23results about "Asynchronous generator control" patented technology

To provide an electric power conversion device and a power generation system, capable of shortening time until it outputs reactive power and improving an output response of the reactive power.SOLUTION: An electric power conversion device according to an embodiment includes: a converter of a power generation system where a direct current side terminal is connected to a direct current linkage unit to which a direct current side terminal of an inverter is connected; and a control device that, when a maximum reactive power command value of the converter is greater than or equal to a reactive power command value of the power generation system, provides the reactive power command value of the power generation system as the reactive power command value of the converter to output reactive power only from the converter.SELECTED DRAWING: Figure 1

The invention discloses an energy storage type phase modifier with a damping structure and a system, and belongs to the technical field of electric power equipment. The brush doubly-fed motor comprises a stator and a rotor. An air gap is formed between the stator and the rotor; three-phase symmetrical windings are arranged in the stator and the rotor; the damping structure is made of an electric conductor material and is arranged along the circumference of the notch of the rotor; the damping structure can be equivalent to a three-phase winding, and in the equivalent three-phase winding of the damping structure, each phase is self-short-circuited. The damping structure optionally comprises at least one of the following structures: a slot wedge made of an electric conductor, a cage bar and an end ring. According to the invention, the energy storage type phase modifier has the capabilities of suppressing the excitation current peak value and improving the short-circuit current on the premise of ensuring the high inertia supporting function, so that an excitation system is effectively protected, and the short-circuit voltage supporting capability of the motor is enhanced.

The application provides a starting method of an asynchronous generator, comprising the steps of: setting an auxiliary AC power supply; connecting the auxiliary AC power supply and a pre-charging loop of an AIM active interface module to limit current, rectifying by an ALM active power module and pre-charging a DC bus; connecting the auxiliary AC power supply and a main loop of the AIM active interface module, disconnecting the auxiliary AC power supply and the pre-charging loop of the AIM active interface module, rectifying by the ALM active power module and supplying power to the DC bus; starting the asynchronous generator by using the excitation energy provided by the DC bus; starting the ALM active power module and the AIM active interface module by using the electric energy generated by the asynchronous generator; disconnecting the auxiliary AC power supply and the main loop of the AIM active interface module, and connecting the main loop of the AIM active interface module and a power grid. The starting method can start the asynchronous generator without the power grid being powered. The application also provides a frequency converter system using the starting method.

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 provides an efficient power generation system for a low wind speed section of a doubly-fed generator, and the system comprises a stator short-circuit contactor which is connected between a stator of the doubly-fed generator and a stator grid-connected contactor. When the wind speed is low and the rotating speed of the generator is lower than a doubly-fed power generation range, a motor stator is short-circuited through a stator short-circuit contactor, and a unit is grid-connected to generate power in an asynchronous motor mode. And when the wind speed is high and the rotating speed of the generator enters a doubly-fed power generation range, the stator short-circuit contactor is disconnected, and the unit performs grid-connected power generation in a doubly-fed motor mode. The stator short-circuit contactor is connected between the stator of the doubly-fed generator and the stator grid-connected contactor, when the rotating speed of the low-wind-speed generator is lower than the doubly-fed power generation range, the stator of the motor is short-circuited through the stator short-circuit contactor, and the unit is in grid-connected power generation in an asynchronous motor mode. The power generation capacity of the wind turbine generator set under the low-wind-speed condition can be fully released, the overall power generation benefit of a wind power plant is improved, and efficient and stable operation of the wind turbine generator set under the low-wind-speed condition is achieved.

The invention provides a double-winding induction motor power generation system output voltage balance control method and system, aims to solve the problems of low output voltage balance degree and the like caused by uncertain and asymmetrical load disturbance of an aircraft variable-frequency alternating-current power generation system, and belongs to the technical field of variable-frequency alternating-current power generation. According to the invention, active suppression of the imbalance of the output voltage is realized, and the power supply quality is improved. The method can estimate and compensate the unbalanced voltage of the power winding side in real time, thereby effectively suppressing the unbalance degree of the output voltage, ensuring the symmetry and stability of the three-phase voltage, improving the electric energy quality of a double-winding induction motor power generation system, decomposing the three-phase asymmetric voltage into a positive sequence component and a negative sequence component, and improving the reliability of the double-winding induction motor power generation system. The negative sequence component in the power winding side voltage is accurately separated in real time through the orthogonal signal acquirer, and the unbalance degree of the voltage is judged according to the magnitude of the negative sequence voltage. The power supply can be applied to independent power supply application occasions such as airplanes and ships, and is high in universality.

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.

An electrical machine comprising a rotatable shaft; an induction generator mechanically coupled to the rotatable shaft and defining a power output connectable with an electrical load, wherein the power output defines a desired constant voltage output; a converter electrically connected with the power output; and a controller connected to the converter, the controller configured to at least one of provide supplemental power at the power output or absorb excess power at the power output.

