A Three-Phase Grid Emulator Based on a Harmonic Rotation Matrix for Power Quality Tests

This paper proposes a vector control system based on a rotation matrix that is capable of inducing harmonics in a three-phase control application. This control system is designed to establish the harmonic distortion in the output states of a threewire three-phase grid emulator. The rotation matrix operation principle consists of three steps; 1) It is built from a distorted and unbalanced three-phase vector that contains the specific harmonic spectrum to be induced in the grid emulator output states; 2) It projects all the system space vectors into a special reference frame called Harmonic Synchronous Reference Frame; and 3) The desired distortion is induced by making a linear controller, in the HSRF, to follow a constant in time control reference. The proposed control system advantages are demonstrated by establishing the harmonic profile of its output voltages. The simulation and experimental results presented show the excellent performance the Harmonic Rotation Matrix has.