Passivity-Based Control for Output Voltage Regulation in a Fuel Cell/Boost Converter System

Abstract

In this paper, a passivity-based control (PBC) scheme for output voltage regulation in a fuel-cell/boost converter system is designed and validated through real-time numerical results. The proposed control scheme is designed as a current-mode control (CMC) scheme with an outer loop (voltage) for voltage regulation and an inner loop (current) for current reference tracking. The inner loop’s design considers the Euler–Lagrange (E-L) formulation to implement a standard PBC and the outer loop is implemented through a standard PI controller. Furthermore, an adaptive law based on immersion and invariance (I&I) theory is designed to enhance the closed-loop system behavior through asymptotic approximation of uncertain parameters such as load and inductor parasitic resistance. The closed-loop system is tested under two scenarios using real-time simulations, where precision and robustness are shown with respect to variations in the fuel cell voltage, load, and output voltage reference.

Output voltage regulation of a fuel cell/boost converter system with uncertain load: An adaptive PI‐PBC approach

“…The system is described in detail in Reference 18—the reader is referred to it for further details on the components of the experimental setup and their characteristics. The behavior of the system's fuel cell is shown in Figure 3.…”

“…Moreover, the aforementioned linear and non-linear approaches use two simplified fuel cell polarization curve models to represent the PEMFC static current-voltage characteristics. 18 In particular the rational model proposed in Reference 19 and the two-termed power function proposed in Reference 20, which are obtained from experimental data and requires the knowledge of three parameters to be implemented.…”

“…The overall scheme consist of two control loops: an inner current loop based on dynamic backstepping approach plus an I&I estimator for load approximation and an outer voltage loop based on a PI action over the output voltage. Additionally, a CMC combined with PBC scheme for output voltage regulation in a fuel cell‐boost converter system is proposed in Reference 18. In this case, the current loop is designed with PBC to take advantage of the passive map of the control signal to the inductor current, meanwhile the voltage loop is designed to generate the desired current reference with a PI action over the voltage error.…”

“…In this case, the current loop is designed with PBC to take advantage of the passive map of the control signal to the inductor current, meanwhile the voltage loop is designed to generate the desired current reference with a PI action over the voltage error. In both previous cases, 17,18 due to the merging of the two control loops through the time‐derivative of the current reference, these approaches result in an intricate control laws where the proportional gain of the voltage loop is bounded by system parameters in order to assure a well‐defined control law. Moreover, the aforementioned linear and non‐linear approaches use two simplified fuel cell polarization curve models to represent the PEMFC static current‐voltage characteristics 18 .…”

“…In both previous cases, 17,18 due to the merging of the two control loops through the time‐derivative of the current reference, these approaches result in an intricate control laws where the proportional gain of the voltage loop is bounded by system parameters in order to assure a well‐defined control law. Moreover, the aforementioned linear and non‐linear approaches use two simplified fuel cell polarization curve models to represent the PEMFC static current‐voltage characteristics 18 . In particular the rational model proposed in Reference 19 and the two‐termed power function proposed in Reference 20, which are obtained from experimental data and requires the knowledge of three parameters to be implemented.…”