Variable-Speed Wind Power System with Improved Energy Capture via Multilevel Conversion

Stage: Development


Power converters are used to convert alternating current (AC) electric power from a fixed-frequency and fixed-voltage to different frequencies and different voltages for powering loads, such as electric motors. They are also used in reverse to convert variable-frequency, variable-voltage, AC electric power to fixed-frequency, fixed-voltage electric power. Electric generators driven by wind turbines rotate at different speeds, depending on wind conditions, so they produce variable-frequency, variable-voltage, AC electric power. Therefore, power converters are used to convert such wind electric power to fixed-frequency, fixed-voltage, AC power to match public utility and similar AC power systems. However, wind turbine power systems also spend lots of time operating at light loads or fractions of their rated power capacities, whereas standard, state-of-the-art, power converters are designed to operate most efficiently at full-rated power most all of the time.



Engineers at the National Renewable Energy Laboratory (NREL) have developed a system that improves existing variable-speed, wind power technology by achieving high efficiency at low wind speeds and capturing more wind energy. This is done by providing improvements in AC power converter technologies to enable more efficient and reliable conversion of variable-frequency, variable-voltage, AC power to fixed-frequency, fixed-voltage, AC power and vice versa. The system also provides more efficient and reliable power converters for wind power generator applications in which generated AC power varies over wide ranges of frequencies, voltages, and load levels, for converting such AC power to fixed-frequency, fixed-voltage, AC power for public utility and similar AC power systems.

For more information, please contact Erin Beaumont at:

Erin.Beaumont@nrel.gov

U.S. Patent # 6,900,998

ROI 01-50

Applications and Industries

  • Wind power systems
  • Wind energy

Benefits

  • Improves over existing technology to provide higher efficiency at low wind speeds
  • Captures more wind energy
  • More reliable and efficient power conversion

Attachments

US Patent 69...8.pdf

Aug 22, 2019