Elimination of dead-time distortion using time-feedback

Abstract

A fully-digital algorithm to shape the spectrum of dead-time distortion in power inverters is presented. Dead-time is required to avoid short circuits of the power source by the legs of a power inverter due to the finite turn-on and turn-off times of the switches. Dead-time modifies the pulse widths of the PWM signal causing high harmonic distortion. The proposed approach is based on measuring the pulse widths at the output of the power stage, and does not require to measure the sign of the current, which is usually necessary for dead-time compensation algorithms. Furthermore, the quantization noise produced by digital PWM is also reduced, and it has a minimal computational cost.