QFT-Based Robust Tracking Control of Nonminimum Phase Boost DC–DC Converter with Sensor Noise Suppression

This work addresses the problem of fast and robust tracking of large output voltage set point changes and sensor noise suppression in nonminimum phase (NMP) boost type dc–dc (BTDCDC) converters under voltage mode control. The tracking and sensor noise problems become highly challenging in the presence of the converter model uncertainties, source voltage variations, and control bandwidth limitation due to NMP behavior. To tackle these challenges, in this letter, the frequency domain quantitative feedback theory (QFT) is adapted to systematically design a robust control system for NMP boost type converter. The benefits of the proposed QFT-based design are: first, additional flexibility to achieve the fast tracking of large variation in output voltage setpoint without overshoot in the presence of converter parameter uncertainty and desired robust stability margin; Second, low transient inductor current; third, inclusion of NMP dynamics in the controller loop-shaping design, which respects the bandwidth limitation; fourth, low output voltage deviation from the steady state for a sudden input voltage variation; and finally, suppression of high-frequency sensor noise. To validate the efficacy of the proposed robust control design, experiments are conducted on a BTDCDC converter prototype using only sensed output voltage as feedback. The experimental results obtained with the proposed design demonstrate superior tracking and regulation performance besides sensor noise suppression against the existing designs.