General Electric Company

Gautam Sinha

Robert Dean King

Luis Jose Garces

Robert William Delmerico

Harold Copeland Sanderson

William James Premerlani

Patrick Lee Jansen

Mark Edward Cardinal

James Patrick Lyons

Yan Liu

William Robert Pearson

Mark Dame

John Harold Parslow

Rodney A Lawson

Vlatko Vlatkovic

Michael John Ryan

Bruce Allen Gerritsen

Mohammed Kassem Saleh

Ivan Elmo Freeman, Jr

A brushless exciter for a synchronous generator or motor generally includes a stator and a rotor rotatably disposed within the stator. The rotor has a field winding and a voltage rectifying bridge circuit connected in parallel to the field winding. A plurality of firing circuits are connected the voltage rectifying bridge circuit. The firing circuit is configured to fire a signal at an angle of less than 90&#xb0; or at an angle greater than 90&#xb0;. The voltage rectifying bridge circuit rectifies the AC voltage to excite or de-excite the field winding.

Brushless exciters using a high temperature superconducting field winding

An uninterruptible power supply system has standby and backup modes and can change to backup mode upon detection of a grid fault. In both modes an alternator rotates at synchronous speed so that backup mode capability is ready. An energy storage unit through a DC-AC inverter remains coupled to the grid in standby mode so that it is charged, ready to supply power when changed to backup mode. In standby mode, first and third clutches are disengaged and engaged, transmitting alternator rotary motion to a flywheel but not therefrom to a heat engine. In backup mode, first and third clutch are engaged and disengaged to permit the alternator, via a second clutch, to overrun the flywheel and allow transmitting of flywheel torque to accelerate the heat engine to starting speed for driving the alternator to supply power to the grid after the engine is at operating speed and coupled to the alternator through a locked second clutch and an engaged third clutch.

Low-energy storage fast-start uninterruptible power supply method

An apparatus for controlling a microturbine, the apparatus including: a rectifier adapted for converting at least one generated voltage from the microturbine to a DC link voltage; an inverter adapted for converting the DC link voltage to at least one inverter output voltage, the at least one inverter output voltage being electrically coupled to an external power bus; a starter drive adapted for converting at least one starter input voltage to at least one starter output voltage, the at least one starter input voltage being electrically coupled to the external power bus, the at least one starter output voltage being electrically coupled to the microturbine.

Method and apparatus for controlling a microturbine

A power electronic based DR (distributed resource e.g., a UPS (uninterrupted power supply), Fuel Cell or Microturbine) is controlled to emulate a voltage source behind an impedance and behave as a power system stabilizer. The impedance in the DR is emulated and an estimate of impedance at the power/electronic interface is derived and applied to the control of the DR in a manner wherein the power and voltage swings on systems (loads) that otherwise would have difficulty with dynamic loads, are stabilized. Damping and synchronizing power are provided measuring only voltage, current and frequency at the interface between the DR and the load. The DR may include some energy storage.

Distributed resource (DR) stabilization control for microgrid applications

The field ground fault detector of the present invention detects a ground fault that occurs in the field circuit and in any associated circuits galvanically connected to the field. The field ground fault detector discerns the ground resistance so that it can be monitored to detect gradual degradation of the ground resistance. The detector estimates the resistance of the ground fault and the location of the ground fault. The detector is able to estimate the location of the ground fault during system operation and during periods of non-operation. The invention utilizes a low frequency square wave oscillator to permit measurement of the ground fault resistance when field voltage is not applied, to insure that there are no blind spots when the field is energized, and to provide a method for estimating the ground fault resistance. The field ground detector can differentiate between ground faults that occur on the AC side form those on the DC side of the Thyristor Bridge.

