48results about "Generator control circuits" patented technology

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.

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.

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 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.

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.

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 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 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.

The application provides a kind of multi-wind turbine cooperative operation control method for avoiding frequency secondary drop, comprising the following steps: first, the required DFIG for frequency support is dynamically selected by the real-time disturbance power of power grid and the speed level of each DFIG.Second, the virtual inertia control parameter is adaptively adjusted according to the system frequency and the speed change of DFIG participating in frequency support, to meet the demand of frequency support.Finally, the rotor kinetic energy of the remaining DFIG is released to support the recovery of the selected DFIG speed, to reduce the energy absorbed from the power grid in this process.The application adaptively adjusts the virtual inertia control parameter according to the system frequency and the speed change of DFIG participating in frequency support, to meet the demand of frequency support.And the rotor kinetic energy of the remaining DFIG is released to support the recovery of the selected DFIG speed, to reduce the energy absorbed from the power grid in this process, reduce the probability of frequency secondary drop and excessive speed drop of DFIG, so that DFIG can actively support the system frequency more stably.

The invention discloses a doubly-fed fan frequency change suppression method, system and device and a medium, and belongs to the technical field of doubly-fed fan control, and the method comprises the steps: collecting the detection data of a power grid where a doubly-fed fan is located, and calculating the phase locking frequency according to the detection data; calculating the frequency change rate of the power grid according to the phase locking frequency and the transfer function; according to the frequency change rate, a control signal is calculated and obtained through a reactive df / dt control algorithm; adding the control signal to a current instruction of the doubly-fed fan, and adjusting an internal potential component of the doubly-fed fan; adjusting the power angle difference between the internal potential of the doubly-fed fan and the power grid terminal voltage according to the internal potential component, and controlling the power grid frequency; and the output of the signal is controlled by judging the change trend of the power grid frequency. According to the invention, the problem that the recovery speed of the doubly-fed fan is slowed down or the safe operation of equipment and a system is affected by the existing df / dt control is solved.

The application discloses a double-fed converter LC virtual damping control method and device, the double-fed converter comprises a machine-side inverter, a double-fed generator and a network-side LC filter which are connected in sequence, the method comprises the following steps: obtaining a rotor instruction current according to a stator instruction current and a stator output current; obtaining a rotor output voltage according to a rotor output current and the rotor instruction current; and performing pulse modulation on the machine-side inverter according to the rotor output voltage, so as to control and adjust the output voltage of the machine-side inverter in the double-fed converter, indirectly control and adjust the output voltage of the generator stator, and realize virtual damping control of the network-side LC filter. The application has the advantages of simple realization method, low cost, high efficiency, and the ability to realize active damping of the network-side LC filter when the network-side output voltage is insufficient.

A method for operating a generator of a grid-forming inverter-based resource. The generator has a rotor and a stator. The method includes receiving, via a controller, an actual generator signal associated with a reference signal or a command signal of the generator. The method also includes determining, via the controller, an expected generator signal associated with the actual generator signal based, at least in part, on a plurality of electrical feedback signals. Further, the method includes determining, via the controller, an error signal based on a difference between the expected generator signal and the actual generator signal. The error signal is representative of a rotor position error with respect to a synchronous reference frame. Moreover, the method includes correcting, via the controller, a rotor signal associated with a command signal or a feedback signal of the rotor based on the error signal. In addition, the method includes controlling, via the controller, the generator based on the corrected rotor signal.

The invention discloses a method for judging transient instability of a doubly-fed wind power generation grid-connected system, which comprises the following steps of: during a transient period, calculating positive and negative sequence active and reactive current limits meeting a transient balance point under an asymmetric fault of a power grid; furthermore, whether the system has a transient equilibrium point or whether the acceleration and deceleration energy of the system is matched is judged by calculating the acceleration and deceleration areas of the positive and negative sequence components in the transient period, and then whether the system has transient instability is judged. According to the method, the transient stable state of the doubly-fed wind power stand-alone system in the asymmetric fault period can be accurately judged, the reason for instability of the doubly-fed power generation system is visually reflected, the direct-current voltage level of the unit in the transient stable state is evaluated, and then a theoretical basis is provided for research of a transient stability control scheme of the system.

The system includes a mains power supply (102) configured to supply power to at least one pulsed electrical load (114). The system also includes a propulsion converter (202) configured to drive a propulsion motor (204). The system further includes field-controlled induction electromachines (116, 224) coupled to at least one pulsed load. The field-controlled induction electromachines are configured to suppress one or more propulsion current harmonics generated by the propulsion converter and affecting at least one pulsed load.

