Abstract: Disclosed herein are methods and systems for modeling and controlling the disparate components (e.g. generators, storage, propulsors, and power electronics) that comprise an aircraft turbo-electric distributed power (TeDP) system. The resulting control system is hierarchical and interactive. Layer one is the physical electric power system. Layer three is an optimization system that determines set points for system operation. Layer two, in between layer one and layer three, includes nonlinear, fast, dynamic power-electronic controllers that hold the operation of the power system to the desired set points. Communication between these layers ensures feasibility and stability of the controlled operation. Simulations demonstrate that the resulting control system ensures stability and maximum efficiency.

Abstract: A power supply circuit for supplying electrical energy in an aircraft, the circuit including a power supply generator configured to be driven in rotation by the engine of the aircraft to power electrical equipment of the aircraft engine. The power supply generator includes an asynchronous machine connected to an excitation device. The asynchronous machine includes a rotor configured to be driven in rotation by the engine and a stator connected to the electrical equipment. The excitation device is configured to cause a reactive current of flow in the stator.

Abstract: The present techniques include methods and systems for operating converter to maintain a lifespan of the converter. In some embodiments, the operating frequency of the converter may be increased such that stress may be reduced on the bond wires of the converter. More specifically, embodiments involve calculating the aging parameters for certain operating conditions of the converter operating in a maximum power point tracking (MPPT) mode and determining whether the MPPT operation results in aging the converter to a point which reduces the converter lifespan below a desired lifespan. If the MPPT operation reduces the converter lifespan below the desired lifespan, the frequency of the converter may be increased such that the converter may be controlled to operate at a percentage of MPPT. Thus, in some embodiments, power output may be optimized with respect to maintaining a desired lifespan of the converter.

Abstract: 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.

Abstract: The present subject matter is directed to systems and methods for improving reliability of dual bridge doubly fed induction generators (DFIGs) by reducing the number of required components in the converters associated with such DFIGs. A converter is constructed using a pair of current conducting bridges wherein one of the current conducting bridges is controlled and the second is not controlled. The uncontrolled bridge may correspond to a pair of diodes while the controlled bridge may correspond to a pair of transistors, in particular, a pair of IGBT transistors.

Abstract: The invention relates to a method to control power output of a doubly-fed induction machine to a grid including the steps of measuring grid voltage and grid current in a three phase coordinate system, transforming grid voltage and grid current into a stator frame coordinate system, decomposing the grid voltage and grid current in the stator frame coordinate system in a positive sequence system and in a negative sequence system, calculating active and reactive power in the positive and negative sequence system, and controlling active and reactive power in the positive and negative sequence system.

Abstract: A power supply circuit for supplying electrical energy in an aircraft, the circuit including a power supply generator configured to be driven in rotation by the engine of the aircraft to power electrical equipment of the aircraft engine. The power supply generator includes an asynchronous machine connected to an excitation device. The asynchronous machine includes a rotor configured to be driven in rotation by the engine and a stator connected to the electrical equipment. The excitation device is configured to cause a reactive current of flow in the stator.

Abstract: A permanent magnet machine (PMM) has a kinetic portion electrically coupled to a power conversion portion. Motive power is provided to the kinetic portion by a torque applied to a motive shaft coupled to a prime mover, such as an aircraft engine or an automobile engine. A sensor is effective to detect a fault condition in the kinetic portion. When a fault is detected, the sensor applies a voltage to a winding within the kinetic portion generating an opposing directional counter torque to the motive shaft. A combination of the torque and counter torque exceeds a fracture yield strength of the motive shaft. The fault condition is then rendered safe while the prime mover may continue normal operation.

Abstract: 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.

Abstract: 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.

Abstract: An electric power generator for generating a substantially constant frequency output from a varying mechanical speed input such as from a wind or water turbine, comprises a three-phase induction machine in which at least one stator winding is magnetically and electrically decoupled from at least one other stator winding which is arranged to be connected to an external load, and a power source is arranged to excite said at least one stator winding with an AC current at a desired output frequency. The power generator can be directly connected to the mains grid without requiring a power electronics rectifier and inverter stage to convert the generator output to constant frequency AC.

