Features & Benefits
- Unique converter control architecture provides high reliability and complete monitoring
- Optimized IGBT switch frequency and grid-connected filter design results in low harmonics
- Completely isolated power conversion circuitry and control circuitry enables higher insulation and safe operation
- Optimum control for grid connection results in low in-rush current
- Compact and neat mechanical design enables space saving and easy installation
- Built-in fault ride-through design for grid faults ensures to meet the requirement of LVRT/ZVRT/HVRT
Fundamentals
The stator of the doubly-fed induction generator is connected to the grid through the main circuit breaker while the rotor is connected through DFIG converter to the grid. When a turbine’s rotation speed varies with the wind speed, the converter changes the frequency of the rotor magnetizing current by controlling the excitation current frequency of the rotor, which results in the output voltage and frequency of turbines in consistent with those of the grid.
System Architecture
A DFIG converter consists of a distribution cabinet, control cabinet and power cabinet. The distribution cabinet provides the housing f or the s wit c h gear s which connect the converter and the grid as well as the stator. The auxiliary power supplies and the protection switches are included to meet customers’ distribution requirements. The control cabinet provides signal conditioning, control, and communication. The power cabinet enables the interaction and the transmission between rotor slip power and the grid, and controls the rotor excitation current, thus controlling the voltage, frequency, and active and reactive status of the stator.