Abstract
Introduction: Electric motors account for approximately 65% of global industrial electricity consumption, mainly due to oversizing and the use of inefficient flow-control methods.
To address this issue, the adoption of high-efficiency electric motors and the widespread adoption of variable frequency drives (VFDs) have emerged as key strategies for energy savings. However, the successful implementation of these technologies depends not only on technological innovation but also on the availability of robust standardized evaluation and classification procedures.
The International Electrotechnical Commission (IEC) introduced the IEC 61800-9-2:2023 standard, which defines testing procedures and classification systems for variable-speed electric drives. Nevertheless, its suitability for advanced variable-speed electric drives, such as Permanent Magnet-assisted Synchronous Reluctance Motors (PMa-SynRM) systems, operating under realistic industrial load profiles and harsh industrial conditions remains insufficiently validated.
Methods: In this work, an experimental study was conducted on a commercial PMa-SynRM driven by a Yaskawa A1000 VFD, comparing system losses obtained using the IEC 61800-9-2:2023 test procedure against an alternative method based on thermal stabilization at the eight standardized operating points.
Results: The comparison revealed consistent discrepancies between the IEC-based approach and the thermal stabilization method, with the largest deviations occurring away from rated conditions. These findings have relevant implications for the comparison of different power drive system (PDS) technologies.
Conclusion: For PMa-SynRM operated with Yaskawa A1000, the IEC 61800-9-2:2023 procedure leads to inaccurate loss measurements under practical load conditions. Therefore, the following recommendations are proposed: (i) consider thermal stabilization for the eight standardized operating points, and (ii) avoid misinterpretation and improve the technical suitability of IEC 61800-9-2, developing separate IEC standards, one for induction motors and another for synchronous
motors.
