Second-order odd-harmonic repetitive control and its application to active filter control

High order repetitive control has been introduced toovercomeperformance decay of repetitive control systems undervarying frequency of the signals to be tracked/rejected orimproving the interhamonic behavior. However, most highorder repetitive internal models used to improve frequencyuncertainty are unstable, as a consequence practicalimplementations are more difficult. In this work a stable,second order odd-harmonic repetitive control system ispresented and studied.The proposed internal model has been implemented andvalidated in a shunt active filter current controller. Thishigh order controller allows dealing with the gridfrequency variations without using adaptive schemes

Galerkin-based sliding mode tracking control of non-minimum phase DC-to-DC power converters

Output voltage control of nonlinear DC-to-DC power converters is handicapped by the non-minimum phase character exhibited by these systems. The problem has been usually solved with indirect control strategies that work through the input current. In this article, we report a robust control methodology that uses Galerkin-based sliding manifolds, which use full state reference profiles and an estimate of the disturbed load parameter. The sliding surface incorporates a first-order Galerkin approximation of the input current that provides robustness to piecewise constant load perturbations by dynamic compensation: it allows on-line accommodation to the action of the load estimator. This results in high-accuracy tracking of periodic references at the output resistance of boost and buck-boost converters. Copyright © 2006 John Wiley & Sons, Ltd

Nonminimum phase output tracking control strategies for DC-to-DC power converters

Switched mode DC-to-DC power converters [1] are used in a variety of electric power supply systems, including cars, ships, aircraft and computers. Application of Sliding Mode Control [2, 3] in tracking a real-time voltage profile is very promising because a switching control strategy is traditionally employed in power converters, and because of the inherent robustness properties of the sliding mode. Contributions to sliding mode control [2, 3] of power converters are available in many papers [l, 4, 5, 10]. Direct regulation/tracking control of the output voltage for boost and buck-boost power converters results in a nonminimum phase system and therefore an unstable controller. It has been shown in [6, 7, 9, 17, 18, 21] that controlling the current can indirectly control the output voltage in both converters. In particular, a variable unknown load was considered in [18, 21] using an optimal estimator