ABSTRACT

Pulse Width Modulation variable speed drives are increasingly applied in many new
Industrial applications that require superior performance. Recently, with developments
in field of power electronic devices and microprocessors, various pulse width
modulation (PWM) techniques are becoming popular in AC motor drive application.
Now a day's number of Pulse width modulation (PWM) techniques are used to obtain
variable voltage and frequency supply. The most widely used P WM techniques for
three phase voltage source inverters are carrier-based sinusoidal P WM (SPWM), third
harmonic injection PWM (THIPWM) and space vector PWNI (SVPWM).

In this thesis first a models of sinusoidal PWM, third harmonic injection P WM and
Space vector P WM is made and simulated using MATLAB/SIMULINK software. The
waveform of various voltages, line to neutral and line to line voltages is generated and
T HD of various voltages has been calculated using fast Fourier transform tool
available in MATLAB .And on the basis of THV and dc bus utilization performance
of Sinusoidal PWM, Third harmonic injection PWM and space vector PWM are
compared. The simulation result shows that Space vector PWM utilizes dc bus voltage
more effectively and generates less THV when compared with sinusoidal PWM and
third harmonic injection PWM.

Keywords: PWM Techniques SPWM, THIPWM, SVPWM, THD