Homogeneous Disturbance Observer Based on Sliding Mode Observer and Controller for T-Type Inverter

This paper proposes a novel sliding mode control (SMC) for the T-Type inverter in the standalone mode. Firstly, the accuracy of the estimated states used to construct the fixed-time SMC and the disturbance observer (DOB) is improved by a proposed sliding mode observer (SMO). Secondly, a DOB is designed without the requirement of the first derivative or the format of the disturbance. Thirdly, an advanced reaching law is utilized for both the SMO, the DOB, and the SMC controller for the chattering elimination. Fourth, the stability of the proposed controller is confirmed by the Lyapunov condition. The performance of the proposed control strategy is validated by simulations and experiments with the same scenarios of nonlinear load and parameter variations. The results prove that the output voltage of the proposed control method meets the standard EN 62040 with the total harmonic distortion being lower than 5% in all cases, which is superior to the performance of the traditional controller.