08-16-2017, 11:00 PM
The power electronics device which converts DC power to AC power at required output voltage
and frequency level is known as inverter. Inverters can be broadly classified into single level
inverter and multilevel inverter. Multilevel inverter as compared to single level inverters have
advantages like minimum harmonic distortion, reduced EMI/RFI generation and can operate on
several voltage levels. A multi-stage inverter is being utilized for multipurpose applications, such
as active power filters, static var compensators and machine drives for sinusoidal and trapezoidal
current applications. The drawbacks are the isolated power supplies required for each one of the
stages of the multiconverter and it s also lot harder to build, more expensive, harder to control in
software.
This project aims at generation of carrier based PWM
scheme using POD strategy through the means of an AT89C51 microcontroller. The salient
features are: Firstly, Both the high frequency triangular carrier wave and the sinusoidal reference
signal are being generated in the microcontroller. The digital to analog converter(DAC0808)is
then employed for converting them into their analog signal forms An opamp based comparator
then compares these two carrier & reference signals to give us the desired sinusoidal pulse width
modulated signal as the required final-output. The PWM signal thus generated is then used as
triggering pulses for the multilevel inverters.
