The ever-increasing demand for compact, efficient, and high-performance traction drive systems for transportation applications has accelerated the development of integrated electric drives. In these systems, the electric machine and inverter are integrated within a single housing, offering significant advantages in electrical performance, volume, weight, cost, and overall system efficiency. Despite these benefits, such high levels of integration introduce a new set of challenges, particularly in power electronic design and component selection. This article presents an in-depth investigation of a highly integrated electric drive architecture with an internal stator-mounted inverter, highlighting key design considerations and trade-offs aimed exclusively at maximizing system power density.Based on a comprehensive review of the literature, the power density of a voltage-source-inverter–driven electric drive is primarily governed by the volumetric contributions of the power modules, heat sinks, and DC-link capacitors. Accordingly, this work focuses on the optimization of these three critical components to enhance the inverter’s overall power density. The proposed design achieves a power density of 100 kW/L, demonstrating the effectiveness of the presented approach for next-generation integrated electric drive systems.

This paper presents a comparative study of fuel cell-battery hybrid powertrains (FCBHPs) for a Class-8 heavyduty vehicle. System-level efficiency is evaluated over a representative driving cycle for an FCBHP incorporating a bidirectional DC/DC converter (BDC) between the battery and the traction inverter. The BDC enables dynamic adjustment of the inverter DC-bus voltage to reduce inverter and motor losses. Under selected operating conditions, such as regenerative braking, BDC switching is disabled to eliminate switching losses. For benchmarking, an alternative FCBHP configuration without a battery-side BDC is also analyzed. The results quantify the efficiency tradeoffs associated with variable DC-bus voltage control and converter operating strategies in heavy-duty fuel-cell electric drivetrains.

This paper proposes a four-phase wireless power transfer (FPWPT) system for high-power energy transfer applications. Compared with conventional circular three-phase WPT systems, the proposed FPWPT reduces magnetic flux density and heat flux while improving space utilization by fully occupying square or rectangular areas. Each phase coil can be implemented in a rectangular shape, offering greater flexibility for installation in space-constrained under-vehicle environments. The system also demonstrates strong interoperability with existing single-phase circular and double-D (DD) coils. In addition, the FPWPT mitigates magnetic flux crowding and reduces ripple currents at both the input and output DC terminals. The system is modeled and simulated using finite element analysis (FEA) and circuit-level tools. Results show that the FPWPT achieves low stray magnetic fields and heat flux and reduces the required DC bus filter capacitance.

The rapid growth of AI workloads is driving unprecedented increases in data center power demand, current transients, and thermal stress, exposing fundamental limitations in traditional 48 V rack architectures, low-voltage AC distribution, and line-frequency transformer interfaces. This paper reviews the three stages of architectural shifts required to support next-generation AI data centers and identifies three enabling technological building blocks: high-voltage conversion-ratio DC/DC converters, facility-level low-voltage DC distribution, and medium-voltage solid-state transformers. The advantages, technical challenges, and potential solutions associated with each building block are reviewed. Finally, future research directions and open challenges are discussed.

On-road wireless charging of electric vehicles (EVs) in motion could potentially reduce range anxiety or battery size with widespread deployment. The planning and implementation of such systems are greatly complicated due to their susceptibility to load variation inherent to traffic flow. This article proposes a method for derisking the potential for traffic slowdowns by compensating for reduced vehicle speed and investigates how implementation may affect system performance. A load modeling case study is presented at 200 kW for a mile of high-speed roadway employing speed-based power regulation with results indicating average power usage, and maximum car hosting capability can be reduced by 20% and increased by 30%, respectively. An 85-kHz power electronics model is developed based on designs and prototypes for an 11-kW, 190-m airgap static system and a 200-kW dynamic wireless track. The simulation is validated in the 11-kW experimental prototype and modified for 200-kW operation to compare with simulated performance. Sensitivity studies are performed in MATLAB/Simulink to evaluate how parameters influence system performance and confirm the capability to reduce output power and maintain efficiency at 11 and 200 kW. The static 11-kW experimental system operates at 93.6% efficiency and multiple options exist to reduce power while maintaining efficiency greater than 90%. The capability to dynamically modify power output from wireless power transfer (WPT) coils, in an experimentally validated simulation, enables techniques to significantly mitigate load variability due to reductions in vehicle speed.

