Evaluation of Torque Ripple of an Optimal Designed 3-Phase Induction Motor Using Uncertainty

Background/ Objectives: This paper aims to reliably evaluate the torque ripple of an optimal designed 3-phase induction motor using the measurement uncertainty theory. Methods/ Statistical analysis: The measurement uncertainty theory is statistically applied to the actual test. To apply the measurement uncertainty theory to the simulation result such as torque ripple, the type-A standard uncertainty can be calculated through the periodical calculation of torque ripple and the type-B standard uncertainty expressing non-statistical factors such as measurement environment, instrument or method is regarded as 0 in the uncertainty evaluation process. Findings: The general expression of torque ripple of an optimal designed 3-phase induction motor is not dependable because of the fluctuating torque at steady state. Therefore, in this paper, the uncertainty of the torque ripple is evaluated by using the type-A and the type-B standard uncertainty which is regarded as 0. As a result, the torque ripples before and after the optimal design are reliably evaluated in a specific confidence level. Also, it is known that the uncertainty can be easily applied to the torque ripple as well as other motor parameters such as power loss, output power density and so on. Improvements/ Applications: Since this paper deals with evaluation method of torque ripple of a 3-phase induction motor with respectively low torque ripple, it could be applied to motors with large torque ripple.