The document is a presentation by Abhishek Choksi on 'Third Harmonic PWM' prepared for the Electrical Engineering department. It explains pulse width modulation (PWM) as a technique for generating analog signals digitally and focuses on a method where the reference signal combines the fundamental frequency with the third harmonic. The document also cites references related to PWM techniques and harmonic elimination.

1. 6th Sem
Electrical Engineering Department
Batch – B1 (2014 Batch)
Abhishek Choksi
(140120109005)
Power Electronics 2 (2160902)
ALA Presentation
On
“Third Harmonic PWM”
Prepared By: Guided By:
Prof. Jaydeep Vanapariya
Gandhinagar Institute Of Technology

2. Pulse width Modulation
• Pulse Width Modulation, or PWM, is a technique for
getting analog results with digital means.
• Digital control is used to create a square wave, a signal
switched between on and off.

4. Third Harmonic PWM
• In this method, the reference signal is not a pure sinusoidal wave, but
the sum of the fundamental and the third harmonic. It is shown with
curve f(wt) in the following figure.

5. Third Harmonic PWM
• Same as the SPWM method, this signal will be compared with the
triangle signal to generate PWM signals.

6. Third Harmonic PWM
• This concept is derived from the nature of three-phase motors that
the third harmonic will be filtered out in the windings. And thus only
the fundamental part will remain.

7. References
• Hirak Patangia, Sri Nikhil Gupta Gourisetti, “Real Time Harmonic
Elimination Using a Modified Carrier”, CONIELECOMP, Mexico, Feb
2012.
• Hirak Patangia, Sri Nikhil Gupta Gourisetti, “A Novel Strategy for
Selective Harmonic Elimination Based on a Sine-Sine PWM Model”,
MWSCAS, U.S.A, Aug 2012.
• Wikipedia -- https://en.wikipedia.org/wiki/Pulse-
width_modulation#Principle