Search

The transition to electric road transport technologies requires electric traction drive systems to offer improved performances and capabilities, such as fuel efficiency (in terms of MPGe, i.e., miles per gallon of gasoline-equivalent), extended range, and fast-charging options. The enhanced electrification and transformed mobility are translating to a demand for higher power and more efficient electric traction drive systems that lead to better fuel economy for a given battery charge. To accelerate the mass-market adoption of electrified transportation, the U.S. Department of Energy (DOE), in collaboration with the automotive industry, has announced the technical targets for light-duty electric vehicles (EVs) for 2025. This article discusses the electric drive technology trends for passenger electric and hybrid EVs with commercially available solutions in terms of materials, electric machine and inverter designs, maximum speed, component cooling, power density, and performance. The emerging materials and technologies for power electronics and electric motors are presented, identifying the challenges and opportunities for even more aggressive designs to meet the need for next-generation EVs. Some innovative drive and motor designs with the potential to meet the DOE 2025 targets are also discussed. [ABSTRACT FROM AUTHOR]

The concept of the magnetic amplifier, a common electromagnetic device in electronic applications in the past, has seldom been used in power systems. The magnetic amplifier-based power-flow controller (MAPFC), an innovative low-cost device that adopts the idea of the magnetic amplifier for power-flow control applications, is introduced in this paper. The uniqueness of MAPFC is in the use of the magnetization of the ferromagnetic core, shared by an ac and a dc winding, as the medium to control the ac winding reactance inserted in series with the transmission line to be controlled. Large power flow in the line can be regulated by the small dc input to the dc winding. A project on the R&D of an MAPFC has been funded by the U.S. Department of Energy (DOE) and conducted by the Oak Ridge National Laboratory (ORNL), the University of Tennessee-Knoxville, and Waukesha Electric Systems, Inc. since early 2012. Findings from the project are presented along with some results obtained in a laboratory environment. [ABSTRACT FROM AUTHOR]

This paper presents a two-phase cooling method using the R134a refrigerant to dissipate the heat energy (loss) generated by power electronics (PEs), such as those associated with rectifiers, converters, and inverters for a specific application in hybrid-electric vehicles. The cooling method involves submerging PE devices in an R134a bath, which limits the junction temperature of PE devices while conserving weight and volume of the heat sink without sacrificing equipment reliability. First, experimental tests that included an extended soak for more than 850 days were performed on a submerged insulated gate bipolar transistor (IGBT) and gate-controller card to study dielectric characteristics, deterioration effects, and heat-flux capabilities of R134a. Results from these tests illustrate that R134a has high dielectric characteristics and no deterioration of electrical components. Second, experimental tests that included a simultaneous operation with a mock automotive air-conditioner (A/C) system were performed on the same IGBT and gate-controller card. Data extrapolation from these tests determined that a typical automotive A/C system has more than sufficient cooling capacity to cool a typical 30-kW traction inverter. Last, a discussion and simulation of active cooling of the IGBT junction layer with the R134a refrigerant is given. This technique will drastically increase the forward current ratings and reliability of the PE device. [ABSTRACT FROM AUTHOR]

Silicon carbide (SIC) unipolar devices have much higher breakdown voltages than silicon (Si) unipolar devices because of the ten times greater electric field strength of SiC compared with Si. 4H-SiC unipolar devices have higher switching speeds due to the higher bulk mobility of 4H-SiC compared to other polytypes. In this paper, four commercially available SiC Schottky diodes with different voltage and current ratings, VJFET, and MOSFET samples have been tested to characterize their performance at different temperatures ranging from -50°C to 175°C. Their forward characteristics and switching characteristics in this temperature range are presented. The characteristics of the SiC Schottky diodes are compared with those of a Si pn diode with comparable ratings. [ABSTRACT FROM AUTHOR]

In this paper, an analytical model for a vertical double implanted metal-oxide semiconductor (DIMOS) transistor structure in 4H-Silicon Carbide (SIC) is presented. Simulation for transport characteristics of the SiC MOSFET with the exact device geometry is carried out using the commercial device simulator MEDICI. A rigorous experimental testing and characterization is done on a 4H-SiC DIMOS transistor test device. SPICE parameters are extracted from the measurements, and a SPICE model for the DIMOS transistor has been developed. The presented work is a part of team efforts of material, device, and power electronics researchers at the University of Tennessee and. Oak Ridge National Laboratory. [ABSTRACT FROM AUTHOR]