Integrated battery charger and motor drive design for electric vehicles
Class
Article
Department
Electrical and Computer Engineering
Faculty Mentor
Regan Zane
Presentation Type
Oral Presentation
Abstract
Battery charger and motor drive are two major components of an electric vehicle (EV) that utilize power electronic technologies. An important design criterion in charger design is its power handling capability. Higher power is desirable as an empty-to-full charge can be completed in shorter amount of time. Off-vehicle chargers typically offer higher power-ratings than on-vehicle ac-dc chargers, but their accessibility can be limited. To overcome this, one can design more powerful on-vehicle chargers. However, this approach adds to EV's cost and weight and is not always preferred. In research years, there has been active research in the integration of on-vehicle charger and motor drive. This approach exploits the drive's power-bidirectional capability and the fact that charging activities usually occur in a parked vehicle when the motor is inactive. Most of the published methods are based on and preserve the popular pulse-width modulated voltage-source inverter with little to no power-stage changes. In charger mode, the inverter is disconnected from the motor and then connected to the ac source. From a system perspective, this method eliminates the need of a separate on-vehicle charger unit. The main disadvantage is the need of a dc-dc converter between the battery and inverter to optimize the combined efficiency of inverter/motor and to provide galvanic isolation for safety. This work presents a novel integrated charger/drive system using a low-frequency three-phase unfolding circuit (Unfolder) and two series-resonant converters (SRC). The Unfolder offers improved efficiency over a similarly-rated inverter due to lower switching-loss. The charger operation of the proposed system has previously been demonstrated in unity power factor ac-dc rectification. In this presentation, the system's drive operation is described, and its full functionality in an EV environment is demonstrated.
Start Date
4-9-2015 2:00 PM
Integrated battery charger and motor drive design for electric vehicles
Battery charger and motor drive are two major components of an electric vehicle (EV) that utilize power electronic technologies. An important design criterion in charger design is its power handling capability. Higher power is desirable as an empty-to-full charge can be completed in shorter amount of time. Off-vehicle chargers typically offer higher power-ratings than on-vehicle ac-dc chargers, but their accessibility can be limited. To overcome this, one can design more powerful on-vehicle chargers. However, this approach adds to EV's cost and weight and is not always preferred. In research years, there has been active research in the integration of on-vehicle charger and motor drive. This approach exploits the drive's power-bidirectional capability and the fact that charging activities usually occur in a parked vehicle when the motor is inactive. Most of the published methods are based on and preserve the popular pulse-width modulated voltage-source inverter with little to no power-stage changes. In charger mode, the inverter is disconnected from the motor and then connected to the ac source. From a system perspective, this method eliminates the need of a separate on-vehicle charger unit. The main disadvantage is the need of a dc-dc converter between the battery and inverter to optimize the combined efficiency of inverter/motor and to provide galvanic isolation for safety. This work presents a novel integrated charger/drive system using a low-frequency three-phase unfolding circuit (Unfolder) and two series-resonant converters (SRC). The Unfolder offers improved efficiency over a similarly-rated inverter due to lower switching-loss. The charger operation of the proposed system has previously been demonstrated in unity power factor ac-dc rectification. In this presentation, the system's drive operation is described, and its full functionality in an EV environment is demonstrated.