Many control schemes for dc-dc converters begin with the assertion that inductor currents are "fast" states and capacitor voltages are "slow" states. This assertion must be true for power factor correction (PFC) converters to allow independent control of current and voltage. In the present work, singular perturbation theory is applied to boost converters to provide rigorous justification of the time scale separation. Krylov-Bogoliubov-Mitropolsky (KBM) averaging is used to include switching ripple effects. A relationship between inductance, capacitance, load resistance, and loss resistances derives from an analysis of an approximate model. Similar results hold for buck and buck-boost converters. An experimental boost converter and a simulated PFC boost support the derived requirement.

Meeting Name

38th IEEE Annual Power Electronics Specialists Conference (2007: Jun. 17-21, Orlando, FL)


Electrical and Computer Engineering


National Science Foundation (U.S.)


This work was supported in part by the National Science Foundation under NSF Award ECS 06-21643.

Keywords and Phrases

Averaging; Integral Manifold; Power Factor Correction; Singular Perturbation; AC Generator Motors; Capacitance; Control System Stability; DC-DC Converters; Electric Currents; Electric Power Factor; Power Converters; Power Electronics; Separation; Switching Networks; Approximate Models; Bogliubov; BOOST Converters; Buck-Boost Converters; Capacitor Voltages; Control Schemes; Independent Control; Inductor Currents; Load Resistances; PFC Converters; Power Factor Correction Converters; Ripple Effects; Singular Perturbation Theory; Time-Scale Separation; Perturbation Techniques

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)

0275-9306; 2377-6617

Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 2007 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jun 2007