99results about "Generator control circuits" patented technology

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

The invention provides a zero-voltage ride-through control method for a self-synchronizing voltage source doubly-fed wind turbine generator, which comprises the following steps that: when the self-synchronizing voltage source doubly-fed wind turbine generator is in a transient state, a grid-side converter adopts vector control, and a rotor-side converter adopts additional virtual impedance and annular current limiting; the transient overcurrent of the grid-side converter and the rotor-side converter can be effectively suppressed, so that the continuous operation capability of the wind turbine generator in the zero-voltage ride-through period can be maintained; meanwhile, by improving the transient capacity and the transient reactive current amplitude of the converter, the transient voltage supporting capacity of the wind turbine generator during the zero voltage ride-through period can be effectively provided; when the self-synchronizing voltage source doubly-fed wind turbine generator set is in a transient state, overvoltage of direct-current bus voltage is limited by a Chopper circuit, active-priority current amplitude limiting control is adopted by a grid-side converter, parameters of a current inner ring PI controller of a rotor-side converter are optimized, energy balance of a direct-current side can be achieved in the zero-voltage ride-through period, and stability of the direct-current bus voltage is maintained.

The invention relates to a doubly-fed variable-speed pumped storage unit comprehensive inertia supporting method, device and equipment based on an excitation capacitor. The method comprises the following steps: acquiring a frequency deviation value and a frequency deviation change rate of a grid-connected point after a load connected with a power system is suddenly changed; determining whether to start a comprehensive inertia control strategy according to the frequency deviation value and the frequency deviation change rate; if the comprehensive inertia control strategy is started, dynamically adjusting a DC bus voltage reference value according to the frequency deviation value to determine a d-axis modulation voltage component; acquiring additional electromagnetic increment power; controlling a grid-side converter in the power system to operate according to the d-axis modulation voltage component, controlling a machine-side converter in the power system to operate according to the additional electromagnetic increment power, and providing inertial current impact support for the power system; and if the comprehensive inertia control strategy is not started, the frequency of the power system is kept stable and synchronous, and the doubly-fed variable-speed pumped storage unit of the power system is controlled to work in a constant power state.

The invention discloses a current compensation type three-vector model prediction control method for an off-grid doubly-fed wind turbine generator, belongs to the technical field of doubly-fed wind turbine generator control, and aims to solve the problems of voltage sag and high total harmonic distortion rate of a micro-grid system caused by sudden load change during off-grid operation of the doubly-fed wind turbine generator. The control method comprises the steps that on the basis of virtual synchronous networking control, an off-grid doubly-fed wind turbine generator rotor current prediction model is established, load current, stator side converter current and stator voltage are introduced into three-vector model prediction control, and the voltage coupling effect and current change caused by load abrupt change are compensated in real time, so that the rotor current of the off-grid doubly-fed wind turbine generator is predicted. Obtaining a compensated rotor current reference; a cost function is designed by taking the minimum prediction error of the rotor current as a target, so that accurate prediction of the rotor current during sudden load change is realized, a voltage sag phenomenon caused by sudden load change is effectively inhibited, the harmonic content of output voltage is reduced, and meanwhile, quick response to system frequency and load power is realized.

The invention discloses an AC excitation system no-load voltage buildup and pre-synchronization grid-connected control method and system, and the method comprises the steps: obtaining the amplitude and phase of a power grid voltage in real time through a phase-locked loop when the rotating speed of a doubly-fed induction motor reaches a synchronous rotating speed range; detecting the mechanical position of the rotor by using an encoder and calculating a slip angle; carrying out fundamental component extraction and phase correction on the stator side no-load voltage; setting a stator voltage target value based on power grid voltage directional control and calculating target rotor current; constructing a rotor current inner loop control loop, calculating a feedforward decoupling item and performing phase compensation; superposing a stator voltage outer loop control loop, and correcting the rotor current through closed-loop adjustment to eliminate the deviation between the stator side no-load voltage and the power grid voltage; and when a preset synchronization condition is satisfied, closing the grid-connected circuit breaker and switching a control mode. Accurate no-load voltage buildup and smooth pre-synchronization grid connection of the excitation system are achieved through a double closed-loop control structure, and the stability and reliability of the grid connection process are improved.

