126results about "Asynchronous generator control" patented technology

A controller (28) for a doubly fed induction generator (12,20) adjusts control signals to a rotor side converter (24) and line side converter (22) to adjust rotor current when a voltage transient on a utility grid (10) occurs, so that the doubly fed induction generator can ride through the transient. The controller can also turn off the transistors of the rotor side converter (24) to reduce rotor current and / or activate a crowbar (42) to reduce the voltage of the DC link (26) connecting the converters (22, 24) when significant voltage transients occur on the grid (10). This permits continued operation of the DFIG system without disconnecting from the grid.

A controller (28) for a doubly fed induction generator (12,20) adjusts control signals to a rotor side converter (24) and line side converter (22) to adjust rotor current when a voltage transient on a utility grid (10) occurs, so that the doubly fed induction generator can ride through the transient. The controller can also turn off the transistors of the rotor side converter (24) to reduce rotor current and / or activate a crowbar (42) to reduce the voltage of the DC link (26) connecting the converters (22, 24) when significant voltage transients occur on the grid (10). This permits continued operation of the DFIG system without disconnecting from the grid.

This disclosure relates to transient energy systems for supplying power to a load substantially instantaneously on demand. Transient energy systems may include a flywheel coupled the rotor of an induction motor generator. One embodiment of the disclosure refers to systems and methods for reducing loads on a bearing in a transient energy system. In another embodiment, the disclosure refers to an induction motor generator that is optimized for high power transient power generation, yet low power motor operation. Yet another embodiment of the disclosure refers to using a flywheel as a drag pump to cool components of a transient energy system. In yet another embodiment, a slip control scheme is discussed for regulating a DC bus. In yet a further embodiment of the disclosure a method is provided for reducing unnecessary turbine starts by making turbine start a function of the rotational velocity of a flywheel.

Disclosed herein is an electric power converting device and power converting method for controlling doubly-fed induction generators, which provides a synchronous generator for generating auxiliary electric power independently of a doubly-fed induction generator so as to generate electricity even in a system power-free environment, a grid-side converter is composed of a three-phase four-wire converter so as to generate a balanced voltage even in an unbalanced load condition and automatically synchronize a stator voltage of a doubly-fed induction generator and a system voltage with each other.

Disclosed herein is an electric power converting device and power converting method for controlling doubly-fed induction generators, which provides a synchronous generator for generating auxiliary electric power independently of a doubly-fed induction generator so as to generate electricity even in a system power-free environment, a grid-side converter is composed of a three-phase four-wire converter so as to generate a balanced voltage even in an unbalanced load condition and automatically synchronize a stator voltage of a doubly-fed induction generator and a system voltage with each other.

A system and method for providing constant-frequency electrical power from variable-speed mechanical power are disclosed. The system includes a wound-rotor induction machine generator (WRIMG), a first power converter, e.g., an inverter or a bridge rectifier, that provides power from the stator assembly of the WRIMG to the load, and a second power converter, e.g., an inverter or a bridge rectifier, that provides power from the rotor assembly of the WRIMG to the load. A controller controls the output stator-current based on comparisons between measured DC load bus data and a reference DC load bus voltage value, measured machine shaft angular position and reference rotor frequency data, and measured stator-current data that is fed-back to the stator-current controller by the power converter device(s).

To shorten a startup interval to reach a synchronizing condition, a phase difference and an amplitude difference between the grid voltage and the stator voltage of one phase of a winding are obtained. The difference in amplitude is decreased prior to or in parallel to synchronizing the stator voltage with the grid voltage. The calculated compensation phase compensation value is used as an initial value for synchronizing at the next synchronizing operation.

A system includes an induction generator controller configured to operate an induction generator via a converter. The induction generator controller includes a diagnostic mode configured to instruct the converter to send an input signal to a rotor of the induction generator, receive an output signal from the rotor and a stator of the induction generator, and identify winding faults within the rotor and / or the stator based on the output signals.

