51results about "Asynchronous generator control" patented technology

A method of controlling the operation of a doubly fed induction machine is provided. The DFIM includes a stator electrically coupled to a power grid and a rotor rotating with a rotational speed. The DFIM has a synchronous rotational speed of the rotor and a rated rotational speed of the rotor. Rotation of the rotor at the synchronous rotational speed generates one or more slot harmonic distortions having a harmonic order. The method comprises operating the DFIM at the rated rotational speed of the rotor, wherein the rated rotational speed of the rotor is set to a value selected such that a shift of the harmonic order of one or more of the slot harmonic distortions at the rated rotational speed of the rotor is an integer number or is within a predefined limit of an integer number.

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.

A method of stabilizing a power supply includes, receiving, at a controller connected to an alternating current (AC) excitation source, a plurality of system inputs. The method further includes obtaining a harmonic spectrum of the load current on a hybrid asynchronous induction machine, determining based on the harmonic spectrum, a first low frequency spectrum of the load current with a greatest magnitude of oscillations. Additionally, the method includes controlling the AC excitation source to generate a first compensation signal and providing the first compensation signal to the hybrid asynchronous induction machine.

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.

The present application discloses a complex vector current control method for a dual-winding induction AC / DC generator system, which relates to the field of dual-winding induction motors. The method introduces a complex vector current controller into the current control of the dual-winding induction generator, achieves accurate tracking of the phase current by controlling the phase voltage of the winding, and also takes into account the cross-coupling terms in the antagonistic power winding. By designing the complex vector current and utilizing the decoupling terms to perform decoupling control, the interference between the power winding and the control winding is reduced, ensuring that the dual-winding motor system can stably perform current control at high speeds, thereby achieving better decoupling control in the high-speed AC / DC power generation of the dual-winding induction generator, improving the current decoupling effect at high speeds, and enhancing system performance, thereby effectively improving the system performance and parameter robustness of the dual-winding induction motor during high-speed AC / DC power generation control.

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.

A hybrid asynchronous induction machine includes a stator disposed in a stator housing, the stator comprising an input winding for a polyphase input signal, a primary output winding and a secondary output winding. The machine also includes a rotor having a shaft connected to a flywheel of an energy storage unit. The rotor comprises a primary rotor winding 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.

It is an object of the present invention to provide a drive system for dump trucks that is capable of reducing the capacity of a converter that excites a two-winding induced generator and of performing output control according to the converter capacity. To achieve the object, the drive system includes an induced generator having a primary winding including a main winding and a sub-winding, a rectifier for converting an AC voltage generated across the main winding into a DC voltage, a propulsive machinery side load connected to the rectifier, a converter connected to the sub-winding for exciting a secondary winding of the induced generator and converting an AC voltage generated across the sub-winding into a DC voltage, an accessory side load connected to the converter, and a controller for controlling the converter, in which the controller controls a DC voltage of the accessory side load according to electric power required by the accessory side load and controls a DC voltage of the propulsive machinery side load according to electric power required by the propulsive machinery side load and a converter capacity that represents a current capacity of the converter.

The invention discloses a method for constructing and simulating an electromechanical transient simulation model of a rate doubly-fed motor. The method comprises the following steps: constructing a doubly-fed motor model of the doubly-fed motor; initializing the doubly-fed motor body model to obtain an initialized doubly-fed motor model; solving the doubly-fed motor model by adopting an implicit trapezoidal integral solving method, obtaining the internal potential of the doubly-fed motor at the time step, and calculating the internal potential of the rotor side of a controller of the doubly-fed motor at the time step; solving an injection current based on the internal potential of the doubly-fed motor and the internal potential of the rotor side in the time step, and connecting the equivalent impedance of the rotor side, the equivalent impedance of the induction motor and the calculated injection current to an alternating current power grid of an electromechanical transient program to form an electromechanical transient simulation model containing the constructed doubly-fed motor model; and performing alternate iterative calculation on the electromechanical transient simulation model by adopting a multi-rate simulation method, and performing time-step propulsion to complete simulation of the electromechanical transient simulation model.