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.

The invention provides a multi-target control method for a permanent magnet direct drive fan under an asymmetric fault of a power grid, and solves the technical problems of power fluctuation suppression and current unbalance degree reduction control target coordination optimization in fault ride-through. Comprising the following steps: S1, establishing a positive and negative sequence coordinate system model of a permanent magnet direct-driven wind turbine generator grid-side converter, and carrying out positive and negative sequence separation on voltage and current of the grid-side converter; s2, grid-side converter reference current instructions of the three control targets are calculated; s3, constructing a uniform expression form of the reference current of the grid-side converter; s4, active power fluctuation suppression and negative sequence current suppression are selected as coordinated optimization control targets for control; and S5, constructing a multi-objective optimization function, solving to obtain a current reference value of the converter, and performing current closed-loop control on the grid-side converter. The method has the advantages that multi-target coordination optimization control over the permanent magnet direct-driven wind turbine generator set under the power grid voltage fault is achieved, and the low-voltage ride-through capacity and the grid connection performance of the permanent magnet direct-driven wind turbine generator set are enhanced.

This invention discloses a method and system for no-load voltage build-up and pre-synchronization grid connection control of an AC excitation system. The method includes: acquiring the amplitude and phase of the grid voltage in real time via a phase-locked loop when the speed of the doubly-fed induction motor reaches the synchronous speed range; detecting the rotor mechanical position and calculating the slip angle using an encoder; extracting the fundamental component and correcting the phase of the stator-side no-load voltage; setting a target value for the stator voltage based on grid voltage-oriented control and calculating the target rotor current; constructing an inner-loop control loop for the rotor current, calculating the feedforward decoupling term and performing phase compensation; superimposing an outer-loop control loop for the stator voltage, and correcting the rotor current through closed-loop adjustment to eliminate the deviation between the stator-side no-load voltage and the grid voltage; and closing the grid connection circuit breaker and switching the control mode when the preset synchronization conditions are met. The dual-closed-loop control structure achieves precise no-load voltage build-up and smooth pre-synchronization grid connection of the excitation system, improving the stability and reliability of the grid connection process.

A method for providing grid formation control of a doubly-fed generator of a wind turbine includes receiving one or more voltage commands from an external controller via a stator voltage regulator of a converter controller. Further, the method includes determining one or more rotor current commands from a magnetizing current command and a stator current feedback signal of the doubly-fed generator via the stator voltage regulator. Accordingly, the method includes using the one or more rotor current commands to control a rotor voltage of the doubly-fed generator to achieve the one or more voltage commands.

This invention relates to a method and system for analyzing fault currents and optimizing parameters in doubly-fed induction generator (DFIG) wind turbines, belonging to the field of power technology. To address the shortcomings of existing analytical formulas for DFIG fault currents, including insufficient analysis of control factors in DFIG controllers and poor practicality, this invention first establishes a mathematical model of the DFIG fault current generator (DFIG). Then, it analyzes the roles of RSC, GSC, and Crowbar protection and establishes a fault ride-through controller model. Through the derivation of the mathematical model, a detailed analytical formula for the DFIG fault current is obtained. Finally, using a differential evolution intelligent algorithm based on field-measured DFIG fault current waveforms, the analytical formula is optimized. This invention is used for fault current analysis in doubly-fed induction generator (DFIG) wind turbines.

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 wind turbine generator network-related performance optimization method adaptive to high-power fault impact. The method comprises the following steps: step 1, constructing a multi-sequence domain model of a double-fed wind turbine generator under high-power fault impact; 2, constructing a double-layer optimization model taking the minimum de-excitation time constant as an upper layer and the minimum voltage unbalance degree as a lower layer; and step 3, solving the multi-sequence-domain model based on the double-layer optimization model to obtain rotor de-excitation and positive and negative sequence current instructions. According to the method, rotor multi-sequence domain finger current instructions can be coordinated on the premise that stress constraint is met, the unbalanced voltage suppression capability of the doubly-fed fan is remarkably improved while rapid de-excitation is considered, and a reference is provided for improving the grid-related performance of the doubly-fed fan.

