515 results about "Grid connected inverter" patented technology

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 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 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 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 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 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 relates to the technical field of voltage source type grid-connected inverter control, and particularly discloses a voltage source type inverter active damping control strategy based on power grid voltage feed-forward, which comprises an LCL filter module, an inductance voltage differential feedback active damping loop, a power grid voltage feed-forward compensation loop and a proportion-resonance controller. By introducing a grid-side inductive voltage first-order differential feedback link, the damping characteristic of the system is enhanced, and LCL resonance is suppressed; and meanwhile, a power grid voltage feed-forward loop is designed, so that the interference of power grid disturbance on grid-connected current is eliminated. According to the virtual resistance parameter design method based on the optimal damping ratio and the feed-forward loop transfer function optimization strategy, the dynamic response capability, the resonance suppression effect and the weak power grid adaptability of the voltage source type inverter can be effectively improved, and the system stability and the electric energy quality are remarkably improved.

The invention discloses a multi-loop anti-interference ride-through control system and method for a high-voltage three-level inverter, and is suitable for a three-phase T-type three-level grid-connected inverter. The system comprises a direct current side power supply circuit, an inversion main circuit, a filtering grid-connected circuit, a signal sampling and conditioning circuit, a multi-loop cooperative controller and a PWM driving and protecting circuit. According to the control method, a robust synchronous reference is provided through an outer ring virtual synchronous generator strategy; a middle ring adopts a virtual impedance model containing a high-frequency compensation item to selectively suppress switching noise; the inner ring adopts a quasi-proportional resonance controller to realize fundamental current zero-static-error tracking; the modulation layer dynamically optimizes a discontinuous pulse width modulation strategy based on a real-time EMI index; and the rings are switched to a low-voltage ride-through mode in cooperation when a fault occurs. On the premise of not increasing hardware, the anti-interference capability, the current quality and the ride-through stability of the inverter under the working conditions of strong electromagnetic interference and power grid drop are effectively improved.

The invention relates to the technical field of micro-grids, in particular to a direct-current component suppression method of a grid-connected inverter, the inverter and a storage medium. The direct-current component suppression method comprises the following steps: determining an expression of a direct-current component in grid-connected current according to a grid-connected inverter circuit model and a Kirchhoff's law; based on the expression of the direct-current component in the grid-connected current, virtual impedance capable of inhibiting the direct-current component in the grid-connected current is constructed; the virtual impedance is introduced into a control loop of the grid-connected inverter, and a calculation model of a modulation wave compensation item is obtained through equivalent transformation; and superposing the original modulation wave signal output by the current loop controller and the modulation wave compensation signal obtained based on the calculation model of the modulation wave compensation item to obtain a final modulation wave signal. According to the method, enhanced suppression is carried out on the direct current component by introducing the virtual impedance, the problem is solved from the source, the suppression effect is remarkable, and the alternating current fundamental wave performance is not affected.

The invention belongs to the technical field of grid-connected inverter harmonic analysis, and particularly discloses a grid-connected inverter harmonic closed-loop transmission analysis method and system considering broadband coupling. The method comprises the following steps: respectively establishing a harmonic component transfer function of each module; based on the harmonic component transfer function of the sampling module, calculating to obtain harmonic active power and harmonic reactive power input to the power outer loop control module; based on a harmonic component transfer function of the power outer loop control module, calculating to obtain a harmonic current component in a reference current signal output by a power outer loop; based on a harmonic component transfer function of a current inner loop control module, obtaining a three-phase modulation voltage harmonic component and an inverter port voltage harmonic component through coordinate inverse transformation; on the basis of the inverter port voltage harmonic component, a main circuit harmonic transfer equation is combined, and a grid-connected point harmonic current component is obtained through calculation; the method overcomes the defects that a traditional analysis method cannot consider the control of a whole loop by a closed loop, and the broadband coupling is insufficiently considered.

The invention discloses a grid-connected inverter power and current coordination control method under a harmonic power grid and a related device, and relates to the technical field of renewable energy power generation, and the method comprises the steps: obtaining a two-phase power grid AC voltage based on a three-phase power grid AC voltage; calculating a reference current under a direct power control strategy based on the active power reference value, the reactive power reference value and the two-phase power grid AC voltage; harmonic waves in the reference current under the direct power control strategy are filtered out, and a fundamental component and a harmonic component are obtained; based on a preset adjustment coefficient, the fundamental component and the harmonic component, obtaining a reference current with an adjustable harmonic content; performing zero static error control on the reference current with the adjustable harmonic content to obtain a modulation voltage; and performing sine pulse width modulation on the modulation voltage to obtain a grid-connected current. According to the invention, coordinated control of power constancy and current balance of the grid-connected inverter can be realized.

