DFIG — doubly-fed induction generator for wind turbines up to 10 MW
A series of doubly-fed induction generators for geared wind turbines rated up to 10 MW. The stator is connected directly to the grid, and only about 30 % of rated power passes through the converter in the rotor circuit. The generators are installed on new onshore and offshore wind turbines and as replacements on existing turbines.
- Type
- doubly-fed induction generator with wound rotor and slip rings (DFIG)
- Power
- up to 10 MW (DFIG-F: up to 1.25 MW)
- Versions
- DFIG-A (modular air/air), DFIG-W (modular air/water or water jacket), DFIG-F (finned frame, surface cooling)
- Shaft height
- 500–800 mm (DFIG-F: 355–500 mm)
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
According to the manufacturer, double feeding is still the most widespread concept in wind power. Generators of this type work in their thousands around the world, including in large offshore projects with a combined capacity of several gigawatts. The scheme is designed for a high speed drivetrain with a gearbox.
Speed is controlled through the wound rotor circuit, which is fed from the converter through a slip-ring and brush assembly. The converter turns out small, its losses are low, and the capital cost of the system is lower than with a full-power converter scheme. The high efficiency of the generator itself is complemented by low converter losses, and the efficiency of the whole system increases. Together with the converter, the generator meets current grid codes. The slip-ring and brush assembly is monitored, and its design is built for a long service life.
The catalogue contains three versions. DFIG-A has modular air/air cooling, a shaft height of 500–800 mm and a rating up to 10 MW. DFIG-W with air/water cooling or a water jacket has the same shaft height of 500–800 mm and the same power limit. DFIG-F is built with a finned frame and surface cooling, shaft height 355–500 mm, rating up to 1.25 MW. The generators are built for 50 Hz, 60 Hz or combined 50/60 Hz, and open IP34 cooling is also available.
The insulation is protected against moisture, the windings are vibration-resistant, and versions for cold and hot climates and special paint systems for onshore and offshore sites with a salty atmosphere are provided. As standard the generator has temperature sensors and brush wear monitoring; vibration, leakage and other sensors are an option. The bearings are designed for the whole service life of the turbine and are replaced in the nacelle, and insulated bearings are standard. The second shaft end can carry speed sensors and encoders, and low-noise versions are available.
Each generator is designed for a specific turbine and converter. The composition of the system is chosen with cost in mind, part of the grid matching is taken over by the converter, and the grid connection complies with the connection directives. Before shipment the machine undergoes 100 % quality control, and the design meets the requirements of classification societies and international standards for wind turbines. The manufacturer's service supplies new replacement generators for turbines already in operation.
Technical specifications
| Type | doubly-fed induction generator with wound rotor and slip rings (DFIG) |
|---|---|
| Power | up to 10 MW (DFIG-F: up to 1.25 MW) |
| Versions | DFIG-A (modular air/air), DFIG-W (modular air/water or water jacket), DFIG-F (finned frame, surface cooling) |
| Shaft height | 500–800 mm (DFIG-F: 355–500 mm) |
| Cooling | open IP34, air/air, air/water, water jacket |
| Grid frequency | 50 Hz, 60 Hz or combined 50/60 Hz |
| Converter | in the rotor circuit, about 30 % of rated power |
| Monitoring | temperature sensors and brush wear monitoring as standard; vibration, leakage optional |
| Application | onshore and offshore geared wind turbines |
Request a price and lead time
DFIG — doubly-fed induction generator for wind turbines up to 10 MW. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What share of power does the converter pass in the DFIG scheme?
About 30 % of the rated power of the generator passes through the converter in the rotor circuit. So the converter is smaller and its losses are lower than in a full-power converter scheme.
How do the DFIG-A, DFIG-W and DFIG-F versions differ?
DFIG-A is cooled by an air/air scheme and DFIG-W by air/water or a water jacket; both have a shaft height of 500–800 mm and a rating up to 10 MW. DFIG-F with a finned frame has a shaft height of 355–500 mm and a rating up to 1.25 MW.
What grid frequency are the generators built for?
Versions for 50 Hz, 60 Hz and combined 50/60 Hz are available. Together with the converter, the generator meets current grid codes.
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