The electrification of heavy-duty vehicles (HDVs) is essential for achieving zero-emission freight transport. Conventional 400–800 V powertrains face limitations in supporting megawatt-level fast charging and high continuous power due to excessive current, cable losses, and thermal stress. Recent advances in high voltage (i.e., 1.7 kV, 2 kV, 3.3 kV) silicon-carbide (SiC) power modules and charging standards such as the Megawatt Charging System (MCS, up to 1250 V) have enabled a new generation of 1.2 kV dc-link architectures for HDVs. This paper presents a comprehensive system-level evaluation of increasing the dc-link voltage from 800 V to 1.2 kV, covering the battery, inverter, and motor subsystems. The battery/charging and motor-level results are presented as analytical first-order assessments, whereas the inverter-level loss-modelling methodology is experimentally validated on a 250 kW, 1.2 kV dc-link SiC prototype. A virtual-prototyping framework is used to quantify inverter losses, thermal behavior, and volume trade-offs, and the switching frequency is optimized by jointly considering inverter and motor harmonic losses. Experimental results showthat the analytical models predict measured inverter losses within approximately 10% over the tested operating range. Under the representative charging assumptions adopted in this study, 1.2 kV dc-link voltage enables either an∼56% reduction in cable conduction losses or an∼33% reduction in cable mass, while the prototype achieves an efficiency of ∼99.12%, a specific power density of 49.4 kW/L, and a bounding-box-based volumetric power density of 20.83 kW/L. The results provide system-level assessment and experimentally supported inverter-level design guidance for 1.2 kV HDV powertrains.

This article presents a novel bipolar field excitation system for pole-changing electrically excited synchronous machines. Conventional wireless power transfer (WPT)-based systems realize bipolar field current through receiver-side active converters and wireless gate-signal transmission, which increases complexity and reduces reliability. The proposed approach employs a dual-input, dual-output WPT system with anti-parallel outputs and a self-driven MOSFET-diode configuration, enabling bipolar current flow without rotor-side active converters or control signals. This simplifies the system, reduces control complexity, and enhances reliability. A small-scale proof-of-concept prototype has been experimentally validated, demonstrating bipolar current reversal up to 2.88 A (118 W) with a self-driven rectifier efficiency of 99% under an inductive load emulating the field windings.

Two-level voltage source inverters (2L-VSIs) are widely used in industrial motor drives due to their simplicity and cost-effectiveness. However, their pulsating output voltages introduce common-mode voltage (CMV) issues, leading to challenges such as electromagnetic interference (EMI), winding insulation stress, and bearing currents. While adopting an advanced topology or employing common-mode filters can mitigate CMV-based problems, these solutions often increase system complexity and cost. Alternatively, modulation-based techniques offer a simpler, hardware-free approach to reduce CMV. This paper proposes a modulation-based technique that introduces an adaptive carrier phase shift for sinusoidal pulse width modulation (SPWM) to address CMV issues in 2L-VSIs. Unlike conventional methods that rely on fixed carrier phase shifts (e.g., interleaved 0°, 120°, and 240°), the proposed approach dynamically adjusts the phase shift within each switching interval to effectively suppress CMV. The proposed technique was validated through both experimental testing and analytical modeling to demonstrate CMV reduction. This approach offers a practical and scalable solution for industrial motor drives, still having the inherent simplicity and cost-effectiveness of two-level VSIs.

The utilization of soft-switching inverters is essential for achieving high efficiency and low electromagnetic interference (EMI) in electric vehicle (EV) drive systems. However, inductor design for such converters presents significant challenges. In triangular current mode (TCM)-based zero voltage switching (ZVS) inverters, inductors experience large current ripple and variable switching frequency, leading to excessive core and winding losses. This paper presents a design methodology for a high-power filter inductor specifically suited for TCM-based ZVS inverters. A ferrite pot core was selected, and three winding techniques—Litz wire, copper foil, and solid copper wire—were evaluated. The inductance of the three inductors was determined both experimentally and via simulation using FEMM and ANSYS, while power losses were estimated using FEM-based simulations in ANSYS. Experimental determination of 3C91 core loss coefficients was also performed. The optimal configuration required two parallel inductors per phase, resulting in a final three-phase inverter design with six inductors, each 57 mm high and 66 mm in diameter. By integrating experimental measurements with simulation-based loss estimation, the proposed approach reduces core and copper losses, improves thermal management, and enhances power density, making it suitable for next-generation EV powertrains and renewable energy conversion systems.

