An Improved Control Method Based on Modified Delta-Sigma Modulator for Buck Converter

This paper proposes an improved control method based on modified Delta-Sigma Modulator (DSM) to enhance transient response and improve harmonic contents of buck DC-DC converter. The main advantages of the proposed method are improving the output voltage frequency spectrum, correction of the output voltage harmonic contents and sideband harmonics, reduction of switching noise peaks at the output voltage, operating buck converter in continuous current mode independent of load current, significant reduction of inductor current ripple, improving the transient response of buck converter and correction of the input current harmonics. This progress is achieved by applying improved control method based on proposed forgetting function to enhance transient response of buck converter and also by using modified DSM to improve harmonic spectrum of the output voltage and reduce inductor current ripples. The simulation results confirm performance and feasibility of the proposed system.