Steady-State and Transient Modeling of the Series Resonant Balancing Converter

The active voltage balancing device is a necessary part of some modern power electronics applications. Among numerous possible hardware solutions, the Series Resonant Balancing Converter shows advantages in terms of efficiency and low complexity, due to the soft-switching capability and stable operation in the open-loop. This paper models the steady-state operation of Series Resonant Balancing Converter, including the influence of parasitic components, such as parasitic resistances and semiconductors' forward voltages. Additionally, the dynamic modeling, describing the transient behaviour of the Series Resonant Balancing Converter, is presented, as well as the average model of the Series Resonant Balancing Converter with corresponding transfer functions. Frequency analysis and the low-pass nature of the Series Resonant Balancing Converter is presented and a case in which a large DC bus capacitor is connected externally is discussed. Lastly, the design example of a 7.6 kW, 700 V DC bus voltage, Series Resonant Balancing Converter is presented, and modeled steady-state and transient operations are experimentally verified.