The objective of this research is to investigate, design, and develop an integrated on-board silicon carbide (SiC) based level-3 charger, compatible with level-1 and level-2 charging, using the propulsion machine and its inverter for next generation of plug-in electric vehicles.
The approach is to conduct a comprehensive propulsion motor and inverter analyses to propose a rectifier/charger topology to charge the battery. The research will investigate the possibility of eliminating power factor correction inductors for both single-phase and three-phase charging by utilizing the propulsion machine windings, without producing torque.
Intellectual Merit:
This work will achieve breakthroughs in control, modeling and design of power electronic interfaces for electric vehicles. It will be fundamental research for scientific understanding of motor-integrated inverter/chargers. This important work will (a) lead to generic methodologies for obtaining optimal design of level-3 chargers and introducing control strategies to prevent torque generation during three-phase charging; and (b) involve multidisciplinary research in power electronics, adjustable speed drives, control, and power management.
Broader Impacts:
The projected outcome of this research will promote widespread adoption of EVs through enabling EV owners to take longer trips and refuel along the way, similar to a gas station visit. The highest quality integrated education and research will be ensured to meet the emerging workforce and educational needs of U.S. energy industry by educating young and talented students. The results will be disseminated broadly to enhance scientific and educational achievements. Efforts will be made to engage students from underrepresented groups in the project.
This work is a fundamental research for scientific understanding of reduced-stage chargers as well as motor-integrated inverter/chargers, which involves multidisciplinary research in power electronics, adjustable speed drives, and control. The research team in this project has investigated, proposed, designed, and developed transformative approaches for onboard charging of next generation of plug-in electric vehicles (PEVs), considering the following main objectives: - The first main objective is to substantially reduce the size, weight and cost of the power electronic interfaces inside the vehicles. - The second main objective is to provide convenient high-power onboard charging capability to alleviate the range anxiety for PEV owners. In order to accomplish our objectives in terms of reducing size of onboard chargers we have studied two methods: (1) we have proposed the idea of reduced-stage onboard chargers for PEVs with hybrid energy storage systems and (2) we have introduced the idea of integrated single-phase high-power onboard charging using the vehicle’s propulsion machine and its bidirectional inverter without a need to have access to inaccessible point of the machine windings. (1) In the case of reduced-stage onboard chargers; we proposed a new technique for compensating low frequency component of the battery current in PEVs by injecting second harmonic current, with the same amplitude but 180 degree phase difference through a bidirectional dc/dc converter and a secondary energy storage unit (ESU), practically a smaller sized capacitor. The general concept of the proposed method is then generalized for the resistive and battery loads with voltage and current source power factor correction (PFC) circuits. The proposed method particularly reduces the power electronics size and cost burden in PEVs with hybrid battery/UC energy storage systems, where there is an already available ESU along with its bidirectional converter. Thus, the dc/dc battery current regulation stage, which is present in conventional two-stage charger, can be eliminated. This approach increases the feasibility of battery/UC electric vehicles through introducing a new operation mode for UCs. To verify the proposed control technique, a scaled down proof of concept 360W converter is designed. In this set-up, a 72V/10A battery is charged with 360W, and oscillating 360W power is filtered using a two-quadrant bidirectional converter and a 32V/29F UC pack. (2) In the case of motor integrated chargers; in this project, an innovative single-phase grid-connected integrated charger, using the PEV propulsion machine and its inverter, is introduced. The charger topology is capable of power factor correction (PFC) and battery current regulation without any bulky add-on components. In this technology, the ac machine windings are utilized as a stationary coupled-inductor, to create a two-channel interleaved boost converter. In this work the proposed idea is analyzed, implemented, and validated in the case a permanent magnet synchronous machine (PMSM). An 8-kW, 3-phase, 8-pole round-rotor PMSM is utilized as a three-winding coupled inductor in charging mode. Each phase winding has a 1-mH self-inductance. The 240-VAC, 60-Hz single-phase grid main connection (delta 4-wire system) is utilized as the grid interface. The dc-link voltage is regulated at 380 V based on the rated voltage of inverter. The highest quality integrated education and research is ensured to meet the emerging workforce and educational needs of U.S. energy industry by educating young and talented students. This research promotes widespread adoption of PEVs through enabling PEV owners to take longer trips and refuel along the way, similar to a gas station visit. In order to enhance diversity, talented students from underrepresented groups are engaged in the project. The results are disseminated broadly to enhance scientific and educational achievements.
