138 results about "Induction generator" patented technology

The present disclosure discloses a method for controlling coordinated operation of multiple wind generators to avoid secondary frequency drop. The method includes the following steps: first, the Doubly Fed Induction Generator (DFIG) required for frequency support is dynamically selected based on a real-time disturbance power of a power grid and the rotating speed level of each DFIG; second, the virtual inertial control parameters are adaptively regulated according to the system frequency and the change in the rotating speed of the DFIG participating in frequency support, ensuring that the frequency support requirements are satisfied; and finally, the remaining DFIGs are controlled to release the rotor kinetic energy to support the rotating speed recovery of the selected DFIG, so as to reduce the extra energy absorbed from the power grid in the process.

The invention discloses a VSG-DFIG subsynchronous oscillation adaptive suppression method based on a Hamiltonian model, and belongs to the technical field of subsynchronous oscillation suppression of a power system. The method aims at solving the problem that an existing method for suppressing subsynchronous oscillation existing in grid-connected operation of the doubly-fed induction generator is poor in suppression effect. Comprising the following steps: constructing a port controlled Hamiltonian dissipation model; constructing a closed-loop system dynamic equation based on interconnection and damping distribution under strict passivity; an expected energy function in a unit closed-loop form is constructed, a DFIG unit feedback control law based on a Hamiltonian model is obtained, and further deformation is carried out to obtain a deformed DFIG unit feedback control law; the port controlled Hamiltonian dissipation model is corrected, and a corrected port controlled Hamiltonian dissipation model is obtained; constructing a dynamic equation of the anti-interference adaptive observer, and establishing an error dynamic equation; and constructing a Lyapunov function, and designing an estimation error feedback control law according to the stability condition of the Lyapunov function. The subsynchronous oscillation suppression circuit is used for suppressing subsynchronous oscillation.

The invention discloses a doubly-fed induction generator fault detection method combining a sliding-mode observer and a bilateral cumulative sum algorithm, and the method comprises the following steps: designing a doubly-fed induction generator rotor current sliding-mode observer based on the combination of a novel reaching law and a doubly-fed induction generator state equation; carrying out stability and convergence analysis on the designed novel reaching law by adopting a Lyapunov stability theory; and the fault detection method of the doubly-fed induction generator is designed in combination with the optimized bilateral accumulation sum algorithm. A rotor current sensor fault, an input interference voltage fault, a voltage drop fault and a stator turn-to-turn short circuit fault are introduced. The rotor current tracking performance of the designed sliding-mode observer under different doubly-fed induction generator faults is verified by using a residual value obtained by comparing a doubly-fed induction generator rotor current value estimated by the sliding-mode observer with an actual rotor current output value; and meanwhile, the reliability of the designed doubly-fed induction generator fault detection method based on the optimized bilateral cumulative sum algorithm is verified. The doubly-fed induction generator fault detection method combining the sliding-mode observer and the bilateral cumulative sum algorithm has the advantages of being high in tracking precision and accurate in fault state characterization, meanwhile, weak fault features can be effectively converted into digital signals to be output, and faults of the doubly-fed induction generator are detected.

The invention discloses a time sequence fault current-limiting control method and system compatible with a grid-connected guide rule for a network construction type doubly-fed wind turbine generator, and the method comprises the following steps: freezing external power control when a low-voltage ride-through event of a power grid is detected at the initial stage of a fault, and suppressing transient overcurrent through dynamically adjusting the resistance component of virtual impedance; in the fault stable stage, an electromotive force compensation increment is calculated on the basis of grid-connected guide rule requirements at the moment 4 tau after the fault occurs; in the fault clearing stage, after it is detected that the fault is cleared, electromotive force compensation is stopped; gradually recovering the virtual impedance to a rated value through the dynamic coefficient A; in the fault recovery stage, active control and reactive control are recovered in sequence, power output is recovered to the level before the fault within one second, and meanwhile the virtual impedance amplitude is gradually recovered to the rated value along with the voltage phase difference; the voltage phase jump amplitude and the voltage drop amplitude determined by the method have high robustness.

