259 results about "Grid connected inverter" patented technology

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 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 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 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 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 DC bus voltage stabilization system and method for an AC / DC micro-grid. The method comprises the following steps: transmitting photovoltaic electric energy to a DC bus through a Boost converter of a photovoltaic power generation unit; a super capacitor energy storage branch and a storage battery energy storage branch of the hybrid energy storage unit are connected in parallel to a direct current bus through independent bidirectional Buck-Boost converters; the direct current bus electric energy is converted into alternating current electric energy through a grid-connected inverter of the alternating current inversion grid-connected unit; after the direct-current bus voltage, the voltage of each unit, the current and the energy storage charge state information are obtained through a sampling link of the special control unit, an adjusting instruction is generated through operation, the direct-current bus voltage is stably controlled, and the stability of the direct-current bus voltage is kept. Through hardware design optimization, the DC bus voltage anti-disturbance capability is significantly improved, and the service life of energy storage equipment is prolonged.

The invention discloses a power distribution network harmonic suppression method based on virtual admittance of a photovoltaic grid-connected inverter, and the method comprises the following steps: generating a harmonic compensation current through the photovoltaic grid-connected inverter, constructing a virtual admittance control mechanism based on the harmonic compensation current, and obtaining a mapping relation between a virtual admittance value and a phase angle on the harmonic suppression effect; modeling a photovoltaic grid-connected inverter of the power distribution network, and constructing a virtual admittance regulation mechanism of the power distribution network; and based on a virtual admittance control mechanism, taking each virtual admittance parameter as an optimization variable, and carrying out a multi-photovoltaic grid-connected inverter collaborative optimization strategy to realize graded treatment of power distribution network harmonics. According to the method, a virtual admittance control mechanism is constructed, and a photovoltaic grid-connected inverter is equivalent to earth admittance; and harmonic fractional compensation and global optimization configuration are realized by combining sensitivity analysis of voltage distortion of each node. The problem that the VDAPF only adjusts through harmonic conductance and neglects the impedance characteristic of the power distribution network and the uncertainty of the harmonic phase is solved, and the harmonic compensation capability is remarkably 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 DC component suppression method comprises the following steps: establishing a state space model according to a grid-connected inverter circuit and a Kirchhoff's law; expanding a direct-current component into a new state variable in the state space model by utilizing the slow variation characteristic of the direct-current component in the grid-connected current to obtain a state space expansion model; performing real-time estimation on the direct current component through a state observer based on the state space expansion model to obtain a direct current component estimation value; and taking a result obtained by subtracting the direct-current component estimation value from the original reference value of the grid-connected current as a final reference value of closed-loop control of the grid-connected current. According to the method, the result obtained by subtracting the direct current component estimation value from the grid-connected current original reference value serves as the final reference value of grid-connected current closed-loop control, and suppression of the direct current component in the grid-connected current is achieved.

The invention relates to an anti-countercurrent device suitable for a miniature grid-connected inverter system, which is characterized in that an anti-countercurrent electric meter and at least one miniature grid-connected inverter form a local area network through a local router to form a system, and the anti-countercurrent electric meter accurately acquires power grid parameters through a power grid voltage sampling terminal and a current measurement signal input terminal of the anti-countercurrent electric meter; and the real-time grid-connected power of each micro grid-connected inverter is inquired regularly as a control center, a power adjustment instruction is calculated and broadcasted, and finally all the micro grid-connected inverters are driven to adjust output synchronously. An anti-countercurrent electric meter is used as a unified control core, and a unified power adjustment instruction is calculated based on real-time countercurrent power and total generated power, so that all micro inverters can adjust power synchronously and proportionally, accurate cooperative control of multiple micro inverters is realized, and power oscillation is avoided; the whole control closed loop operates in a high-speed local area network, is quick in response, meets the grid-connected standard requirement for eliminating countercurrent, and effectively guarantees the safe operation of a power grid.

The invention relates to a dual-mode seamless switching three-phase grid-connected inverter control system and method. The system comprises a GFL outer loop control module, a GFM outer loop control module, a current inner loop control module, a power grid impedance tracking module, a calculation processing module and a switching buffer control module. The power grid impedance tracking module is used for detecting and calculating power grid impedance Lg in real time; the calculation processing module analyzes the power grid impedance Lg and then generates a switching control instruction group, the switching buffer control module receives the switching control instruction group, and a plurality of change-over switches in the switching buffer control module change states according to instructions so as to select to start a GFL or GFM control path; according to the cooperative working mechanism, the system can automatically and smoothly switch between the following network type control strategy and the construction network type control strategy in real time according to the impedance state of the power grid, so that the adaptability and the operation stability of the three-phase grid-connected inverter under the wide-range power grid impedance change are remarkably improved.

