III–V concentrator photovoltaic systems attain high efficiency through the use of series connected multi‐junction solar cells. As these solar cells absorb over distinct bands over the solar spectrum, they have a more complex response to real illumination conditions than conventional silicon solar cells. Estimates for annual energy yield made assuming fixed reference spectra can vary by up to 15% depending on the assumptions made. Using a detailed computer simulation, the behaviour of a 20‐cell InGaP/In0.01GaAs/Ge multi‐junction concentrator system was simulated in 5‐min intervals over an entire year, accounting for changes in direct normal irradiance, humidity, temperature and aerosol optical depth. The simulation was compared with concentrator system monitoring data taken over the same period and excellent agreement (within 2%) in the annual energy yield was obtained. Air mass, aerosol optical depth and precipitable water have been identified as atmospheric parameters with the largest impact on system efficiency. Copyright © 2012 John Wiley & Sons, Ltd.

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The status of the development of a new concentrator module in Japan is discussed based on three arguments, performance, reliability and cost. We have achieved a 26Á6% peak uncorrected efficiency from a 7056 cm 2 400Â module with 36 solar cells connected in series, measured in house. The peak uncorrected efficiencies of the same type of the module with 6 solar cells connected in series and 1176 cm 2 area measured by Fraunhofer ISE and NREL are reported as 27Á4% and 24Á8% respectively. The peak uncorrected efficiency for a 550Â and 5445 cm 2 module with 20 solar cells connected in series was 28Á9% in house. The temperature-corrected efficiency of the 550Â module under optimal solar irradiation condition was 31Á5 AE 1Á7%. In terms of performance, the annual power generation is discussed based on a side-by-side evaluation against a 14% commercial multicrystalline silicon module. For reliability, some new degradation modes inherent to high concentration III-V solar cell system are discussed and a 20-year lifetime under concentrated flux exposure proven. The fail-safe issues concerning the concentrated sunlight are also discussed. Moreover, the overall scenario for the reduction of material cost is discussed.

A multi-junction concentrator system computer model is presented, that aims to accurately m odel the power generated based on environmental data input, such as the irradiance, air temperature, humidity and pressure. The device model is discussed, illustrating the importance of statistical variation of module components when simulating a multi-cell module. This comprehensive concentrator computer model will be released for general use, aiming to become a useful resource for those designing and testing multi-junction based concentrator systems.

Right now, there is no agreed definition and measurement method for rating concentrator photovoltaic. This paper discusses present situation of the ratings of CPV modules and systems. First, it was analyzed which factors have influence to the performance to CPV modules and systems. Next, the linear interpolation method that is known as a robust estimator especially to multi-junction thin film modules is discussed. The test data was provided from Toyohashi University of Technology where a 550 X CPV module (20 cells connected in series and the total area is 5,445 crrr) was tested independently. The relative standard deviation was 0.89 0/0, whereas that of the linear interpolation method was 1.2 0/0. Different from the linear interpolation method, this stratified averaging method is unbiased.