Three-Level Inverting Buck-Boost Converter for Low Inductor Ripple

The patent segments the switching operation across multiple switches (first switch and second switch) operating in parallel with different duty cycles. This allows the system to achieve effective current ripple reduction without requiring excessively high switching frequencies, as the distributed switching strategy spreads the switching losses across multiple devices operating at optimized frequencies, thereby reducing total switching loss compared to a single high-frequency switch.

The patent changes the operating parameters by using different duty cycles for the first and second switches. The first switch operates with a duty cycle of D1 and the second switch with duty cycle D2, where D1 ≠ D2. This parameter variation allows the system to optimize the balance between current ripple reduction and switching loss, achieving effective ripple suppression without requiring uniform high-frequency switching that would increase losses.

The patent extends the basic two-switch converter into a four-switch configuration with two parallel inductors and two capacitors. This segmentation creates multiple current paths and voltage conversion routes, allowing the system to reduce inductor current ripples and switching losses while maintaining manageable complexity. The additional components are strategically placed to provide redundant current paths that reduce stress on individual components and improve overall efficiency.

The patent combines multiple functional elements (two inductors, two capacitors, four switches) into an integrated converter architecture where the first and second inductors operate in parallel, and the first and second capacitors work together to smooth voltage outputs. This merging of components creates synergistic effects where the distributed architecture reduces current ripples and switching losses while achieving voltage conversion efficiency superior to simple two-switch converters.