Experimental evaluation of the incidence of operating conditions on measurement uncertainty of conducted emissions by power drive systems

An experimental study about uncertainty in measurements of conducted emissions of variable speed drives due to variations of operating conditions is presented in this paper. The research is part of a wider experimental program aimed at determining what quantities affect emissions most significantly so that electromagnetic compatibility test procedures are performed under appropriate conditions according to the specific destination of the equipment under test, in such a way that results represent the worst case scenario for compliance testing. A global index based on the average weighted distance between measurements and standard limits is introduced to help determine which parameters show predominant influence. Effects of voltage asymmetry and amplitude, motor's frequency, and applied torque have been investigated. Results show that frequency of motor and load applied cause the most relevant changes in emissions