100kVA electric vehicle charger using resonant buck-type AC-DC converter

This paper describes the design of 100kVA EV (electric Vehicle) Charger which outputs 750V/150A. For the requirement of different type of EV, 13 units are in series; this can make the output voltage as the following: 40V–60V, 400V–600V or 500V–750V, and output voltage and current of each unit are 48V/150A. AC/DC of unit is Buck-type converter, this makes 350V of DC bus; it is very cheap for selection of power device of DC/DC. Resonant circuits are used in this part for high efficiency. It makes voltage of power device become zero before the power device turns on, so turn-on loss can be ignored. DC/DC part uses LLC resonant circuit, and power device can work in ZVS (zero voltage switching) condition and high frequency (about 100 kHz), so this part has high efficiency and small volume. To make charging faster and more security, two control loops are used in the power supply: one is voltage-loop and the other is current-loop. Power factor of input is above 0.99, and harmonic of input is less than 5%, the overall efficiency is more than 92% by charging experiment for bus.