This article proposes an inverse segmented motor drive (SgMD) utilizing dual active neutral point clamped (ANPC) inverters. In the proposed configuration, the neutral point current and common-mode (CM) voltage is topologically canceled, achieving zero total neutral point current and CM voltage under ideal conditions. Also, the zero total neutral point current minimizes the neutral point voltage imbalance in ANPC inverters. The mechanisms behind neutral point current and CM voltage cancellation in the proposed inverse SgMD are first introduced. The modifications to the motor windings for implementing the inverse SgMD are explained, showing that a standard motor can be readily adapted for the proposed configuration. A space vector modulation (SVM) scheme tailored for the proposed topology is presented, along with a carrier-based implementation. Simulation results validate that the proposed topology can achieve zero total CM voltage and neutral point current. It is also shown that the proposed inverse SgMD can reduce neutral point voltage fluctuation by about 90% and RMS current stress in the dc-link capacitors by about 43% compared to the conventional SgMD.

In spite of the high energy efficiency and environmental benefits of electric vehicles (EVs), adoption rates are increasing at a relatively slow pace, primarily because of EVs' limited range and long charging durations. To reduce EV charging times to be comparable to refueling times of conventional vehicles, extreme fast charging (XFC) systems are required. Such charging systems would reduce drivers' range anxiety and enable long-distance interstate travel with EVs. This substantial target in charging rates with 15-20 min of recharging times requires research and development from grid to batteries with advanced charging systems. Wireless power transfer (WPT) systems for EV charging applications are flexible, convenient, and highly efficient, and they allow automated charging. This article reviews the power electronics and winding and resonant tuning network configurations for polyphase WPT systems for high-power wireless charging applications.

In this paper, an integrated capacitor design is proposed for higher-order resonant tank topologies for self-resonant coils, such as series, parallel, LCC, LLC, etc. The capacitor is one of the large, lossy, and thermally vulnerable components of a high-frequency resonant tank, and designing a high-voltage, thermally stable resonant capacitor can be highly challenging. Designing the extremely high-voltage capacitor as an integral part of the coil reduces the size and complexity of the coil assembly. This paper proposes a low-loss PCB-based high-voltage capacitor design to achieve that target, which can be implemented as an integral part of the coil. The proposed capacitor designs are simulated using Multiphysics FEA and tested experimentally. A 23 kV, 133 pF capacitor prototype was built and tested as part of a 1 kW long-distance wireless charging system. The test results verify the capacitor’s voltage, current, and thermal resiliency performance.

Dynamic wireless power transfer (DWPT) can provide energy to EVs in motion and extend the drive range. Upscaling the charging power to 200 kW (High Power DWPT) reduces the percentage of electrified roadway required, and the solution becomes cost-effective. To smooth the power at the battery and grid, a secondary regulation stage must be added. The DWPT system therefore relies on power electronics to interface with the coils and regulate the power flow. Designing this high power system using wide bandgap devices makes ensuring high efficiency, small size, and reliable operation very challenging, and significant engineering effort is required to build such complicated systems for large-scale installation and deployment. This paper describes a modular design approach for the power electronics to achieve the 200 kW wireless power transfer. As described, the SiC power electronics building block is designed, simulated, and characterized. The approach is validated in the DWPT system to build the inverter, the rectifier, and the DC/DC converter, which demonstrated high performance and reliable operation with 188 kW power.

Two three-phase interleaved inverters have been used in traction drive applications to reduce the current stress in a DC link capacitor bank. In such applications, either carrier-based or space vector modulation is used to select the optimum switching sequences, and the results show 50% less capacitor current than that of a single three-phase inverter. The switching state selection process for this inverter is tedious, and there has been no research to find the optimal switching state. To overcome this challenge, this research employed a simple finite set model predictive control to select the optimum switching sequence for a dual three-phase interleaved topology, called a segmented inverter. The results show that the predictive control algorithm can provide a simple solution and can reduce the current stress by 27% compared with traditional modulation techniques for the segmented inverters.

This paper presents a 200 kW high power density traction drive inverter design for higher power and performance electrical vehicles applications. The design employs the segmented drive topology to reduce the DC bus capacitor, low-profile double sided cooled SiC MOSFET power modules, compact mini-channel heat sinks optimized using genetic-algorithms, and high-ripple current capacitors. The paper includes design details and experimental results for a 200 kW inverter prototype with a power density of 110 kVA/L.

Electric vehicles (EVs) can provide power to the grid or buildings similar to distributed energy resources (DER) for energy balancing applications or optimizing the operation of the microgrids in harmony with the other DER assets. This article presents the operating modes of a bidirectional wireless power transfer (WPT) system designed for a medium-duty package delivery vehicle. The WPT system designed for this study can transfer 20 kW of power across 11 in of air gap using custom-designed double-D (DD) couplers with LCC-LCC tuning networks. The proposed system utilizes a 480-V three-phase grid connection, a plug-in hybrid delivery truck with bidirectional WPT, and a stationary energy storage system (SESS) that can be connected to the primary-side dc link. Due to the differences in primary and secondary dc bus voltages, and considering the voltage of the SESS, asymmetric voltage gains were used in the system. Sensitivity analyses of this system with respect to these voltage levels are presented. Five different operating modes of the grid, SESS, and the EV battery are investigated with experimental results. Control algorithms are described for grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operating modes. A bidirectional WPT system is operated with a power factor of 0.99 on the grid side in every operating mode. The EV battery was charged with 20.3 kW with an overall efficiency of 93.02% in the G2V operating mode. In the V2G operating mode, the WPT system provided 12.82 kW of power back to the grid with an overall efficiency of 89.08%.

