Nonlinear Control of Electronic Capacitor for Enhanced Stability and Dynamic Response
Alexei Mutovkin, Vladimir Yuhimenko, S. E. Schacham, Alon Kuperman
Abstract
This article focuses on improving the control structure of electronic capacitor (EC), formed by a bidirectional dc-dc converter terminated with small auxiliary capacitance. Typical application of such a system is mimicking the dynamic behavior of a bulk dc-ink capacitor while actually employing a component with much lower capacitance value. It was previously revealed that EC may be treated as output-voltage regulated wide-input-range converter feeding a bidirectional power load. Dual-loop voltage-current linear cascaded regulator, typically employed for EC terminal voltage control, imposes slow unstable mode when absorbing power from the dc-link. This article demonstrates that performing a transformation from voltage-current to power-energy domain by feedback linearization-based nonlinear control simultaneously eliminates the unstable mode and increases control bandwidth. Revealed findings are well-supported by simulations and experiments.