Evaluation of motor PWM loss increase due to zero common-mode voltage modulation strategy of multilevel converter

Voltage source converter Pulse Width Modulation common-mode voltages have an adverse affect of inducing motor shaft voltages and bearing currents that result in premature bearings failure. Common-mode voltage cancellation PWM strategies significantly compromise the optimal voltage quality of the nearest three space vector modulation. The paper presents a quantitative estimation of associated motor PWM loss increase for a three-phase multilevel converter.