The present application relates to a grid-forming power source system, a control method and apparatus therefor and a controller therefor, and a medium, and belongs to the technical field of power. The grid-forming power source system comprises: a new-energy power generation unit, which is connected to a power grid by means of a power output line; and an energy storage unit, which is connected to the power output line for the new-energy power generation unit, and is connected to the power grid after being connected in parallel with the new-energy power generation unit, wherein the energy storage unit comprises an energy storage converter, and the energy storage converter is used for controlling the magnitude of an output current of the energy storage unit, such that the total current output by the grid-forming power source system meets power grid requirements. By means of the embodiments of the present application, the safety and stability of a power system can be improved.

The application discloses a double-fed fan subsynchronous oscillation additional damping controller based on capacitor current compensation and relates to the field of novel power system stability analysis and control; solves the problems that the existing controller is relatively complex in determining control parameters, lacks universality and operation parameters cannot be modified at will; comprises a small signal model structure based on double-fed induction fan and weak power grid grid connection, and a general phase lead compensation link controller; phase compensation controller parameters are determined through double-fed induction fan voltage and current frequency response curves; the original system control structure can be not changed, the original control parameters of the system do not need to be adjusted, direct DC current signals are obtained from the DC capacitor part of the double-fed fan, control currents are injected in the form of controlled current sources, the rotor side control and the grid side control are decoupled, and the subsynchronous oscillation phenomenon caused by the interaction between the double-fed fan phase-locked loop and the weak power grid is suppressed.

The application discloses a kind of static reactive generator and the reactive compensation method of double-fed fan cooperation, including obtaining the data information of target power system, static reactive generator and double-fed fan;It is determined and the power distribution of reactive compensation that target power system reactive compensation is carried out;According to the power distribution result, double-fed fan is preferentially mobilized, and the reactive compensation of double-fed fan is realized;According to the power distribution result, static reactive generator is called, and the reactive compensation of static reactive generator and double-fed fan cooperation is realized.The application also discloses a kind of system for realizing the reactive compensation method of static reactive generator and double-fed fan cooperation.The application sets up reactive compensation priority scheme according to the characteristics of static reactive generator and double-fed fan, and continues to correspond to the control of double-fed fan and static reactive generator, so the application not only can realize the reactive compensation of static reactive generator and double-fed fan cooperation, but also has higher reliability and better accuracy.

The application discloses a full-order terminal sliding mode control method for a brushless doubly-fed motor independent power generation system, and belongs to the field of motor control. The application solves the problem that the traditional full-order terminal sliding mode control algorithm does not simultaneously consider the matching and non-matching uncertainty caused by motor parameter perturbation in the motor model, resulting in low system output voltage precision, poor system anti-interference ability and control effect. According to the brushless doubly-fed motor mathematical model, the application considers the matching and non-matching uncertainty caused by brushless doubly-fed motor parameter perturbation, determines the voltage loop state equation of the non-matching power winding outer ring voltage subsystem and the current loop state equation of the matching control winding inner ring current subsystem, and designs corresponding inner and outer loop full-order terminal sliding mode controllers for the subsystems to compensate the uncertainty, so that the tracking error of the power winding voltage amplitude converges to zero, and the tracking error of the control winding current amplitude converges to zero. The application is mainly suitable for independent power generation control when the brushless doubly-fed motor is connected to a balanced load.

A method for operating a multi-stage bridge power converter in an electrical power system includes connecting multiple phases of the power converter to a common terminal on the DC side of the power converter to effectively make the multiple phases equal at a common potential. The method may further include fault monitoring of multiple devices of the power converter via a controller. Upon detecting a fault in one or more of the multiple devices, the method includes activating one or more protective devices of the power converter via the controller to prevent further faults in the remaining devices by diverting energy from the remaining devices.

