Modified SHE for Grid Connection.pdf

This paper presents an improved selective harmonics elimination technique for PV assisted single phase

grid-tied pulse width modulated (PWM) voltage source

inverter (VSI). The switching angles are determined offline

through numerical techniques and stored in microcontroller

memory as a function of modulation index md for online

application. For multiple solution, the solution which leads to

lower change of switching angles (α) from the previous md, is considered for storing in the processor memory. This leads to less no. of sections for the processor when a piecewise mixed model is considered for storing the entire switching angle curve. This technique is well suited for limiting voltage THD in two level grid connected VSI with L-C filter. The verification of theoretical concept is done in laboratory prototype of PV (500 W) connected to grid-tied PWM inverter. The control environment is realized in embedded FPGA interfaced national instrument hardware.