The invention provides a deep-sea mining system, and relates to the technical field of deep-sea mining. The deep-sea mining system comprises a decision-making layer, the decision-making layer is connected with a coordination layer through a quantum encryption underwater acoustic communication module, the coordination layer is connected with an execution layer through a bionic tentacle electromechanical interface, and the execution layer is connected with a compensation layer through an ecological data bus; the decision-making layer comprises a phase resource management module which comprises a marine rhythm analysis unit, an ore deposit respiration model engine and a mining window decision-making device; the biological contract agreement module comprises a microorganism symbiotic culture cabin, a sound wave induction generator and a tentacle mechanical learning unit; the coordination layer comprises a dynamic topology network which comprises a cluster self-organizing controller, a real-time damage evaluation unit and a topology reconstruction algorithm library. Through collaborative design of the decision-making layer, the coordination layer, the execution layer and the compensation layer, intelligent and efficient deep-sea mining is achieved, and the mining efficiency and the resource utilization rate are remarkably improved.

Systems and method to minimize conditions that cause sub-synchronous oscillation (SSOs) associated with series compensated transmission grids. The implementations ensures the correct development of methods and systems that can mitigate sub-synchronous oscillation (SSOs) associated with a series compensated transmission grid and enhance the series compensation efficiency. An example implementation is a network-based SSO mitigation technology, and another example implementation is a generator-based SSO mitigation technology. The discovery and example implementations are applicable to series compensated transmission networks with synchronous generators, induction generators, wind turbines, solar photovoltaic generators, charging stations, battery storage systems, high-voltage DC transmission systems, STATCOMs, inverter-based data centers, and other inverter-based resources.

The invention relates to a doubly-fed induction generator (DFIG) fault detection and early warning method based on multi-scale latent variable regression (MSLVR), is suitable for multiple fault types and complex coupling effect scenes, and belongs to the technical field of fault detection. According to the method, firstly, key coupling variables influencing the DFIG are analyzed and selected from the angle of information theory, and the time scale is expanded through multivariate variational mode decomposition (MVMD), so that the data quality is optimized. Then, aiming at the defect that latent variable regression (LVR) is difficult to pay attention to the local influence of a sub-mode in multi-scale data processing, designing a serial architecture to gradually extract and eliminate interference of different components; and the residual subspace is processed by further combining principal component analysis (PCA), so that the online detection method capable of identifying early DFIG faults is developed. Through training and optimization, the model is finally stored for calling, the influence of the coupling effect on the DFIG can be effectively eliminated, efficient and accurate fault detection and early warning can be realized in various fault type scenes, and the detection accuracy is obviously superior to that of the existing mainstream method.

A DFIG wind power facility configured to be operated during grid faults is provided. The wind power facility includes a Doubly-Fed Induction Generator, a control system, an electric converter, a short-circuit controlled switch to selectively short-circuit the stator and a Stator Neutral Brake Chopper coupled to the stator. The DFIG includes a rotor and a stator, the stator including at least one three-phase winding. The electric converter includes a Machine Side Converter, a Grid Side Converter and a DC link connected therebetween. The SNBC includes a three-phase rectifier including three inputs, an impedance and an active high-frequency switch configured to vary the average value of the impedance by adjusting its duty cycle; each of the three inputs of the rectifier is connected to a phase of the at least one three-phase winding of the stator. Methods for operating a DFIG wind power facility during grid faults are also provided.

The invention relates to a stable control method and a stable control system for accessing a network construction type heterogeneous power supply to a direct current system, belongs to the technical field of power system control, and solves the problem of serious active power vacancy when an alternating current tie line of an existing multi-source access direct current sending end system fails. The method comprises the steps that energy flow paths among subsystems in the system are analyzed to identify key control links causing instability of the system and orthogonal interaction energy of the key control links, and the orthogonal interaction energy is an interaction energy item which has the largest influence on the stability of the system in interaction energy among modules of the subsystems; based on a minimization principle of total stored energy of the system, coordinating and adjusting a doubly-fed fan active instruction, a direct current system current instruction and an energy storage active instruction in real time; keeping a negative value according to the total interaction energy of the system to compensate the orthogonal interaction energy among the subsystems; and according to the state feedback signal, the active power instruction of each subsystem is dynamically adjusted in combination with the control switching logic. The adaptive capacity and the dynamic recovery performance are improved, and accurate matching and quick response to various fault working conditions are achieved.

