HELP FOR A PURE SINEWAVE INVERTER PROGRAM CODE USING PIC

Please I will like someone to help me out...
I am designing a pure sine-wave inverter using PIC18F252.
My problem is that I dont know how to go about writing the code. I am still learning about Micro-controller programming. And this project is so critical that I have to do anything possible to make it work.

Please I will like any one who has good knowledge in micro-controller programming and, or inverter designing to sincerely help me out.
The inverter will be powered with 24VDC and the expected out put is 240VAC, 50Hz, pure-sine-wave with the least distortion and high efficiency.

THE CIRCUIT DETAILS FOR THE PROJECT IS ATTACHED HERE
Thanks so much in advance.

 

The paper shows that the sine wave is combined with a sawtooth signal to produce a PWM output. If this is also your intent, it might be less intensive to generate the sine wave by means of an oscillator - http://www.electronics-tutorials.ws/oscillator/wien_bridge.html

The suggestion is made as a microprocessor DAC will not approach a wien bridge oscillator for spectral purity.