Current controlled-based modulation strategies for common-mode voltage mitigation in PWM inverters-fed AC motor drive systems

Common-mode voltage (CMV) appears in motor drives due to working principles of the pulse width modulation (PWM) inverters. This voltage is the main source of many unwanted problems in AC drive systems. Previous methods for CMV mitigation cause extra harmonic in output currents, since they are based on voltage control. This paper proposes new modulation strategies based on predictive current control (PCC) for three-phase PWM inverters-fed AC motor drive systems which mitigate the CMV and moreover, decrease the harmonic contents of output currents. As PCC can be employed in low voltage and medium voltage drive applications, the proposed strategies have been implemented on two-level and three-level neutral-point clamped (NPC) inverter. A comparative study of proposed techniques with traditional ones has been carried out from the output current total harmonic distortion (THD) point of view. Simulation results and mathematical analyses, along with experimental tests for two-level inverter using Texas Instrument digital signal processor (DSP) model TMS320F28335, confirm that the new strategies improve behavior of drive systems in comparison with previous methods.