Advanced Control of Active Filters in a Battery Charger Application
Martin Bojrup
External reviewer: Åke Ekström, High Power Electronics, KTH

In this thesis, a high performance battery charger for electric vehicles (EVs) is investigated. By including active power line conditioning capabilities in the battery charger, a viable concept for a fast charging infrastructure is obtained, beneficial both to the EV users and the power distributors.

The thesis contains discussions on modelling aspects and design considerations for the proposed battery charger, based on a carrier wave modulated self commutated 2-level voltage source converter topology. Furthermore, model based controller synthesis is employed, and thorough analysis of the controller characteristics is given.

Emphasis is put on the active filtering performance of the battery charger. The weaknesses of the model based control system in active filter applications are revealed, where especially the inherent phase deviation of the control system and the sensitivity to system parameters deteriorates the performance of the active filter.

In order to overcome the deteriorating properties of the model based controller, a controller structure for active filters based on several integrators in multiple reference frames is proposed. It is shown, both theoretically and experimentally, that the proposed controller exhibits low sensitivity to system parameters and provides for complete compensation of the inherent phase deviation. The result is excellent conditioning performance of the proposed active filter controller in steady state.

Last updated 1999-12-06