Author(s)

Natesan Sivakumar¹, S. Sumathi²

¹Department of EEE, Jayalakshmi institute of technology, Thoppur, India.
²Department of ECE, Adhiyamaan College of Engineering, Hosur, India.

Multilevel inverter (MLI) is one of the most efficient power converters which are especially suited for high power applications with reduced harmonics. MLI not only achieves high output power and is also used in renewable energy sources such as photovoltaic, wind and fuel cells. Among various topologies of MLI, this paper mainly focuses on cascaded MLI with three unequal DC sources called asymmetric cascaded MLI which reduces the number of power switches. Various modulation techniques are also reviewed in literature [1]. In this paper we focus on sinusoidal (or) multicarrier pulse width modulation (SPWM) which improves the output voltage at lower modulation index for obtaining lower Total Harmonic Distortion (THD) level. The gating signal for the 13-level hybrid inverter using SPWM technique is generated using Field Programmable Gate Array (FPGA) processor. The proposed modulation technique results in reduced percentage of THD, but lower order harmonics are not eliminated. So a new technique called Selective Harmonic Elimination (SHE) is also implemented in order to reduce the lower order harmonics. The optimum switching angles are determined for obtaining minimum THD. The performance evaluation of the proposed PWM inverter is verified using an experimental model of 13-level cascaded hybrid MLI and compared with MATLAB/SIMULINK model.

Asymmetric Cascaded Multi Level Inverter (ACMLI), Total Harmonic Distortion (THD), Sinusoidal Pulse Width Modulation (SPWM), Field Programmable Gate Array (FPGA), Selective Harmonic Elimination (SHE)

Sivakumar, N. and Sumathi, S. (2016) Reduction of THD in Thirteen-Level Hybrid PV Inverter with Less Number of Switches. Circuits and Systems, 7, 3403-3414. doi: 10.4236/cs.2016.710290.