Abstract: A method and system for an engine starter/generator is provided. The starter/generator system includes a three phase squirrel cage induction machine, a three phase inverter/converter electrically coupled to the three phase squirrel cage induction machine. The starter/generator system also includes a bidirectional DC-DC converter electrically coupled to the three phase inverter/converter, and a digital control board configured to sensorlessly determine a rotor angle from a plurality of phase currents to the induction machine during a start mode. During the start mode, logic in the digital control board configures the starter/generator system into a combination of an induction motor, a three phase DC-AC inverter, and a DC-DC boost converter, and during a generate mode, the logic in the digital control board configures the starter/generator system into a combination of an induction generator, a three phase AC-DC converter, and a DC-DC buck converter.

Abstract: A power converter arrangement for connecting an induction generator to an electric power network comprises a first path provided for transferring electric power from the induction generator to the electric power network during a first operation condition, and a second path provided for transferring electric power from the induction generator to the electric power network during a second operation condition, where the first path includes an AC-AC converter and the second path includes a switch. A capacitor arrangement is interconnected between the induction generator and the first and second paths and a first AC reactor device is interconnected between the capacitor arrangement and the first and second paths, where the capacitor arrangement is provided for compensating for a magnetization current of the induction generator.

Abstract: 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.

Abstract: 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.

Abstract: A device for providing a regulated, limited generator excitation current to a generator to acquire a regulated output voltage of the generator, the device including a combiner for weighted combining a first system deviation on the basis of a setpoint voltage and of the regulated output voltage, and a second system deviation on the basis of a predefined current value and of the regulated generator excitation current so as to acquire a combination signal based on the combination of the first system deviation and the second system deviation, a provider for providing a actuating variable on the basis of the combination signal and a regulation specification, and a provider for providing the regulated, limited generator excitation current to the generator on the basis of the actuating variable, so that the regulated output voltage may be provided by the generator.

Abstract: 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 ?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 Ic to the control coils at least partially magnetically saturates the shunts to reduce shunting of air gap magnetic flux ?

Abstract: A device and method for controlling the output of a wide speed range high reactance permanent magnet machine based PGS is provided. The windings of a permanent magnet machine are coupled to a three-phase diode bridge. A transistor is used for temporarily short-circuiting said diode bridge. A capacitor smoothes the voltage at a voltage detection point. A control unit generates a signal that switches the transistor in response to a voltage detected at the voltage detection point. The control unit signal modifies the duty cycle of the switching of the transistor in response to variations in the speed of the power generator to maintain a desired voltage at the voltage detection point.

Abstract: An electrical power generator includes a controller for making a full power capacity of the generator available for consumption by at least one intelligent load coupled to an output of the generator. The controller obtains data from which both a present output power of the generator and a power capacity of the generator can be determined. The controller then provides the intelligent load with data indicative of both the present output power and the power capacity of the generator for use by the load in controlling its power consumption.

Abstract: 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.

Abstract: 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).

Abstract: A method for enhancing the operation of an electrical power supply includes selecting a prime mover having a chosen power rating. An induction motor having a first power rating at a rated speed and a second power rating at an overspeed is chosen. The overspeed may be at least about 10%, or at least about 25%, 50%, 75%, 10 to 300%, 25 to 300%, or 50 to 100%, greater than the rated speed. The induction motor may be chosen so that the second power rating is substantially the same as the chosen power rating of the prime mover. The induction motor is driven by the prime mover so that the induction motor acts as an induction generator. The system may also comprise a control module to monitor the performance of the power supply and to provide a throttle control signal in response to a control parameter signal. A circuit input of a phase shift circuit may be connected to a generator output. A converter input of an AC to DC converter may be connected to a circuit output of the phase shift circuit.

Abstract: 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).

Abstract: The invention provides an electrical generating system comprising an AC electrical generator (G) having an output, and a capacitor arrangement (Ca) provided at the output of the generator and arranged so as to offset a drop of voltage from no-load to full-load occurring at the output of the generator. As described, the generator (G) is a permanent-magnet generator having a plurality of terminals and associated output lines, and the capacitor arrangement comprises a respective capacitor (Ca) connected in series in each of the output lines, with the value of the capacitance of each capacitor being selected such that a drop of voltage from no-load to full-load occurring at the associated generator terminal is substantially offset at an output terminal of each said capacitor.