The invention discloses a doubly-fed fan frequency change suppression method, system and equipment based on a phase-locked loop, and a medium, and belongs to the technical field of doubly-fed fan change suppression, and the method comprises the steps: collecting a power grid terminal voltage and doubly-fed fan data, inputting the power grid terminal voltage to the phase-locked loop for processing, and obtaining an initial output signal; the method comprises the following steps: acquiring initial output signals of a phase-locked loop, screening the initial output signals through a phase threshold to obtain output signals, judging an internal potential frequency change trend of the doubly-fed fan according to data of the doubly-fed fan, combining the change trend with the output signals to obtain phase adjustment signals of the phase-locked loop, and when frequency oscillation occurs in the doubly-fed fan, outputting the phase adjustment signals of the phase-locked loop. And adjusting lead-lag compensation according to the data of the doubly-fed fan, processing the phase adjustment signal according to the adjusted lead-lag compensation to obtain a compensation signal, feeding back the compensation signal to the doubly-fed fan, and adjusting the operating parameters of the doubly-fed fan. According to the invention, the frequency change of the doubly-fed fan of the phase-locked loop is suppressed, and the system stability is ensured.

This disclosure is directed to a method for operating a wind turbine which includes a speed-variable drive system. The system includes an electrical machine and a pulsewidth modulation-controlled converter. The speed-variable drive system is connected to an electrical grid. In the event of a transient grid fault, a frequency of the pulsewidth modulation is determined in response to a current in an electrical circuit connected to the converter.

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.

A system includes a main power source (102) configured to provide power to at least one pulsed electrical load (114). The system also includes a propulsion converter (202) configured to drive a propulsion motor (204). The system further includes a controllable-field induction electrical machine (116, 224) coupled to the at least one pulsed load. The controllable-field induction electrical machine is configured to suppress one or more propulsion current harmonics generated by the propulsion converter that affect the at least one pulsed load.

The application discloses a kind of double-fed network unit positive and negative sequence current collaborative control method and system, it is related to double-fed unit network control technical field, the method includes: S1.data acquisition;S2.coordinate transformation and positive and negative sequence separation;S3.negative sequence current collaborative enabling logic design and negative sequence current instruction distribution;S4.network loop control;S5.positive and negative sequence reference voltage synthesis and generation rotor reference voltage.The application aims to solve how to improve positive and negative sequence separation method to adapt to double-fed unit variable speed operation characteristics and combined with network control, and how to design the collaborative control strategy of machine network side negative sequence current ring, to realize the high stability, high reliability operation of double-fed unit under the condition of weak power grid and asymmetric power grid.

The invention discloses a wind storage joint black-start method and system fusing coupling terms and improved virtual synchronization, and belongs to the technical field of black-start power supply control. A control signal is determined by introducing a V / F control strategy of a coupling term and is output to a battery energy storage unit, and the battery energy storage unit is used for providing excitation for the doubly-fed asynchronous wind generating set to realize self-starting of the doubly-fed asynchronous wind generating set; an improved virtual synchronous control strategy is adopted to control a rotor side converter, the doubly-fed asynchronous wind generating set is connected into a power grid, and the doubly-fed asynchronous wind generating set which is successfully connected with the power grid is utilized to start remaining wind power plant units; and switching the V / F control strategy introduced with the coupling item into the P / Q control strategy introduced with the coupling item, and starting the thermal power generating unit. Through coupling item control, cooperation and flexible switching of a virtual synchronization strategy are improved, wind storage combined black start is efficiently achieved, stable grid connection and efficient power grid recovery are guaranteed, and the method adapts to a new energy scene.

The application provides a doubly-fed wind turbine controller additional damping control method and device, determines a doubly-fed wind turbine rotor current reference value, determines a pre-set current inner loop damping controller additional oscillation damping control instruction, and determines a doubly-fed wind turbine rotor control instruction; and controls the excitation current of the doubly-fed wind turbine rotor. The application determines the doubly-fed wind turbine rotor control instruction through the current inner loop damping controller additional oscillation damping control instruction, realizes the doubly-fed wind turbine controller additional damping control, the control process is simple, the calculation amount is small, and the damping system oscillation capacity can be provided, thereby improving the anti-interference capacity of the wind power grid-connected system; on the basis of the doubly-fed wind turbine rotor simplified control instruction and the doubly-fed wind turbine rotor control instruction compensation amount, the current inner loop damping controller additional oscillation damping control instruction is added, the equivalent damping of the wind power grid-connected system in the subsynchronous frequency band is increased, and the subsynchronous oscillation of the wind power grid-connected system is effectively inhibited.