On Some Nonlinear Current Controllers for Three-Phase Boost Rectifiers

Several flatness-based current controllers for three-phase three-wire boost rectifiers are compared. For this purpose, the flatness of a rectifier model is shown, and a trajectory planning algorithm that nominally achieves voltage regulation in finite time is given. The main focus lies on the inner loop current controllers. On one hand, linearization-based controllers using exact feedback linearization, exact feedforward linearization, and input-output linearization are discussed. On the other hand, two passivity-based approaches are compared. The first one is the energy shaping and damping injection method, and the other one uses exact tracking error dynamics passive output feedback. Furthermore, a reduced-order load observer is given, and a method that allows the prevention of invalid switching patterns is presented. The presented control algorithms are tested by simulations on a switched model.