Patents by Inventor Paolo Piagi

Paolo Piagi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20240006635
    Abstract: Provided are flow batteries, comprising: a first reservoir containing a first electrolyte solution and one or more battery packs. A battery pack comprises a battery stack, an enclosure enclosing the battery stack, a first supply flow path, and a first return flow path. The first supply flow path comprises a substantially U-shaped bend such that a first portion of the first supply flow path and a second portion of the first supply flow path are positioned substantially parallel to each other and within the enclosure. The first return flow path comprises a substantially U-shaped bend such that a first portion of the first return flow path and a second portion of the first return flow path are positioned substantially parallel to each other and within the enclosure. These flow batteries are useful to mitigate inter-stack shunt currents.
    Type: Application
    Filed: June 28, 2023
    Publication date: January 4, 2024
    Inventors: Andrew Joseph Melough, Kean Duffey, Adam Morris-Cohen, Paolo Piagi
  • Patent number: 7932637
    Abstract: A method includes operating a microsource in a grid mode in which the microsource is connected to a utility grid. The microsource is located in a microgrid and is configured to deliver a power P1 at a frequency ?1. During operation in the grid mode ?1 is a first frequency and P1 is a first power. The first frequency is an operating frequency of the utility grid. The microsource is transferred from the grid mode to an island mode, causing a frequency change such that ?1 changes to a second frequency and a power change such that P1 changes to a second power. The frequency change occurs at a first rate with respect to the power change while ?1 is less than a slope switch frequency. The frequency change occurs at a second rate with respect to the power change while ?1 is greater than the slope switch frequency.
    Type: Grant
    Filed: February 11, 2010
    Date of Patent: April 26, 2011
    Assignee: Wisconsin Alumni Research Foundation
    Inventors: Robert H. Lasseter, Paolo Piagi
  • Patent number: 7920942
    Abstract: A microsource is provided, which includes an energy storage device, a power generation device, and a controller. The energy storage device is operably coupled for power transfer to a load through a first power bus. The power generation device is operably coupled for power transfer to the load through a second power bus. The controller determines a mode of operation for the energy storage device and the power generation device based on an energy level of the energy storage device and on the load; determines minimum power set points and maximum power set points for the energy storage device and the power generation device based on the determined mode of operation, on a storage output power measured at the first power bus, and on a generation output power measured at the second power bus; and controls an output power of the energy storage device and an output power of the power generation device based on the determined minimum and maximum power set points.
    Type: Grant
    Filed: March 1, 2007
    Date of Patent: April 5, 2011
    Assignee: Wisconsin Alumni Research Foundation
    Inventors: Robert H. Lasseter, Paolo Piagi
  • Patent number: 7787272
    Abstract: A microsource is provided, which includes an inverter, an energy storage device, and a controller. The controller calculates a maximum frequency change for the inverter based on a first comparison between a first power set point and a measured power from the inverter. The first power set point is defined based on a charge level of the energy storage device. A minimum frequency change for the inverter is calculated based on a second comparison between a second power set point and the measured power from the inverter. An operating frequency for the inverter is calculated based on a third comparison between a power set point and a measured power flow. A requested frequency for the inverter is calculated by combining the maximum frequency change, the minimum frequency change, and the operating frequency. The requested frequency is integrated to determine a phase angle of a voltage of the inverter to control a frequency of an output power of the inverter.
    Type: Grant
    Filed: March 1, 2007
    Date of Patent: August 31, 2010
    Assignee: Wisconsin Alumni Research Foundation
    Inventors: Robert H. Lasseter, Paolo Piagi
  • Publication number: 20100207456
    Abstract: A method includes operating a microsource in a grid mode in which the microsource is connected to a utility grid. The microsource is located in a microgrid and is configured to deliver a power P1 at a frequency ?1. During operation in the grid mode ?1 is a first frequency and P1 is a first power. The first frequency is an operating frequency of the utility grid. The microsource is transferred from the grid mode to an island mode, causing a frequency change such that ?1 changes to a second frequency and a power change such that P1 changes to a second power. The frequency change occurs at a first rate with respect to the power change while ?1 is less than a slope switch frequency. The frequency change occurs at a second rate with respect to the power change while ?1 is greater than the slope switch frequency.
    Type: Application
    Filed: February 11, 2010
    Publication date: August 19, 2010
    Inventors: Robert H Lasseter, Paolo Piagi
  • Patent number: 7687937
    Abstract: A method of controlling the output inverter of a microsource in a distributed energy resource system is disclosed. Embodiments of the invention include using unit or zone power controllers that reduce the operating frequency of the inverter to increase its unit output power. Preferred embodiments includes methods wherein the inverter reaches maximum output power and minimum operating frequency at the same time, and further comprising using a voltage controller implementing a voltage vs. reactive current droop. Other aspects of this embodiment relate to an inverter that implements such methods, and a microsource containing such an inverter. These methods can be extended to control inverters in a plurality of microsources, organized in a single zone or in a plurality of zones.
