A power flow controller (PFC) may be needed to control the currents and power transmitted in the transmission lines in a highly meshed HVDC system. The paper presents a new and simple topology for series interline PFC for a simple 3 terminal HVDC system. Interline PFCs do not need an external power supply to change the current distribution in the HVDC system. The performance of the proposed PFC during steady state operation and ground faults is analyzed in detail using PLECS software. A protection circuit and its design aspects are also proposed for ground faults on one of the cables.

Power flow controllers (PFCs) can give added benefits in meshed High-Voltage Direct Current (HVDC) grids to increase renewables integration. Interline PFCs have been gaining attention for the last decade due to their easy structure and no need for an external power supply. This paper discusses various interline PFC topologies along with their advantages and disadvantages. The existing topologies are compared with respect to several aspects. These aspects include, for instance, modularity, the number of capacitors, the control range of the PFC, the shape of voltage waveforms inserted by the PFC on the lines, number of devices, the directionality of the current, simplicity of the topology, total power semiconductor rating and losses, and protection of the topologies for external faults. It is concluded that the topology of a PFC for a particular application can be chosen depending on the main goal since the topologies come with their advantages and disadvantages when classified based on various aspects.

This paper presents a soft-switched buck converter using Autonomous Gate Drivers (AGDs) for power electronic converters. Operating at a 400 V DC-link, typical of Electric Vehicles (EVs) and industrial systems, the converter achieves Zero Voltage Switching (ZVS) during turn-on and turn-off via AGD circuitry and optimized snubber capacitance. Operating in Triangular Current Mode (TCM), the converter utilizes inductor current ripple to enable ZVS. Experimental results confirm reliable soft-switching and suppression of voltage overshoot under realistic conditions. While the validation uses a buck converter, the proposed AGDs are directly applicable to more complex converters, including three-phase inverters with sinusoidal reference currents, relevant to EVs, renewable energy, and industrial drives. This work demonstrates a scalable solution for reducing switching losses and improving efficiency in advanced high-voltage converters.

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.

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 an adaptive control scheme for cascaded H-bridge modular multilevel converters that reduces the voltage stress on selected components estimated to have degraded health. The proposed method independently controls the average voltage of each SM according to its estimated state of health. It is shown that the combination of the proposed control system and the virtual flux-based modulation results in minor changes in the quality of the output current while the converter operates with unequal submodule voltages.

This article presents a novel method for accurate online extraction of semiconductor ON-state resistance in the presence of measurement noise. In this method, the ON-state resistance value is extracted from the measured ON-state voltage of the semiconductors and the measured load current. The extracted ON-state resistance can be used for online condition monitoring of semiconductors. The proposed method is based on the extraction of selective harmonic content. The estimated values are further enhanced through an integral action that increases the signal-to-noise ratio, making the proposed method suitable in the presence of noisy measurements. The efficacy of the proposed method is verified through simulations in the MATLAB/Simulink environment, and experimentally. The estimated ON-state resistance values from the online setup are compared to offline measurements from an industrial curve tracer, where an overall estimation error of less than 1% is observed. The proposed solution maintains its estimation accuracy under variable load conditions and for different temperatures of the device under test.

Commercially available semiconductor devices have a limited range of operating voltages. This operating voltage can be increased through series connection of the devices. In this paper, a novel active snubber circuit (ASC) is proposed that protects series-connected semiconductor devices from overvoltages during operation. The unique advantage of the proposed solution is that it does not use additional sensors or an external controller for voltage protection. That is, each ASC is equipped with sufficient components to protect its respective device. The proposed solution is mainly developed for cascaded H-bridge (CHB) and modular multilevel converters (MMCs) intended for flexible alternating current transmission systems (FACTS) and high-voltage direct current (HVDC) applications, which typically operate at low switching frequencies. Suitable extensions of the proposed design are provided for increased current capability and for possible fault-ride-through functionality. The efficacy of the proposed solution is verified by simulations in the MATLAB/Simulink environment.