A power converter system includes an asynchronous induction generator electrically coupled to an inverter / converter / controller (ICC). The ICC is coupleable to an electrical load. The ICC can include an AC-DC converter and a DC-DC converter. The DC-DC converter is configured to operate at a duty cycle substantially equal to 1 in a first operating mode. In the event of a short-circuit fault in the electrical load, the DC-DC converter is configured to operate at a duty cycle less than 1 in a second operating mode.

A transient stability control method and apparatus for a wind-thermal-bundled system. The method comprises: acquiring in real time terminal voltage of a doubly-fed induction generator when the wind-thermal-bundled system experiences a fault (S1); in response to the terminal voltage of the doubly-fed induction generator being within a first voltage sag interval, increasing a reactive current injection coefficient of the doubly-fed induction generator on the basis of a preset adjustment rule, to reduce the swing amplitude of a synchronous generator during an acceleration phase under fault conditions (S2); in response to the terminal voltage of the doubly-fed induction generator being within a second voltage sag interval, increasing the reactive current injection coefficient of the doubly-fed induction generator on the basis of the adjustment rule, to reduce the swing amplitude of the synchronous generator during the acceleration phase and the swing amplitude thereof during a deceleration phase under fault conditions (S3); and in response to the terminal voltage of the doubly-fed induction generator being within a third voltage sag interval, decreasing the reactive current injection coefficient of the doubly-fed induction generator on the basis of the adjustment rule, to reduce the swing amplitude of the synchronous generator during the deceleration phase under fault conditions (S4).

This invention discloses a method for designing an additional stabilizer to suppress low-frequency oscillations in a doubly-fed induction generator (DFIG) wind turbine. The method includes: constructing the input and output terminals of the additional stabilizer and designing the control loop; plotting the Bode plot of the closed-loop transfer function of the original system to determine the dominant oscillation frequency w. d and the phase lag value θ h Perform parameter tuning calculations for the phase compensation stage in the control loop; select the proportional coefficient K of the isolation stage of the additional stabilizer. e The quality coefficient ξ of the second-order bandstop filter with added stabilizer s and resonance coefficient K s Initialize the values; calculate the time δt required to suppress the disturbance and perform iterative calculations; and obtain the optimal parameter K. e ξ s and K s The values ​​are then substituted into the expressions for the isolation stage and the second-order band-stop filter. The additional stabilizer and design method for suppressing low-frequency oscillations in doubly-fed induction generator (DFIG) wind turbines provided by this invention can effectively suppress low-frequency oscillations in DFIG grid-connected systems and significantly enhance the system's stability under small disturbances.

The present invention provides an offshore wind power control system based on disturbance observation and global fast integral sliding mode, including an offshore wind turbine, a doubly-fed induction generator, an optimal angular velocity tracking module, and a global fast integral sliding mode control module; the offshore wind turbine is used to convert the captured offshore wind energy into mechanical energy; the doubly-fed induction generator is used to convert mechanical energy into electrical energy; the maximum power point tracking module is used to calculate the variant power coefficient curve at the current moment considering unknown errors; based on the variant power coefficient curve, a disturbance tracking strategy is adopted to calculate the optimal angular velocity; the global fast integral sliding mode control module is used to control the current by adopting a PI control strategy. In the outer loop controller, a sliding mode surface function is set and a global fast control law is adopted for control to quickly adjust to the optimal angular velocity.