This invention discloses an enhanced hybrid synchronization control method for grid-type doubly-fed induction generator (DFIG) wind turbine converters, belonging to the field of electrical engineering. The control method includes enhanced hybrid synchronization control based on an adaptive integrator, reactive power-voltage droop control, and dual closed-loop control of stator voltage and rotor current. Traditional hybrid synchronization control algorithms for grid-type converters, which rely on virtual impedance, cannot solve the resynchronization stability problem of grid-type DFIG wind turbine converters when facing fault scenarios such as grid voltage dips. Furthermore, existing parameter design methods are no longer applicable to grid-type DFIG wind turbine converter systems. This invention introduces a voltage synchronization loop based on an adaptive integrator, effectively ensuring the existence of a stable operating point during faults. The established adaptive integrator parameter design principles can guarantee the adaptive adjustment capability of the DFIG wind turbine converter for synchronous stability under different fault conditions.

A method for isolating faults in an electrical power system connected to a power grid includes dividing the electrical power system into a plurality of power modules each including a plurality of electrical power subsystems and a substation. Each of the electrical power subsystems defines a stator power path and a converter power path for providing power to the power grid and having a partial power transformer. The method also includes coupling each of the power modules to the power grid via a primary electrical line. Further, the method includes monitoring the electrical power system for faults. In response to detecting a fault in one of the power modules, the method includes isolating the fault to the power module experiencing the fault. In contrast, if the fault is detected in the primary electrical line or the power grid, the method includes tripping the electrical power system.

A control system 200 for an electrical machine is provided. The electrical machine configured to be electrically coupled to an electric power system, wherein the electric power system is configured to transmit at least one phase of electric power to and from the electrical machine, the control system facilitates the electrical machine remaining electrically connected to the electric power system during and subsequent to at least one voltage amplitude of the electric power operating outside of a predetermined range for an undetermined period of time.

This invention discloses a method for suppressing subsynchronous oscillations in a doubly-fed grid-connected system, relating to the field of power system stability control technology. The specific steps of the method are as follows: S100 extracting the amplitude and phase angle of the subsynchronous frequency component; S200 generating a rotor compensation current command from the amplitude, phase angle, and dynamic gain of the subsynchronous component; S300 dynamically adjusting the gain during operation based on the suppression rate and the target magnetic field amplitude; S400 calculating the feedforward decoupling voltage; S500 calculating the suppression rate after injection and executing a hierarchical control strategy. This invention achieves subsynchronous oscillation suppression at the electromagnetic level. By real-time monitoring of the subsynchronous component of the air gap magnetic field and injecting a reverse-phase compensation current on the rotor side, the stator and rotor magnetic fields actively interfere and cancel each other in the subsynchronous frequency band, directly blocking the energy transfer path of the subsynchronous oscillation and destroying the oscillation formation conditions. The dynamic gain adjustment mechanism optimizes the compensation intensity based on the real-time suppression effect to cope with the frequency variation of the 5-45Hz subsynchronous oscillation.

The present invention relates to a method of operating an inverter-based resource connected to a series-compensated transmission system. A method for operating an inverter-based resource includes monitoring a current magnitude value in the inverter-based resource. The method also includes monitoring a voltage magnitude value in the inverter-based resource. Further, the method includes comparing the current magnitude value in the inverter-based resource to a primary current threshold. Moreover, the method includes comparing the voltage magnitude value in the inverter-based resource to a voltage threshold. As such, the method also includes disabling switching of switching elements of a power converter when the current magnitude value increases above the primary current threshold and the voltage magnitude value decreases below the voltage threshold to bypass the switching elements of the power converter until excess energy in the inverter-based resource is dissipated.

The application discloses a direct power control method of a brushless doubly-fed generator under an unbalanced power grid, and aims to solve the technical problems of great limitations of vector control and great steady-state error of a system in the prior art. The application establishes a mathematical model of positive and negative sequence coordinate axes of the brushless doubly-fed generator by positive and negative sequence voltage decomposition under unbalanced power grid voltage; and establishes a relational equation between the voltage at the control winding side and active power and reactive power at the power winding side based on the positive and negative sequence voltage vectors to realize decoupling control of the active power and the reactive power; and improves a sliding mode control approach law to overcome the shortcomings of traditional sliding mode control chattering and discontinuous high-frequency switching control, adopts an extended state observer to suppress system disturbance, and reduces the steady-state error of the system; and given negative sequence current commands are regulated by PI regulation to realize multi-target control and make the brushless doubly-fed generator achieve stable operation under the unbalanced power grid, can effectively reduce power fluctuation caused by unbalanced power grid voltage, has strong robustness, and improves the stability of the system.

