**Nomenclature**

and experimental normalized power curves can be explained with the fact that the simulated power output is just based upon the number of radiation received at the outlet apertures of homogenizer. However, for experimental curve, the power output is the actual electrical power obtained from CPV module but at a constant load. As the load across CPV module is constant, therefore, excessive ray loss causes its maximum power point to shift, resulting in a decrease in its output and performance. That is why it also deviates from the simulated curve. To carefully understand the varying trend of simulated and experimental normalized power curves, the simulated irradiance map at all four outlet apertures of homogenizer is shown in **Figure 14**. The irradiance maps are plotted against different points mentioned on experimental normalized curve. It can be seen from **Figure 14(A)**, which shows the irradiance map at point 'A', that the solar cells 3 and 4 are coming under shadow. For simulated curve, this shadow is just a decrease in the number of rays coming out of the homogenizer. However, in actual system, the electrical output of the CPV system is greatly disturbed as all MJCs are connected in series. The maximum power point for cells under shadow changes, and they also pulls down the performance of other MJCs due to their series connection. Therefore, overall electrical output of complete CPV module decreases. At points 'B', 'C' and 'D', the normalized electrical power output of CPV system is almost same as 50%. This is because of the fact that at this point, only two cells are operating, while the other two cells are under complete shadow, as shown in **Figure 14(B)**–**(D)**. However, for simulated power curve, there is still a gradual decrease for these points which implies that the net flux output is not reduced to 50% for all these three points, i.e., 'B', 'C' and 'D'. The main reason for half of electrical output is because of the shift in the maximum power point for the entire CPV system, which is effected by the

After increasing deviation angle beyond point 'D', the experimental curve again starts to drop till point 'E'. This is because of the fact that now the other two cells are also coming under shadow, as can be seen in **Figure 14(D)**. At point 'E', the remaining two cells are under only partial concentration. That is why the power output reduced to a low value. The power output remains stable for a while after point 'E' which is just because of partial concentration that moves around the cell area due to leftover and scattered radiations. With further increase in the deviation angle, the power output slowly dies to zero. The normalized power output curve shows that the develop CPV system, based upon the proposed MCA, has acceptance angle of 1° as designed. However, it has a capability of operation for deviation angle as high as 6.5°. However, the power output drops significantly, but the system can still respond to the

In the current photovoltaic market, with dominating share of single-junction solar cells, the highly efficient concentrated photovoltaic systems (CPV), utilizing third-generation multi-junction solar cells, have yet to exploit their market potential due to their design complexities. The conventional CPV module design utilizes individual concentrator for each MJC. This chapter has introduced a novel design of CPV concentrating assembly where single

two cells under shadow.

126 Solar Panels and Photovoltaic Materials

received radiations.

**6. Summary of the chapter**


AH area of center hole in primary reflector of multi-leg homogenizer concentrating assembly (mm<sup>2</sup> )

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Multicell Design for Concentrated Photovoltaic (CPV) Module

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