The present subject matter is directed to systems and methods for controlling variable speed generators, particularly converters associated with doubly-fed induction generators (DFIG) to permit use of harmonic attenuating filters that are generally smaller and less costly than previous similar filters. The subject matter provides for controlling line-side and rotor-side converters in such a manner that the frequencies generated by the converters are interleaved in a manner that the filters see a higher switching frequency and thus may be designed based on those higher frequencies, thereby requiring smaller and less expensive components.

A wind turbine and generator arrangement comprises a turbine that drives a self-excited induction generator via a shaft and mechanical gearbox. The induction generator includes an electrical circuit that includes a variable capacitance and a variable resistance. The variable capacitance may be constituted by a fixed capacitor and a triac under the control of a controller, or by a bank of capacitors switched by a relay under control of the controller. The variable resistance includes a triac controlled resistor or a bank of relay-switched resistors which constitute heating elements for heating domestic hot water. In use the generator frequency and voltage are allowed to ‘float’ whilst the optimal generator power output is maintained, but adjusting the impedance of the electrical circuit as the wind speed varies.

An apparatus for producing hydrogen having compressor motor speed control. The apparatus includes a hydrogen generator for producing a product comprising hydrogen and a compression unit for compressing the product. The hydrogen generator can include a fuel processor having an oxidizer and a reformer. The compression unit has an induction motor and means for regulating the speed of the motor. The means for regulating the speed of the motor can include a variable frequency drive or soft start device having a plurality of switches and an adjustable ramp timer. A downstream unit including one or more of a purification unit, a second compression unit, and a storage unit is disposed downstream of the compression unit. A method for producing hydrogen is provided that includes generating a product comprising hydrogen in a hydrogen generator, compressing the product in a compression unit having an induction motor and regulating the speed of the motor in response to transient operations of the hydrogen generator.

The invention provides a current control method and device without a phase-locked loop of a dual-fed induction power generator. The method comprises the steps of acquiring a parameter of the dual-fed induction power generator, and performing coordinate conversion to obtain a stator voltage vector U<s Alpha Beta> and a stator current vector I<s Alpha Beta>; performing coordinate conversion on the stator voltage vector U<s Alpha Beta> and the stator current vector I<s Alpha Beta> to obtain a stator voltage vector U<s d q> and a stator current vector I<s d q>; calculating a d-axis instruction and a q-axis instruction of the stator current vector I<s d q> of the dual-fed induction power generator; calculating a rotor voltage instruction U<r d q> under a virtual synchronous rotation coordinate system; performing coordinate conversion on rotor voltage instruction U<r d q> to obtain a rotor voltage instruction U<r Alpha Beta> under a two-phase static Alpha-Beta coordinate system, and further generating a group of pulse width modulation (PWM) signals so as to control a rotor converter of the dual-fed induction power generator. With the technical scheme provided by the invention, the design and implementation process of a control system is simplified, and the adaptability to parameter change of the power generator of the control system is improved.

An electrical power generator is provided which is a direct drive induction generator capable of being directly connected to the power grid for the creation of electrical power. The rotor of the induction generator is located along the outside periphery of the stator and the stator may be provided with a plurality of poles. The number of poles provided on the stator may be adjusted to obtain an optimal rotational speed required to generate power. Using this arrangement, a low cost, efficient, reliable and easy to build wind generator may be provided.

The invention discloses a control system for improving the frequency support capability of a wind turbine generator set by a super capacitor. The system comprises a wind wheel, a gear case, a generator, a converter, a crowbar protection, a box transformer substation and the super capacitor, wherein the wind wheel, the gear case, the generator, the converter and the crowbar protection are orderly connected with one another; the box transformer substation is connected with a power grid; the super capacitor is added to a DC bus of the converter; the super capacitor is connected with the DC bus of a wind turbine converter through a DC / DC converter; and the super capacitor can carry out ordered charging and discharging and maintain the operating conditions according to the operating state of the wind turbine generator set, and has relatively good reliability.

