according to the information. It is ensured that the system still has good stability margin when the power grid impedance fluctuates in a wide range, and the adaptability of the grid-connected inverter under different power grid working conditions is improved.

The invention relates to the technical field of power systems, in particular to a power distribution network voltage sag compensation method, system and device and a medium. The method comprises the following steps: monitoring the voltage level of a power distribution network in real time by using a high-precision voltage sensor to obtain voltage data; identifying a voltage sag event based on the acquired voltage data; performing feature extraction on the determined voltage sag event; according to the extracted characteristic quantity, a compensation strategy is dynamically formulated, and the compensation strategy comprises the step of determining the amplitude and duration of compensation; executing voltage compensation through the grid-connected inverter according to the determined compensation strategy, wherein the output of the grid-connected inverter is adjusted according to the impedance change of the power grid and the influence of voltage disturbance; and monitoring the compensated power grid voltage, evaluating a compensation effect, and feeding back an evaluation result to optimize a subsequent compensation strategy. According to the invention, the voltage sag event can be rapidly and accurately detected, and an effective compensation strategy is formulated for compensation.

The invention discloses a grid-connected inverter complementary sliding mode control method based on a cascade generalized proportional-integral observer, and the method comprises the steps: firstly building a mathematical model of a grid-connected inverter, and enabling the mathematical model to be used for the design of a controller; and a cascade generalized proportional integral observer is introduced to estimate the lumped disturbance of the hyper-local model so as to improve the anti-disturbance capability and the noise suppression capability of the system. By introducing the complementary sliding mode controller, compared with a traditional sliding mode, the position tracking error is reduced by half. By introducing the improved reaching law, a large reaching speed can be kept when the system state is far away from the sliding mode surface, and the sliding mode reaching speed is weakened when the system state approaches the sliding mode surface, so that the chattering phenomenon of the sliding mode is reduced. According to the control method, the coupling influence of the d axis and the q axis can be obviously inhibited, the harmonic content of the three-phase current is reduced, and stable operation of the grid-connected inverter is facilitated.

The invention provides a grid-connected inverter impedance detection method based on an L-shaped filter, and belongs to the technical field of grid-connected inverter impedance detection. A multi-frequency-point disturbance signal is injected into a preset grid-connected inverter working point, time domain data of inverter side current and common coupling point voltage are collected, fast Fourier transform analysis is carried out on the collected data, amplitude and phase information corresponding to each injection frequency point is extracted, and a frequency domain feature vector matrix is established; and establishing a frequency compensation matrix model to compensate and correct high-frequency band measurement data based on a frequency characteristic attenuation vector, calculating to obtain optimal estimated values of power grid impedance and grid-connected inverter output impedance, performing error analysis and precision verification on an impedance detection result, and outputting a verified impedance parameter value. The technical problem of insufficient power grid impedance detection precision caused by high-frequency band attenuation of the L-shaped filter is solved.

The invention discloses a grid-connected inverter fault diagnosis method based on dynamic response, and particularly relates to the technical field of grid-connected inverter fault diagnosis, and the method comprises the steps: decomposing a dynamic response signal of a grid-connected inverter through fractional order wavelet transform, dynamically adjusting a fractional order parameter based on weak power grid impedance estimation, screening a sub-band signal through Tsallis entropy, and carrying out the fault diagnosis of the grid-connected inverter. Generating a time-frequency characteristic tensor; processing the time-frequency feature tensor by adopting dynamic diffusion mapping, and outputting a spectrum embedding vector and an abnormal scale index; analyzing a spectrum embedding vector by using a causal variation auto-encoder, constructing a cross-scale causal graph based on a structural causal model, initializing prior distribution by using a time-frequency feature tensor, and outputting a causal edge weight and a potential feature subset; the potential feature subsets are fused through a physical constraint neural differential equation, a fault feature vector is generated through random perturbation regularization, the fault type and position are output, and the problem that the false alarm rate is high due to insufficient resolution and noise interference under a weak power grid is solved.

