124results 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.

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.

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).

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.

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 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.

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 Φ_g 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 I_c to the control coils at least partially magnetically saturates the shunts to reduce shunting of air gap magnetic flux Φ_g, thereby increasing magnetic flux linkage Ψ_M between the PMs and the stator coils and increasing generated electromagnetic force (EMF) at lower levels of rotor assembly angular velocity.

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).

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.

A generator control arrangement for an electrical power generator, the arrangement comprising a controller arranged to regulate output voltage from a generator to a target value, the controller including a voltage comparator for comparing a presented voltage with a desired output voltage, the presented voltage derived in a transfer comparator by combination of a reference voltage value and an error value between a reference electrical current value and a measured electrical current value subject to a processor gain whereby the processor gain can be specifically set at zero to enable control by voltage or the processor gain can be specifically set at greater than zero to enable control by electrical current.