Publication Date


Document Type


Committee Members

Marian K. Kazimierczuk (Advisor), Saiyu Ren (Committee Member), Ronald G. Riechers (Committee Member)

Degree Name

Master of Science in Engineering (MSEgr)


Pulse Width Modulated (PWM) Forward DC-DC converter is a buck-derived isolated power converter which is used extensively in low power to medium power applications. Satisfactory operation of the transformer utilized in forward converter plays a crucial role in the overall operation of the forward converter. Hence detailed analysis pertaining to design of forward transformer is important. The forward transformer is unique as the magnetizing inductance is not required to store magnetic energy. Additionally, the forward transformer has a tertiary winding, which is required to reset the core and to prevent core saturation. This adds to the complexity of design and analysis as compared to a flyback transformer. The effect of winding losses due to High-Frequency (HF) eddy currents caused by harmonics is also considered in this work. Dowell's equation was extended to determine the winding resistances for forward transformer in Continuous Conduction Mode (CCM). The Fourier series of the transformer winding current waveforms are derived. The winding resistances derived based on the Dowell's expression and the current expressions derived based on spectral analysis are employed in evaluating the winding losses. The procedure to design a HF forward transformer in CCM is presented. The effect of harmonics was computed using MATLAB, and verified by circuit simulation with Saber Sketch. The results were found to be in good agreement.

Page Count


Department or Program

Department of Electrical Engineering

Year Degree Awarded