Innovative solution for microgrid components testing: Real time line impedance emulation

Abstract

This paper proposes an enhanced control for a converter based three phase line impedance emulator in order to improve clean energy sources integration. In fact, the proposed emulator is used to perform tests related to the integration of renewable energy systems with public grids according to international codes and standards. The emulator control includes a power converter control and an impedance emulation algorithm. Conventional power converter controls for line impedance emulators are based on PI or resonant controllers. However, the stability region of this kind of controls is limited. In addition, existing impedance emulation algorithms are complicated, difficult to implement and very greedy in computing resources. In view of this, the presented work investigates the dead beat predictive control for the power converter associated to an optimized impedance emulation algorithm. 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 line impedance emulator are presented to prove the performances and the efficiency of the proposed control strategy.