Browsing by Author "Burgos Mellado, Claudio"

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    Optimal ZCS Modulation for BidirectionalHigh-Step-Ratio Modular Multilevel dc-dc Converter
    (2021) Pineda Fornerod, Cristian Andres; Pereda Torres, Javier Eduardo; Rojas, Félix; Droguett Olea, Gabriel; Burgos Mellado, Claudio; Watson, Alan J.
    Recent developments in dc powered technologies have increased interest in highly efficient dc-dc converters, especially at high voltage and high-step voltage ratios. Modular multilevel converters (MMCs) are an attractive alternative approach to this demand because they can manage medium and high dc voltages while using standard semiconductor devices with high efficiency if they employ soft-switching techniques. However, the latest soft-switching techniques require resonant circuits, limiting their operation. This paper proposes an optimal modulation technique for a high-step-ratio dc-dc MMC, which achieves minimal rms current and zero-current switching. The proposed optimization generates trapezoidal or triangular current to operate the converter over a wide output voltage and power range, while using a simple control scheme to regulate the output voltage and the voltage balance among the floating cell capacitors. The theoretical analysis has been verified with a laboratory-scaled prototype, demonstrating the effectiveness of the approach and excellent dynamical response.
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    Zero-Current Switching (ZCS) for a High Step Ratio Modular Multilevel dc-dc Converter with wide voltage range operation
    (IEEE, 2020) Pineda, Fornerod, Cristian Andres; Pereda Torres, Javier Eduardo; Burgos Mellado, Claudio; Watson, Alan; Rojas, Félix
    The rise of new dc technologies is pushing the development of highly efficient dc-dc converters, especially at high voltage and high step ratio. Modular multilevel converters (MMCs) are an attractive alternative because they can manage medium and high dc voltages with standard semiconductor devices with high efficiency if they employ soft-switching techniques. However, the latest soft-switching techniques have been proposed for fixed voltage range, limiting their operation. This paper proposes a soft-switching modulation for the high step ratio Modular Multilevel dc-dc Converter in extended voltage range. The proposal achieves zero-current switching and regulates the voltage balance among the floating cell capacitors, while using a simple control scheme to regulate the output voltage. The theoretical analysis has been verified with full-scale simulations, demonstrating excellent dynamic response and reduced rms current.