Accurate electromagnetic simulation takes superconductors from research to production

July 22, 2013 // By Graham Prophet
Factory testing of a pioneering superconducting generator for hydroelectric applications from GE Power Conversion business has demonstrated a high correlation between the accuracy of the Opera electromagnetic simulation tool used during the design process, and the performance of the finished product.

The proven fidelity of the simulation, for such a complex electrical machine with 28 poles, could help GE to create advanced solutions for numerous emerging superconducting applications in markets such as wind, wave and hydroelectric power generation, and electric motors for ship propulsion.

The testing results were for the Hydrogenie generator for hydroelectric applications, which was developed by a team from GE and partners, with financial support from the EU. The generator employs high temperature superconducting (HTS) wire, to provide both a step increase in output efficiency, and size and weight reductions of some 70% when compared to a conventional electrical machine.

The correlation between predicted and measured results is extremely close. For example, the Opera finite element design tool from Cobham Technical services predicted the efficiency of the machine to an accuracy within 0.1% of the final built product. This has many potential advantages for the electrical machine developers at GE.

As this was GE Power Conversion's first venture into HTS generator engineering, the development team employed conservative rules to create a machine capable of meeting the target output figure of 1.7 MW. The conservatism ensured that the machine would meet the real-world specification. However, the new factory tests have shown that the generator is actually capable of providing considerably more output power than the target figure. Consequently, now that the accuracy of the simulator has been proven, GE developers are confident that the Opera simulator will help engineers to create cost-effective superconducting models for future applications.

"Testing proves that our superconducting generator design ideas work well, but also that we can predict performance with very good accuracy. Being able to produce very lean superconducting models - that are even more compact and perfectly matched to the application - could really make a big difference in the cost effectiveness of projected future applications such as wind power," says Martin Ingles, Hydrogenie project manager at GE Power Conversion.

During the