The invention discloses a method, device and equipment for determining parameters of a proportional resonance controller and a medium, the proportional resonance controller is applied to a current controller of a three-phase grid-connected inverter, the parameters of the proportional resonance controller comprise a proportionality coefficient, a first damping coefficient and a second damping coefficient, the first damping coefficient is greater than the second damping coefficient, and the second damping coefficient is greater than the first damping coefficient. The three-phase grid-connected inverter further comprises a filter. The proportional resonance controller is low in parameter coupling, can be independently designed, and is simple in engineering implementation; in the target open-loop transfer function, the proportionality coefficient determines the basic proportional gain, the damping coefficient controls the attenuation speed of the corresponding resonance factor, the difference between the first damping coefficient and the second damping coefficient can influence the gain bandwidth, and the larger the difference between the first damping coefficient and the second damping coefficient is, the more significant the attenuation speed difference between the second resonance factor and the first resonance factor is. The wider the high gain interval at the specific frequency of the power grid is, the higher gain is still kept even if the frequency of the power grid fluctuates, and the adaptability and robustness to the frequency deviation of the power grid are improved.

The invention discloses an anti-saturation equivalent virtual impedance grid-forming type SVG fault current-limiting control method, which comprises the following steps of: inverting a direct current into an alternating current through an inverter, and filtering high-frequency harmonics through a filter to obtain a sine wave alternating current meeting a grid-connected requirement. A three-phase alternating current signal is collected in real time, coordinate transformation is carried out through a Park transformation module, and a modulation signal is obtained. The modulation signal is compared with a triangular carrier signal, a driving signal is generated, the on-off time of a power switching device of the inverter is controlled, the amplitude and phase of output voltage and current are adjusted, accurate control over the output power of the grid-connected inverter is achieved, and the power grid access requirement is met. According to the method, the limitation of traditional fixed parameters is broken through, and the robustness of the system to a complex fault scene is improved. In addition, manual intervention or a complex mode switching program is not needed, automatic smooth transition between different working conditions can be achieved, and powerful technical guarantee is provided for stable operation of a power grid.

The present invention discloses a normalized evaluation method and system for a grid-connected inverter, belonging to the technical field of power quality control of power grids. The evaluation method not only evaluates the stability of the grid-connected inverter, but also evaluates the rapid control performance of the grid-connected inverter. The specific steps are: normalizing the filter parameters, calculating and simplifying the transfer function of the controlled object of the grid-connected inverter, calculating the control closed-loop transfer function of the grid-connected inverter, solving the normalized control parameters, controlling the grid-connected inverter, and calculating the normalized instability evaluation index S of the grid-connected inverter. inv and the normalized evaluation index N of the grid-connected inverter control rapidity inv The normalized evaluation index of the control rapidity of the grid-connected inverter obtained by the present invention provides a direction for the subsequent parameter design and performance optimization of the grid-connected inverter.

The invention discloses a grid-connected inverter control method based on an MAGRNN neural network observer, and aims to solve the problems that a model prediction control method is insufficient in state estimation precision and worsened in control performance under the conditions of model mismatch, parameter offset and power grid voltage distortion. For an LCL type grid-connected inverter, firstly, a prediction model is established based on a state-space equation; secondly, real-time estimation parameters of an inductance parameter state observer are constructed; the method comprises the following steps: firstly, estimating an interference compensation item through a neuron self-adaptive adjustment mechanism, then introducing an MAGRNN neural network as a dynamic error compensator, using input and output of the observer as MAGRNN input, estimating the interference compensation item through the neuron self-adaptive adjustment mechanism, and finally, feeding back the interference item predicted by the MAGRNN to a model prediction controller for interference compensation. By utilizing the strong nonlinear fitting capability of the MAGRNN, the state estimation precision under complex working conditions such as parameter change and power grid disturbance is remarkably improved, and the control performance of the system is effectively improved.