Abstract: An automotive generator/motor is driven by a battery via an inverter. Resistance 2Ra0 is expressed by 2Ra0=Vmax/?{square root over (3)} Iamax, where Vmax is a maximum voltage applicable across any two terminals from the inverter and Iamax is a maximum current which must be fed from the inverter into each of the terminals when the maximum voltage Vmax is applied for maximizing torque produced by the automotive generator/motor at a power factor of 1 under voltage saturation conditions, and the armature winding is configured such that resistance 2Ra across any two terminals satisfies a relationship expressed by 0.8Ra0?2Ra?3.8Ra0.

Abstract: A variable speed system for use in systems, such as, for example, wind turbines, is described. The system comprises a wound rotor induction generator, a torque controller and a proportional, integral derivative (PID) pitch controller. The torque controller controls generator torque using field oriented control, and the PID controller performs pitch regulation based on generator rotor speed.

Abstract: A vehicular alternator failure determination apparatus is capable of making a failure determination accurately. The apparatus includes a maximum voltage detection part (1) for detecting a maximum voltage of an alternator commutating device which commutates an AC output of the alternator driven by an engine, a minimum voltage detection part (2) for detecting a minimum voltage of the alternator commutating device, a voltage difference calculation part (3) for detecting a difference voltage from outputs of the maximum and minimum voltage detection parts, and a failure determination part (4) which determines that the alternator is in a failure state, when an output of the voltage difference calculation part is equal to or greater than a prescribed voltage.

Abstract: A method and apparatus of stator voltage control for an induction generator. Each phase of the induction generator stator is connected through a secondary coil of a transformer to a utility grid. A stator voltage control circuit is connected in parallel with a primary coil of the transformer. The stator voltage control circuit consists of an on/off switch device connected to a full wave rectifier comprised of four silicon diodes. A single pulse width modulation (PWM) control is utilized to control the on/off switch devices of each phase of the induction generator stator.

Abstract: A power generation plant comprising a power generating unit that includes at least one first generator, such as an induction generator, coupled to at least one synchronous generator having a rotor with a superconducting (SC) coil. The induction generator and the SC synchronous generator are coupled so that the SC synchronous generator supplies the induction generator with reactive power. Sufficient reactive power is preferably generated by the SC synchronous generator to meet the demand of the induction generator for VARs, as well as permit the induction generator to have a relatively large airgap.

Abstract: The invention relates to a method for constant-current generation by means of a rotational energy source, a generator and a control circuit connected to the generator. Mechanical rotational energy is generated by the energy source and the mechanical rotational energy is transmitted to the generator rotor. The magnetic field distribution produced in the generator is controlled by the control circuit that controls the current distribution in the generator between load current and generator current by feedback control by generating an opposing magnetic field. The power uptake and the current output are adapted without losses and the alternating current generated by the generator is transferred to an averaging direct-current circuit. The invention further relates to a suitable device for carrying out the inventive method.

Abstract: An induction generator power supply comprises a prime mover, an induction generator operably connected to the prime mover and having a generator output, and a phase shift circuit, having a circuit input and a circuit output, the circuit input connected to the generator output. The power supply also comprises an AC to DC converter, having a converter input and a converter output, the converter input connected to the circuit output, and an energy reservoir having a reservoir input connected to the converter output.

Abstract: An induction generator having one or more energy windings and one or more auxiliary windings where the auxiliary windings have fixed and switched capacitors which are used to control the induction generator output under variable load conditions. The auxiliary windings are electrically and magnetically isolated from the energy windings. The fixed capacitors are used under minimum load condition and the switched capacitors added in response to controls signals. The control signals are determined by analyzing the load voltage and current and the voltage across the particular capacitor being added. The induction generator is included in systems where the generator is rotationally driven by an engine and which couples the energy windings to a power grid and/or to a variable load. The engine may also employ a controller that receives the load current and voltage signals to determine engine speed.

Abstract: A method of controlling an induction generator such as an automotive starter-alternator or a windmill is disclosed. The method comprises using a minimal number of current sensors and controlling at least one of a machine flux, an output voltage and generator torque, based on the stator or rotor flux magnitude and position. This method comprises measuring a plurality of current amounts; transforming them into a two phase reference system; measuring a DC voltage; measuring voltage amounts in the generator; transforming the plurality of voltage amounts into the two phase reference system; calculating a flux in the generator; comparing the calculated flux magnitude with a desired flux; determining a d-axis voltage; determining a desired torque amount; comparing the desired torque amount with an estimated torque amount; determining a q-axis voltage; and transforming the d-axis voltage and the q-axis voltage to stationary reference frame n-phase voltages using the position of the flux.