    Type: Grant
    Filed: March 18, 2005
    Date of Patent: March 30, 2010
    Assignee: Wisconsin Alumni Research Foundation
    Inventors: Robert H. Lasseter, Paolo Piagi
  • Publication number: 20090326724
    Abstract: A microsource is provided, which includes an energy storage device, a power generation device, and a controller. The energy storage device is operably coupled for power transfer to a load through a first power bus. The power generation device is operably coupled for power transfer to the load through a second power bus. The controller determines a mode of operation for the energy storage device and the power generation device based on an energy level of the energy storage device and on the load; determines minimum power set points and maximum power set points for the energy storage device and the power generation device based on the determined mode of operation, on a storage output power measured at the first power bus, and on a generation output power measured at the second power bus; and controls an output power of the energy storage device and an output power of the power generation device based on the determined minimum and maximum power set points.
    Type: Application
    Filed: March 1, 2007
    Publication date: December 31, 2009
    Inventors: Robert H. Lasseter, Paolo Piagi
  • Patent number: 7521825
    Abstract: A method and apparatus for an interface switch having an external terminal electrically connected to an AC voltage ? at a frequency ?0 (for example a utility supply), and an internal terminal electrically connected to an AC voltage V at a selectable frequency ? (for example a microsource). In one embodiment, the interface switch is closed when the voltage difference between ? and V and the relative phase angle ?EV between ? and V are both small, and when the higher frequency voltage (as between ? and V) leads the lower frequency voltage. In another embodiment, the interface switch is closed when the envelope of the voltage difference between ? and V reaches a local minimum at a point of inflection.
    Type: Grant
    Filed: November 4, 2005
    Date of Patent: April 21, 2009
    Assignee: Wisconsin Alumni Research Foundation
    Inventors: Robert H. Lasseter, Paolo Piagi
  • Publication number: 20080212343
    Abstract: A microsource is provided, which includes an inverter, an energy storage device, and a controller. The controller calculates a maximum frequency change for the inverter based on a first comparison between a first power set point and a measured power from the inverter. The first power set point is defined based on a charge level of the energy storage device. A minimum frequency change for the inverter is calculated based on a second comparison between a second power set point and the measured power from the inverter. An operating frequency for the inverter is calculated based on a third comparison between a power set point and a measured power flow. A requested frequency for the inverter is calculated by combining the maximum frequency change, the minimum frequency change, and the operating frequency. The requested frequency is integrated to determine a phase angle of a voltage of the inverter to control a frequency of an output power of the inverter.
    Type: Application
    Filed: March 1, 2007
    Publication date: September 4, 2008
    Inventors: Robert H. Lasseter, Paolo Piagi
  • Publication number: 20070129110
    Abstract: A method and apparatus for an interface switch having an external terminal electrically connected to an AC voltage E at a frequency ?0 (for example a utility supply), and an internal terminal electrically connected to an AC voltage V at a selectable frequency ? (for example a microsource). In one embodiment, the interface switch is closed when the voltage difference between E and V and the relative phase angle ?EV between E and V are both small, and when the higher frequency voltage (as between E and V) leads the lower frequency voltage. In another embodiment, the interface switch is closed when the envelope of the voltage difference between E and V reaches a local minimum at a point of inflection.
    Type: Application
    Filed: November 4, 2005
    Publication date: June 7, 2007
    Inventors: Robert Lasseter, Paolo Piagi
  • Patent number: 7116010
    Abstract: A power electronics interface in a microsource controller allows efficient connection in a power system of small, low cost and reliable distributed generators such as microturbines, fuel cells and photovoltaic. Power electronics provide the control and flexibility to insure stable operation for large numbers of distributed generators. The power electronics controls are designed to insure that new generators can be added to the system without modification of existing equipment. A collection of sources and loads can connect to or isolate from the utility grid in a rapid and seamless fashion, each inverter can respond effectively to load changes without requiring data from other sources, and voltage sag and system imbalances can be corrected.
    Type: Grant
    Filed: September 17, 2002
    Date of Patent: October 3, 2006
    Assignee: Wisconsin Alumni Research Foundation
    Inventors: Robert H. Lasseter, Paolo Piagi
  • Publication number: 20060208574
    Abstract: A method of controlling the output inverter of a microsource in a distributed energy resource system is disclosed. Embodiments of the invention include using unit or zone power controllers that reduce the operating frequency of the inverter to increase its unit output power. Preferred embodiments includes methods wherein the inverter reaches maximum output power and minimum operating frequency at the same time, and further comprising using a voltage controller implementing a voltage vs. reactive current droop. Other aspects of this embodiment relate to an inverter that implements such methods, and a microsource containing such an inverter. These methods can be extended to control inverters in a plurality of microsources, organized in a single zone or in a plurality of zones.
    Type: Application
    Filed: March 18, 2005
    Publication date: September 21, 2006
    Inventors: Robert Lasseter, Paolo Piagi
  • Publication number: 20040051387
    Abstract: A power electronics interface in a microsource controller allows efficient connection in a power system of small, low cost and reliable distributed generators such as microturbines, fuel cells and photovoltaic. Power electronics provide the control and flexibility to insure stable operation for large numbers of distributed generators. The power electronics controls are designed to insure that new generators can be added to the system without modification of existing equipment. A collection of sources and loads can connect to or isolate from the utility grid in a rapid and seamless fashion, each inverter can respond effectively to load changes without requiring data from other sources, and voltage sag and system imbalances can be corrected.
    Type: Application
    Filed: September 17, 2002
    Publication date: March 18, 2004
    Inventors: Robert H. Lasseter, Paolo Piagi