Capstone Turbine Corporation

Capstone Trubine Corporation

Mark G Gilbreth

Joel B Wacknov

Simon Wall

Simon R Wall

James Brian Dickey

Ake N C Almgren

Ed Edelman

Edward C Edelman

Jeffrey W Willis

Guillermo Pont

Ken Keller

Everett R Geis

Kenneth W Keller

Brian J Budzyn

Claude Khalizadeh

David McShane

Charles R Gilbreth, Jr

Michael J Ryan

Cassie Weissert

A system and method for pre-charging the DC bus of a utility connected power converter. In one embodiment, a full-wave rectifier circuit is coupled to the utility grid through an isolation transformer and circuit protector. The rectifier circuit output is connected to the DC bus of the power converter to provide a pre-charging current to the DC bus capacitors. The output from the rectifier circuit also supplies power to the control circuit power supply for the converter. When the control circuit closes the contactor of the converter system and activates the converter, the voltage across the DC bus capacitors is increased above the level of the rectified power grid voltage provided at the output of the pre-charge circuit. This reverse-biases the rectifier diodes, placing the pre-charge circuit into an inactive state. The impedance of the isolation transformer limits the in-rush current into the DC bus capacitors during the pre-charge.

System and method for pre-charging the DC bus of a utility connected power converter

A power controller controls the turbine of a turbine powered generating system regardless of the load on the system to maximize the efficiency of the turbine and maintains the turbine at a substantially constant temperature during a system load change by using an energy storage device to provide power to the load while the turbine is changing speed to meet the new load demand.

Method and system for control of turbogenerator power and temperature

A power controller controls the turbine of a turbine powered generating system regardless of the load on said system to maximize the efficiency of the turbine and maintains the turbine at a substantially constant temperature during a system load change by using an energy storage device to provide power to the load while the turbine is changing speed to meet the new load demand.

A continuous power supply may include a turbogenerator to provide power to supply the load and or an energy storage element and possibly also to the primary energy source. Utilizing an isolated DC bus architecture permits bi-directional power flow among interconnected elements.

Continuous power supply with back-up generation

An energy generation network according to the present disclosure includes energy generating elements organized in a tree structure of superior and inferior system levels, with control systems and a communication network. In a currently preferred embodiment, energy generating elements are turbogenerators as described above. Communications and processing are distributed throughout the systems and sub-systems of energy generating elements. Inferior sub-systems and systems of sub-systems appears as a single unit to the superior system or sub-system level. Thus, the energy generating elements appears as a seamless single energy generating unit. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Distributed control method for multiple connected generators

A method and system to automatically restart a permanent magnet turbogenerator/motor when a fatal fault is detected. The automatic restart logic includes time constraints and limitations on the number of iterations, and is useful regardless of whether the permanent magnet turbogenerator/motor is in a grid connect mode or a standalone mode, and regardless of how the fatal fault originates or is detected. Additional control logic is utilized to handle grid transients and over load conditions to prevent a fatal fault from occurring by using time constraints and an iterative process, together with a brake resistor to control DC bus voltage.

Automatic turbogenerator restarting system

A method of controlling a permanent magnet turbogenerator/motor includes providing a protected load connected in parallel with the turbogenerator/motor through a pulse width modulated inverter configured in a first operating mode to supply controlled current from the turbogenerator/motor to a utility electrical power source, and selectively connected to the utility electrical power source through an isolation device, monitoring the utility electrical power source, and automatically disconnecting the protected load from the utility electrical power source while reconfiguring the pulse width modulated inverter in a second operating mode to supply controlled voltage to the protected load when a fault is detected in the utility electrical power source. The present invention provides an external or integrated dual mode controller which can be used to provide automatic transitions of a turbogenerator/motor between grid-connected modes where a PWM inverter provides a controlled AC current source to stand-alone modes where the PWM inverter provides a controlled AC voltage source to a protected load. Three phase rotation sequence can be set to positive or negative rotation, or be set to the last measured rotation for the utility grid to enable automatic transitions from stand-alone to grid-connect modes. In addition, the present invention provides for detecting a reference phase angle of the three-phase power provided by a utility grid such that gradual synchronization/resynchronization of a protected parallel connected load can be performed by appropriately controlling the PWM inverter prior to re-connection to the utility grid.

System and method for dual mode control of a turbogenerator/motor

A turbogenerator is controlled by a temperature loop that provides fuel to the combustor to maintain a desired turbine exhaust temperature, and by a speed control loop that controls the speed of the turbogenerator to provide a desired power output. When the desired power output is reduced, the turbogenerator speed is reduced accordingly, and the desired turbine exhaust temperature is increased temporarily to maintain sufficient fuel flow to the combustor to prevent combustor flame-out.

Transient turbine exhaust temperature control for a turbogenerator

A method and system to automatically restart a permanent magnet turbogenerator/motor when a fatal fault is detected. The automatic restart logic includes time constraints and limitations on the number of iterations, and is useful regardless of whether the permanent magnet turbogenerator/motor is in a grid connect mode or a standalone mode, and regardless of how the fault originates or is detected. Additional control logic is utilized to handle grid transients and over load conditions to prevent a fatal fault from occurring by using time constraints and an iterative process, together with a brake resistor to control DC bus voltage.

Automatic turbogenerator restarting method and system

A method and system for connecting a plurality of power generators, each having an electrical power converter output and adjustable output voltage magnitude and frequency, with at least one digital communications bus to provide synchronization and load sharing. One of the plurality of power generators is designated a master unit and the remainder are designated as slave units.

Multiple power generator connection method and system

A method and apparatus for starting a turbogenerator having a sensorless magnetic rotor supported for rotation in a stator by a compliant foil fluid film bearing, the method comprising energizing the stator to generate a continuously rotating magnetic field to capture the magnetic rotor and thereafter accelerating the rotational speed of the magnetic field to substantially minimize the time required for the magnetic rotor to reach a liftoff speed associated with the compliant foil fluid film bearing.

Method and apparatus for controlling rotation of magnetic rotor

A power controller provides a distributed generation power networking system in which bi-directional power converters are used with a common DC bus for permitting compatibility between various energy components. Each power converter operates essentially as a customized bi-directional switching converter configured, under the control of the power controller, to provide an interface for a specific energy component to the DC bus. The power controller controls the way in which each energy component, at any moment, will sink or source power, and the manner in which the DC bus is regulated. In this way, various energy components can be used to supply, store and/or use power in an efficient manner. The various energy components include energy sources, loads, storage devices and combinations thereof.

Power controller

A system and method for modular control of a multi-fuel turbogenerator include separate controllers for controlling fuel supplied to the combustor and power output from the generator. The power controller generates a fuel command based on the required turbine exhaust temperature, where the fuel command is independent of the particular fuel being used. Fuels may include natural gas, diesel, propane, waste gas, or gasoline, for example. The power controller communicates the fuel command and the airflow or calculated air/fuel ratio to the fuel controller which selects an appropriate mode of operation for the injectors. Injector operating modes include one or more pilot modes where fuel is not mixed with air prior to combustion, and one or more premix modes where fuel is highly mixed with air prior to combustion. The fuel controller implements closed-loop feedback control of a fuel metering device and controls the fuel injectors in the appropriate operating mode based on the fuel command, the energy content of the fuel being used, and the air/fuel ratio.

Growing community of inventors

Woodland Hills, CA, United States of America

Mark G Gilbreth