Analysis of Eddy Current and Loss of a Novel Canned Switched Reluctance Machine

An electrical machine applied as a hydraulic pump drive is featured by having ametallic can shield structure in airgap. Due to the eddy current induction on the can, electromagnetic features of a canned machine make a principal difference. Instead of the traditional canned induction machines, this paper analyzes the eddy current and loss due to the use of cans on a salient switched reluctance machine (SRM). First, at typical rotor positions, eddy current distribution on cans by a single phase followed by all phases is analyzed. Next, consequent ohmic loss on cans (can loss) is studied, which is extended to one stroke period and further to different control modes. Finally, compared to a standard SRM, the feature of airgap flux and eddy current loss due to the use of cans is shown. A three-dimensional finite-element method is used to show eddy current distribution, including end effect. The can loss simulation is verified by measurement.