Abstract: The generator includes an asynchronous machine with a wound rotor driven mechanically and a stator connected to the network. The rotor is excited by a constant DC voltage source via an inverter controlled by a pulse width modulation control circuit. In accordance with the invention, the following are generated: a stator frequency set point, a rotor frequency set point which is a function of the stator frequency set point and the rotation speed of the machine, an rms stator voltage set point, an error signal which is a function of the difference between the rms stator voltage set point and the actual rms stator voltage. A rotor voltage set point is imposed on the control circuit which is a function of the error signal and the rotor frequency set point.

Abstract: A method of controlling an induction generator such as an automotive starter-alternator or a windmill is disclosed. The method comprises using a plurality of flux sensing coils and controlling at least one of a machine flux and an output voltage based on the stator or rotor flux magnitude and position. One embodiment of the invention only uses flux sensing coils without requiring current sensors or position sensors.

Abstract: An uncluttered secondary induction machine (100) includes an uncluttered rotating transformer (66) which is mounted on the same shaft as the rotor (73) of the induction machine. Current in the rotor (73) is electrically connected to current in the rotor winding (67) of the transformer, which is not electrically connected to, but is magnetically coupled to, a stator secondary winding (40). The stator secondary winding (40) is alternately connected to an effective resistance (41), an AC source inverter (42) or a magnetic switch (43) to provide a cost effective slip-energy-controlled, adjustable speed, induction motor that operates over a wide speed range from below synchronous speed to above synchronous speed based on the AC line frequency fed to the stator.

Abstract: A rotary induction machine in which operating characteristics of the machine are controlled by adding impedance elements to the rotor windings in which the impedance elements are stationary and connected to the rotor windings by a rotary transformer.

Abstract: An asynchronous alternating current motor/generator having an armature winding which includes interspersed energy coils and reflux coils which are electrically and inductively isolated from each other, but which are paramutually inductively coupled through the rotor. Each reflux coil is positioned at 90 electrical degrees to the adjacent energy coil and is tuned to minimize the inductive reactance of the motor/generator.

Abstract: A rotary induction machine having wound primary and secondary windings with resistive means connected in series with secondary windings and inductive reactive means connected across said resistive means, with the inductive reactance means and resistive means selected to provide an effective resistance which controls the current in the generator secondary windings, whereby the generator rated current is reached at the highest slip for the range of desired power output.

Abstract: In an induction generator, an additional set of stator windings is provided, separate from and secondary to the main stator windings upon which the generator's output voltage is generated and supplied to the load. This separate stator winding is provided for the purpose of supplying the generator with the reactive electrical power it needs to maintain the rotating stator field and supplying any reactive power needed by the load. Thus, there is no need to use a capacitor assembly, for supplying the reactive power needed by the generator. Currents are injected into this separate winding in such a way that only reactive power is supplied to the generator. Specifically, a power measuring circuit measures the power in the additional set of stator windings, and a power error signal is formed by algebraically adding the outputs of the power measuring circuit.

Abstract: The invention is an induction electrical power generation system for generating alternating current varying within a frequency range; the system includes an induction electrical generator (52) for generating the alternating current having a rotor and a stator, the stator having at least one phase winding for outputting the generated alternating current and a plurality of poles with at least two different numbers of poles within the plurality of poles being selected to generate the alternating current, an exciter winding wound on the stator which is driven by AC excitation which varies in frequency during generation of the alternating current and the rotor operating with slip during the generation of the alternating current; a variable speed drive coupled to the rotor for driving the rotor in a speed range during generation of the alternating current; an exciter generator (54) coupled to the exciter winding for generating the variable frequency AC excitation; a speed sensor (56) for producing a signal which is

Abstract: An electric power starter generator system comprises a synchronous generator and an induction motor/generator mutually coupled to a shaft being driven to an external prime mover. The synchronous generator and the induction motor/generator are driven by the shaft at the same speed. The system includes a rectifier/inverter having ac terminals coupled to the output of the induction motor/generator, and dc terminals coupled to a dc bus. This rectifier/inverter allows bi-directional power flow to effectuate both power generation as well as electric start of the prime mover. The synchronous generator is excited by a commonly driven permanent magnet generator and a modulated exciter field control. The induction motor/generator is self-exciting through the rectifier/inverter once a voltage is established on the dc bus. The establishment of this voltage may be accomplished by a battery, or by connection of the synchronous generator's output to the input of the rectifier/inverter through a poly-phase contactor.

