Analysis and design of phase-interleaving series-connected module-integrated converter for DC-link ripple reduction of multi-stage photovoltaic power systems

Abstract

Recently, installation of photovoltaic power systems such as building-integrated photovoltaic in urban area has been spotlighted in renewable energy engineering field, even at the expense of the performance degradation from partial shading. The efficiency degradation of maximum power point tracking (MPPT) performance can be compensated by a kind of power-conditioning system architecture such as module-integrated converters (MIC), which can handle the optimal-operation tracking for its own photovoltaic (PV) module. In case of a MIC with series-connected outputs, it is easy to obtain a high DC-link voltage for multiple stage PV power conditioning applications. However, switching ripple of the DC-link voltage also increases as number of the modules increases. In this paper, as a solution for the ripple reduction, interleaved pulse width modulation-phase synchronizing method is applied to the PV MIC modules. The switching-ripple analysis of the MPPT power modules were performed and compared between the cases such as phase control or not. For the implementation of the phase control among the modules, Zigbee (XBee Pro, Digi International, Minnetonka, MN, USA) wireless communications transceiver and DSP (TMS320F28335, Texas Instruments, Dallas, TX, USA) series communications interface are utilized. Hardware prototype of the double-module boost-type 80-W MICs has been built to validate the DC-link voltage ripple reduction. Copyright (c) 2012 John Wiley & Sons, Ltd.