Analysis of sinusoidal current reference generation with flat instantaneous active power for unbalanced grids

Since the demand of energy with high quality and reliable power is growing and temporary faults in the grid are common, the analysis of unbalanced voltage conditions has become increasingly important. Power converters can control the instantaneous active and reactive power and manage them in order to improve the voltage conditions at the point of common coupling. The current reference generation strategies are an important component of this system, since they can generate the proper current reference to manage the instantaneous powers and can be easily controlled by the power converter. Multiple current reference strategies for unbalanced systems have been proposed in literature in order to achieve sinusoidal currents or flat instantaneous powers. However, due to fundamental restrictions in the controllability of the system, both control objectives cannot be achieved at the same time. This work presents a current reference strategy which deliver sinusoidal currents and flat instantaneous active power for all operating conditions. Additionally, the resulting reactive power ripple amplitude is analyzed and its performance is compared with previously proposed control methods. Results showing the performance of the current reference generation strategy are given.