The invention relates to the technical field of power electronic converters, and discloses a grid-connected inverter multi-parameter online setting method, system and device and a medium. The method comprises the following steps: establishing a circuit simulation model of the grid-connected inverter; output currents of the grid-connected inverter under different power grid impedance working conditions are obtained through the circuit simulation model, and target control parameters of the grid-connected inverter under different power grid impedance working conditions are obtained through iterative search by adopting a particle swarm optimization algorithm through the circuit simulation model; performing off-line training on the parameter reasoning model through the output current of the grid-connected inverter under different power grid impedance working conditions and the target control parameter under the corresponding power grid impedance working condition; acquiring an output current of the grid-connected inverter in real time, and inputting the output current acquired in real time into the trained parameter reasoning model to obtain a corresponding target control parameter; and on-line setting is performed on the control parameters of the grid-connected inverter through the target control parameters output by the parameter reasoning model, so that rapid setting can be realized.

The invention relates to the technical field of self-synchronizing voltage source control, and discloses a balance current controlled self-synchronizing voltage source control method and system. The method comprises the following steps: acquiring and preprocessing operation data of a grid-connected inverter to obtain active / reactive components of voltage and current of a filter element; generating a three-phase terminal voltage instruction of the self-synchronizing voltage source based on the components, and determining a current instruction signal in combination with the grid-connected voltage; a three-phase modulation signal is generated through adjustment of a PIR controller and coordinate inverse transformation, then a filter inductance value is calculated according to the ripple characteristic of the modulation signal and a switching period, a filter capacitance value is determined by combining resonant frequency, and finally accurate control of the self-synchronizing voltage source is realized according to a filter parameter. By dynamically calculating the matching parameters of the filter inductance and the filter capacitance, the active regulation and control capability of the output impedance characteristic of the inverter is enhanced, and the resonance risk during the impedance change of the power grid is effectively inhibited. The technical problem that the stability is limited due to insufficient impedance regulation and control in the prior art is solved.

The invention discloses a grid-connected inverter control method, system and device and a medium. The method comprises the steps of obtaining a power grid operation parameter, a system power instruction and a direct current bus voltage provided by a photovoltaic side hybrid energy storage system; a virtual inertia parameter is dynamically adjusted through an active-frequency control loop of the virtual synchronous machine in combination with an adaptive inertia algorithm, and a virtual rotor angular speed and an active power reference value are obtained through calculation according to a second-order motion equation of the synchronous generator; in combination with a reactive power instruction, a virtual internal potential amplitude is calculated according to a reactive-voltage droop relation through a reactive-voltage control loop of the virtual synchronous machine; and generating a three-phase voltage reference signal of the grid-connected inverter through synchronous rotation coordinate transformation. According to the invention, the dynamic performance, the operation efficiency and the grid-connected stability of the system under complex working conditions are obviously improved.

The invention discloses a method and system for directly controlling the internal potential of a bridge arm of a new energy grid-connected inverter, belonging to the technical field of grid-connected inverter control. The control method comprises the following steps: obtaining measured values ​​by measuring the port voltage and current of the grid-connected inverter, and calculating instantaneous active and reactive values; obtaining the phase angle reference and amplitude reference of the internal potential of the bridge arm of the grid-connected inverter respectively, and then generating the internal potential reference of the bridge arm; at the same time, estimating the internal potential of the bridge arm of the grid-connected inverter based on the port voltage and current measured values ​​and the grid-connected inverter model by using an observer; finally, using the estimated internal potential as a feedback signal of the closed-loop feedback control of the internal potential, comparing it with the generated internal potential reference of the bridge arm, and sending it to the internal potential controller, thereby obtaining a modulation signal and sending it to the PWM module, so as to realize direct control of the internal potential of the bridge arm of the grid-connected inverter; compared with the existing control method of the grid-connected inverter, the method of the invention improves the dynamic performance of the grid-connected inverter and improves the power quality.

