Lamination core loss measurements in machines operating with PWM or nonsinusoidal excitation

Variable speed drives (VSDs) are becoming standard supplies for motors in industries because of their benefits in increased process control and energy savings. The benefits of employing a VSD are derived at a cost of increased core losses and motor temperature rise. Core loss measurements with sinusoidal supplies are guided by international standards. However, there are currently no international standards for the fast growing variable frequency supplies and the associated core losses. In this paper, a test bench for core loss measurements under variable frequency supplies proposed by A. Boglietti et al. (1997) is adopted. Work reported in this paper serves to validate the proposal and extends the test bench proposal to switched reluctance motor (SRM) lamination core loss measurements. An Epstein frame was used for direct core loss measurements. The methods and test bench used are detailed in the paper, along with test results.