Revisiting the argmin direct control for the Cascaded H-Bridge Inverter

This paper addresses the direct control of the Cascaded H-Bridge (CHB) converter as an inverter (DC-AC), using the argmin control law. This control law derived from the literature on switched affine systems has been used in the control community for direct control of DC-DC converters. However, it has limited effectiveness with the CHB, as it fails to take advantages of the modularity of this topology. To overcome this, a revisited argmin control law is proposed. This new version imposes extra constraints on control inputs to improve the tracking of a suitable reference, offering advantages over the classical argmin control law for this specific converter. Specifically, it significantly reduces switches commutations and the harmonic distortion. Results are further extended with a state feedback version to specify the closed-loop dynamic. All results are illustrated with simulations using PSIM.