Short Course on CPV-Concentrated Photovoltaics Indoor/Outdoor Characterization

Concentrating Photovoltaic technology CPV has become a relevant technology for the solar energy conversion in electricity   enabling  high system efficiencies of PV system comparable to more conventional solar thermal and with competitive  levelized cost of electricity in regions with a large fraction of direct irradiance. Conversely CPV modules are made up by complex mechanical, optical and electrical components which have to be installed on performing high-accuracy sun trackers to  concentrate light on smaller PV receivers.  That requires specific characterization techniques in order to assess its performance in a meaningful and reproducible way- This introduction provides an overview of the main scientific/technical aspect related to CPV characterization by leaving to next speeches the opportunity to deepen on them

The International Electrotechnical Commission’s Technical Committee 82 Working Group 7 (IEC TC82 WG7) is devoted to the development of international standards for Concentrator Photovoltaics (CPV). These include the IEC 62670 series related to the rating of CPV.

1. IEC 62670-1 (Concentrator Photovoltaic (CPV) Performance Testing – Part 1: Standard Conditions) has been published in 2013 and defines the standard conditions for the rating of CPV devices.

2. IEC 62670-2 (Concentrator Photovoltaic (CPV) Performance testing – Part 2: Energy Rating by measurement) is in the draft phase and will define methods for the performance of a long term energy output measurement of CPV systems.

3. IEC 62670-3 (Concentrator Photovoltaic (CPV) Performance Testing – Part 3: Performance Measurements and Power Rating) will define procedures for a power rating of CPV modules and systems

This webinar introduce to this by fostering discussion among the participants

In the frame of the European project SOPHIA a concentrator photovoltaic (CPV) module measurement round robin has been initiated. The round robin includes measurements of four CPV modules at seven different test laboratories located in Europe. IV curves of the modules are measured with different measurement equipment under various climatic conditions. The aim of this activity is to perform at each site a rating of the modules at concentrator standard operating conditions CSOC according to IEC 62670-1. The outcome of the round robin is intended for direct feedback to the current draft standard IEC 62670-3 “Concentrator Photovoltaic (CPV) Performance Testing - Performance Measurements and Power Rating”. Data treatment and the characteristics and accuracy of different power rating methods are discussed PV Technologies : CPV Concentration Photovoltaics

A methodology to determine the spectral influece based on component cells (placed in collimating tubes to form a spectroheliometer) is presented, useful to characterize spectrally Multi-Junction (MJ) solar cells and Concentrating Photovoltaics (CPV) modules and systems. The Spectral Matching Ratio (SMR) between two subcells for a given spectrum is defined and then can be used to filter those moments whose spectra are equivalent to the reference one (AM1.5D-G173-03). Furthermore, annual data from a spectroheliometer can be used to determine the periodic spectral influence in a given location. In the frame of the European project SOPHIA, a spectral network based on component or isotype cells has been created. Among the members of this project, several instruments were installed in the last years, allowing the collection of minute-resolution spectral data useful for CPV technology across Europe.

Indoor characterization tools are valuable for the development and optimization of concentrator PV systems, and critical for the large-scale deployment of CPV. Yet they remain not widely known or understood. In this talk we will review the main instruments and methods currently used in indoor testing of CPV optics and modules. Notably, we will describe the principles of a CPV solar simulator and the main requirements it should fulfill in order to provide significant measurements. Furthermore, we discuss appropriate reference sensors for light intensity and spectrum, typically based on component cells and single-lens concentrator units (mono-modules). Methods for meaningfully assessing irradiance and spectral conditions are detailed.