Linearized sensorless adaptive voltage positioning controller for DC-DC boost power converter

Abstract

Adaptive voltage positioning (AVP) has been used in DC-DC switching power converters for powering integrated circuits due to its advantages of utilizing allowable output voltage tolerance while decreasing the output filter capacitance requirement, and achieving faster transient response. Most of the AVP control schemes in the published literature require current sensing and sampling circuits which increase cost, size, complexity and can cause inaccuracies of AVP operation. A SLAVP controller of DC-DC buck converter is recently proposed in the literature which can achieve AVP control based on the linear relationship between the output current value and the duty cycle value while using the duty cycle value as an indicator of current value. However, this SLAVP control scheme cannot be directly applied to DC-DC boost converter topology because of two reasons. One is the RHP (Right Half Plane) zero of boost converter which might yield system stability issues and ringing effects during light to heavy load transients. Second, the relationship between the output current value and the duty cycle value of the DC-DC boost converter is nonlinear. This paper proposes a linearized sensorless AVP (L-SLAVP) control scheme which successfully addresses the second issue. The theoretical basis of the proposed scheme is given and a simulation model of boost converter with L-SLAVP controller is developed in MATLAB®/SIMULINK® environment for verification and evaluation.