The development of electric vehicles (EVs) is an important step towards clean and green cities. An electric powertrain provides power to the vehicle and consists of a charger, a battery, an inverter, and a motor as the main components. Supplied by a battery pack, the automotive inverter manages the power of the motor. EVs require a highly efficient inverter, which satisfies low cost, size, and weight requirements. One approach to meeting these requirements is to use the new wide-bandgap (WBG) semiconductors, which are being widely investigated in the industry as an alternative to silicon switches. WBG devices have superior intrinsic properties, such as high thermal flux, of up to 120 W/cm² (on average); junction temperature of 175–200 °C; blocking voltage limit of about 6.5 kV; switching frequency about 20-fold higher than that of Si; and up to 73% lower switching losses with a lower conduction voltage drop. This study presents a review of WBG-based inverter cooling systems to investigate trends in cooling techniques and changes associated with the use of WBG devices. The aim is to consider suitable cooling techniques for WBG inverters at different power levels.

Active Front-End (AFE) rectifiers have regained momentum as the demand for highpower Electric Vehicle (EV) charging infrastructure increases exponentially. AFE rectifiers have high efficiency and reliability, and they minimize the disturbances that could be generated due to the operation of the EV charging systems by reducing harmonic distortion and operating close to the Unity Power Factor (UPF). The purpose of this review is to present the current state-of-the-art AFE rectifiers used in fast chargers, focusing on the comparison between different AFE topologies and their components, as well as modular AFE solutions. Furthermore, different control strategies of AFE converters are presented and compared. Some of their more widely used control techniques, namely Voltage Oriented Control (VOC), Direct Power Control (DPC), Hysteresis Current Control (HCC), and Model Predictive Control (MPC), have been implemented, and their performance compared. Centralized and distributed control systems are compared for operating parallel AFE rectifiers for modular, fast charging systems. An overview of cooling systems and reliability evaluation tools is also presented. Finally, trends and future outlooks are analyzed.

This paper proposes the fast and accurate electro-thermal model of the existing Simrod three-phase inverter for an electric vehicle (EV) application. The research focuses on analytical and dynamic electro-thermal models of inverters that can be applied for multi-applications. The optimal design approach of passive filters is presented for the DC and AC sides of the inverter. The analytical model has been established, including a mathematical representation of the inverter and induction motor (IM). The high-fidelity electro-thermal simulation model of an inverter with integrated power loss and thermal model is established. The state-space thermal model (for the IRFS4115PbF device) has been created and incorporated into the MATLAB simulation. The simulation model is then validated with the PLECS software-based thermal model to confirm the accuracy. Indirect field-oriented control (IFOC) is designed for squirrel-cage IM at a maximum power rating of 45 kW and implemented on MATLAB/Simulink. The comparative analysis between the real and simulated results is performed to validate the simulation model at a specific speed, torque, and current. Furthermore, the electro-thermal simulation model has been validated with experimental data using efficiency and temperature comparison. The developed simulation model is beneficial for designing, optimizing, and developing advanced technology-based inverters to achieve higher efficiency at a particular operating range of temperature and power quality. The new European driving cycle (NEDC) speed profile simulation results are demonstrated.

This paper presents a design optimization for grid-connected modular Active Front-End (AFE) rectifiers with an evaluation of efficiency, lifetime, cost, volume, and weight. This tool optimizes the rectifier switching frequency, component sizing and selection, and the number of parallel converters by designing and evaluating every possible configuration of the AFE rectifier system defined by the end user. The design of the LCL filter, magnetic design of inductors, selection of the inductor core and winding, and selection of SiC switches and MLC capacitors are discussed. Rapid Low-Fidelity (Lo-Fi) electro-thermal and lifetime models that are fast enough to be used in an optimization process have been developed. The rapid Lo-Fi models estimate component losses, temperatures, and lifetime for given load profiles and converter configurations. This Lo-Fi approach accelerates the processing time to generate the thermal data for the converter mission profile and allows us to skip rainflow-counting algorithm to assess the accumulated thermal damage to the SiC switches at the design and development stage. This in turn allows engineers to design converters with a longer predicted lifetime. Moreover, optimization of the grid-side three-phase LCL filter is performed considering efficiency, cost, and volume trade-off between the grid-side and converter-side inductors to achieve up to 50% decrease in losses, and 23% decrease in cost. Moreover, a 21-22% decrease in the system losses, 23-27% decrease in system cost, and tenfold improvement of the system lifetime can be achieved by optimizing the converter switching frequency and number of parallel modules. A 15 kW hardware prototype consisting of three 5 kW AFE rectifier modules is built and used to validate the efficiency from the fast Lo-Fi models. The validation of the detailed loss model and junction temperature swing is performed against a High-Fidelity (Hi-Fi) simulation in MATLAB Simulink environment.