University of South Wales Master of Sciences Thesis
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| 2.9.1. Solar Cell
The Solar Cell block represents a solar cell current source. The solar cell model includes the following components: • Solar-Induced Current • Temperature Dependence Solar-Induced Current The block represents a single solar cell as a resistance Rs that is connected in series with a parallel combination of the following elements: Current source Two exponential diodes Parallel resistor Rp Standalone hybrid generation system for the remote area of Thar, Pakistan Fig. 2.42 Block representation of the solar cell The output current I is 5.1 Where: - • Ir is the irradiance (light intensity) in W/m2 falling on the cell. • Iph0 is the measured solar-generated current for the irradiance Ir0. • Is is the saturation current of the first diode. • Is2 is the saturation current of the second diode. • Vt is the thermal voltage, kT/q, where: k is the Boltzmann constant. T is the device operating temperature parameter value. q is the elementary charge on an electron. • N is the quality factor (diode emission coefficient) of the first diode. • N2 is the quality factor (diode emission coefficient) of the second diode. • V is the voltage across the solar cell electrical ports. The quality factor varies for amorphous cells, and is typically 2 for polycrystalline cells. The block lets you choose between two models: An 8-parameter model where the preceding equation describes the output current and a 5-parameter model that applies the following simplifying assumptions to the preceding equation: • The saturation current of the second diode is zero. • The impedance of the parallel resistor is infinite. If you choose the 5-parameter model, you can parameterize this block in terms of the preceding equivalent circuit model parameters or in terms of the short-circuit current and open-circuit voltage the block uses to derive these parameters. All models adjust the block resistance and current parameters as a function of temperature. |