S. Y. Mosazade ¹, S. H. Fathi ¹, H. Radmanesh ²

Affiliations
1 Electrical Engineering Department, Amirkabir University of Technology, Tehran, IR
2 Department of Electrical Engineering, Islamic Azad University, Takestan Branch, Takestan, IR

Abstract

In this paper different high frequency switching methods for multilevel inverters which has been proposed for PV applications is analyzed; furthermore, the output harmonics content of phase shifted PWM (PSPWM) and in phase disposition PWM (IPDPWM) switching methods are comprised. This simulation results show that total harmonics content in IPDPWM is less than PSPWM method; besides, modified switching method of IPDPWM which solves the unequal power sharing problem of it is also proposed. This switching method is applied to a 7 levels inverter which is fed by three PV array DC sources and supply an AC load. These PV arrays deliver maximum power via DC-DC converter and perturb and observe algorithm. Simulation results show effectiveness of this method in sharing equal powers among different cells of the multilevel inverter which are supposed to be PV arrays; furthermore, results show that DC voltage ripples which cause inter harmonics are less than previous similar switching method; Hence for allowable DC voltage ripple, smaller capacitor is required. Simulation is implemented by MATLAB/SIMULINK software.

Keywords

Multilevel Inverter, Photovoltaic System, Power Conditioning

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