<p>A normalized-error-based modified sliding-mode control scheme is proposed to achieve regulation in a two-phase interleaved boost converter affected by load, line, and system parameter variations. The goal is to stabilize the load voltage in the occurrence of these uncertainties, which is achieved by proposing a fast-terminal sliding mode control combined with a novel disturbance observer. A normalized error-based two-time scale estimation (TTSE) method is presented to estimate the disturbances and unmodeled dynamics. A sliding surface of the adopted control strategy is represented such that an integral term in the resulting TTSE acts upon a normalized voltage error. The use of normalized error-based TTSE improves the range of controller gains while ensuring overall stability and avoids the saturation problem during transient response. The control approach used guarantees large-signal stability based on a Lyapunov function. Some simulation outcomes are provided to compare the performance of the proposed control scheme with recent advanced sliding-mode controllers. Finally, the proposed controller is validated experimentally to verify robustness and stability in the presence of parameter variations.</p>