A Multi-Sampled Pulse Width Modulator in DC-AC Converters for Eliminating Vertical Crossings

Multisampling method is one of the effective solutions to reduce control delay. However, the method introduces switching ripple to the control loop, causing vertical crossings which eventually leads current distortion. This paper proposes a novel multi-sampled pulse width modulator for DC-AC converters to eliminate the vertical crossings, which estimates the switching instant with analog PWM and adds a compensation on the modulation signal to approximate the switching instant. The proposed control scheme features better dynamic performance than existing schemes. The effectiveness of the proposed modulator is validated by simulation results.