The invention belongs to the technical field of electronic power, and particularly relates to an LCL grid-connected inverter model-free predictive current control system and method based on sampling noise compensation, and the system comprises an inverter main circuit, an LCL filter and a controller. The controller is configured to firstly calculate a current gradient and a voltage gradient according to a collected system operation signal; then, a second-order generalized integrator is used for conducting accurate compensation on sampling noise contained in the gradient; and finally, executing a model-free predictive control algorithm based on the compensated gradient, and preferably selecting an optimal voltage vector through a multi-objective value function integrating inverter side current, capacitor voltage and network side current. According to the method, sampling noise interference is effectively suppressed, the control precision and the anti-interference capability of the system are improved, and stable and efficient operation of the LCL grid-connected inverter can be realized without additional damping.

The invention discloses a grid-connected inverter fusion control method based on voltage and current source time sharing, and relates to the technical field of electric power automation, and the method comprises the steps: carrying out the two-phase rotating coordinate system conversion of power grid coupling data, and generating a voltage-current joint component; performing power error analysis on the voltage-current joint component, outputting a power grid state vector, performing modal decomposition on the power grid state vector, obtaining a dominant oscillation mode matrix, performing Lyapunov exponent calculation on the dominant oscillation mode matrix, forming a stability pre-judgment mark, and inputting the stability pre-judgment mark into a time-sharing fusion decision network model to obtain a time-sharing fusion decision network model. The characteristic coupling layer carries out cross physical quantity correlation, and the stability evaluation layer carries out stability boundary calculation and outputs a voltage-current source control signal. Through the intrinsic orthogonal decomposition algorithm and the time-sharing fusion decision network model, the response speed and the fusion control capability of the grid-connected inverter are improved.

The invention discloses a combined control method for an MMC grid-connected inverter, and the method comprises the steps: employing passive sliding mode control as a main structure of a current inner loop, introducing slope control on the basis, constructing slope passive sliding mode control, effectively suppressing the buffeting problem, and improving the system output precision; meanwhile, the model prediction control strategy is used in the nearest level approximation algorithm of the modulator, and the grid-connected electric energy quality is further improved. An MMC grid-connected inverter electromagnetic transient model is built by using a Simulink simulation platform, and simulation verification is performed on different working conditions such as normal operation and load abrupt change. According to the method, passive sliding mode control is used as a current inner loop control structure, slope control is introduced on the basis, and buffeting is suppressed through a simple and efficient method; moreover, model predictive control is introduced in a modulation link, and a composite control structure with high robustness and high precision is formed.

The invention discloses a stabilization and hierarchical cooperative stabilization control method for a heterogeneous inverter parallel system, and belongs to the field of grid-connected inverters. The method is characterized in that the capacity ratio of the heterogeneous inverter parallel system and cooperative regulation and control of key control parameters are fully considered, and the stability margin of the system can be effectively increased. The method comprises the following two layers of control: 1, when the operation condition of the system is changed, adjusting the capacity of a network-following inverter and a network-constructing inverter in the heterogeneous system; and 2, if the system still loses stability after the network following / constructing capacity ratio is changed, the stability of the system is improved by adjusting key control parameters of the heterogeneous parallel system. Based on the method, through reasonable configuration of the two types of inverters, the system achieves better dynamic and steady state characteristics, so that performance optimization and stability enhancement of the parallel system are realized.

Systems, devices, and methods for controlling grid-tied inverters with instantaneous synchronization and low-voltage-ride-through (LVRT) capabilities under a wide range of grid cable impedance without using a phase-locked loop.

The invention discloses a grid-connected inverter double-closed-loop control method based on a two-stage coupling expansion state observer, and belongs to the field of three-phase photovoltaic grid-connected inverters, and the method comprises the steps: building an inverter mathematical model, and determining that id is a control signal of stable DC bus voltage Udc; establishing a novel LADRC controller based on a two-stage coupling extended state observer; a high-performance double-closed-loop grid-connected control system is constructed based on an LADRC controller and a QPR controller, the LADRC controller acting on a voltage outer loop carries a two-stage coupling expansion state observer, more efficient suppression and compensation can be achieved aiming at interference components of different frequency bands, and the LADRC controller is matched with the QPR controller acting on a current inner loop, so that the high-performance double-closed-loop grid-connected control system is achieved. And the robustness and the stability of the grid-connected system controller are improved.