The invention relates to the technical field of grid-connected inverter networking synchronization control, and relates to a networking inverter adaptive synchronization control method considering dynamic performance and stability. The method comprises the following steps: firstly, injecting a harmonic signal with a specific frequency into a power grid from an inverter side, acquiring a voltage and current signal corresponding to the harmonic signal with the specific frequency at a grid-connected point, and calculating to obtain power grid side impedance; then, converting a grid-connected inverter adaptive control optimization problem into a Markov decision process based on the power grid side impedance; and finally, substituting the Markov decision process into a reinforcement learning algorithm framework for reverse training to obtain an optimal control law of the grid-connected inverter based on hybrid synchronous control, and controlling the grid-forming inverter based on the optimal control law. The invention provides the self-adaptive synchronous control method for the grid-forming inverter, which gives consideration to the dynamic performance and the stability, so that an inverter grid-connected system can operate stably, has enough stability margin and also has good dynamic performance.

The invention discloses a composite impedance remolding stability improving method based on power grid voltage feedforward, and the method comprises the steps: connecting a low-pass filter in series in a power grid voltage proportion feedforward link, maintaining the power grid voltage feedforward low-frequency harmonic suppression capability, and improving the phase margin of the output impedance of an inverter in a middle-high frequency band at the same time. And a power grid voltage feed-forward branch for eliminating the negative damping influence of the phase-locked loop is added to a public grid-connected point, so that the stability of the grid-connected inverter is improved, the phase margin of the system is greatly improved, and the grid-connected inverter can still keep higher robust stability when the impedance of the power grid is higher. The stability of the grid-connected inverter is improved when the impedance of the power grid changes in a wide range, the quality of grid-connected current is improved, and the problem that the system is faced with instability after the influence of power grid voltage feedforward and PLL is considered under a weak power grid is effectively solved.

The invention discloses a Cuckoo search algorithm-based grid-connected inverter multi-objective optimization control method, which comprises the following steps of: constructing a three-level grid-connected inverter mathematical model, and calculating to obtain an inverter side current reference value; constructing a current prediction model of the inverter side; constructing a value function control item of the inverter side current by adopting a value function in a square error form; constructing a cost function by taking the neutral-point potential balance and the switching frequency as control items; and iteratively calculating a weight factor by adopting an improved self-adaptive cuckoo retrieval algorithm to realize multi-objective optimization control of the grid-connected inverter. According to the multi-objective optimization control method for the grid-connected inverter based on the cuckoo search algorithm, the problem that the control performance is limited due to the fact that weight factors are difficult to set in multi-objective optimization of the grid-connected inverter in the prior art is solved.

The invention relates to the technical field of photovoltaic grid-connected control, and discloses a data acquisition and control system of a photovoltaic grid-connected inverter. The system comprises an operation environment modeling module which constructs an irradiance discrete state matrix by associating the real-time irradiance of a photovoltaic array, the temperature of a component and voltage and current sampling values at the output end of an inverter; the electrical topology generation module divides a grid-connected node cluster and generates a topology path set based on the identifier and the monitoring point coordinate in the matrix; the fluctuation characteristic analysis module calls the same cluster data and quantifies the response characteristics of the inverter under the fluctuation of the power grid; the strategy control module identifies abnormal points of cross-cluster groups to form an abnormal operation point set; and the coordination output module marks nodes needing to be controlled and generates a cluster coordination control instruction set. The system can comprehensively analyze the influence of environment and power grid factors, achieves the precise coordination control of the inverter cluster, and improves the operation performance of a photovoltaic power generation system.

The invention discloses a two-degree-of-freedom prediction control method of an LCL filtering type three-phase grid-connected inverter system, and belongs to the field of power electronic converter control. A prediction control reference instruction is obtained by sampling parameters of inverter side current, capacitor voltage, network side current and power grid voltage at the moment k, and a continuous and discrete model of an LCL filtering type three-phase grid-connected inverter system is established; designing a control function based on a grid-side current reference tracking error and a gradient thereof, and establishing a prediction model; constructing a prediction cost function based on a control function, and obtaining a prediction control reference instruction by using a minimum value of the prediction cost function; and determining an optimal voltage vector and an action duty ratio according to the prediction control reference instruction, generating a control pulse signal according to a symmetrical five-section pulse mode, and acting on each switching tube in the inverter to realize prediction control of the LCL filtering type three-phase grid-connected inverter system. The method is simple in step, convenient to use, constant in switching frequency and good in stability.

