Abstract: In order to improve the control performance of grid connected converter, a new method of the phase-locked loopless (PLL-less) control is proposed in this paper. This method will effectively eliminate the influence of phase-locked loop (PLL) on its dynamic performance and simplify its control system. Firstly, based on the single-phase cascaded H-bridge (CHB) multilevel converter, an enhanced observer is introduced to accurately calculate the fundamental component of grid flux. Secondly, the realization process of PLL-less control is deduced in detail, and the expression of current reference is given. Then, aiming at the problem of harmonic interference in the grid voltage, the system harmonic suppression ability is analyzed through the impedance modeling. Therefore, a modified current controller is proposed, realizing the control targets of the sinusoidal output current and the fast dynamic response. In addition, the balancing control is adopted to maintain the stability of the DC-link voltages. Finally, the proposed method is verified by simulation and experiment.