Rapid synchronization technique for enhanced low voltage ride-through operation of a distributed energy resource

Abstract

A rapid grid synchronization technique is proposed for enhanced low voltage ride-through (LVRT) operation of voltage source inverter based distributed energy resource (DER). The proposed synchronization method aims at enhancing the LVRT capability by providing fast information of the fundamental positive and negative sequence components of the grid voltage vector. This is achieved by a novel pre-filter, based on complex frequency integrators, which is capable of faster fundamental voltage sequence separation. This information is crucial for optimal and accurate current reference generation during LVRT. Improved dynamics of the prefilter also allow higher phase lock loop (PLL) bandwidth compared to existing pre-filter based synchronization techniques. The higher bandwidth of the PLL based on proposed pre-filter allows for fast fundamental positive sequence grid voltage vector angle tracking which is crucial for a current controller in the synchronous reference frame. The method is implemented on TMS320F28335 controller, and key results are presented.