This application provides a grid-tied inverter apparatus and a grid-tied control method. The inverter apparatus includes an inverter circuit, a controller, and a filter circuit. The controller is configured to adjust switching frequencies of a plurality of power switching transistors based on an output current value of the inverter apparatus, to adjust a resonance frequency of the filter circuit through different resonant branches, so that the resonance frequency meets a grid-tied requirement. In this application, when the switching frequencies of the plurality of power switching transistors in the inverter circuit are reduced due to overload of a power supply system, resonance may be produced through different resonant branches, to adjust the resonance frequency of the filter circuit in a timely manner, so as to ensure that the resonance frequency of the filter circuit meets a requirement for system stability. A response is fast, and a control method is simple, so that system stability and security are improved, and applicability is high.

The application discloses an inverter nonlinear composite control method and system based on a PR controller and belongs to the field of power electronics. In view of the problems that the existing control scheme is weak in control performance or even fails when facing actual inverter parameter uncertainty, external disturbance during grid connection or load access operation and the like, Taylor series is adopted to solve the problem that a nonlinear model predictive control structure is complex and difficult to implement, and a nonlinear disturbance observer is introduced to improve control accuracy, so that the finally constructed grid-connected inverter nonlinear composite control inverter has the advantages of simple control structure implementation and convenient actual application while being capable of realizing good tracking capability on a reference signal and rapid inhibition capability on external interference.

The invention discloses a photovoltaic fault active compensation control system and method, and relates to the technical field of power electronics and new energy, and the system comprises a data collection module which is used for collecting a three-phase grid-connected current signal of a photovoltaic system at a common coupling point in real time; the fault feature extraction module is used for performing multi-scale decomposition and spatial-temporal feature fusion based on the three-phase grid-connected current signal to obtain a deep fusion feature; the quantization factor generation module is used for converting the deep fusion features into quantization factors representing fault dynamic influences; the active compensation control module is used for generating a compensation control instruction through a reinforcement learning algorithm according to the quantization factor and the power grid state information; and the compensation execution module is used for receiving and executing the compensation control instruction, driving the grid-connected inverter to inject compensation current and actively counteracting fault disturbance. And the stability and the electric energy quality of the high-proportion new energy power system are improved.

The invention provides a grid-connected inverter control method and device, a controller and a grid-connected inverter, and relates to the technical field of power electronics. The method comprises the following steps: obtaining the harmonic content of the current of the output end of a target grid-connected inverter; and determining a corresponding reactive power transformation proportion in a preset corresponding relation based on the harmonic content. And controlling the reactive power actually output by the target grid-connected inverter by taking the reactive power variation proportion as a target. According to the method, the reactive power transformation proportion can be dynamically determined based on the harmonic content of the output end of the grid-connected inverter, the reactive power transformation proportion is the proportion of the maximum reactive power which ensures that the inverter is not off-grid relative to the rated reactive power, the off-grid risk caused by harmonic superposition is counteracted through the dynamic transformation, extra redundancy is not reserved, and the power consumption is reduced. The inverter can output the maximum reactive power within the current safety boundary under the harmonic content of each gear, the off-network risk can be reduced, reactive power output can be improved as much as possible, and balance between safe operation and maximum reactive power output is achieved.

The application provides a grid-connected inverter and a control method and controller thereof, and relates to the technical field of inverter control. The method comprises the following steps: detecting the variation characteristics of the output port voltage of the grid-connected inverter; judging whether the grid-connected inverter is in a weak power grid environment based on the variation characteristics; and controlling the grid-connected inverter to output capacitive reactive power to improve the active power output capability of the grid-connected inverter in the case that the grid-connected inverter is in the weak power grid environment. The application can solve the problem of poor stability of the grid-connected inverter in a weak power grid.

The invention relates to the technical field of inverters, in particular to an off-grid and grid-connected inverter, a system thereof, a charging and discharging control method, a medium and equipment. The method comprises the following steps: determining a required working mode according to a setting state of a battery charging stop mark; if the required working mode is a Buck Boost mode, controlling to enter the Buck Boost mode, configuring the driving signal duty ratios of the first switch tube and the second switch tube to be complementary, configuring the driving signal duty ratios of the third switch tube and the fourth switch tube to be complementary, and controlling the first switch tube, the second switch tube, the third switch tube and the fourth switch tube to be normally conducted; and if the required working mode is a Boost mode, controlling to enter the Boost mode, configuring the driving signal duty ratios of the first switch tube and the second switch tube to be complementary, configuring the driving signal duty ratios of the third switch tube and the fourth switch tube to be complementary, controlling the second switch tube and the third switch tube to be normally conducted and work, and simultaneously turning off the first switch tube and the fourth switch tube. The high-voltage battery can be prevented from being overcharged, and stable power supply of the system is ensured.

