Stability enhancement method for interleaved boost converter based on virtual DC machine and passivity-based control

DC/DC converters are widely employed in dc distribution systems and motor-drive power supplies to provide voltage conversion, dc-bus regulation, and power-flow control between distributed sources, energy-storage units, and power-electronic loads. When downstream tightly regulated converters behave as constant power loads (CPLs), their negative incremental impedance can reduce dc-bus damping and enlarge voltage overshoot. To improve the large-signal stability and transient performance of an interleaved Boost converter, this paper proposes a composite control strategy combining a virtual dc machine (VDCM) voltage loop and a passivity-based control (PBC) current loop. An averaged model of the two-phase interleaved Boost converter in continuous conduction mode is first derived, and an Euler-Lagrange representation with a CPL is formulated. Then, an inner-loop PBC law is designed from the error-energy function and damping injection, which ensures convergence of the inductor-current tracking error. Furthermore, a VDCM outer loop is introduced to emulate the external characteristic of a dc machine with virtual inertia and damping, and its output is converted into the total inductor-current reference. The effectiveness of the proposed method is evaluated through comparisons with PI + PI and PI + PBC control. Finally, a prototype of an interleaved Boost converter based on GaN devices with a rated power of 3 kW and a power density of 9 kW/L is designed and built. Experimental results from the prototype further validate the accuracy of the simulation results and the excellent steady-state performance of the proposed composite control strategy across the full load range.