This paper proposes a bipolar-dc-bus Electric Vehicle (EV) charging station without a line-frequency transformer at the medium-voltage grid side. It is mainly composed of the Neutral Point Clamped (NPC) converter based central ac-dc station and the parallel isolated three-level DC-DC converter based fast chargers. Due to the elimination of the line-frequency transformer, the volume and cost of the system are reduced. Meanwhile, the isolation and step-down between high dc-bus voltages and low load voltages are performed through the high-frequency transformers, leading to increased voltage utilization of switching devices. In order to guarantee the bipolar dc buses balance and minimize the dc-bus voltage ripples, the 180°-interleaved operation for the two parallel isolated three-level DC-DC converters is proposed to make the total neutral-point current zero so that all fast chargers do not bring any unbalance problems. The proposed 180°-interleaved operating principle has been analyzed in detail, then simulation results are presented to verify its performance.
|Title of host publication||IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|Number of pages||6|
|State||Published - 2015|
|Event||41st Annual Conference of the IEEE Industrial Electronics Society, IECON 2015 - Yokohama, Japan|
Duration: 9 Nov 2015 → 12 Nov 2015
|Name||IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society|
|Conference||41st Annual Conference of the IEEE Industrial Electronics Society, IECON 2015|
|Period||9/11/15 → 12/11/15|
Bibliographical notePublisher Copyright:
© 2015 IEEE.