Predictive strategy to control common-mode voltage in loads fed by matrix converters

Common-mode voltages (CMVs) cause overvoltage stress to the winding insulation and bearings deterioration, reducing the lifetime of electric machines. This paper presents a predictive strategy that effectively mitigates CMVs from matrix converters (MCs), without affecting its functionality and allowing the use of rotating vectors. The method was experimentally tested on an MC feeding an induction machine, mitigating CMVs in 70% and reducing abrupt changes. The reduction is achieved with no tradeoff on the performance of the drive until reaching 40%, point where further reduction comes with an increase on the total harmonic distortion of line side currents. The designer can adjust the method in order to protect the ac machine, extending its lifetime and reducing negative effects of CMVs, and still comply with the standard for connection to the grid due to the flexibility allowed by the proposed strategy.