Output voltage switching noise peaks and utility AC input harmonic current characteristics of delta-sigma modulated AC-DC converter with boost-buck circuit topologies

A high frequency carrier PWM regulator used for various types of switch-mode power converters are based on the digital or analog signal comparison processing. The voltage-mode or current-mode PWM strategies due to comparison signal processing between voltage/current reference and periodic carrier signals cause the switching noise peaks dependent on the multiple numbers of carrier signal frequency. In general, the switching noise peaks are actually difficult to remove. On the other hand, the utility AC grid side AC-DC converter with the cascaded DC-DC converter stage includes low frequency components of its line current. This paper deals with a delta-sigma pulse modulation AC-DC power converter with AC-boost DC and Boost-DC-Buck DC two-stage circuit topologies. This AC-DC converter with boost-buck circuit topology includes the switching noise peaks characteristic of the output DC voltage as well as utility AC grid side harmonic current components suppression characteristic. The effectiveness of two stage boost-buck AC-DC converter controlled by current-mode delta-sigma and voltage-mode delta-sigma pulse modulation schemes is verified by evaluation as compared with PWM-based AC-DC converter about the utility AC current and switching noise peaks of the output voltage performances.