The invention discloses a wind power generation system for direct-drive dual stator-winding induction generator, which is characterized in that the wind power generation system for direct-drive dual stator-winding induction generator comprises a main loop, a detection loop and a control loop; the main loop consists of a direct-drive dual stator-winding induction generator, a rectifier bridge, a power winding side DC capacitor, a filter inductor, a control convertor, an excitation capacitor bank, and a control-side DC capacitor; the detection loop consists of a current sensor, and voltage sensors the number of which is m; the control loop consists of a digital signal processor and a drive circuit for control convertor. The wind power generation system for direct-drive dual stator-winding induction generator outputs higher voltage (which can reach the KV level) under a low speed and the control winding of the wind power generation system for direct-drive dual stator-winding induction generator is designed to operate under a lower voltage class. By jointly controlling the excitation capacitor bank and control convertor, the wind power generation system has better steady-state and dynamic performance and has the advantages of direct drive operation, inexistence of brush slip ring, wide wind velocity power generation, low cost, etc.

A system and method is provided for generating DC power using a synchronous reluctance machine (12) or a salient-pole synchronous machine (102) and a power converter (110). The present invention can be used to achieve power production for a synchronous reluctance machine (12), or can be used to achieve partial production of power from a traditional salient-pole synchronous machine / starter (102) in the case where the salient-pole synchronous machine / starter has degenerated into a synchronous reluctance machine due to, for example, a loss of excitation. In a power generation system, a control system and method can include a power converter (110), controlled by a voltage command and at least one of a measured DC link (120) voltage or DC link (120) current, for use with a synchronous reluctance machine armature winding (102A) and a prime mover (116), such that movement of the synchronous reluctance machine rotor of the synchronous reluctance machine can be used to produce at least partial DC power generation.

A permanent magnet (PM) electric generator with directly controllable field excitation control comprises: a drive shaft; a PM rotor assembly with multiple PMs arranged around an outer axial periphery of the rotor assembly; a stator assembly comprising a ferromagnetic stator yoke, multiple ferromagnetic stator teeth mounted to the stator yoke with distal ends proximate the outer axial periphery of the rotor assembly separated by an air gap and multiple stator coils mounted between the stator teeth; multiple saturable ferromagnetic shunts, each shunt coupling adjacent distal ends of the stator teeth to shunt air gap magnetic flux Φg generated by the PMs across the air gap through the distal ends of the stator teeth; and multiple saturation control coils, each saturation control coil wrapped about a saturable region of an associated one of the shunts; wherein application of a control current Ic to the control coils at least partially magnetically saturates the shunts to reduce shunting of air gap magnetic flux Φg, thereby increasing magnetic flux linkage ΨM between the PMs and the stator coils and increasing generated electromagnetic force (EMF) at lower levels of rotor assembly angular velocity.

A wind turbine generator system can regulate the rotational velocity of the wind turbine within an operation range even when the wind velocity suddenly changes and can perform continuous operation of the wind turbine. The wind turbine generator system includes a generator connected to the shaft of the wind turbine and a converter connected to the generator. When the rotational velocity of the wind turbine is within a predetermined range, power outputted from the generator is controlled so as to follow the instruction concerning the generator output given from the wind turbine to the converter. When the rotational velocity of the wind turbine is out of the predetermined range, the power outputted from the generator is controlled without following the instruction concerning generator output given from the wind turbine to the converter.

An apparatus including a fixed part, a rotary support configured to be driven in rotation relative to the fixed part, at least one item of electrical equipment carried by the rotary support, and a power supply device configured to supply electrical energy to the electrical equipment. The power supply device includes an asynchronous machine including a stator fixed to the fixed part and a rotor carried by the rotary support, and an excitation device. The stator includes an electrical circuit including at least one switch configured to switch between an open state in which the electrical circuit is open and a closed state in which the electrical circuit is closed. The rotor includes at least one winding connected to the electrical equipment. The excitation device is configured to provide a reactive current to the electrical circuit of the stator or to the winding of the rotor.