The invention discloses a doubly-fed wind turbine generator-oriented wind power plant model aggregation method and device and a medium. The method relates to the field of wind power generation, and solves the problem that wind power plant model aggregation cannot simultaneously guarantee analysis precision and reduce calculation burden requirements. Based on a hybrid wind power plant structure, a dynamic mathematical model of a single machine and a whole wind power plant is obtained, contribution of each WTG to power grid injection current is quantified into a dynamic weight coefficient, the coefficient is updated in real time along with operation conditions, and the limitation that only a single machine type is concerned or dynamic characteristics are simplified in a traditional method is broken through. The method comprises the following steps: constructing an equivalent model for electrical and control mechanical parameters of a wind driven generator, a wind energy capture characteristic of a turbine and an impedance distribution characteristic of a line, ensuring that an aggregation model retains a core physical mechanism of an original wind power plant, and replacing detailed modeling of dozens of to hundreds of WTGs with a single-unit equivalent model. And the problem of calculation burden of large-scale wind power plant modeling is solved on the premise of ensuring the precision.

The invention relates to the technical field of wind power, in particular to an anti-overtemperature monitoring system and method for a high-speed shaft brake of a doubly-fed wind turbine generator, and the system comprises an infrared sensor, a PT100 temperature sensor, a two-channel temperature controller, a PLC, an SCADA monitoring system, an infrared sensor support, a miniature circuit breaker and the like. The system monitors the temperature of a brake disc in a non-contact mode and monitors the temperature of a brake pad in a contact mode through double sensors, the temperature is converted into a standard analog quantity signal through a temperature controller, a series detection loop and differentiation threshold judgment are combined, and a PLC outputs an instruction; the method comprises the steps of two-way temperature measurement, signal processing, logic control and remote monitoring, and is adaptive to the potential hazard of heat generation by friction of aging of a brake of an old unit. According to the invention, a double-point redundancy monitoring system is constructed, the defects of single temperature measurement and lack of verification in the prior art are overcome, the reliability and accuracy of overtemperature identification are improved, false triggering is avoided, the operation and maintenance convenience is optimized, and the operation safety of the wind turbine generator is comprehensively guaranteed.

The invention relates to a power converter and a system for an engine starter generator. A power converter system includes an asynchronous induction generator electrically coupled to an inverter / converter / controller (ICC). The ICC may be coupled to an electrical load. The ICC may include an AC-DC converter and a DC-DC converter. The DC-DC converter is configured to operate at a duty cycle substantially equal to 1 in a first mode of operation. In the event of a short-circuit fault in the electrical load, the DC-DC converter is configured to operate at a duty cycle of less than 1 in the second mode of operation.

An induction generator (2) is configured for driving an induction circuit (4), in particular for driving an induction coil of an induction hob (30). The induction generator (2) comprises: a power supply unit (8) configured to provide an input voltage (Vi) with respect to a common voltage (Vc); a driving unit (10) configured to provide a first and a second transistor driving voltage (Vg1, Vg2); a half-bridge arrangement (12) comprising a first transistor and a second transistor (14, 16) connected to each other at a middle node (22), wherein the first and second transistors (14, 16) are connected between the input voltage (Vi) and the common voltage (Vc), wherein the first transistor driving voltage (Vg1) is applied to the gate of the first transistor (14), and wherein the second transistor driving voltage (Vg2) is applied to the gate of the second transistor (16); a resonance circuit (4) comprising an induction coil element (6) being electrically connected at one end to the middle node (22) and being configured to emit an electromagnetic field when in operation; a control unit (20) having an output configured to supply a control signal to the driving unit (10) and having an input electrically connected to the middle node (22) configured for sensing the middle voltage (Vm) at the middle node. The control unit (20) is configured to apply the control signal at a setpoint frequency to the driving unit (10) such that via the first and second transistor driving voltages (Vg1, Vg2) a temporal switching sequence is implemented where the first transistor (14) is switched on and off and the second transistor (16) is switched on and off with a delay period (To) between switching off the first transistor (14) and switching on the second transistor (16). The control unit is further configured to detect the middle voltage (Vm) and / or the complimentary middle voltage (Vm*); and to evaluate the amplitude of the middle voltage (Vm) or the temporal behavior of the middle voltage (Vm) in relation to the switching off of the first transistor (14) and / or in relation to the switching on of the second transistor (16), and / or to evaluate the amplitude of the complimentary middle voltage (Vm*) or the temporal behavior of the complimentary middle voltage (Vm*) in relation to the switching off of the second transistor (16) and / or in relation to the switching on of the first transistor (14). The control unit is further configured to increase or to decrease or to maintain the setpoint frequency of the switching sequence being applied via the control signal in dependency of the evaluation. Alternatively or additionally the control unit is further configured to increase or to decrease or to maintain an on-time ratio (Ta / Tb or Tb / Ta), where within a switching sequence Ta is the duration of switching on the first transistor (14) and Tb is the duration of switching on the second transistor (16).