Minimizing parasitic inductance of power modules is needed to advance their electrical performance. Innovation in the past decade has driven down the inductance of SiC half-bridge power modules to around 1–2 nH by using multilayer, embedded, and hybrid structures. Further reduction becomes difficult, mainly limited by the excessive interconnects required for the planar placement of vertical conducting chips. To address this, a vertically stacked-die approach is proposed in this paper, taking advantage of the vertical conducting nature of the SiC chips. With ceramic decoupling capacitors integrated, 0.48 nH overall loop inductance is achieved and validated by experimental measurement. This paper also discusses potential approaches to further reduce the inductance.

In wireless power transfer (WPT) systems, output power $(P_{out})$ can be controlled through input parameters such as, input voltage $(V_{in})$ , duty cycle $(d)$ , and switching frequency $(f_{sw})$ . The impact of these control parameters on the overall system efficiency has not been explored in previous studies. This paper focuses on the efficiency $(\eta)$ and $P_{out}$ sensitivity to these control parameter variations in an LCC-Series tuned WPT system. There are multiple combinations of $V_{in},\ d$ , and $f_{sw}$ that can achieve a specified target $P_{out}$ . However, it is important to determine the optimal combination of these control variables that will yield the maximum $\eta$ for a target $P_{out}$ . A MATLAB/Simulink model is built to calculate and measure $\eta$ and $P_{out}$ . In order to achieve this result, several simulations are run where $V_{in},d$ , and $f_{sw}$ are swept across a wide range to cover all possible combinations. MATLAB's Sensitivity Analysis toolbox is used to evaluate how the parameters influence the model's output. Finally, an experimental prototype is implemented. The optimal values acquired using the sensitivity analysis is then plugged into the hardware prototype and compared with the simulation. The results obtained confirm the validity of the proposed method.

Due to fast fluctuating input voltage, dynamic wireless charging requires a post-regulator stage for battery charging control and management. This regulator stage has a high requirement on efficiency, size as well as control performance to ensure tight regulation and fast trainset. This paper addresses the control challenges by modeling the system and designing the compensator with input voltage feedforward control. In addition, high resolution PWM is implemented to improve transient performance and current balancing among the phases. Experimental results prove the effectiveness of the proposed schemes and validates 180 kW closed-loop 4-phase operation at 99% efficiency.

In wireless power transfer (WPT) systems, voltage and current distortions are observed at the vehicle side rectifier when power flow is from grid to vehicle (G2V) under light load conditions. These distortions can increase switching losses and decrease the overall efficiency of the WPT system. To address this issue, this paper proposes adding a higher value inductor in series with the original LCC tuning network at the vehicle side. However, increasing the series inductance causes the input impedance and phase angle to move away from the resonant frequency. To solve this problem, a capacitor is added in series to tune out the difference between the original and modified inductor values. This series tuning capacitor also improves the power factor and brings the input impedance and phase angle back to the resonant frequency. The traditional LCCLCC and proposed LCC-CLCC WPT systems are compared and analyzed analytically, and simulated in a MATLAB/Simulink environment to verify parameters such as efficiency and power transfer capacity. An experimental prototype is implemented and compared with the simulation. The obtained results confirm the validity of the proposed method.

In this paper, the design methodology of a high-frequency, high-power, long-distance inductive wireless power transfer (WPT) is presented. The airgap (d) of a traditional high-power (>1 kW) WPT is limited to a few hundred millimeters, which is almost 1/4th of the coil diameter, D; d ≤ D/4. In this paper, the power transfer distance is significantly increased (d ≥ 1.5D) by adopting a high-frequency magnetic design and GaN-based power electronics. The material and design of the coil and shield are investigated using FEA and tested experimentally. A high frequency 6.78 MHz wireless charging system was built to transfer 1 kW power over 3 m airgap.

This paper presents an analysis and optimal position alignments of the transmitting and receiving couplers for achieving interoperability between a three-phase and a single-phase inductive wireless power transfer (WPT) system. In addition, single-phase operation modes for the six-switch three-phase inverter are identified for maximal power transfer from the three-phase transmitter pad to the single-phase receiver pad. Simulation results are included to show the power transfer capability between a 50 kW three-phase and an 11 kW double-D or circular single-phase WPT system at various alignment positions of the couplers.