Robust Model Reference Adaptive Control Applied to Three-Phase Uninterruptible Power Supplies

In the high power converters such as three-phase inverters is recommended to operate at low frequencies, due to the switching losses. In addition, modeling errors and non linear loads with unmodeled dynamics frequently degrade the controllers performance resulting in a poor transient response and instability. This paper presents a robust model reference adaptive controller (RMRAC) for three-phase uninterruptible power supplies. The three-phase system model is rewritten, using a synchronous transformation in dq coordinates, and a RMRAC controller is used to assure system robustness and performance. Simulation and experimental results are used to show the closed-loop system performance under several operation conditions.