The application discloses a double-fed induction generator rotor speed estimation method based on maximum cross-correlation entropy weighting, and belongs to the field of motor control. The method creatively applies cross-correlation entropy theory to noise covariance estimation of EKF, and designs a complete algorithm system containing dynamic weighting, adaptive kernel bandwidth, mixed robust weighting and numerical reinforcement. The progressiveness is reflected in that the method comprehensively solves the shortcomings of traditional methods in response speed, parameter disturbance resistance and non-Gaussian noise resistance. Theoretical proof and comprehensive simulation experiments prove that the method has better estimation accuracy, robustness and reliability in complex industrial environments such as wind power generation.

The invention relates to a self-adaptive fractional order sliding mode control method of a doubly-fed wind power system, solves the problem that chaotic oscillation of a doubly-fed induction generator cannot be effectively suppressed, and belongs to the technical field of wind power generation control. The method comprises the following steps: establishing a chaos sensitive parameter identification model of the doubly-fed induction generator, and estimating system state variables and harmonious scheduling in real time; calculating a chaos intensity index through a chaos phase trajectory prediction module based on a system state variable and harmonious scheduling k; the method comprises the following steps: establishing a fractional order adaptive adjustment mechanism, and dynamically adjusting the fractional order of a fractional order sliding mode surface; according to the method, a fractional order sliding mode surface with a dual-mode switching characteristic is designed; constructing a multi-time scale nonlinear disturbance observer to obtain a total disturbance estimated value; based on the sum fractional order sliding mode surface, designing a chaos feedforward compensator to obtain a feedforward compensation control signal; and performing fusion based on the fractional order sliding mode surface, the total disturbance estimation value and the feedforward compensation control signal to obtain a final control signal.

The invention discloses a method for discriminating transient synchronization stability of a multi-wind-power grid-connected system in an asymmetric short-circuit scene, which comprises the following steps of: firstly, calculating positive and negative sequence components of generator end voltage of double-fed wind turbine generators in an asymmetric short-circuit fault of a power grid, and then calculating positive and negative sequence q-axis components of the generator end voltage of each double-fed wind turbine generator; if the positive and negative sequence components of the output current of each unit in the system can be reasonably distributed and the q-axis components of the generator terminal voltage of all the doubly-fed wind turbine generators are corrected to be zero, the transient state of the system is stable under the asymmetric short-circuit fault of the power grid; otherwise, transient synchronous instability of the system occurs. According to the method, the coupling effect caused by control performance and response characteristics of different doubly-fed units between positive and negative sequence networks of the system under the asymmetric short-circuit scene of the power grid is comprehensively considered, and whether transient synchronization of the system is stable or not can be intuitively judged according to the criterion provided by the method.

This invention provides a control method for a doubly-fed induction generator (DFIG) wind turbine with DC-side energy storage grid construction based on hybrid synchronization, belonging to the field of wind power generation and energy storage control technology. This control method calculates and generates modulation voltage commands through a rotor current inner-loop controller based on sampled stator voltage values ​​and reference values, enabling grid-connected operation of the rotor-side converter. Based on the grid-side converter current commands and sampled current values, a switching signal is calculated and generated through a grid-side current inner-loop controller, enabling the grid-side converter to control the voltage across the capacitor. Based on the DC-side battery current commands and energy storage inductor current, the DC-side energy storage bidirectional DC-DC converter is driven through calculation and modulation, achieving active support of the grid frequency by the DC-side energy storage system. This invention achieves inertia support and primary frequency regulation capability, ensuring stable operation of the DFIG wind turbine under weak grid conditions while also improving its grid support capability.