The invention discloses a method, a system, equipment and a medium for adaptively improving an inertial response effect and frequency damping based on a phase-locked error, and relates to the technical field of power grid inertial response, and the method comprises the following steps: representing the phase-locked error through a q-axis voltage component obtained through coordinate transformation of a grid-connected point three-phase voltage signal; inputting the q-axis voltage component into an inertia control link to obtain an additional torque or active power instruction value; adaptively adjusting the damping coefficient T based on the absolute value of the q-axis voltage component; superposing the additional torque or active power instruction value with active power or torque instruction values generated in other links to obtain a target instruction value at the next moment; and d-axis and q-axis components of the excitation voltage are calculated through a proportional-integral controller, and a control signal of the rotor-side converter is generated through inverse coordinate transformation. A q-axis component in three-phase voltage of a grid-connected point is extracted to accurately represent a phase locking error, and in combination with adaptive damping adjustment, rapid identification and active response to power grid frequency disturbance are realized.

The present invention relates to systems and methods for controlling reactive power from a reactive power compensation device, and in particular a method for operating a power generation system that provides active and reactive power to a power grid includes receiving a reactive power demand made to the power generation system in operating conditions of the power generation system and the power grid. Further, the method includes separating reactive power control and voltage control between a generator and the reactive power compensation device in order to reduce an oscillatory response of the reactive power output from the reactive power compensation device and the generator. Further, the method includes operating the reactive power compensation device in a reactive power control mode via a device controller to generate at least a portion of the reactive power demand.

A hybrid asynchronous induction machine (600) includes a stator (601) disposed in a stator housing (603), the stator comprising an input winding (605) for a polyphase input signal, a primary output winding (610) and a secondary output winding (615). The machine also includes a rotor (650) having a shaft (651 ) connected to a flywheel (653) of an energy storage unit (125). The rotor comprises a primary rotor winding (655) for a polyphase AC excitation signal and a secondary rotor winding for bidirectional power flow. The hybrid asynchronous induction machine is further configured to receive a compensation signal for cancelling low-frequency electrical resonances.

The invention is suitable for the technical field of torque control, and provides a torque control method, device and equipment of a wind generating set, the wind generating set comprises a converter and a generator, and the method comprises the steps that the current actual temperature of an IGBT module located in the converter and the current actual rotating speed of the generator are obtained; based on the corresponding relation between the actual temperature and the synchronous rotating speed interval, the current synchronous rotating speed interval is determined according to the current actual temperature; determining a corresponding current torque threshold value according to the current actual rotating speed based on a corresponding relation between the actual rotating speed and the torque threshold value in the current synchronous rotating speed interval; determining a target torque according to the current torque threshold value, so that the target torque of the generator is smaller than or equal to the current torque threshold value; and by controlling the alternating current device, the generator outputs the target torque. According to the invention, the technical problem that the reliable operation of the converter is affected due to the fact that the generator is easy to respond to large torque and the temperature of the IGBT module is too high when the generator operates near the synchronous rotating speed for a long time can be solved.

A method of detecting whether a stator distortion filter is connected to a generator of an electrical power system includes temporarily interrupting magnetic flux excitation of a generator of the electrical power system. The method also includes observing a sinusoidal waveform of one or more electrical feedbacks of the generator. Further, when the sinusoidal waveform persists longer than a predefined duration, the method includes determining that the passive load is connected to the generator of the electrical power system. When the sinusoidal waveform abruptly decays below a threshold in a time period less than the predefined duration, the method includes determining that the passive load is not connected to the generator of the electrical power system. Moreover, the method includes implementing a control action based on whether the passive load is connected to the generator of the electrical power system.