1-kW 2000–4500 r/min Ferrite PMSM Drive: Comprehensive Characterization and Two Sensorless Control Options

An optimal design of internal Ferrite permanent-magnet motor with embedded key finite-element method verification is presented with the scope to increase the efficiency of the small power motors without using expensive rare earth permanent magnets. Two internal flux concentration topologies are analyzed, and the geometric dimensions and performances are presented for three cases, all at 1-kW rated power at 4500 r/min rated speed. The 6/8 poles ferrite-spoke permanent-magnet synchronous motor prototype was built and test results prove an efficiency larger than 88% for a large load range. Two sensorless control methods based on active flux observer are presented, with the key simulation results including acceleration, speed reversal, loading, and unloading speed responses.