The application provides a double-fed induction generator control system based on a data-driven estimator, comprising a power comparison unit, a PI controller, a rotor current comparison unit, a d-axis filter, a q-axis filter, a d-axis state estimator, a q-axis state estimator, a d-axis data-driven adaptive unit, a q-axis data-driven adaptive unit, a d-axis neural network unit, a q-axis neural network unit, a d-axis controller, a q-axis controller and a double-fed induction generator. The application can accurately estimate system uncertainty and environmental disturbance, adopts a topology structure of a stator side connected to a non-controlled rectification bridge, directly connects a direct current power grid in parallel, controls the motor system by controlling the rotor side inverter to regulate the excitation current, so as to realize direct power control of the double-fed motor direct current power generation system.

The invention discloses a double-fed fan subsynchronous oscillation suppression system. Comprising four control loops, namely a doubly-fed fan rotor rotating speed output feedback control loop, a doubly-fed fan stator reactive output current output feedback control loop, a doubly-fed fan grid side converter reactive output current output feedback control loop and a doubly-fed fan back-to-back converter direct current link capacitor voltage output feedback control loop. Four output variables are utilized to form four feedback control channels, and each control channel is provided with a cascade high-gain observer and an output feedback controller. According to the method, subsynchronous oscillation disturbance caused by series compensation line grid connection of the doubly-fed fan can be effectively suppressed, and the method has very high robustness on system operation working conditions and system parameters. The method can be widely applied to the field of stability control of power systems.

The application discloses a kind of grey-box isomeric doubly-fed wind farm low-frequency oscillation suppression method based on virtual damping modulation, comprising: 1 grey-box isomeric doubly-fed wind farm is divided into white box and black box unit, and the state space model of all white box units of traditional doubly-fed induction generator, virtual synchronous machine control and installation additional damping controller is established;2 improve subspace identification method to obtain black box unit model;3. white box and black box model are coupled by feedback interconnection, and the overall state space model of wind farm is constructed;4 determine target low-frequency oscillation mode based on coefficient matrix;5 real-time extraction and target mode strong correlation common bus power signal, combined with adaptive time-varying gain generates virtual synchronous machine damping coefficient adjustment amount;6 according to complex mode controllability factor and unit distribution coefficient, allocate the virtual damping modulation instruction of each white box unit.The application realizes the identification and suppression of grey-box isomeric doubly-fed wind farm low-frequency oscillation, and improves the ability of wind farm damping low-frequency oscillation.

The invention provides a doubly-fed induction stator current control method and system based on a resonance controller, and the method comprises the steps: collecting a stator current and a rotor current of a doubly-fed induction generator in real time, and separating a negative-sequence component and a harmonic component of the stator current; inputting the separated negative sequence component and harmonic component into a composite resonance controller, and outputting a compensation voltage signal; a compensation voltage signal output by the composite resonance controller and a fundamental wave voltage instruction output by a traditional PI controller are superposed, and a total voltage instruction of the rotor side converter is generated; after the total voltage instruction is subjected to PWM modulation, an IGBT switching device of a rotor side converter is driven, suppression of a negative sequence component and harmonic waves is achieved, and stator current is balanced. The second-order resonance controller is adopted for the 100 Hz negative sequence component, the sixth-order resonance controller is adopted for the fifth-order harmonic component and the seventh-order harmonic component, and the operation performance of the doubly-fed wind turbine generator under the condition of unbalanced power grid voltage is improved through a composite control strategy.

