Unbalanced Voltage Compensation in the Primary and Secondary Control Levels of AC Microgrids

As an inevitable issue, voltage unbalancing can have some adverse effects on the power systems equipment. This paper investigates a double synchronous reference frame-based control method to compensate unbalanced voltage, helping to properly active and reactive power-sharing. This approach controls the positive and negative components of the voltage separately, which can be implemented in the primary and secondary control levels of islanded AC microgrids. The secondary control is based on the dynamic consensus algorithm that helps restore deviated voltage and frequency induced by the primary control, but it also improves the proposed control scheme performance. The proposed control strategy's effectiveness is investigated based on some simulations in the MATLAB Sim/Powersystem environment.