Abstract: The cascaded H-bridge (CHB) multilevel inverter is widely used in grid-connected systems for its modular characteristics. However, due to the strongly coupled nonlinear characteristics, the CHB grid-connected inverter system with linear control strategies such as PI closed-loop control strategy has poor rapidity and multiple control parameters that are difficult to tune. To solve this problem, an energy-shaping control strategy is proposed. Firstly, the port-controlled Hamiltonian (PCH) model in the synchronous rotating coordinate system is established by instantaneous power observation, and the energy-shaping controller of the system is designed. Secondly, the influence of the control parameters on the control performance is analyzed, and a general tuning method of the control parameters is given. Finally, simulation and experimental results verify the rationality of the proposed control parameter tuning method, and it is also verified that the designed control strategy has fewer control parameters and better rapidity than the PI closed-loop control strategy.