Irradiance estimation for a smart PV array

Electrical mismatch between modules in a PV array due to partial shading causes energy losses beyond the shaded module. This occurs because unshaded modules are forced to operate away from their maximum power point in order to compensate for the shading. Here we present an irradiance estimation algorithm for use in a mismatch mitigation system. Irradiance is estimated using measurements of module voltage, current, and back surface temperature. These estimates may be used to optimize an array´s electrical configuration and reduce the mismatch losses caused by partial shading. Propagation of error in the estimation is examined; we find that accuracy is sufficient for use in the proposed mismatch mitigation application.