ABB is launching a new series of high speed permanent magnet generators for full converter concept. The design is based on ABB's proven technology and long experience in low, medium and high speed PMG's since 1990s.
In a permanent magnet generator (PMG) the rotor windings are replaced by permanent magnets enabling high power from small size and the highest efficiency at all speeds, offering maximum annual production of energy with lowest lifetime cost. High speed (HS) PMG is mechanically interchangeable with the doubly-fed generator and our adaptable turbine interface makes it the easiest way to upgrade to the full converter (FC) concept. This PMG series range from 1.5 to 3.6 MW featuring a rotor overspeed withstand up to 3000 rpm.
Permanent magnet technology
Designing a cost-effective PM generator for serial manufacturing demands experience. The most critical factor is the magnetic circuit itsef. Selecting the right NdFeB material as well as correct positioning and fastening of the magnets for different speed range solutions are also important. The design must prevent high temperatures, which in a fault situation like a short circuit could cause weakening of the magnetic properties. Stabilizing and deageing of the magnets and corrosion protection are needed for a long operational lifetime. Know-how is also required in meeting the challenges of serial production incorporating extremely powerful magnets.
New rotor design
Patented rotor designFeatures of the new generator also include a patented rotor design withstanding overspeeds up to 3000 rpm. The generator is small-sized and has the highest efficiency at all speeds, especially at low wind, offering the maximum annual production of energy with the lowest lifetime cost. ABB’s optimized product platform and large-scale manufacturing experience using powerful magnets enable it to offer cost-efficient generators with fast delivery times.
More about the full converter (FC) wind turbine concept
PM generators are synchronous machines with rotor windings replaced by permanent magnets. They need no separate excitation so rotor excitation losses - about 30% of total generator losses - are eliminated. This results in high power density and small size with the highest efficiency at all speeds.
The full converter (FC) concept where all the generated power goes through the converter, enables the turbine to operate across the whole speed range. The converter´s DC link decouples the generator and the mechanical drivetrain from the grid allowing maximum drivetrain damping, leading to easier design and low weight. The turbine can thus operate at any rotor speed and the grid independent voltage means that changes in the grid do not affect generator dynamics. The FC solution therefore provides all the benefits of the doubly-fed system and many more, offering full grid compliance with the most advanced grid fault support and ride-through capability, full control of the generator and the grid. In addition, generator topologies which allow 100% speed variation can enable greater aerodynamic efficiency.