State-Feedback Control of Interleaved Buck–Boost DC–DC Power Converter with Continuous Input Current for Fuel Cell Energy Sources: Theoretical Design and Experimental Validation

Abstract

It is well known that the classical topologies of Buck–Boost converters drain pulsating current from the power source. These pulsating currents entail acceleration of the aging rate of the fuel cell. In this paper, we are considering a Buck–Boost DC–DC converter topology featuring continuous input current. The converter interleaved structure ensures the substantial increase in power density compensating power losses related to the converter switching nature. The control objective is to enforce the DC-bus voltage to track its desired value despite load uncertainties and to ensure adequate current sharing between the different parallel modules of the fuel cell interleaved Buck–Boost converter (FC-IBBC). The point is that the internal voltage of the fuel cell is not accessible for measurement. Therefore, the state-feedback control, which consists of nonlinear control laws, is designed on the basis of a nonlinear model of the FC-IBBC system. We formally prove that the proposed controller meets its objectives, i.e., DC-bus voltage regulation and equal current sharing. The theoretical proof relies on the asymptotic stability analysis of the closed-loop system using Lyapunov stability tools. The theoretical results are well confirmed both by simulation, using MATLAB®/Simulink®, and by experimental tests using DS 1202 MicroLabBox.

A Critical Comparison of the Cuk and the Sheppard–Taylor Converter

“…Moreover, the average steady-state value is 0.5 A for i 2 and 0.25 A for i 1 . These values correspond to those obtained from (10) and (9). Finally, current i 1 has a greater ripple than current i 2 because the value of inductance L 1 is lower than the value of inductance L 2 .…”

“…These converters are very common in renewable energy source applications. The most basic DC-DC converter topologies are the buck and boost converters [8][9][10]. However, there are many other types of DC-DC converter topologies, such as in the examples of the Sheppard-Taylor and Cuk converters.…”

State Feedback with Integral Control Circuit Design of DC-DC Buck-Boost Converter

“…Using (21), ζ, and ω n , the dominant closed-loop poles are s 1, 2 = −3089 ± j3258. However, since the closed-loop control system in (15) comprises three state variables (inductor current, capacitor voltage, and output voltage error), a third pole should be placed far to the left at s 3 = −12000 on the s-plane, so that the desired transient response is not affected.…”

“…However, if the system response requires further enhancement, the closed-loop poles' location can be adjusted and the controller gains are re-calculated for verification. The dominant closed-loop poles are obtained using the characteristic equation of the second-order system given in (21). Next, based on ( 22), the desired percentage overshoot and settling time yield the required damping ratio and natural frequency, which give the desired dominant poles.…”

“…Experimental validation has been performed on a dc-dc buck converter with a constant power load (CPL) using a hardware-in-the-loop (HIL) system, where dSPACE DS1104 has been utilized to implement the control law. In [21], a state feedback control via pole placement is designed on the basis of a nonlinear model of a fuel cell interleaved buck-boost converter. The aforementioned control systems yield robust control performance, mitigate the non-minimum phase issue, and improve the transient response of the power converter.…”