Robust tracking method of a DC-AC PWM converter for green energy applications

摘要

This paper proposes a robust tracking method with application to the DC-AC PWM converter of the green energy. The proposed method has the merits of hyperbolic tangential sliding hyperplane (HTSH), grey prediction (GP) and firefly algorithm (FA). The HTSH has the robustness of classical sliding mode control (SMC) and increases the system's convergence speed. However, once a highly nonlinear load occurs, the chatter and steady-state errors still exist. The chatter and steady-state errors may yield high total harmonic distortion (THD) in DC-AC PWM converter output-voltage, even leads to the instability of green energy system. The GP is thus employed to reduce the chatter when system uncertainty bounds are overestimated, and simultaneously the control gains of the HTSH can be tuned by the FA so that steady-state errors problem can be resolved. By combining HTSH, GP, and FA, the DC-AC PWM converter of green energy system will yield high-quality AC output. Simulation and experimental results are given to conform that the proposed converter can obtain low THD and fast dynamic response.