The application discloses a data-driven optimal control method for a grid-connected inverter. The method comprises the following steps: constructing a DeePC optimization controller of the grid-connected inverter on the grid side; acquiring a data matrix of the grid-connected inverter in a preset historical period and an initial trajectory after a preset adjacent period, inputting the controller, setting parameters for different control targets and types of the grid-connected inverter, outputting an optimal input data sequence after processing, generating a sinusoidal pulse width modulation wave signal and acting on the grid-connected inverter, and realizing data-driven optimal control. The method can automatically perceive and adapt to the dynamic characteristics of the actual power grid through real-time data-driven predictive control, can present or enhance the control behavior of the grid-constructing or grid-following inverter by modifying the cost parameters, can realize multi-mode flexible, optimal and coordinated control, has excellent dynamic response and steady-state performance, is beneficial to safe and stable operation, and improves the ability to adapt to complex and variable operating conditions and power grid strength.

The invention relates to the technical field of energy storage, in particular to an energy storage system, a battery active equalization method and device thereof and a computer program product. The system comprises a battery module, a bridge circuit topology and a control loop; wherein the battery modules are electrically connected through the bridge circuit topology to form a battery cluster; the control loop is configured to control the working state of the battery module connected to the battery cluster by controlling the on-off of a switching device in the bridge circuit topology; the working state comprises a power-on state and a bypass state, and the power-on state comprises a charging state and a discharging state; and when the working state of the battery module is controlled, feedforward control is performed on a direct current bus of the energy storage system through a grid-connected inverter of the energy storage system. According to the scheme provided by the invention, online hundred-ampere-level battery active equalization management can be provided, the equalization duration is effectively shortened, and the full-capacity network-hanging standby time of the energy storage device is prolonged.

The invention discloses a compound control method for improving the current control performance of a three-phase LCL type grid-connected inverter. The method comprises the following steps: establishing a system loop gain based on digital control delay; composite control is realized by adopting a mode of combining a capacitance current sampling modification mode and a delay compensation link, and the capacitance current sampling modification mode is used for shortening capacitance current sampling delay and comprises the steps of sampling grid-connected current at a wave trough of a triangular carrier wave, sampling capacitance current at a wave crest of the triangular carrier wave, and carrying out delay compensation on the grid-connected current. A modulation signal is loaded at the next grid-connected current sampling moment, and capacitance current sampling delay is shortened by half beat; the delay compensation link is used for compensating the influence of digital control delay, the influence of digital control delay is reduced by embedding a lead phase compensator in a capacitive current feedback loop, and the stability of the system and the quality of grid-connected current are improved. According to the invention, composite control is realized by adopting a mode of combining a capacitor current sampling modification mode and a delay compensation link addition mode.

This invention discloses a method for improving the synchronization stability of a grid-connected inverter based on backstepping, comprising: setting a low-pass filter in the active power-frequency droop control loop of the grid-connected inverter; establishing a corresponding state model based on the dynamic characteristics of the low-pass filter; constructing intermediate state variables according to the state model; and recursively deriving the control input expression based on the intermediate state variables using the backstepping control method to obtain a control law that satisfies the Lyapunov stability condition; introducing the control law into the active power-frequency droop control loop to adjust the output frequency of the grid-connected inverter, thereby optimizing the active power-frequency droop control strategy of the grid-connected inverter. This invention only requires superimposing the designed controller on the synchronization loop to effectively enhance the dynamic stability of the system and avoid instability and oscillations caused by factors such as temperature drift and component aging.

This application describes examples of a grid-tied inverter apparatus and a grid-tied control method. In one example, the grid-tied inverter apparatus includes an inverter circuit, a controller, and a filter circuit. The controller is configured to adjust switching frequencies of a plurality of power switching transistors based on an output current value of the inverter apparatus, to adjust a resonance frequency of the filter circuit through different resonant branches, so that the resonance frequency meets a grid-tied requirement.

The invention provides a grid-connected inverter control method and device based on deep reinforcement learning. The method comprises the steps of determining three-phase reference current of a power grid based on phase information of power grid voltage and expected power of the power grid; constructing a state space about a three-phase current state based on the obtained actual three-phase current of the power grid and the three-phase reference current; an action space is constructed, and the action space comprises on and off action values of each power switch tube in a three-phase inverter of the power grid; and inputting the state space into a pre-constructed target model, so that the target model is combined with an action space to obtain a control strategy for controlling turn-off or turn-on of the power switch tube, and the target model is a deep neural network model supporting deep reinforcement learning. The state space matching module is used for matching and outputting a control strategy for controlling each power switch tube to be switched off or switched on at least according to an input state space; and controlling the three-phase inverter based on the control strategy.

