Harmonic Interference Observer Sliding Mode Control for DC-AC Inverters with Periodic Mismatch Disturbances

This paper aims to address the output voltage regulation problem in typical high-performance DC-AC inverter systems under the influence of variable disturbances during mismatches. To achieve this, a Harmonic Disturbance Observer-based Sliding Mode Control (HDO-SMC) method is proposed. To suppress the impact of high-order harmonics, such as non-matching periodic disturbances, the common state of the reference and disturbance observers is extended, leading to the creation of the Harmonic Disturbance Observer capable of comprehensively suppressing multiple harmonics. Subsequently, the estimated information is incorporated into the sliding mode surface to formulate a composite sliding mode controller. Experimental results confirm the effectiveness of this approach in eliminating the influence of non-matching periodic load disturbances and ensuring the stability of the closed-loop system. This strategy, requiring only a voltage sensor, addresses the challenge of periodic non-matching disturbances in DC-AC inverters during routine usage, not only reducing practical costs but also providing superior anti-interference performance.