IEEE Access (Jan 2024)
Passivity-Based Nonlinear Control Approach for Efficient Energy Management in Fuel Cell Hybrid Electric Vehicles
Abstract
This study investigates a hybrid system comprising a fuel cell (FC), a battery, and an ultra-capacitor (UC) that drives a car. The primary focus of the research is to integrate passivity theory into the control strategy for DC-DC power converters in fuel cell hybrid electric vehicle systems (FCHEV). A fault-tolerant control scheme, coupled with energy management, is formulated, considering the battery, FC, and UC, with specific attention given to addressing challenges related to nonlinearity and fault control robustness. The work presents the mathematical modeling of the system using a passivity-based nonlinear control approach. The manuscript outlines a method for determining reference currents for batteries, FCs, and UCs, streamlining current distribution to optimize overall system efficiency. The control framework incorporates passivity theory principles to ensure control and stability. In comparison to other advanced control methods like variable structure control and backstepping control, the proposed passivity-based nonlinear control approach demonstrates efficiency gains of 29.9% and 38.5% in settling time, respectively, particularly in the context of controllers for tracking $I_{UC}^{*}$ . The effectiveness of the proposed approach becomes evident when examining the root mean square (RMS) voltage, where it outperforms by 49.9% and 43.4%, respectively, in terms of efficiency. The superiority of the scheme is further evident in the domain of controllers for tracking the $V_{0}^{*}$ profile. In this context, the proposed approach showcases a remarkable efficiency improvement of 22.4% and 36.7% in settling time and RMS voltage, respectively. Another novel aspect of study is consideration of sensor and SOC faults. In the event of a 30% and 50% fault scenario for SOC, the initial reference current for the battery is 1.9 A and 0.8 A, respectively. The results further demonstrate that the incorporation of supplementary control input, including an energy shaping component and a fractional-order proportional-derivative sliding mode surface, enhances the controller’s performance by expediting convergence and improving the closed-loop FCHEV system’s robustness. The use of fault-tolerant control and the energy management system yields positive and satisfactory outcomes, as the battery compensates for the lost power of the faulty FC based on its available energy. The obtained results align precisely with the proposed scenario, contributing to the ongoing development of sustainable energy solutions and transportation.
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