Experimenting a Distributed Passive MPPT Based on Mini-Battery-Packs to Cope with Short-Term Critical Partial Shadings on PV-Generators

Experimenting a Distributed Passive MPPT Based on Mini-Battery-Packs to Cope with Short-Term Critical Partial Shadings on PV-Generators

Rosario CarboneGiuseppe A. Maiolo 

“Mediterranea” University of Reggio Calabria, Department D.I.I.E.S., Via Graziella, Reggio Calabria 89123, Italy

Corresponding Author Email: 
rosario.carbone@unirc.it
Page: 
113-121
|
DOI: 
https://doi.org/10.18280/mmc_b.870301
Received: 
12 February 2018
|
Accepted: 
16 April 2018
|
Published: 
30 September 2018
| Citation

OPEN ACCESS

Abstract: 

The common use of by-pass diodes, to contain power generation losses and to avoid “hot-spot” phenomena in presence of short-term, repetitive and critical partial shadings on a PV-field, is experimentally investigated, for demonstrating that bypass diodes are not the optimum choice. Active distributed maximum power point trackers (DMPPTs) can offer a better solution; nevertheless, they are based on complex circuitries and control algorithms, with a reduced reliability and additional power losses. In this contest, the aim of the paper is to present and discuss experimental results obtained by testing a homemade PV-generator prototype in which only a wisely designed and distributed mini-storage based on commercial rechargeable batteries is introduced, to be employed as a “passive” DMPPT, without any active DC/DC converter. The prototype is also experimented to make a comparative performance analysis (i) without bypass diodes, (ii) with bypass diodes and (iii) by introducing our mini-battery-pack, under identical partial shadings, artificially caused and characterized by different degrees of criticality. Experiments demonstrate that wisely designed distributed mini-battery-packs, based on commercial rechargeable batteries, can effectively operate as a passive DMPPT able to cope with short-term critical partial shadings for avoiding “hot-spot” issues and for guaranteeing a significant improvement of the net generated power together with the conventional storage task.

Keywords: 

PV-generators, short-term partial shadings, hot-spot on PV-cells, distributed battery storage, bypass diodes, distributed MPPTSPV-generators, short-term partial shadings, hot-spot on PV-cells, distributed battery storage, bypass diodes, distributed MPPTS

1. Introduction
2. Some Insights About Partial Shading Issues and Limits of Bypass-Diodes
3. Maximum Power Point Trackers (MPPT) Distributed at The Sub-PV-Module Level
4. Experimental Tests
5. Conclusions
Nomenclature
  References

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