Abstract: An electric power generating device including an induction type electric rotating machine rotating in interlock with an engine comprises an inverter connected at the AC side to and end of an armature winding and at the DC side to an electric power storing device, a detecting means for detecting the quantity of state related to the electric power generating voltage of the induction type electric rotating machine excluding the measured RPM of the induction type electric rotating machine but including the electric power storing voltage of the electric power storing device, and an electric power generation controlling means for maintaining the electric power storing voltage within the preset range by controlling the frequency of the controlling voltage of the inverter based on the quantity of state related to the electric power generating voltage.

Abstract: A rotary induction generator having a stator with stator windings defining a three-phase stator and a rotor mounted for rotation therein, and having wound thereon three rotor windings defining a three-phase rotor and having resistive-reactive means connected to said secondary windings to increase the efficiency of said generator and limit the power output to the capacity of the generator over a wide range of speeds.

Abstract: A motor vehicle drive system includes a brushless motor driven by a battery and directly coupled to the vehicle wheels for providing primary motive power. During braking, the motor acts as a generator for recharging the battery. Preferably the recharging current is first allowed to build up by shunting the motor so that the regeneration may occur at both high and low speeds. The regenerative current period may be varied with the speed of the vehicle.

Abstract: An AC variable speed drive (VSD) system having a brushless doubly-fed motor receives power from an electric power grid at a system frequency of the grid and drives a mechanical load. The motor has a rotor with rotor windings and a stator with stator windings comprising first and second polyphase stator systems. The first stator system receives power from the grid at the system frequency. A sensor senses a parameter of the received power by the drive and produces a corresponding power sensor signal. A VSD controller receives and processes the power sensor signal and a reference signal which has been established according to a desired motor operation strategy, and generates therefrom a controller signal. A converter, such as a power electronic converter, receives and converts power from a converter powThis invention was made with government support under Grant No. 79-85BP24332, awarded by the Bonneville Power Administration. The United States government has certain rights in this invention.

Abstract: Each of at least two asynchronous generators connected to a common electrical load for uninterruptibility of the power supply is driven by a corresponding one of at least two drives in such a way that when any one of the generators is driven above synchronous speed by a slip fraction while its stator is electrically excited, its shaft mechanical power is converted to electrical output power at its output terminal. A control circuit is connected to the load, coupled to the output terminals of the generators and connected to the input terminals of the generators and provides an excitation voltage and controls the phase of the excitation voltage of each of the generators with respect to the load voltage. This controls the slip fraction of each of the generators loosely whereby load current from any source is completely controlled.

Abstract: An uninterruptible power source includes an induction motor/generator assembly and a continuously on line variable speed drive connected to inductively accelerate the motor/generator assembly to near rated speed. When the motor/generator assembly reaches rated speed, the motor/generator is switched to synchronous operation, while still under control of the variable speed drive. The variable speed drive includes slip compensation to maintain the motor at rated speed. The variable speed drive operates in response to a utility power signal and to a standby power signal. When the utility power signal fails, operation of the drive is maintained, without interruption, by the standby power.

Abstract: An uninterruptible power source is disclosed and claimed which includes a synchronous motor/generator assembly and a continuously on line variable speed drive connected to inductively accelerate the motor/generator assembly to near synchronous speed. When the motor/generator assembly reaches near synchronous speed, the motor/generator is switched to synchronous operation, while still under control of the variable speed drive. The variable speed drive is connected to maintain synchronicity with the motor/generator during acceleration. Resultantly, when switchover to synchronous operation occurs, no synchronization of the motor/generator to the variable speed drive is required. The variable speed drive operates in response to a utility power signal and to a standby power signal. When the utility power signal fails, operation of the drive is maintained, without interruption, by the standby power.

Abstract: An induction generator is disclosed wherein both the stator and rotor windings are utilized to generate power with the three phase winding of the stator and rotor each connected in parallel with a delta connected capacitive network connected therebetween. The electrical output may thus be increased by a factor of four over a conventional generator of the same size.