<p>The LCL filters in grid-connected inverters are being replaced by LCCL filters, because the former can complicate the design of the current controller, while the latter can reduce the inverter systems from third-order to first-order systems. However, the LCCL type grid-connected inverter has new problems such as uncertain inductance parameters and a slow dynamic current response. This article proposes dual-band disturbance observer sliding mode control (DBOSMC) for LCCL-type grid-connected inverter systems. It improves the dynamic response by introducing a sliding mode control (SMC) into the active disturbance rejection control (ADRC). A dual-band disturbance observer (DBO) is designed to improve the control accuracy of SMC and alleviate its chattering. Besides, a new reaching law is designed to achieve fast convergence of the tracking error in finite time. The stability of the controller is verified through Lyapunov theory. It is demonstrated through simulation and experimental results that the proposed control method performs the best in terms of steady state tracking error, dynamic response speed, and total harmonic distortion (THD) compared to the conventional PI control and ADRC.</p>