The invention provides a fault-tolerant instantaneous torque controlled asynchronous motor power generation system and a control method thereof. The fault-tolerant instantaneous torque controlled asynchronous motor power generation system comprises a main circuit, an initial excitation circuit, a detection circuit and a control circuit, wherein the main circuit comprises an asynchronous motor, a fault-tolerant converter, a first bus capacitor and a second bus capacitor; the fault-tolerant converter is composed of a three-phase bridge arm and a bidirectional thyristor; after the asynchronous motor power generation system is subjected to fault tolerance, a three-phase six-switch converter is turned into a two-phase four-switch converter; as long as a new optimal voltage vector selection table is redesigned according to the characteristics of the voltage vector of the two-phase four-switch converter, quick control of the instantaneous torque of the asynchronous motor power generation system can be continuously achieved, so that the asynchronous motor power generation system after being subjected to the fault tolerance keeps the advantages that the control algorithm is simple, the effect of motor parameters is less and the dynamic property is good. The fault-tolerant instantaneous torque controlled asynchronous motor power generation system is reasonable in design and simple in circuit structure, the cost increase is limited, and the working reliability of the asynchronous motor power generation system is greatly improved.

Conventional electric power generation system employ a solid state electronically controlled IM that may be capable of self-start motoring and power generation, but, when the DC bus voltage collapses upon a failure, an additional external source of DC voltage is not available for IM excitation. The present invention provides an internal bus that does not collapse when the main DC bus is shorted. This internal or auxiliary bus may be used to excite the IM to provide generation function. The power generation systems of the present invention may play a significant role in the modern aerospace and military industries.

A system and method is provided for generating AC power using a synchronous reluctance machine (12) or a salient-pole synchronous machine (102) and a power converter (110). The present invention can be used to achieve power production for a synchronous reluctance machine (12), or can be used to achieve AC power from a traditional salient-pole synchronous machine / starter (102) without dependence upon a rotor current which is subject to failure. In the power generation system, the control system and method can include a power converter (110), controlled by a voltage command and at least one of a measured AC bus (125) current and voltage, and a DC link (120) voltage, for use with a synchronous reluctance machine (102) and a prime mover (116), such that movement of the rotor of the synchronous reluctance machine (102) can be used to produce at least partial AC power generation on the AC bus (125).

Conventional electric power generation system employ a solid state electronically controlled IM that may be capable of self-start motoring and power generation, but, when the DC bus voltage collapses upon a failure, an additional external source of DC voltage is not available for IM excitation. The present invention provides an internal bus that does not collapse when the main DC bus is shorted. This internal or auxiliary bus may be used to excite the IM to provide generation function. The power generation systems of the present invention may play a significant role in the modern aerospace and military industries.

The invention provides a doubly-fed induction generator control method based onan energy storage device. The energy storage deivceis mainly used for maintaining the voltage stability of a fault transient DC bus of a power network. The specific method is that the energy storage device is connected with the DC bus, the rotor-side converter adopts constant voltage, and the grid-side converter cooperates with the control strategy of the energy storage device to keep the DC bus voltage constant. When a fault occurs at the connection point, the voltage drop of the connection point is detected, and then the energy storage device is put into use to stabilize the voltage of the DC bus bar during the fault. At the same time, as the DC bus voltage is no longer controlled by the grid-side converter, the grid-side current command is calculated according to the active power of the rotor side, which is used for the transmission of the active power from the rotor side to the power grid. At that same time, the residual capacity of the rotor convert can be used to output reactive pow to the power network and to support the voltage of the parallel connection point. The invention has the advantages ofimproving the voltage dynamic performance of the machine terminal, improving the voltage stability of the DC bus bar, reducing the capacity of the energy storage device and the like.