Direct-current Vector Control of Three-phase Grid-connected Converter with L, LC, and LCL Filters

Abstract With the growing use of grid-connected converters in distributed generation systems, the problem of injected harmonics becomes critical. These harmonics require the connection of low-pass filters between the converter and the network. An LC or LCL filter has shown better attenuation to switching harmonics than a simple L filter and has recently drawn great attention in distributed generation areas. However, the control design of an LC- or LCL-filter-based grid-connected converter is more challenging. This article presents a novel vector control design for a grid-connected converter with an LC or LCL filter based on a direct-current vector control method. The behavior of the proposed control technique is compared and evaluated in a simulation and hardware experiment environment, which demonstrates that the proposed control approach has strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy various grid-connected converter control needs for different filtering configurations.