Charging Electric Vehicle Batteries: Wired and Wireless Power Transfer: Exploring EV charging technologies

Abstract

Due to the environmental concerns about CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -caused global warming, policymakers are pushing electrified vehicles (EVs) to reduce these emissions. For passenger vehicles only, the electrified fleet is forecasted to reach 80 million in the U.S. and 500 million globally by 2040. Key enablers for such rapid EV adoption include the improvement of battery energy density, lifespan and safety, and drastic cost reduction of batteries and power electronics. The technology of power electronics nowadays can be found in many aspects of EVs. It alters and transforms the energy from the power source to different forms to feed the loads. For example, the on-board charger (OBC) accepts ac input and converts it to high voltage (HV) dc to charge the propulsion battery. An auxiliary power module (APM) steps down the HV battery voltage to low voltage (LV) to charge the LV battery <xref ref-type="bibr" rid="ref1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[1]</xref> . The HV dc bus voltage is converted to an ac form to drive the propulsion motor, forming the motor drive inverter. Putting the power electronics system and the batteries together, the typical structure of an EV is shown in <xref ref-type="fig" rid="fig1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Figure 1</xref> . In addition, power electronics can be found in other onboard auxiliary circuits, such as LED lighting and battery management system (BMS).