Analysis and Performance Evaluation of a Two-Stage Resonant Converter for Wide Voltage Range Operation

Abstract

This paper proposes a two-stage isolated dc-dc converter for electric vehicle charging applications, where high efficiency over a wide range of battery voltages is required. It employs a first pre-regulation stage and a second half-bridge LLC stage, integrated with the first. The second stage is always operated at resonance, ensuring very high efficiency. The first pre-regulation stage is responsible for the desired input-to-output voltage conversion ratio and the zero-voltage switching operation of all the switches. This allows low conversion losses even with voltages that may vary over a wide range. The conversion structure is shown considering a first experimental prototype that interfaces a 750-V dc-link with an output bus with nominal voltage range 250V-500V. The implemented module is rated 5 kW and achieves a peak efficiency of 98.0% at 3 kW output power.

Fourth-Order Quadratic Buck Converter Controller Design

“…Buck converters, also known as step-down converters, are widely used in applications where a regulated voltage needs to be obtained from a higher voltage source. Examples of such applications are industrial applications [1,2], like motor drives or factory automation [3,4], telecommunications [5], solar power systems [6], automotive [7], and voltage regulators [8][9][10][11][12]. This ability to reduce the voltage level is essential in many electronic devices, and in the literature, different topologies, starting with the classical step-down buck converter [13], other types of non-isolated [14,15] converters or isolated step-down converters [16][17][18] can be found.…”