Traction inverters are crucial components of modern electrified automotive powertrains. Advances in power electronics have enabled lower cost inverters with high reliability, efficiency, and power density, suitable for mass market consumer automotive applications. This paper presents an independent review of the state-of-the-art traction inverter designs from several production vehicles across multiple manufacturers. Future trends in inverter design are identified based on industry examples and academic research. Wide bandgap devices and trends in device packaging are discussed along with active gate driver implementations, current and future trends in system integration, and advanced manufacturing techniques.
A semi-active hybrid energy storage system, consisting of a Li-ion battery pack, dc/dc converter, and Li-ion capacitor pack is developed for a range extended plug-in vehicle application. The vehicle has a series-parallel drivetrain with two electric motors, a gas engine, gearbox, and a clutch to allow the engine to run decoupled from the gearbox in range extending mode. The peak dc electrical requirement of the electric drivetrain is about 175kW, which is similar to the peak power capability of the developed hybrid energy storage system. A model of the prototype hybrid energy storage system, which has the Li-ion capacitor pack connected directly to the motor drive's dc bus and the battery pack connected to the Li-ion capacitor pack via a dc/dc converter, is developed and used to determine the optimal power split between the battery and Li-ion capacitor packs. A dynamic programming algorithm is used to determine the optimal power split, with the optimization goals of reducing energy storage system loss, maximizing regenerative braking energy capture, and minimizing motoring power limiting. The hybridized system is shown to reduce battery pack losses and increase vehicle range compared to a system only utilizing the battery pack.
This paper discusses the design of a switched reluctance motor (SRM) for pump jacks that are commonly used in oil extraction industry. An SRM is designed as an alternative to a 10-hp induction motor. It is designed to have the same volume so it can utilize the same NEMA frame. Optimization through the number of turns per phase, stator and rotor pole arc angles, and conduction angles is carried out. Selection of conduction angles for the motor drive is based on a multi-objective constrained genetic algorithm optimization to achieve the required torque with the same phase current as the reference induction machine. Thermal analysis of the proposed machine is conducted to demonstrate its suitability for extended continuous operation.
A semi-active hybrid energy storage system, consisting of a Li-ion battery pack, dc/dc converter, and Li-ion capacitor pack was developed for a range extended plug-in vehicle. The vehicle has a series-parallel drivetrain with two electric motors, a gas engine, gearbox, and a clutch to allow the engine to run decoupled from the gearbox in range extending mode. The peak dc electrical requirement of the electric drivetrain is about 175 kW, which is similar to the peak power capability of the developed hybrid energy storage system. A model of the prototype hybrid energy storage system, which has the Li-ion capacitor pack connected directly to the motor drive's dc bus and the battery pack connected to the Li-ion capacitor pack via a dc/dc converter, is developed and used to determine the optimal power split between the battery and Li-ion capacitor packs and for tuning the developed real-time control system. The real-time control system is shown through modeling and experimental testing of the full scale hybrid energy storage systems to reduce battery pack losses, increase vehicle range, and to have performance approaching that of the optimal control solution as calculated via dynamic programming.
The electric revolution is underway in the transportation sector, and the aviation industry is poised to embrace fundamental disruption. Moving to electric aircraft brings undeniable benefits in terms of environmental impact, cost savings, maintenance, noise pollution, and safety. Nevertheless, several technical challenges are yet to be overcome to build electric airplanes that meet public needs while gaining acceptance and trust. From urban air mobility to long-haul flight applications, hundreds of projects are under research to push toward more electrification. At the heart of each aircraft architecture, power electronics plays a crucial role in the new era of transportation. This article aims to provide a comprehensive analysis of state-of-the-art power electronics in electric aircraft. A review of the current status of aircraft electrification will be provided, and technology surveys of power electronic converters will be detailed. Challenges for forthcoming power electronics in response to the future trends of the electrical network will be explained. Finally, emerging technologies regarding wide bandgap devices, advanced topologies and control, thermal management, passive components, and system integration will be discussed.
The fast development of electric vehicles (EVs) provides significant opportunities to further utilize clean energies in the automotive. On-board chargers (OBCs) are widely used in EVs because of their simple installation and low cost. Limited space in the vehicle and short charging time require an OBC to be power-dense and highly efficient. Moreover, the possibility for EVs to deliver power back to the grid has increased the interest in bidirectional power flow solutions in the automotive market. This paper presents a comprehensive overview and investigation on the state-of-the-art solutions of bidirectional OBCs. It reviews the current status, including architectures and configurations, smart operation modes, industry standards, major components, and commercially available products. A detailed overview of the promising topologies for bidirectional OBCs, including two-stage and single-stage structures, is provided. Future trends and challenges for topologies, wide bandgap technologies, thermal management, system integration, and wireless charging systems are also discussed in this paper.
This paper investigates efficiency gains achieved using an 800 V DC bus and wideband gap silicon carbide (SiC) semiconductors for a light-duty electric vehicle (EV), rather than an insulated-gate bipolar transistor (IGBT) inverter with a 400 V bus as is commonly used for EVs. Analytical inverter loss models with 600 V and 1200 V IGBTs, and 1200 V hybrid SiC and 1200 V All-SiC semiconductors are incorporated into a Chevrolet Bolt EV model and simulated over standard drive cycles. Battery pack voltage variations throughout the drive cycles, as well as variations in junction temperature, resulted in 16 to 27 % increased loss compared to fixed voltage and temperature assumptions. To validate the models, experimental testing was performed on a 1200 V IGBT inverter and a 1200 V SiC inverter both powering 160+ kW rated traction machines. Experimentally measured loss was typically within 100 W of the model, demonstrating its accuracy. Going from a 400 V to an 800 V DC bus with IGBTs, EV range was modeled to increase 1.2 %, while an 800 V bus and all SiC inverter results in a range increase of 5.0%. An empirical loss model fitted to measured inverter data shows the analytical model estimates range within 6 km.
This paper proposes a new integrated charger topology based on a four-phase asymmetric bridge converter and switched reluctance machine. The topology is capable of power factor corrected three-phase charging and both buck and boost output voltage control. No modifications to the machine are required while a limited number of additional inverter components are added. An equivalent-circuit based model of the machine is developed to facilitate investigation of the integrated charger performance. A control strategy for the charging mode is developed. The proposed topology is demonstrated through simulation of two distinct three-phase grid based charging applications.
