Robust L2 based PI controller design for voltage regulation of auxiliary power units in electric vehicles through polytopic modeling

This paper aims to introduce a new design approach for auxiliary power unit voltage regulation in electric vehicles. The single-input triple-output converter has gained prominence to offer low voltage to electric vehicle auxiliary power units. Closed-loop is typically implemented using the conventional PI controller that effectively regulates output voltages but struggles with transient performance due to abrupt load variations and intermittent supply failures. To address this issue, the proposed system includes the L2 based PI controller accompanied by a pole placement in the linear matrix inequality region for the auxiliary power unit’s voltage regulation, enhancing transient performance. Furthermore, polytopic modeling of SITO converter ensures uncertainties and external disturbances are considered in the design within a bounded region, resulting in improved voltage regulation. A comparative study on transient and error analysis between the L2 based PI controller and the conventional PI controller has been accomplished using MATLAB/Simulink. The outcomes of transient performance analysis reveal that the L2 based PI controller tracks desired output voltages: VO1 = 24 (V), VO2 = 14.4 (V), and VO3 = 5 (V) in negligible rise times of 0.0027 (s), 0.016 (s), and 0.011 (s) with admissible maximum overshoots of 0.357 (V), 0.29 (V), 0.4 (V), and minimal steady-state errors of 0.1 (V), 0.16 (V), and 0.05 (V), respectively. Eventually, the OPAL-RT real-time simulator validates the effectiveness of the proposed methodology and proves that the L2 based PI controller is optimal for auxiliary power unit voltage regulation.