The invention discloses a composite active-disturbance-rejection control method of a grid-connected inverter system based on a duplex-winding induction motor, and belongs to the technical field of motor control. Aiming at the control problems of multivariate, strong coupling and complex disturbance of the duplex-winding induction motor, the method comprises the following steps: firstly, listing a state equation of the duplex-winding induction motor; furthermore, a composite extended state observer is designed, a proportional element and a quasi-resonance controller are introduced into the observer on the basis of a traditional structure, and aperiodic disturbance and periodic disturbance with specific frequency can be estimated at the same time with high precision. According to the invention, the inhibition capability of the system on various disturbances is effectively improved, and the dynamic response speed and the steady-state control precision of the double-winding induction motor driving system are obviously improved.

An electrical machine comprising a rotatable shaft; an induction generator mechanically coupled to the rotatable shaft and defining a power output connectable with an electrical load, wherein the power output defines a desired constant voltage output; a converter electrically connected with the power output; and a controller connected to the converter, the controller configured to at least one of provide supplemental power at the power output or absorb excess power at the power output.

The invention belongs to the technical field of power system automation, and provides a new energy station voltage support type doubly-fed asynchronous motor control method and device, and the method comprises the steps: building an equivalent circuit model under a grounding short circuit fault of a new energy station; wherein a bus of the new energy station is connected with the doubly-fed asynchronous motor; establishing a power equation of the new energy station according to the equivalent circuit model; and controlling the doubly-fed asynchronous motor according to the power equation and the maximum voltage of the bus. According to the method provided by the embodiment of the invention, the active power and the reactive power emitted or absorbed by the doubly-fed asynchronous motor are coordinated and controlled, so that the voltage of the power grid system during the fault period can be supported to the maximum extent.

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.

An object of the present invention is to provide an electric power generation system that can stably control, with one electric power converter, output electric power of a main winding and an auxiliary winding of a dual-winding induction electric power generator. For this purpose, in an electric power generation system including an electric power generator having a stator including a main winding and an auxiliary winding, a rectifier connected to the main winding, an electric power converter that is connected to the auxiliary winding and controls voltages of the main winding and the auxiliary winding, and a controller that outputs a control signal according to a voltage command value of the auxiliary winding to the electric power converter, the controller calculates a voltage change amount of the auxiliary winding generated by interference of a magnetic flux of the main winding with the auxiliary winding, on the basis of a current and the voltage of the main winding, and adds the voltage change amount to the voltage command value of the auxiliary winding.

To provide a power generation system capable of suppressing fluctuation of DC voltage obtained from a main winding of a two-winding induction generator and fluctuation of DC voltage obtained from an auxiliary winding by one power converter.SOLUTION: A control unit 11 is configured to perform the steps of: calculating a state quantity KR that changes according to fluctuations in the required power of a load 4 connected to a rectifier 3 or a power converter 7; based on the state quantity KR, calculating a first voltage correction value ΔVmDC* for compensating for fluctuations in a first DC voltage VmDC and a second voltage correction value ΔVaDC* for compensating for fluctuations in a second DC voltage VaDC; adding the first voltage correction value ΔVmDC* to a command value VmDC* of the first DC voltage VmDC; and adding the second voltage correction value ΔVaDC* to a command value VaDC* of the second DC voltage VaDC.SELECTED DRAWING: Figure 9

A method of controlling an induction generator (3) connected to a utility grid (47) is described, the method comprising: receiving an actual grid frequency (f); and controlling a rotor winding (15) of the generator (3) by rotor control signals (25a, b, c) having a rotor winding reference frequency (Ω_ref) set in dependence on the actual grid frequency (f).

The invention relates to the technical field of induction motors. The technical problem to be solved is that the induction motor returns electric energy in heavy-load and overspeed states, increases power and returns electric energy at the same time in heavy-load and overspeed states, and increases resistance and returns electric energy at the same time in overspeed. And calculating the optimal working point and the control method of the common induction motor according to the characteristics of the energy return motor. According to the technical scheme, the energy-returning motor is composed of an input end, a rotor and an output end. The input end injects energy into the rotor, the rotor transmits the energy of the input end to the output end, and the output end induces the energy of the rotor to the output end to output electric energy. The energy return mode of the energy return motor must be that electric energy is returned from a rotor to a stator coil at an output end and cannot be returned from an input end to an output end directly. Main parameters influencing the energy-returning motor comprise power supply frequency, coil pole pair number or magnet pair number, coil and rotor combination mode and the like. The motor is mainly applied to places needing common motors in industry and agriculture.

An electric vehicle (EV) comprising a three-phase motor comprising a rotor and a stator, wherein the stator comprises N number of slots, and an inverter, configured to receive a sensed a three-phase current of the three-phase motor, and generate, based on the three-phase current, a three-phase alternating current (AC) voltage. The three-phase AC voltage comprises a harmonic that is associated with a fundamental frequency associated with a speed of a rotation of the three-phase motor. The three-phase AC voltage is fed as input to windings of the three-phase motor and causes the rotation of the rotor.

