A fast dynamic photovoltaic simulator with instantaneous output impedance matching controller

Solar PV simulators are commonly used to test and evaluate solar power conditioning systems. One of the main challenges remaining for switching mode PV simulator is its dynamic response time during transients. In existing switching mode PV simulator methods, the power conversion stage responds according to the controller loop, hence, dynamic response time is limited by output filter dynamics. This paper proposes a way to decouple the output filter dynamics from the controller loop by introducing a novel Instantaneous Output Impedance Matching (IOIM) controller for a voltage mode control dc-dc buck based PV simulator. The IOIM controller determine the operating point voltage reference on the I-V curve, directly, without looping through the power conversion circuit. This is performed by quickly matching both load characteristics and solar PV characteristics. An inner control loop uses a boundary controller, with second order switching surface, to control the capacitor voltage at a pre-determined reference. Simulations have been performed to verify the proposed idea. Furthermore, a 260 W dc-dc buck converter prototype with input voltage 120 V has been implemented. Experimental results show that, under large signal disturbances, the system can find its new operating point relatively fast, which proves its fast dynamic characteristics. Simulations and experimental validation show proper agreement with the theory.