Evaluation of medium voltage electric propulsion drive for electromagnetic compatibility using multidomain modeling

Abstract

Ensuring electromagnetic compatibility of medium voltage, multiMW electric drive systems requires an intimate understanding of the behaviors and interactions between, the motor, the electrical supply grid, controls and sensors. A correct prediction of electromagnetic interference (EMI) (conducted and radiated) requires not only accurate models for the EMI sources and conduction paths, but also a combination of simulation/analysis tools. This multidomain simulation approach is comprised of circuit simulation tools, finite element analysis (FEA) tools, and computational tools for post processing data. For this information to be meaningful, a correct understanding of the EMI standards and the relationship between emissions and susceptibility is required. A full and flexible switching model is developed and implemented with a differential equation-based continuous simulation tool (simulink). Experimental results show that this model accurately predicts conducted EMI up to 300 kHz on a lower voltage/horsepower system. The model is then appropriately applied to the full multiMW drive system and multidomain modeling techniques are demonstrated. Circuit-based simulators (simpIorer/PSim) which better reflect power semiconductor impact on conducted EMI are used in cosimulation with the existing simulink model. Stator currents generated from this full multiMW drive model are fed into a FEA model which is used to predict the radiated magnetic field of a given cable grouping between the motor and drive. Matlab scripts are used to post-process data for comparison with EMI standards. The multidomain simulation approach is shown to be effective in predicting both conducted and radiated emissions, thus helping to make design decisions to ensure compatibility of the final medium voltage, multiMW drive system.