The invention discloses a power distribution control method and device for a photovoltaic hybrid energy storage direct current microgrid based on fuzzy second-order high-pass filtering, and the method comprises the steps: researching the topological structure and working principle of the photovoltaic hybrid energy storage direct current microgrid and the energy management of the microgrid, and obtaining a power balance relation of the direct current microgrid; a comprehensive operation control strategy of the micro-grid is established, and it is determined that a photovoltaic power generation unit adopts maximum power point tracking control of fuzzy control, a grid-connected inverter adopts double closed-loop control of a voltage outer loop and a current inner loop, and a hybrid energy storage unit adopts fuzzy second-order high-pass filtering algorithm control; frequency division distribution and stability of a traditional second-order high-pass filter are studied, so that the second-order high-pass filter based on fuzzy logic is further studied, the SOC of the super capacitor is determined as a control index, and a fuzzy rule of a filtering time constant is adaptively adjusted; the established fuzzy logic variable time constant second-order high-pass filtering control simulates and compares the hybrid energy storage system power, the DC bus voltage and the super capacitor SOC under the variable illumination and load conditions with the fixed constant second-order high-pass filtering control, and compares the change curves of the super capacitor SOC of two strategies under the condition of changing the initial SOC value of the super capacitor. Three-phase current and current total harmonic distortion of the two strategies are compared, and it is verified that the efficiency of a photovoltaic power generation system is improved under the strategies, the SOC of a super capacitor changes within a reasonable range, a micro-grid can stably operate in a grid-connected mode, and grid-connected current harmonic distortion is effectively reduced.

The invention relates to the technical field of photovoltaic three-phase grid-connected inverter fault detection, and discloses a three-phase inverter direct current side grounding weak fault type detection method and system, and the method comprises the steps: S1, carrying out the preprocessing of collected leakage current data, and extracting leakage current mechanism features and leakage current statistical features; s2, constructing a fault feature system based on leakage current mechanism features and leakage current statistical features obtained through preprocessing, and generating a fault classification model; and S3, classifying the test set data by using the fault classification model, and outputting a fault detection result. The method has high identification precision, strong generalization capability and short calculation time, and provides theoretical and technical support for rapid diagnosis of grid-connected inverter direct current side grounding weak faults in practical engineering.

The invention provides a broadband oscillation suppression method and device for a three-phase grid-connected inverter and a medium, and belongs to the field of new energy grid-connected broadband oscillation suppression. According to the impedance characteristic of the three-phase grid-connected inverter, a voltage feedback transfer function is designed, the transfer function is subjected to equivalence, complex coefficients in the transfer function are replaced, and the broadband oscillation suppression of the three-phase grid-connected inverter is achieved. And the method has definite physical significance and realizability. Meanwhile, a digital peak filter is introduced to serve as a frequency component selection channel, a delayer serves as a phase correction channel, a frequency component selection device only allowing a target frequency component to pass through is formed, a designed voltage feedback transfer function is combined, and a complete damping channel with a broadband oscillation suppression effect is formed. According to the channel, only the impedance characteristic of the target frequency can be changed, the impedance characteristic of the non-target frequency band is not influenced, the damping borrowing phenomenon is avoided, meanwhile, the coefficient can be changed according to the oscillation frequency, and full-band broadband oscillation can be suppressed.

The invention relates to the technical field of power electronics, and discloses a power adapter control method for stabilizing a grid-connected inverter system, which comprises the following steps: S1, data acquisition and preprocessing, S2, power regulation modeling, S3, optimization control strategy solving, S4, optimal control signal generation, S5, control signal execution, and S6, real-time feedback and adjustment. The invention further provides a power adapter control system for stabilizing the grid-connected inverter system, the power adapter control system comprises a power grid state monitoring module, an optimization algorithm module, a feedback and adjustment module and an execution and adjustment module, and the power adapter comprises an input interface, a power conversion circuit, an output interface, a sensor module and a control unit. Through voltage-current-power coupling control, a self-adaptive adjustment mechanism, dynamic error compensation and intelligent parameter self-learning, high-precision power adjustment is realized, load change is quickly responded, grid-connected stability is improved, and long-term operation performance is optimized.