Measurement Technique for the Permanent Magnet Rotor Thermal Time Constant Determination

In this paper, an innovative measurement technique that allows the determination of the permanent magnet thermal time constant of permanent magnet synchronous machines is proposed. The novelty of the proposed procedure consists of the determination of the permanent magnet thermal time constant without the test being influenced by the other rotor parts such as lamination, shaft, etc. Therefore, it can be applied to any permanent magnet synchronous machine type, assuming general validity. The proposed experimental setup consists of controlling the currents of the machine under test while an external electric drive sets its speed. Experimental results for two permanent magnet synchronous machine types are presented, demonstrating the feasibility of the proposed procedure.