Control of Cascaded Inverters with MPPT for Grid-Connected Photovoltaic Generators

Conference: Intelec 2013 - 35th International Telecommunications Energy Conference, SMART POWER AND EFFICIENCY
10/13/2013 - 10/17/2013 at Hamburg, Deutschland

Proceedings: Intelec 2013

Pages: 6Language: englishTyp: PDF

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Authors:
Li, Hong; Abu-Qahuoq, Jaber (Department of Electrical and Computer Engineering, The University of Alabama)

Abstract:
A single-phase cascade inverter for grid-connected PV system with phase shift control is presented in this paper. Individual MPPT is introduced to maximize the power extracted from the PV panel. A control scheme with module index is added to achieve sharing the current under different panel input situation, and phase shift control with current tracking function and individual PWM signal. This paper presents two-stage photovoltaic grid-connected cascaded inverters. The MPPT senses the output voltage, then the MPPT output along with the grid voltage will produce the current reference needed, which will further produce PWM signal for each inverter. Since the current is controlled to track the grid voltage, this will keep the output voltage and current in phase. Appropriate duty cycle of each PWM signal will keep the both the PV panels work on the MPPT point. The first stage is a DC-DC boost circuit that is controlled by MPPT; the second stage is a DC-AC H-bridge inverter that converts a direct current waveform to a sinusoidal waveform with a low harmonic distortion current and connected to utility.