Phase Compensated Reduced Order Generalized Integrators for Grid-Tied VSCs With Harmonics Compensation Capability
Current control is a crucial issue of the operation of grid-connected voltage source converters (VSCs). The challenge of the current control lies in how to track the current reference in a fast and accurate way. A second-order generalized integrators (SOGIs)-based current controller is one of the highly popular ways to achieve these objectives since they can track ac signals of both positive and negative frequencies/sequences without steady-state error. However, this may lead to extra unnecessary computational burden when SOGIs are applied in three-phase systems. Therefore, a reduced order generalized integrators (ROGIs)-based current controller is proposed to reduce the computational burden. In this paper, a phase compensation embedded ROGI is proposed, which can not only retain the advantage of a less computational burden of the conventional ROGI compared with the SOGI, but also more importantly, further improve the harmonic control bandwidth and frequency adaptivity in comparison with the SOGI or conventional ROGI. In addition, the derivation of the phase compensated ROGI is provided in the paper along with its parameters tuning strategy analysis. A case study regarding an LCL-filtered three-phase grid-connected VSC with auxiliary harmonic compensation capability is given in detail. Finally, the experimental results are presented to validate the superiority of the proposed method.