Energy control of multi-switch power supplies; an application to the three-phase buck type rectifier with input filter

The first part of the paper presents a systematic method for the modeling of power electronic networks with multiple switches using the classical Lagrangian framework. The main advantage of this method is its structured and general character compared to other methods. The power of working with Lagrangian dynamics, especially when very large networks have to be analyzed, is that Kirchhoff´s voltage law is given in advance, while the interconnection structure is based on Kirchhoff´s current laws only. The physical nonlinear structure of these systems is revealed and can be used for feedback controller design and stability analysis. The second part concentrates on the proposed passivity-based controller design technique based on the Lagrangian structure. Besides its physical significance, this approach appears to be an interesting alternative when dealing with the problem of input filter influences in power electronic systems. With this technique, artificial damping is injected such that the impedances of the in- and output filters can be matched. In this way power is not reflected and resonance problems, especially during the start-up and transient conditions, are minimized. A unity power factor passivity-based control algorithm for the three-phase buck type rectifier with an input filter is proposed that does not require current sensors but only measurements of the capacitor voltages.