The Switch, a manufacturer of permanent magnet generators and full-power converters, announced that its 8.6 MW permanent magnet generator (PMG) for offshore use passed initial no-load testing. The massive drive train component is scheduled to undergo complete full-load tests in the upcoming weeks.
The Switch’s medium-speed, rear-mounted PMG design brings together both low- and high-speed technology, resulting in increased annual energy production, particularly at partial loads. Medium-speed is a winning combination for offshore by lowering the generator weight without compromising on reliability, the manufacturer said.
Careful material selection and accurate calculation of the generator design make the drive trains stronger when it comes to reliability and durability. The Switch full-power liquid-cooled converters are modular, compact, efficient and redundant, offering extremely high availability, which The Switch said extends the system’s lifetime in the rugged coastal conditions and significantly lowers maintenance requirements.
Jukka-Pekka Mäkinen, The Switch CEO, commented, “This latest PM generator is bigger, better and stronger than anything built by The Switch so far with a power rating of 8.6 MW. It crowns off our successful offshore wind achievements to date. The Switch was born offshore, starting with an offshore turbine project for the Hundhammerfjellet wind farm in Norway back in 2003. The learnings from eight years of field experience have been brought into our new designs. And last year, we went on to install our first 5 MW high-speed drive trains in Chinese tidelands for CSIC (Chongqing) Haizhuang Windpower Equipment Co., Ltd (HZ Windpower), a Chinese wind power equipment manufacturer. This successful project has been followed by two further projects from turbine manufacturers for their new turbines in the 5-6 MW power class.”
The Switch PMGs and FPCs have been appropriately adopted to operate reliably in the harsh offshore environment for which they were specifically developed. Compared with a traditional double-fed induction generator (DFIG) drive train, The Switch PMG technology offers a higher annual energy production (AEP) rate and lower operations and maintenance costs. This makes it a more ideal solution for offshore use, where maintenance costs can be excessively high.
The company’s simple PMG design eliminates fail-prone components. Optimized magnet material use lowers investment costs. Plus, the special segmented structure both in the mechanical and electrical parts allow easy and more cost-efficient maintenance.
Medium-speed drive trains reduce the weight, and help lower the costs. They also require only 10% of the magnets needed for a direct-drive generator of the same power rating. Additionally, efficiencies that exceed 97% approach values that are normally typical only for high-speed generators. All of this adds up to a higher annual energy production and better wind turbine profitability – offshore as well as onshore.