Elimination of load harmonics can be achieved by either filtration of selected harmonics or the use of pulse-width modulation PWM technique. Many PWM techniques are developed, but the most commonly used in industrial applications is the SPWM technique where the distortion factor DF (one of the most important performance parameters of the quality and efficiency of a lot of the electronic devices) is significantly reduced. In this paper,the SPWM technique for harmonic elimination (HE)is implemented using 8051 microcontroller and the well known MATLAB software. The result is tested on a prototype inverter which was designed since 1998. This method is based on the analysis of Fourier series and Fourier coefficients of the required SPWM output voltage waveform.
In this paper, the odd function technique with three and five pulses per half cycle to generate the required SPWM control signals is achieved. The basic flow chart of the control program, samples of the experimental results as well as an appendix illustrating the complete source code programs (INV1) and (INV2) in an assembly language of 8051 microcontroller are given.
Key words :Harmonics elimination, PWM,Microcontroller, Inverter .