72results about "Asynchronous generator control" patented technology

A control system configured to control switching of taps of an on-load tap changer provided on an electric power transformer. The on-load tap changer includes switches that are controllable to switch between transformer taps. The control system includes a detector configured to detect an indication of a zero crossing of a transformer voltage of the transformer and a control signal generator configured to generate a control signal that controls a switching of the switches for performing a tap change to a new transformer tap. The control signal generator is configured to determine the timing of the control signal for changing the transformer tap based on the detected indication of the zero crossing of the transformer voltage such that the switching of at least one of the switches for performing the tap change occurs a predetermined time prior to a zero crossing of a tap voltage at the new transformer tap.

The invention discloses an integrated control mode flexible connection switching method applied to a DFIG (Distributed Feedback Induction Generator). The method comprises the following steps of: ensuring that the current limiting performance of a current limiting module can be exerted to the greatest extent in each implementation stage of a control strategy by using the current limiting module; a resistance-capacitance crowbar is introduced to realize current limiting and reactive compensation, switching impact limiting of a control mode is carried out, an input and removal reference mechanism matched with control switching is designed, and then key problems encountered by crowbar use are effectively solved; a state follow-up module is integrated in a DFIG converter control framework, parameter synchronization in the control mode switching process is ensured, the system is effectively prevented from being subjected to great switching impact, and smooth transition of the control mode is further achieved. In the state follow-up period, a network construction control strategy adopted by the RSC of the DFIG provides a reactive compensation reference for the improvement of the GSC, and it is ensured that in the switching process, a tight internal relation is established between different control modes instead of simple time sequence splicing.

The invention discloses an adaptive power control method for a duplex-winding induction generator system, and belongs to the technical field of generator control. The double-winding induction generator system is composed of a double-winding induction generator, an energy storage unit, a static excitation converter and a diesel engine. According to the self-adaptive power control method, control winding current is decoupled into excitation control and electromagnetic torque control through coordinate transformation based on rotor flux linkage orientation, independent adjustment of output power of the generator is achieved, passive regulation and control of power of an energy storage unit are achieved through control of electromagnetic torque of the generator, and the self-adaptive power control method is achieved. The problem that the control freedom degree of a single converter system is insufficient is solved. Besides, according to the control method adopted by the invention, a dynamic planning-based generator / energy storage unit power distribution strategy with minimum fuel loss as a target is adopted, so that the generator is ensured to always work in a high-efficiency interval of the diesel engine within a wide load change range, and the power generation cost is remarkably reduced.

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 relates to the technical field of power generation control, and discloses a doubly-fed asynchronous power generation system and method for intelligently adjusting a converter module, and the system comprises a generator set, a dynamic converter, a converter controller, and a DC excitation controller. The generator set is a doubly-fed asynchronous generator in a synchronous generator state or an asynchronous generator state and a driving prime mover of the doubly-fed asynchronous generator; the dynamic converter sets the working mode of the generator according to the rotating speed value of the generator set; the variable current controller is used for performing power generation adjustment on the generator set according to the power generation mode and determining an excitation control scheme of the generator set; and the direct current excitation controller is used for carrying out direct current excitation on the doubly-fed asynchronous generator which is in a synchronous generator state and runs in a full-power conversion mode according to the excitation control scheme. Different power generation modes are adopted according to the operation rotating speed value of the doubly-fed asynchronous generator, the excitation control scheme is generated in the power generation process according to the power generation modes, and the power generation efficiency and the operation flexibility of a unit can be improved.

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.

This invention belongs to the field of generator systems and provides a self-excited switched reluctance generator system. The system includes: a generator stator and rotor, permanent magnets, a motor A-phase winding, a motor B-phase winding, a motor C-phase winding, and a controller. The generator stator and rotor include: a first stator core, a second stator core, a first output coil, an inner end plate, a bracket, a magnet slot, a second non-output coil, an outer end plate, a rotor core, and a motor shaft. This invention solves the problem of the switched reluctance generator failing to start under conditions without external excitation power by charging the capacitor within the controller using permanent magnets installed in the magnet slots. It also solves the problem of the switched reluctance generator system collapsing when a sudden load is applied, as the system capacitor voltage is pulled down to zero.

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.

The invention discloses a complex vector current control method for a duplex-winding induction AC / DC generator system, and relates to the field of duplex-winding induction motors, and the method introduces a complex vector current controller in the current control of a duplex-winding induction generator, and achieves the precise tracking of a phase current through the control of the phase voltage of a winding. Meanwhile, a cross coupling term in a countermeasure power winding is also considered, and decoupling control is performed by designing complex vector current and utilizing a decoupling term, so that interference between the power winding and a control winding is reduced, and a double-winding motor system can be ensured to stably perform current control at a high rotating speed; therefore, better decoupling control can be realized under the condition of high-rotating-speed alternating-current and direct-current power generation of the duplex-winding induction generator, the current decoupling effect under the high rotating speed is improved, the system performance is improved, and the system performance and parameter robustness during high-rotating-speed alternating-current and direct-current power generation control of the duplex-winding induction generator are effectively 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.

A propulsion channel for aircraft at least one first dual-fed polyphase asynchronous rotating electric machine configured to be mechanically coupled to a turbine engine. The propulsion channel further includes at least one second polyphase rotating electric machine electrically coupled to the first asynchronous rotating electric machine, and a control and storage module configured to control the first polyphase asynchronous rotating electric machine. The module is connected to the first dual-feed polyphase asynchronous rotating electric machine as well as to the at least second polyphase rotating electric machine. The at least second polyphase rotating electric machine includes a polyphase synchronous rotating electric machine with permanent magnet.

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 a drive system that is provided with an induction generator having a primary winding including a main winding and an auxiliary winding and a secondary conductor, can vary the voltage of the main winding, and can increase the maximum output power of the auxiliary winding. Therefore, provided is a drive system, which is provided with an induction generator having a primary winding including a main winding and an auxiliary winding and a secondary conductor, including: a starting battery that starts the induction generator; a traction inverter that drives a traction motor; an auxiliary device inverter that drives an auxiliary device motor; a rectifier the input side of which is connected to the main winding and the output side of which is connected to the traction inverter; and a power generation inverter the output side of which is connected to the auxiliary winding and the input side of which is connected to the auxiliary device inverter and the starting battery.

There is described a method of controlling an asynchronous generator system (3) connected to a utility grid (47), in particular an asynchronous generator system (3) of a wind turbine (1), the method comprising setting a rotational speed reference (n) of the asynchronous generator system (3) depending on a utility grid voltage (Ug).

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.