A new control method for distortions compensation and power control using microgrid connecting voltage source converters

Abstract

In this paper, a new control method is proposed for microgrid-connected voltage source converters (VSCs), which generally contain voltage and current control loops. The voltage of the point of common coupling (PCC) is analyzed by recursive least squares (RLS) algorithm and its fundamental positive symmetric components are extracted by the voltage control loop. Using the fundamental positive symmetric component, the required active and reactive powers are injected into the main grid via the microgrid-connected VSC without any distortions. This control loop is equipped with two PI controllers for the DC and AC voltage regulation. On the other hand, the same as the PCC voltage assessment, the local load current signal is evaluated by the RLS algorithm in the current control loop, with its harmonics and unbalanced components extracted. Eventually, the reference signal is obtained using these two control loops for generating switching pulses of the microgrid-connected VSC. Accordingly, the VSC acts as a shunt active power filter (APF), and also simultaneously injects the required active and reactive powers to the main grid. The proposed control method has high accuracy and fast dynamic response, and also its performance is independent of system parameters. The effectiveness of the proposed method has been verified by simulation and experiment.