It’s taken awhile, but the wind power generation market has now come to the point that we’ve been prophesizing the entire time. And it seems our belief has proved to be correct. At The Switch, we have been the only ones for the past decade that fully backed the undisputable advantages of using a full-power converter (FPC) in wind turbines. FPC is becoming the standard in newer turbines on the market and the ones now being developed by the major players, including Vestas, Goldwind, Siemens, GE, Enercon and Gamesa to name a few.
At the Recharge Technology Roundtable debate at WindEnergy Hamburg on September 24, 2014, a panel of the top experts in wind turbine technology held a heated discussion on the topic of “Beyond Drive-Trains – PMG or DFIG”.
Although the focus was on whether the fast-rising permanent magnet generator (PMG) or tried-and-tested double-fed induction generator (DFIG) would ultimately be the choice for new ultra-large class wind turbines, the panel was unanimously of the opinion that FPC is the only way to ensure superior grid performance with its fault ride-through compliance. As well, it was concluded that PMG will be the winner in the long run.
This conclusion comes years after wind turbine manufacturers have struggled to make the partial converter with a DFIG a viable and cheaper option with high manufacturing volumes. Upfront investment costs look good on paper. However, the FPC with its in-built reactive power inherently includes fault ride-through performance. And the FPC operates more predictably. And no large and costly capacitor banks need to be constructed as a compensation afterthought to help the partial converter with a DFIG connect to the grid with stable electricity quality required by the utility.
If the FPC is now the new golden standard, why are wind turbine manufacturers still questioning the use of a PMG to capture the maximum amount of wind energy?
The debate showed the industry is still clearly divided. Some of the disbelievers are hesitant due to the perceived costs of permanent magnet material or because of the bad reputation that the rare earth mines have created for themselves.
Today we know that the price of rare earth materials has stabilized and that new mines have adapted sustainable practices as illegal mining is weeded out and strict international standards are implemented. Therefore, we continue to believe strongly that the advantages of PMG technology will prevail.
Now as a Yaskawa company, The Switch is eager to bring its FPC and PMG technology to the Japanese market, where there’s a real interest in it, as the Japanese industry has been widely using PM machines in smaller powers. In addition, we can now extend our converter range with medium-voltage drive to accommodate bigger turbines with reduced losses and cable size.
Looking forward to taking the next step towards practically 100% FPC + PMGs.