WARF TECHNOLOGIES

Wind-powered generators are an increasing source of power for many countries. However, before their use can become widespread, they must be able to work effectively with the existing utility grid.

Voltage sags and other disturbances can occur during grid faults. But the conventional electrical architecture for doubly fed induction generator (DFIG) wind turbines fails during extreme voltage sags, and existing patchwork solutions are not effective or economical.

UW-Madison researchers have developed a viable solution that allows DFIG wind turbines connected to the grid to ride through a voltage sag. The turbines need converters, such as a DC/AC inverter, to change the power generated into a form that is compatible with the utility grid. In a conventional DFIG wind turbine, the grid-side converter is connected in parallel with the stator windings of the generator. This approach has the converter connected in series instead. The DC voltage bus of the converter is fed from the induction generator rotor windings through a second, machine-side converter. Connecting the grid-side converter in series allows continuous control of shaft torque and power delivered to the grid even during grid faults, enabling inherent voltage sag ride-through capability.

• Wind-powered generators

• Maintains connection to the grid and control of torque and current, even during grid faults
• Enables wind turbine power generation to conform to utility system operating requirements
• Allows wind turbine generators to effectively interface with the utility grid
• Operation of both converters is coordinated to control wind turbine rotor speed for maximum power extraction and efficiency.

For More Information About the Inventors

• Venkata Giri Venkataramanan

Tech Fields

• Clean Technology : Solar, wind & water technologies
• Engineering : Power electronics & control systems