<i>H<sub>∞</sub> </i> Criterion Based PI Controller Design for DC-DC Step-Up Converters
Sumit Ranjan Kumar, Md Nishat Anwar, Purnima Verma, M. Ram, Sarva Ruvinigya Somanshu
Abstract
Step-up converters are well known for its diverse orders and dynamics, as well as non-minimum phase behavior. The diverse behavior is generally dealt with specific controller and its unique design technique as reported in literature. Further, the changing dynamics with the operating condition due to non-linear nature of these converters make the control aspect challenging. A robust control technique with sufficient stability margin to operate these converters in a wide operating region is much required. The proposed work advocates a simple, unified H∞ criterion-based graphical approach of controller design for any step-up converters. The proposed technique easily manages the diverse nature of step-up converters in a unified way. The controller is designed with fixed maximum sensitivity (γ) to ensure minimum phase margin (Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> ) and gain margin (G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> ). A set of stabilizing PI controllers has been obtained with the specified stability margin. The centroid of all stabilizing set yields the most suitable controller parameters. The efficacy of the proposed design method is further investigated and validated through two converters (i) DC-DC boost converter and (ii) DC-DC high gain converter. The performance of the proposed control technique is validated in Simulink as well as with the hardware setup of both the converters. The hardware and software results well agree with each other and thus confirm the suitability of the proposed technique for different step-up converters.