Enhanced Real Time Impedance Emulation for Microgrid Equipments Testing and Applications

Abstract

The impedance emulator is a useful tool for microgrid applications and it is required for standards compliance of industrial and laboratory measuring instruments and/or equipment under test. This paper deals with an improved control of line impedance emulator, indeed earlier researchers applied PI controllers and resonant controllers associated to impedance emulator algorithm to emulate the desired impedance. However, these kinds of controls are characterized by limited stability region and additional damping methods are required to ensure system stability. Also, most used emulation algorithms are complicated, difficult to implement and very greedy in computing resources. This study investigates the dead beat predictive control associated to an optimized impedance emulation algorithm for a converter based three phase impedance emulator. The proposed control is characterized by its fast dynamic response, simple design and minimized computational resources, while the proposed impedance emulation algorithm is characterized by its precision, efficiency and decoupled inductive and resistive impedance components variation. Indeed, these characteristics allow flexible, precise and accurate impedance emulation based tests. Simulation and experimental results for the impedance emulator are presented in order to show the performances and efficiency of the suggested control strategy.