State-Space Representation of ISOP Systems to Study Natural Power Sharing of Common Frequency-Controlled LLC-Based Systems

Breidenstein D, Kohlhepp B, Blamberger L, Dürbaum T (2025)

Publication Type: Journal article

Publication year: 2025

Journal

IEEE Journal of Emerging and Selected Topics in Power Electronics Institute of Electrical and Electronics Engineers (IEEE)

Book Volume: 13

Pages Range: 7328-7339

Journal Issue: 6

DOI: 10.1109/JESTPE.2025.3609531

Abstract

The input-series and output-parallel (ISOP) connection of multiple dc–dc converters enables high-input-voltage applications with high output currents. These systems require an equal distribution of power and thus input voltage. To avoid the need for isolated input voltage sensing, stable operation is achieved by driving all converter modules with a common control signal. However, parameter mismatches between the modules lead to uneven power distribution. Just like in the previous design process of the single module, studying the applicability of the common control approach requires many simulation runs and, therefore, a fast and efficient simulation model, like time-discrete modeling, which is based on the state-space equations of each subcircuit. Directly deriving the state-space representation of the complete ISOP system is cumbersome due to the number of state variables and switching elements. Therefore, this article demonstrates how to extend the single module’s state-space representation—previously used in the design process of the single module—to the otherwise hard-to-obtain ISOP system’s representation. This enables parameter studies by fast time-domain simulation with time-discrete modeling. To demonstrate the general applicability of the proposed method, simulation results of an ISOP system consisting of two LLC converters are compared to measurements, proving the feasibility of the approach. A parameter sensitivity analysis over the input voltage and load range reveals the impact of parameter mismatches on the power sharing in the common frequency-controlled system.

Authors with CRIS profile

Daniel Breidenstein Lehrstuhl für Optoelektronik Thomas Dürbaum Professur für Elektromagnetische Felder

Involved external institutions

Technische Universität Berlin DE Germany (DE)

How to cite

APA:

Breidenstein, D., Kohlhepp, B., Blamberger, L., & Dürbaum, T. (2025). State-Space Representation of ISOP Systems to Study Natural Power Sharing of Common Frequency-Controlled LLC-Based Systems. IEEE Journal of Emerging and Selected Topics in Power Electronics, 13(6), 7328-7339. https://doi.org/10.1109/JESTPE.2025.3609531

MLA:

Breidenstein, Daniel, et al. "State-Space Representation of ISOP Systems to Study Natural Power Sharing of Common Frequency-Controlled LLC-Based Systems." IEEE Journal of Emerging and Selected Topics in Power Electronics 13.6 (2025): 7328-7339.

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