The invention discloses a three-phase grid-connected system based on hybrid energy storage complementation of a lithium battery and a super capacitor. Comprising a hybrid energy storage system unit, a control unit of a bidirectional energy storage circuit, a three-phase bridge-type grid-connected inverter and a control unit of the three-phase bridge-type grid-connected inverter, the hybrid energy storage system unit comprises a lithium battery energy storage unit and a super capacitor energy storage unit, and the lithium battery energy storage unit and the super capacitor energy storage unit are connected with the direct current bus through a bidirectional DC / DC converter; the control unit of the bidirectional energy storage circuit is used for obtaining reference power required to be provided by the lithium battery and the super capacitor through power distribution, taking a reference power signal as an input signal, and forming a control signal of a switching device through signal processing and conversion, so that the energy storage equipment is charged and discharged according to the reference power; the three-phase bridge-type grid-connected inverter and the control unit thereof are used for controlling the three-phase bridge-type inverter through PWM pulse signals. The stability and reliability of the power grid can be improved, and the operation cost of the power system is reduced.

The invention discloses a three-phase grid-connected inverter current sensor-free control method based on model identification perception. And the inverter control link modulating wave and the alternating current side power grid voltage are used as input to reconstruct alternating current side current. According to the implementation method, a current reconstruction function model on the alpha-beta axis is identified through the voltage and current of the filter inductor on the alpha-beta axis of a two-phase static coordinate system, the precision of a current reconstruction function is ensured by adopting an online identification method, and effective observation of the inverter alternating current side current is realized. In addition, in the current feedback control of the grid-connected inverter, the observation current can replace the sensor sampling current, so that the control without the current sensor is realized. According to the method, the application range of a grid-connected inverter current reconstruction model is expanded, the method can be applied to various inductance filtering application scenes, timely and accurate current reconstruction and non-current sensor control are achieved after the sensor is aged or breaks down, and the operation safety and reliability of the grid-connected inverter are improved.

The application discloses an inverter grid-connected current harmonic suppression method and system, collects inverter bridge arm current and grid-connected point voltage, carries out operation on the inverter bridge arm current and the grid-connected point voltage to obtain grid-connected current, carries out harmonic suppression on the grid-connected current through a harmonic suppression ring to obtain harmonic suppression ring output value, obtains feedforward value of the grid-connected point voltage and fundamental wave current loop control output value, takes a negative value of the harmonic suppression ring output value and superimposes the feedforward value of the grid-connected point voltage and the fundamental wave current loop control output value, obtains modulation voltage of the inverter, carries out PWM modulation on components of the modulation voltage to generate a switching signal for driving the grid-connected inverter to work. The application estimates the grid-connected current, suppresses specific harmonics in the grid-connected current, makes the grid-connected current harmonic suppression effect better, adopts feedforward on the grid-connected point voltage, makes the inverter have better dynamic performance and stability under strong grid or weak grid, and reduces the grid-connected current harmonic suppression difficulty.

The application discloses a control method of an LCL type grid-connected inverter based on capacitor voltage feedforward compensation and composite active damping, which comprises the following steps: collecting a coupling point voltage from a common coupling point of an LCL type grid-connected inverter, processing the coupling point voltage to obtain phase angle information; collecting a grid current, calculating a first damping signal based on the grid current, and calculating an original reference current based on the grid current and the phase angle information; calculating an error signal based on the grid current and the original reference current, generating an original reference voltage based on the error signal; collecting a capacitor voltage of an LCL filter circuit in the LCL type grid-connected inverter, calculating a second damping signal based on the capacitor voltage; calculating an optimized reference voltage based on the original reference voltage, the first damping signal and the second damping signal; generating a PWM driving signal based on the optimized reference voltage, and controlling the LCL type grid-connected inverter by using the PWM driving signal. The application not only has good economic efficiency and resonance peak suppression effect, but also can suppress background harmonics while maintaining stable operation of the grid-connected inverter under a weak grid.

This invention relates to the field of power electronics, specifically to an online parameter identification model predictive control method for grid-connected inverters: The method involves measuring the grid-side current and voltage at the start of the current switching cycle; applying a control signal to the grid-connected inverter; calculating the reference current for future switching cycles; identifying the real-time inductance and resistance of the line through online parameters; calculating the grid-side current at the start of the next switching cycle based on the real-time inductance and resistance, and compensating for the current prediction error of the predicted grid-side current in the cycle after that; constructing a reserve set of action vectors based on the current error vector quadrant between the compensated reference current for future switching cycles and the grid-side current at the start of the next switching cycle; and selecting the optimal voltage vector from the reserve set according to a value function for use in the next switching cycle. Compared with existing technologies, this invention addresses the shortcomings of fixed parameters, corrects prediction deviations caused by fixed parameters, and achieves more accurate voltage vector selection.