Passivity-Based Control PI for the Versatile Buck-Boost (VBB) Converter

Abstract

Voltage and current requirements imposed by direct current loads are highly demanding in modern applications such as microgrids and electric vehicles. High-performance converters and controllers are required for these applications. The versatile buck-boost (VBB) converter has shown comparative advantages such as non-inverting output, wide bandwidth, and smooth transition between operation modes and current control loops. The control law can enhance these intrinsic advantages. In this work, a passivity-based current controller is designed and implemented for this converter. The control is based on the system’s dissipative characteristic to match the desired operating point’s power function. The proposed controller maintains the simplicity and robustness of a PI control while guaranteeing high performance and dynamic stability. This control does not depend on the converter’s component values. Theoretical analyses are complemented with numerical simulations and experimental results on a purpose-built prototype. The proposed control shows stable and high performance in both buck and boost modes, demonstrating its effectiveness and reliability in real-world conditions, presenting for the buck and boost modes equal settling times in transitions (about to $100~\mu $ s). These benefits make it particularly suitable for demanding applications requiring robust and efficient power conversion.

Keywords

• Current control
• noninverting buck-boost converter
• passive system
• PI passivity based control
• PI digital control