At present

the five-level inverter from the control strategy is rarely studied. Therefore

we apply the nonlinear passivity-based control（PBC） theory to the control of five-level inverters.In this method

the structure of control system is considered from the viewpoint of energy forming

and the selection of anappropriate energy function and injection damping is needed. Firstly

a mathematical model is deduced according to the topology of the five-level inverter and its switching function. Then

the mathematical model of the five-level inverter is transformed into the passive Euler-Lagrange（E-L） expression by selecting the appropriate energy function and injection damping

and the switching function is combined with modulation algorithm to drive the grid-connected system.Simulation and hardware experiments show that

compared with the traditional PI control

the passivity-based control not only improves the dynamic and static stability of the system

but also reduces the output current harmonics of the inverter and improves the economy of the system.