Prodrive-Select Rectifier

Abstract

This research introduces the Prodrive-Select Rectifier, a novel three-phase buck-type power factor correction rectifier suitable for mains interfaced AC-to-DC conversion as, for example, can be found in on-board battery chargers for electric vehicles. The Prodrive-Select Rectifier shows excellent mains current total harmonic distortion, especially when interleaving of the converter branches is considered, and achieves competitive efficiencies by utilization of three-level buck circuits and a capacitive midpoint which allows for complete zero-voltage switching of the high-frequency power MOSFETs. In this work, two modulation schemes are proposed and analysed with regard to their zero-voltage switching capabilities. In addition, the complete converter analysis including steady-state analysis, transient closed-loop control and component-level volume and loss modelling is thoroughly described. In order to obtain an objective performance indication, the topology is compared to a state-of-the-art buck-type rectifier, namely the Swiss Rectifier. The proposed modelling techniques are implemented by means of a virtual prototyping routine yielding a Pareto-front in the power density versus efficiency performance space from which an optimal design is selected using multi-objective optimization. This Pareto-optimal design operates under partial soft-switching conditions and achieves a conversion efficiency of 98.3% at 2.9kW/dm3 power density. The modelling and optimization techniques are verified by an 11-kW, 1.3-kW/dm3 hardware demonstrator for conversion of a 400-V rms line-to-line AC input into a 400-V nominal DC output. Measurements show efficiencies higher than 97.5% in the range of 4kW- 11kW, with 97.7% peak efficiency and <4% total harmonic distortion at full power.