Apparatus and method for detecting and calculating ground fault resistance

Computer based energy service provider (ESP) information service has been developed for providing operational and management services for distributed local power generation units. The ESP is a subscription service for customers that purchase power from utilities and generate their own power on site from a local power generation unit. The ESP service enables those customers to decide when to purchase power from the utility or generate their own power, and may provide control of the customer's power generation unit. Using the ESP, a customer may select whether to exclusively purchase power from a utility, exclusively generate its own power or allow the ESP service to determine whether power should be purchased or self-generated. The ESP service stores the customer's selections and remotely controls and operates the local power generation unit and a switch which connects the customer site alternatively to a utility power source or the power generation service.

Distributed electrical power management system for selecting remote or local power generators

A method and system are described for providing a direct current (DC) uninterruptible power supply with the method including, for example: continuously supplying fuel to a turbine; converting mechanical power from the turbine into alternating current (AC) electrical power; converting the AC electrical power to DC power within a predetermined voltage level range; supplying the DC power to a load; and maintaining a DC load voltage within the predetermined voltage level range by adjusting the amount of fuel supplied to the turbine.

Direct current uninterruptible power supply method and system

A method for predicting zero crossings of fault currents in a multi-phase power system includes sensing a fault current in each respective phase, estimating parameters of a model of each respective fault current, and independently using the estimated parameters for each respective fault current to predict a zero crossing of the respective fault current.

Method and system for real-time prediction of zero crossings of fault currents

An uninterruptible power supply system has standby and backup modes and can change to backup mode upon detection of a grid fault. In both modes an alternator rotates at synchronous-speed so that backup mode capability is ready. An energy storage unit through a DC-AC inverter remains coupled to the grid in standby mode so that it is charged, ready to supply power when changed to backup mode. In standby mode, first and third clutches are disengaged and engaged, transmitting alternator rotary motion to a flywheel but not therefrom to a heat engine. In backup mode, first and third clutch are engaged and disengaged to permit the alternator, via a second clutch, to overrun the flywheel and allow transmitting of flywheel torque to accelerate the heat engine to starting speed for driving the alternator to supply power to the grid after the engine is at operating speed and coupled to the alternator through a locked second clutch and an engaged third clutch.

Low-energy storage fast-start uninterruptible power supply system and method

A power electrical system is disclosed for a microturbine power generator. The invention permits the microturbine to be started using an external DC power source. The DC voltage is converted to a variable DC voltage by means of a bi-directional buck-boost circuit, DC bus and a DC-to-AC converter. The DC-to-AC converter produces at its output a fixed voltage pattern whose frequency is gradually increased in concert with the DC voltage, to accelerate the microturbine from standstill to startup speed. Once the microturbine is started, the excitation is discontinued, and the DC bus and DC-to-AC are used to produce output AC power at a voltage level and frequency to match an electrical load.

Starting system and method for a microturbine power generation unit

A control system for controlling power flow in a power bus generally powered by a reformer-based fuel cell system (FCS) is provided. The control system comprises an energy storage device (ESD); a power interface unit coupled to selectively and bi-directionally pass power between the energy storage device and the power bus; and a controller coupled to the power bus to receive one or more signals indicative of the instantaneous power delivered by the fuel cell system. The controller may be configured so that the energy storage device may supply power to the power bus at least during transient conditions when the instantaneous power delivered by the fuel cell system drops below a (FCS) power command signal.

System for controlling power flow in a power bus generally powered from reformer-based fuel cells

A power electrical system is disclosed to connect a microturbine and an electrical machine to electrical power sources and a load. The invention permits the microturbine to be started using an external DC power source and/or an external AC power source. DC power is converted to AC power by means of a buck-boost chopper, DC bus and a DC-to-AC converter. AC power, from the AC power source, is converted to frequencies and voltages suitable to start a microturbine by a pair of DC-to-AC converters and the DC bus. The frequency and voltage levels of the AC power are gradually increased to accelerate the microturbine to startup speed. Once the microturbine is started, the external power sources are disconnected, and the DC bus and the DC-to-AC converters produce output AC power at a voltage level and frequency to match an electrical load.

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Clifton Park, NY, United States of America

Gautam Sinha