Provided in the present application is tubular pump power generation grid-connected control system based on a three-phase asynchronous electric motor. The system comprises a power generation module, an electric energy control module and a grid-connected module, wherein the power generation module is configured to convert mechanical energy transmitted by a tubular pump into electric energy, and is electrically connected to the electric energy control module; the electric energy control module generates a pulse signal on the basis of a PI controller and by means of ABC-αβ-dq coordinate transformation and flux linkage estimation, so as to drive the control system to operate, and is configured to convert, into direct-current electric energy, three-phase alternating-current electric energy outputted by means of power generation, and process the direct-current electric energy into electric energy consistent with power grid parameters; and the grid-connected module is configured to safeguard grid connection safety and prevent system operation overcurrent, and is electrically connected to the electric energy control module. In the present application, by means of a tubular pump and a three-phase asynchronous electric motor, mechanical energy is converted and processed into electric energy consistent with power grid parameters, thus being incorporated into a power grid. The system has a simple structure, is very suitable for energy-saving modification of wastewater discharged from a wastewater power plant, and meets the requirements of energy saving and emission reduction.

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.

A method of operating a wind turbine is provided, wherein the wind turbine comprises a power generating system (20) including a doubly-fed induction generator (21) that converts rotational mechanical power to electrical power. The method includes operating the wind turbine (100) in a first operational mode in which a speed of a rotor (101) of the wind turbine is controlled so as to maximize the power generation by the wind turbine. Upon a monitored parameter reaching or dropping below a respective threshold, the wind turbine is operated in a second operational mode. The monitored parameter may include at least one of the rotational speed of the rotor, the rotational speed (ωgen) of the doubly-fed induction generator (21), a wind speed, an active electrical power (Pactive) produced by the doubly-fed induction generator (21), or generator torque. Operating the wind turbine in the second opera- tional mode may include increasing the rotational speed (ωgen) of the doubly-fed induction generator (21) at the expense of the generation of active electrical power by the power generating system

This invention provides a method and system for output voltage balance control in a dual-winding induction motor power generation system, aiming to solve the problem of low output voltage balance caused by uncertain and asymmetrical load disturbances in aircraft variable frequency AC power generation systems. It belongs to the technical field of variable frequency AC power generation. This invention achieves active suppression of output voltage imbalance, improving power supply quality. It can estimate and compensate for unbalanced voltage on the power winding side in real time, thereby effectively suppressing output voltage imbalance, ensuring the symmetry and stability of the three-phase voltage, and improving the power quality of the dual-winding induction motor power generation system. It decomposes the three-phase unbalanced voltage into positive-sequence and negative-sequence components, and uses an orthogonal signal acquisition device to accurately separate the negative-sequence component in the power winding side voltage in real time, judging the voltage imbalance by the magnitude of the negative-sequence voltage. This invention can be used in independent power supply applications such as aircraft and ships, and has high versatility.

The invention relates to the technical field of electric power system modeling, in particular to a construction method and device for a multi-machine equivalent model of a wind power plant and a medium, and the method comprises the steps: carrying out the overall parameter identification of a grid-connected model based on an improved multi-target Lichberg algorithm, and obtaining a control parameter; inputting the control parameters into the grid-connected model to obtain a reactive current track and a dq-axis current component of the doubly-fed asynchronous wind driven generator of the wind power plant, and clustering the doubly-fed asynchronous wind driven generator according to the reactive current track and the dq-axis current component to obtain a plurality of class clusters; and performing parameter equivalence and network equivalence on the doubly-fed asynchronous wind power generator in each class cluster to obtain an equivalent doubly-fed asynchronous wind power generator corresponding to each class cluster, and constructing a multi-machine equivalent model of the wind power plant by using the equivalent doubly-fed asynchronous wind power generator and the static var generator. According to the invention, the deviation between the simulation result of the equivalent model of the wind power plant and the real dynamic behavior of the wind power plant is reduced.

The application discloses a comprehensive control mode flexible connection switching method applied to a DFIG, and the method comprises the following steps: using a current limiting module to ensure that the current limiting performance of each implementation stage of a control strategy can be maximized; introducing a resistance-capacitance crowbar to realize the switching impact limitation of the control mode, and designing an input and cut-off reference mechanism matched with the control switching of the application, so that the key problems encountered in the use of the crowbar are effectively solved; and integrating a state follow-up module into the converter control architecture of the DFIG to ensure the synchronization of parameters in the control mode switching process, so that the system can be effectively prevented from suffering from a major switching impact, and the smooth transition of the control mode is realized. During the state follow-up, the network configuration control strategy adopted by the RSC of the DFIG provides a reactive power compensation reference for the improvement of the GSC, so that a close internal relationship between different control modes is established in the switching process, instead of a simple time sequence splicing.