A system for supporting the stability of an electrical grid comprises an asynchronous electric machine with an accessible rotor circuit and a stator with a stator circuit connected to the grid. A flywheel is coupled to the rotor, for the machine to absorb electric energy and store it as kinetic energy, and to convert the stored kinetic energy in electric energy to be delivered to the grid A static converter is connected between the grid and the rotor circuit An electronic control measures a grid frequency and determines ROCOF values, being a derivative of the frequency In case of a change in the frequency, the machine immediately provides an uncontrolled natural inertial response. Moreover, the static converter is controlled such that the machine supplies a controlled synthetic inertial response wherein the active power absorbed / supplied is modulated according to the determined ROCOF value and the uncontrolled natural inertial response already provided.

The invention provides a method for improving the quality of output electric energy of a natural gas excess pressure asynchronous generator. The method comprises the following steps that 1, a three-phase asynchronous generator and a dynamic reactive power compensation device are connected to a generator set bus in parallel; 2, connecting the generating set bus with a low-voltage side bus of a transformer substation; 3, connecting a control device to the generating set bus; and 4, controlling the bus voltage Vm of the generator set of the dynamic reactive power compensation device and the power factor Pf of the bus contact loop of the transformer substation by the control device. The method for improving the output electric energy quality of the natural gas excess pressure asynchronous generator has the advantages that grid connection stability and power generation stability of the three-phase asynchronous generator set are achieved, and the reactive power adjusting capacity similar to that of the synchronous generator set and the reliable and high-quality electric energy quality are provided.

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 provides a variable-speed pumped storage unit rapid no-load grid connection method based on an improved ADRC controller, and the method comprises the steps: simplifying a variable-speed pumped storage unit into a single AC excitation asynchronous generator, and building a state space model of the AC excitation asynchronous generator under a no-load grid connection condition; an ADRC controller is constructed for the state space model, an extended Kalman state observer is introduced to improve the ADRC controller, and an EKO-ADRC controller is obtained; and the EKO-ADRC controller is used to carry out closed-loop control on the stator voltage amplitude, phase and frequency of the AC excitation asynchronous generator until the stator voltage amplitude, phase and frequency of the AC excitation asynchronous generator are consistent with the voltage amplitude, phase and frequency of a to-be-connected power grid, and zero impact current grid connection is realized. The invention provides a quicker no-load grid connection method for switching in power grid control, so that the soft switching in power grid working condition speed is effectively improved.

The present application relates to motor control technology, and provides a starting method, device and power equipment for a variable-speed pumped-storage unit. By connecting a crowbar device to the rotor of the variable-speed unit, the unit operates in an asynchronous motor mode, avoiding out-of-step of the unit caused by too fast acceleration during back-to-back starting and SFC starting, and increasing the starting success rate.

The present invention discloses a precise dynamic DQ0 equivalent circuit model of a doubly-fed asynchronous generator, comprising a stator circuit, a rotor circuit, and an excitation branch in which the stator circuit and the rotor circuit are mutually coupled, or an excitation branch in which the stator circuit and the rotor circuit are not mutually coupled; an excitation inductance is provided on the excitation branch in which the stator circuit and the rotor circuit are mutually coupled; the stator circuit comprises a stator branch, a stator port voltage, and a stator circuit rotating electromotive force, and the stator branch comprises a stator branch resistance and a stator branch leakage inductance; the rotor circuit comprises a rotor branch, a rotor port voltage, and a rotor circuit rotating electromotive force, and the rotor branch comprises a rotor branch resistance and a rotor branch leakage inductance. This solves the problem that existing conventional models cannot well interpret the internal potential of the stator circuit excited generator and the internal potential of the rotor circuit excited generator / motor potential, as well as the power flow analysis and calculation.

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.