Abstract：The traditional predictive current control for three-phase LCL grid connected inverters has the

problems of large steady-state ripple and unstable switching frequency，which is not conducive to the quality of grid connected current and the design of filters. Therefore，an improved three vector fixed frequency predictive current control method was proposed.By applying three vectors within one control cycle，the control degrees of freedom were maximized. Firstly，an active damping method based on capacitor voltage feedback was designed to suppress resonance. Then，a duty cycle calculation method based on inverter side current deadbeat control and a seven segment symmetric pulse generation scheme were proposed. The simulation results and test results verified the superiority of the proposed method in improving dynamic performance，steady-state performance and fixing

switching frequency.

      Key words：LCL grid connected inverter；model predictive control （MPC）；duty cycle calculations；

modulation；active damping