Recently, there has been significant attention given to the electrification of transportation due to concerns about fossil fuel depletion and environmental pollution. Conventional drive systems typically include a clutch, reduction gear, and mechanical differential, which results in power loss, noise, vibration, and additional maintenance. However, in-wheel motor drive technology eliminates the need for these components, providing benefits such as higher system efficiency, improved wheel control, and increased passenger comfort. This article offers a comprehensive review of the technology and development of in-wheel motor drives. It begins with an overview of in-wheel motor drives in electric vehicles, followed by an exploration of the types of electric motors suitable for in-wheel motor drives. The paper then presents an industrial state of the art of in-wheel motors, comparing them with conventional motor drives, and reviews the implemented power electronics, control system, and cooling systems. Finally, the paper concludes by providing an outlook on the challenges and future trends of in-wheel drive systems.

This paper presents a detailed literature review on switched reluctance motor (SRM) and drive systems in electric vehicle (EV) powertrains. SRMs have received increasing attention for EV applications owing to their reliable structure, fault tolerance ability and magnet free design. The main drawbacks of the SRM are torque ripple, low power density, low power factor and small extended speed range. Recent research shows that multi-stack conventional switched reluctance motors (MSCSRM) and multi-stack switched reluctance motors with a segmental rotor (MSSRM-SR) are promising alternative solutions to reduce torque ripples, increase torque density and increase power factor. Different winding configurations such as single-layer concentrated winding (SLC), single layer mutually coupled winding (SLMC), double layer concentrated winding (DLC), double layer mutually coupled winding (DLMC) and fully-pitched winding (FP) are introduced in the literature in recent years to increase average torque and to decrease torque ripples. This research analyzes winding methods and structure of the SRMs, including conventional and segmental rotors. They have been compared and assessed in detail evaluation of torque ripple reduction, torque/power density increase, noise/vibration characteristics and mechanical structure. In addition, various drive systems are fully addressed for the SRMs, including conventional drives, soft-switching drives, drives with standard inverters and drives with an integrated battery charger. In this paper, the SRM control methods are also reviewed and classified. These control methods include strategies of torque ripple reduction, fault-diagnosis, fault-tolerance techniques and sensorless control. The key contributions of this paper provide a useful basis for detailed analysis of modeling and electromechanical design, drive systems, and control techniques of the SRMs for EV applications.

Multiphase drives (MPDs) have been the subject of research for the last two decades. Despite being a technology that is still in the process of development, a significant number of research studies and developments have been reported in scientific literature over the past few years. This article aims to collect and present a review of these recent contributions, providing a comprehensive and insightful state of the art on this topic and future technology trends. The elaborated aspects include the advantages of multiphase machines, a general introduction to five-phase and six-phase machines, and their modelling techniques. In addition, new promising MPD topologies are covered. Recent advances in modulation techniques and the control of multilevel converters are also discussed. Finally, future trends and challenges in further developing this technology are discussed.

Gallium nitride (GaN) power semiconductors are being explored as promising alternatives for the next generation of high-power traction inverters, suitable for both high- and low-voltage applications. In such scenarios, the peak current can reach several hundred amps. Hence, using multiple GaN HEMT chips or dies in parallel is definitely a design approach to extend power capacity and minimize power losses. However, the parallelization and packaging structure of GaN devices present numerous challenges. Achieving balanced dynamic and static current sharing between paralleled devices, as well as ensuring robust gate driving signals, is indispensable for reliable operation during high dV/dt and di/dt transients, particularly with switching noise-sensitive gate-source threshold voltages. Additionally, thermal dissipation and mechanical stress must fulfill industrial requirements. This paper introduces a compact 100 V/360 A GaN power module specifically designed for packaging on insulated metal substrates (IMS) or direct-bonded copper (DBC). The proposed packaging approach offers superior electrical performance, excellent thermal dissipation, minimal mechanical stress, and a cost-effective solution. Finally, the advantages of the proposed power module design are validated through various experimental setups, including a 48 V/328 A double pulse test, a 48 V/24 V 3 kW buck converter implementation, and a 48 V/5 kW three-phase inverter demonstration.