<italic>H</italic>∞ -LS Current Control Strategy for Single-Phase ANPC Rectifiers Considering Grid-Voltage Harmonics

The variation in the grid-side equivalent inductance of single-phase Active Neutral-Point Clamped (ANPC) rectifiers is recognized as a main factor causing uncertainty in the control object model, which can undermine the stability and adaptability of the system. From a robust control perspective, this paper presents the design of an <italic>H</italic>∞-Loop Shaping (<italic>H</italic>∞-LS) direct current control method. The addition of a compensator to the current control loop enables the establishment of a model that creates ideal amplitude-frequency characteristics curves for the system. This process incorporates normalized coprime factorization for the object control system, leading to the formulation of an <italic>H</italic>∞ problem for the coprime factor vibration model. Additionally, to address grid-side voltage distortions or voltage sampling errors, an improved second-order generalized integrator is introduced to generate virtual signals. Comparative experiments conducted on the experimental platform verified that the proposed <italic>H</italic>∞-LS control strategy reduced current fluctuations by approximately 50% with only 30% inductance parameter variations, thereby enhancing the ANPC rectifier system's adaptability to grid-side inductance parameter changes.