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.

This article presents a unique method of extracting the ON-state resistance of metal-oxide-semiconductor field-effect transistors (MOSFETs) used in power electronic systems. The proposed method uses ON-state voltage measurements of the device-under-test as well as the load current. Contrary to prior-art solutions, the proposed method does not require estimating the device currents, but rather directly uses the load current measurements. This reduces the computational effort for estimation without reducing the estimation accuracy. Moreover, it is shown that unlike time-based estimation techniques such as the recursive least-squares estimation method, the proposed solution does not require ON-state voltage and current measurements to be accurately synchronized. The extracted ON-state resistance can be used for online condition monitoring of semiconductors, as well as for estimating the junction temperature. The efficacy of the proposed method is verified experimentally under constant and variable load conditions. Moreover, the extracted 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.

Grid-forming converters can emulate the behavior of a synchronous generator through frequency droop control. The stability of grid-forming modular multilevel converters can be studied via the impedance-based stability criterion. This paper presents an ac-side impedance model of a grid-forming modular multilevel converter which includes a complete grid-forming control structure. The impact of different control schemes and parameters on the closed-loop output impedance of the converter is thoroughly analyzed and the learnings have been used in mitigating undesired control interactions with the grid. The results are verified through simulations in time- and frequency-domains along with experiments on a down-scaled laboratory prototype.

This study focuses on analyzing and optimizing LC filter components for the triangular current mode (TCM)-based zero voltage switching (ZVS) inverter. The integration of ZVS and TCM control techniques in TCM-based ZVS two-level three-phase inverters significantly reduces switching losses, enhances overall system efficiency and power density, and mitigates electromagnetic interference (EMI) issues. An LC filter is essential for operating the inverter in TCM-based ZVS mode, ensuring soft switching throughout. Optimized LC filters play a crucial role by providing ZVS at turn-on and turn-off, enhancing motor efficiency by achieving sinusoidal waveforms and minimizing harmonics. Additionally, the design increases copper space in motor winding slots, enabling lower temperature operation, extended lifespan, and reduced reliance on cooling systems. Performance analysis, including output waveform examination, fast fourier transform (FFT), total harmonic distortion (THD) evaluation, and EMI highlights the superior effectiveness of this LC filter-optimized TCM-based ZVS inverter configuration over conventional hard-switched inverters.

Double-sided cooled (DSC) power semiconductor modules have garnered increased interest over the past decade due to their ability to offer an additional path for heat removal, facilitating higher power density operation while reducing junction temperatures and thermal stresses. Nevertheless, when operating at similar junction temperatures, DSC modules might exhibit elevated thermo-mechanical stress compared to single-sided cooled (SSC) modules. This increase can be attributed to restricted vertical movement within the DSC modules. Furthermore, the integration of various spacers within the DSC modules, which enable bond wire connections to gate terminals, can significantly influence both the thermal performance and induced thermo-mechanical stresses. Depending on the materials used in the spacer, the thermal performance and thermo-mechanical stresses inside the module can vary. In this study, we have first analysed the thermal performance of the DSC power modules employing different spacers. Following that, we have also performed thermo-mechanical analysis in different solder layers. Finally, fatigue analysis is done to demonstrate the weakest solder layer inside the package.

The demand for highly efficient and dynamic electric vehicles (EVs) has increased dramatically. The traction inverter, a pivotal component in an EV powertrain, plays a crucial role. This study is dedicated to designing a traction inverter with focus on achieving high efficiency and elevated power density and mitigating electromagnetic interference (EMI) issues. To realize these objectives, autonomous gate drivers (AGDs) are proposed and designed using LTspice simulation software. The aim is to achieve zero voltage switching (ZVS) at both turn-on and turn-off through the utilization of triangular current mode (TCM) control on the gate driver. The AGDs implement a current modulation scheme by sensing the current and voltage and generating gate-source voltage signals with minimal delays. The implemented current modulation scheme by the AGDs results in an efficiency exceeding 99% for a 10 kW power rating. The sinusoidal output waveforms not only contribute to extending the motor lifespan by mitigating sharp-edge voltages but also bring advantages such as reduced switch stress, decreased EMI, and simplified thermal management.