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This paper discusses the efficiency of two power electronic converters connected in cascade in aim to generate the maximum power from the fuel cell and regulate the load voltage under different working conditions and load variations. The first converter is an interleaved boost proposed to minimize the fuel cell voltage ripples and determine the optimum duty cycle to generate the maximum of power. Thereafter, the control of this converter is performed through a Maximum Power Point Tracking approach. To meet the load requirements in terms of voltage regulation, a buck boost converter controlled with a Proportional Integral controller is proposed. This configuration allows generating the optimal power and regulating the load voltage at the same time. The both converters are simulated under Matlab-Simulink to validate the robustness and the efficiency of this new design. Obtained results show the robustness of the new design approach and efficiency improvement of the system.

Virtual instrumentation is defined as the combination of measurement and control the hardware and software with industry-standard computer technology to create user-defined instrumentation systems. In this paper, the two-input fuzzy logic controller (FLC) for buck boost converter output-voltage regulation is proposed by using LabVIEW. Here the output voltage has been used as a closed loop feedback to determine the output error (e) and the change in error (Δe) as two inputs to the controller. The elements of the buck boost converter as inductance and capacitor have been selected to insure continuous operating mode (CCM) and low output voltage ripple. The experimental results show that the FLC has a good output voltage response compared with PID controller response. This research has successfully showed that LabVIEW and Fuzzy Logic controller can be applied to develop a system for selecting the modes of controller.

Recently, the circuitry of Multilevel Buck-Boost Converter (here, called MBBC1) is suggested in the literature to attain high inverting voltage by increasing the output levels of the classical buck-boost converter. However, the only circuitry is suggested and detail investigations are not provided. The major drawbacks of MBBC1 are the voltages across the load capacitors side are unequal and the input current is not continuous. Therefore, the MBBC1 is not well suited to feed multilevel inverter where a stack of capacitors is required with equal voltage across each capacitor. A new modified MBBC called MBBC2 is proposed to achieve continuous input current and equal voltage across each capacitor. The circuitry of MBBC1 and MBBC2 configurations are analysed with non-idealities to investigate its effects on the voltage conversion ratio. The Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) boundary conditions and modes of operation for MBBC1 and MBBC2 configurations are presented. The procedure for basics design and components selection is elaborated. Additionally, comparison of MBBC1, MBBC2 and recently proposed a non-isolated DC-DC configuration is provided. The performances of MBBC1 and MBBC2 configurations are tested with simulation and experimental work, and obtained results consistently show a good agreement with the theoretical approach. - The Institution of Engineering and Technology 2019. This publication was made possible by NPRP grant no. [X-033-2-007] from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. Scopus

A novel buck-boost dc-dc converter with high voltage step-up and step-down ability has been introduced in this paper. There are two switches in this converter, of which the sources are connected together and also connected to the ground of the input voltage source. Hence, there is no need for floating gate driver. In addition, the voltage stress of one of the switches is lower than the existing quadratic buck-boost converters. Performance of the analytical results is validated using both simulation in MATLAB/SIMULINK and experimental tests where the proposed converter is evaluated in both buck and boost modes.