To provide a rotating electric machine such as a motor or a generator which avoids a change in a magnetic flux direction adjacent to an air gap.SOLUTION: The disclosed improvements may be applied to a permanent magnet alternator, an induction motor and a generator, a doubly fed induction generator etc. Adaptation of coils to and fixation within required slot geometries are disclosed. Excitation systems collocated within a primary stator core and a primary stator core are also disclosed. Use of rubber vulcanized to the rotor in conjunction with a stainless steel rotor sleeve is also disclosed.SELECTED DRAWING: Figure 4a

The invention discloses a new energy positive and negative sequence voltage coordinated optimization method adaptive to high-power fault impact, which comprises the following steps of: constructing an optimal unbalanced voltage suppression model of a doubly-fed wind turbine generator under an asymmetric fault of a power grid, and taking the minimum voltage unbalance degree of a grid-connected point as a target function by the model to suppress the optimal unbalanced voltage of the doubly-fed wind turbine generator under the asymmetric fault of the power grid; the capacity constraint of the rotor side converter and the synchronous stability constraint of the system are included; based on the optimal unbalanced voltage suppression model, reconstructing a double-sequence synchronous rotating coordinate system; carrying out convexity processing on the reconstructed model, relaxing the capacity constraint of the rotor-side converter into a second-order cone form, and introducing an auxiliary variable to convert a target function and related constraints into a standard second-order cone programming problem; and solving the second-order cone programming problem, obtaining an optimal voltage dynamic control instruction, and controlling the new energy generator set. According to the method, the inter-sequence coupling effect can be accurately considered, so that the optimal suppression of the voltage imbalance is realized on the premise of ensuring the safety and stability of a machine-network system.

This application proposes a frequency domain dynamic equivalent modeling method and apparatus for doubly-fed wind farms based on real-time data. The method includes: for a wind farm with k doubly-fed wind turbines, calculating the equivalent rotational speed coefficient η of the kth doubly-fed wind turbine. k ; Calculate the state coefficient STA of the k-th doubly-fed wind turbine. k According to the rotational speed equivalent coefficient η k and state coefficient STA k Calculate the equivalent impedance Z of the k-th doubly-fed wind turbine. Gk (s); based on the equivalent impedance Z Gk (s) The characteristics in the frequency domain are used to determine the stability of the wind farm in the frequency domain. This invention can efficiently and quickly obtain the equivalent impedance of a doubly-fed induction generator (DFIG) wind farm at various time periods, and the results provide an important basis for the analysis of the impact of wind farm grid connection.

This invention relates to the field of new energy grid-connected control technology, and particularly to a method and apparatus for identifying control modes and parameters of a doubly-fed induction generator (DFIG) converter. The method involves applying small-amplitude step or pseudo-random voltage disturbances at the turbine terminal or grid connection point, collecting three-phase voltage and three-phase current data at the grid connection point, and obtaining the input vector and measurement output vector in a synchronous rotating coordinate system through Park transformation. An augmented state-space model library containing multiple potential control modes is established, and the PI parameters to be identified are incorporated into the augmented state. Unscented Kalman filters are run in parallel for each model to estimate the state / parameters, calculating the innovation residuals and their covariance. Based on Bayesian inference, the posterior probabilities of each model are recursively updated and normalized. The model with the highest probability is selected to determine the control mode, and the corresponding parameter estimates are output. This method does not require preset modes, improves identification accuracy and parameter physical consistency during mode switching or critical operating conditions, and facilitates stability analysis and operating condition migration. It has wide applicability.

This invention provides a grid-actively supported doubly-fed induction generator (DFIG) wind turbine control system, comprising: a DFIG converter power generation system, a wind turbine primary frequency regulation control module, a wind turbine autonomous inertia response control module, a wind turbine autonomous voltage control module, a rotor-side converter current command generation module, a rotor-side converter current control module, a rotor-side converter signal processing module, a grid-side converter synchronization angle control module, a grid-side converter AC voltage amplitude control module, a grid-side converter current command generation module, a grid-side converter current control module, and a grid-side converter signal processing module. Based on the principle that both the turbine-side and grid-side converters of the DFIG wind turbine employ amplitude and phase control, this invention achieves active support control of the grid frequency and voltage by the DFIG wind turbine unit through active primary frequency regulation, inertia response, and autonomous voltage regulation control strategies, without relying on communication with the power station controller.