Abstract:In view of the disadvantages of high current harmonics,poor system stability and slow response speed in the traditional double PI control,this paper presents a control strategy for T-type grid-connected inverter based on the Lyapunov function.On the basis of analyzing the mathematical model of T-type inverter,a voltage-current double closed loop control circuit is designed.From the point of view of stability,a nonlinear control strategy based on Lyapunov function is proposed for the inner loop of current,which realizes the fast tracking of harmonic reference current.The outer loop adopts the traditional PI control to track the capacitor voltage of DC side.Meanwhile,the d-axis expected current from the outer loop is used as the variable input of the inner loop,which improves the anti-disturbance performance of the double loop.Finally,compare the new double loop control strategy proposed with the traditional double PI control strategy in simulation,and the comparison results verify the superiority of the new double loop control strategy in harmonic compensation.