A Model Predictive Current Controller With Improved Robustness Against Measurement Noise and Plant Model Variations

Abstract

This article improves the robustness of a finite control set (FCS)-model predictive controller (MPC) for grid-tied inverters and motor drives applications to plant parameter variations and noise, without reducing its bandwidth or affecting its excellent transient response to disturbances and reference commands. The proposed modification adds an observer to the MPC controller structure, which does not significantly increase the computational burden on the embedded controller. Traditionally, observers are employed to estimate unmeasured variables and cancel the effect of disturbances, but this article employs the observer to estimate a measured variable, the converter output current. This solution leverages the benefits of observers from linear controller theory in order to remove undesired components in the measured current and improve the robustness of the controller; hence it is a valuable solution for practicing power-electronic engineers and researchers in the field of grid-tied inverters and motor drives due to its simplicity compared to some advanced techniques often required in more complex MPC designs.

Keywords

• Current controller
• L filter
• finite control set (FCS) model predictive controller (MPC)
• voltage source converter (VSC)
• inverter
• observer