Common mode voltage elimination in industrial AC-AC converters based on model predictive control

Common-mode-voltage (CMV) is known for creating bearing currents and electromagnetic interference in industrial drive applications. Additionally, as explained in this paper, in underground earthing environment, CMV has safety implications. To address these problems, the paper performs a comparative evaluation of the two converter options: Matrix Converter (MC) and two-level voltage source inverter (VSI) with Active Front End (AFE). While both topologies transform constant AC input into variable AC output, MC has a weight and size benefit, due to the capacitor downsizing. The paper presents a detailed modelling showing the possibility to completely eliminate CMV in both options. Under the imposed condition of zero CMV, the paper compares performance of the two topologies, with respect to the input and output harmonic distortion and robustness under variable frequency operation. As a control strategy, it implements a Modified Model Predictive Control (MMPC), which allows to significantly reduce the computation time. Based on extensive simulations performed in MATLAB-Simulink environment, the paper makes a recommendation about the most suitable topology for an AC drive in CMV-sensitive underground mining applications. Experimental validation of the paper findings is underway.