This paper explores the performance of a dc-dc converter, which emulates the output characteristics of a real photovoltaic (PV) module. The PV simulator uses a double current mode controller to ensure fast and accurate reproduction of a module's current-voltage (IV) characteristics. A portable PV simulator prototype of 85 W is examined in terms of its steady state IV curve matching capacity and the convergence time corresponding to step changes in current source load, voltage source load, and insolation levels. The IV characteristics of the PV module are implemented as a look-up-table, which determines the reference output current from measured output voltage. The Thevenin equivalent circuit of the PV module is used to model its small-signal (linearized) characteristics for stability analysis. Extensive simulation and experimental results, with loads that have current-source, voltage-source, and resistive characteristics, validate the converter's suitability for replacing a PV module in most laboratory situations. Modularity and compatibility with a maximum power point tracker have also been validated.