The demand for robust and energy-efficient traction inverters in heavy-duty electric vehicles (HDVs) has accelerated the development of advanced Power-Hardware-in-the-Loop (PHIL) testbeds that enable realistic and repeatable validation scenarios. This paper proposes an improved back-to-back (B2B) hardware test setup that replicates the full power map of a traction inverter under realistic drive cycle conditions. A passive-damped LCL filter is introduced between inverter phases to enhance power control and maintain a high power factor over a wide frequency range, particularly in the motor's field-weakening region. A two-stage optimization framework is developed to determine the filter parameters, ensuring minimal inductor values while achieving constant power transfer. Furthermore, the feasibility of active damping using capacitor voltage and current sensing is investigated to reduce external power supply losses in the passive damping resistances. The proposed configuration enhances testbed accuracy and efficiency, facilitating safer tests and more effective high-power inverter validation.

This paper investigates the impact of switching frequency and modulation technique on the efficiency of electric drivetrains utilizing inverter-driven Permanent Magnet Synchronous Machines, focusing on heavy-vehicle applications. Accounting for inverter conduction and switching losses, along with machine copper, iron, and magnet losses, a comparison between two- and three-level inverters is performed at key operating points relevant to long-haul truck applications. This study employs current-based finite element analysis for machine loss estimation and a virtual prototyping method for inverter loss estimation to analyze drivetrain efficiency. The findings indicate that there is an optimal switching frequency evidently improving overall efficiency. Moreover, the system using the three-level inverter demonstrates notably lower system losses.

This study analyzes the sequential failure and remaining useful life (RUL) of a multi-chip power module (MCPM) using finite element (FE) simulation, an empirical lifetime model, and recursive deconvolution. The FE model captures electro-thermal interactions, while the empirical model estimates failure probabilities from power cycling test data. The deconvolution method refines the probability density function of the first failure, providing deeper insights into degradation trends. Results show that the first die in an MCPM can fail significantly earlier than the last, with temperature imbalances contributing to this variation. Despite early failures, the system can continue operating with minor thermal impacts. These findings highlight the need for adaptive failure management and improved thermal design to enhance reliability and system life time.

This paper presents a condition monitoring approach for SiC MOSFET devices by compensating the ON-state resistance (R_dson ) to effectively detect package-related failures. While R_dsON is a promising health indicator, its strong dependence on junction temperature (T_j) and threshold voltage (V_th ) can obscure degradation signals. This study proposes compensation techniques to mitigate the influence of T_j and V_th  drift, enabling reliable monitoring. The methodology is validated using a custom-designed power cycling test bench, in compliance with AQG-324, to stress SiC MOSFETs under controlled thermal conditions. Two R_dson drift compensation methods are compared to analyze the evolution of compensated R_dSON: a moving polynomial fit (Method 1) and a derivative-based technique with post-filtering (Method 2). Results show that both methods can differentiate between linear (die-level degradation) and non-linear (package-related failure) regions of R_dsON  drift. However, Method 1 provides more stable estimates with lower noise, especially for smaller window sizes. The findings support the use of compensated R_dSON as a practical and robust condition monitoring parameter for SiC MOSFET reliability assessment.

Accurate estimation of losses in high-power traction converters is essential for an effective design. Precise estimation of switching and conduction losses is crucial for this purpose. In this paper, the widely recognized Double Pulse Test (DPT) is employed to determine these losses. However, time-shift errors and misalignments in measurements can lead to significant deviations in loss estimation of the actual setup. This paper introduces a postprocessing method aimed at mitigating time-shift and misalignment issues in voltage and current waveforms. The proposed method is validated through simulation, demonstrating its effectiveness in improving the accuracy of loss estimation for high-power traction converters.

This paper evaluates traction inverters for heavy-duty electric vehicles, focusing on key criteria such as raised power ratings with improved efficiency and power densities. Boosted voltage and current levels are required to achieve higher power levels and provide megawatt charging system solutions, which results in the need to utilize new semiconductors and topologies. In this study, 3-Level neutral point clamped (3L- NPC) and 2-Level 6-phase (2L-6Ph) voltage source inverters (VSIs) are evaluated and compared to conventional 2-Level 3-phase (2L-3Ph). The comparison uses figure-of-merit parameters and a virtual prototyping method based on several performance indices, such as efficiency, power density, output harmonic quality, and reliability. Then, efficiency maps are acquired to find out the sweet operating points, minimizing losses. Results show that the 3L-NPC VSI system provides a higher switching frequency, which also shrinks the size of the passive elements and cooling system. Although the 3L-NPC inverter requires additional power switches and isolated gate drivers, its estimated performance outweighs such reliability and cost-dependent issues. Therefore, this study concludes that multi-level inverter topologies hold promise for high-voltage, high-power traction drives.