Doctoral Dissertations


"This dissertation focuses on stability issues in single-staged and multi-staged current controlled power electronic converters. Most current-mode control (CMC) approaches suffer from sub-harmonic oscillations. An external ramp is usually added to solve this problem. However, to guarantee stability this ramp has to be designed for the worst possible case which consequently over damps the response. Adaptive slope compensation (ASC) methods are the solution for this problem. In paper 1 of this dissertation, first three ASC methods will be investigated and analyzed through their small signal models. Then, through simulation analyses and experimental test of a variable-input voltage converter the results will be validated. Two of the methods studies in the first paper are peak CMC methods and the last one is called the projected cross point control (PCPC) approach. This method is relatively new. Therefore, a detailed discussion of the principles of operation of PCPC will be presented in paper 2. In addition, the small signal model of PCPC is developed and discussed through simulation and experimental analyses in the second paper of this dissertation. Peak, average, and hysteresis CMC schemes are used for comparison. In paper 3, the stability issues which arise in multistage converters will be addressed. A solid state transformer (SST) as an example of a multistage converter will be studied. A comprehensive small signal modeling will be conducted which helps for stability analysis of SST. Time domain simulations in Computer Aided Design software (PSCAD) are presented which validates the frequency domain analysis"--Abstract, page iv.


Ferdowsi, Mehdi

Committee Member(s)

Fitch, Mark W.
Corzine, Keith, 1968-
Kimball, Jonathan W.
Crow, Mariesa


Electrical and Computer Engineering

Degree Name

Ph. D. in Electrical Engineering


National Science Foundation (U.S.)


Missouri University of Science and Technology

Publication Date

Summer 2012

Journal article titles appearing in thesis/dissertation

  • Adaptive slope compensation methods for peak current mode control of power converters
  • Projected cross point control-modeling and analysis
  • Solid-state transformer stability and control consideration


xiv, 116 pages

Note about bibliography

Includes bibliographical references.


© 2012 Seyed Mostafa Khazraei, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Subject Headings

Electric current converters -- Design
Electric current converters -- Stability
Electric current regulators

Thesis Number

T 10031

Print OCLC #


Electronic OCLC #