Rapid prototyping of a low-cost solar array simulator using an off-the-shelf DC power supply

A method of rapid prototyping of a solar array simulator, based on low cost, off-the-shelf components is proposed in the paper. A commercial constant output voltage switching power supply is utilized as a power stage. It is shown that it is possible to gain control over output voltage of such a device by injecting variable analog voltage into the voltage feedback loop of the supply. As a result, by sensing the power supply output current and varying the injected voltage it is possible to change the output voltage according to a predefined relation and hence any static I-V curve may be emulated by the device. For simulating a solar array output characteristics, the desired I-V curve may be either digitized from a manufacturer provided datasheet, obtained experimentally or estimated from three basic current-voltage pairs (open circuit, short circuit, and maximum power points) using a dedicated algorithm. In order to demonstrate the proposed method, a prototype was designed and built based on available low-cost commercial components. Dynamic characteristics of the prototype were experimentally evaluated and three static I-V curves of a commercial solar panel were simulated. The resulting I-V output characteristics were shown to closely resemble datasheet I-V curves.