This paper presents a three phase seven level photovoltaic (PV) inverter topology for grid connected PV systems with a novel Pulse Width Modulated(PWM) control scheme. Two reference signals identical to each other with an offset equivalent to the amplitude of the triangular carrier signal were used to generate PWM signals for the switches. A digital Proportional-Integral-Derivative (PID) current control algorithm is implemented in DSPTMS320F2812 to keep the current injected into the grid sinusoidal and to have high dynamic performance with rapidly changing atmospheric conditions. The inverter offers much less total harmonic distortion and can operate at near-unity power factor. The proposed system is verified through simulation and is implemented in a prototype.Experimental results are compared with the conventional three phase three level grid connected PWM inverter.
R. Swaminathan and Anand Rajendran, “A Three Phase Seven Level Inverter for Grid Connected Photovoltaic System by Employing PID Controller”, International Journal of Innovative Research in Science, Engineering and Technology, vol. 4, no. 6, pp. 1085-1091, 2015.