Press-pack IGBT power devices are the core component in the new power system application equipment, and health management can improve their service lifetime and operational reliability, thus guaranteeing the safety and stability of new power systems. First, the package structure and main failure modes of press-pack IGBT devices are introduced. Second, the existing health condition monitoring methods are classified and analyzed according to different types of characteristic parameters. Third, the principles and characteristics of the existing lifetime prediction methods for press-pack IGBTs are summarized. Finally, a comprehensive comparative analysis of the existing health management technologies is performed, and the problems in the health management methods for press-pack IGBTs which need to be further studied and the development trends in the future are pointed out.

AC-DC Buck-type power factor correction (PFC) converters are widely applied in low-voltage scenarios. However, they typically suffer from low power factor(PF) and high total harmonic distortions of input current(THDi) caused by the input current dead zones. To solve this problem, firstly, a high PF Buck-type bridgeless PFC converter with hybrid operation modes is proposed by introducing a Buck-Boost converter cell, which operates in the Buck and Buck-Boost modes in the positive and negative half-line cycles, respectively. Although the Buck-Boost cell's efficiency is inferior to that of the Buck cell, the proposed converter can operate in the Buck-Boost mode in the negative half-line cycle, thereby minimizing the dead zones to improve PF and reduce THDi. The proposed converter operates in the Buck mode in the positive half-line cycle, inheriting the high efficiency of the Buck cell. Secondly, the operation modes and PF of the proposed bridgeless converter are analyzed to show its high PF feature. Finally, simulations and experimental tests were conducted to verify the feasibility and theoretical analysis of the proposed converter, and a comparison of performance between the proposed and conventional Buck-type PFC converters was also performed.

In the development of technologies for power electronic devices used in automobiles, the power modules are developing towards the direction of miniaturization and high power density. As a result, the high-frequency switching of power devices used in automobiles will increase the fatigue failure risk of bonding wires. To improve the strength and reliability of bonding, the action mechanism of bonding parameters at different stages was revealed from the perspective of the bonding principle at first, and the optimization intervals for different parameters were obtained using single-factor experiments. Subsequently, a systematic investigation of the influence of wire bonding materials on bonding reliability was conducted through numerical simulations and aging tests. Results indicate that compared with Al bonding wires, Cu bonding wires exhibited higher maximum temperatures and higher maximum equivalent stress. However, due to material properties, Cu bonding wires only achieved half the maximum plastic strain of Al bonding wires. Based on power cycling tests, the lifetime of Cu bonding wires was approximately four times that of Al bonding wires. Moreover, Cu bonding wires exhibited a higher degree of variability in bonding quality, with the phenomenon of stepwise signal escalation due to the detachment of a single wire serving as an early warning signal for potential failures in daily operations.

To study the degradation mechanism of silicon carbide metal-oxide-semiconductor field effect transistors (SiC MOSFETs) under dynamic drain-source stress, a dynamic reverse bias test platform with an adjustable dVds/dt capability up to 80 V/ns was developed. A dynamic high-temperature reverse bias test of commercial SiC MOSFET was carried out, and the effect of dynamic drain-source stress with a high voltage change rate on the electrical characteristics of SiC MOSFET was discussed. Experimental results show that the threshold voltage and forward conduction voltage of the bulk diode increased, indicating that the gate oxygen layer and the bulk diode above the JFET region of the device may be degraded. Sentaurus TCAD was used to analyze the weak position of plane-gate SiC MOSFET under high drain-source voltage and a high voltage change rate, and hole traps were set at the gate oxygen layer junction and the body diode region to simulate the effect of dynamic high-temperature reverse bias on the dynamic and static parameters of SiC MOSFET.

The accurate and reliable switching current information is important for power electronic converters to realize closed-loop control, harmonic suppression and short-circuit protection, which is conducive to further improving the reliability of power devices. The PCB Rogowski coil current sensor has an important research value and application prospect owing to its advantages of high bandwidth, small size, low cost and low intrusion. However, its measurement accuracy is seriously limited by the drift error and droop error in the traditional integral processing circuit. A resettable integrator is used to avoid the continuous accumulation of drift error while eliminating the influence of droop error. At the same time, a digital compensation strategy for the drift error and offset error in the resettable integrator is proposed, which uses a digital signal processor to control the digital-to-analog conversion module to generate an analog compensation signal and eliminates errors by means of a high-speed subtractor. As a result, this method has advantages of a high compensation accuracy and simple adjustment, and it can greatly reduce the influence due to integral errors. Finally, double-pulse, multiple-pulse and short-circuit protection experiments were carried out based on a double-pulse test platform, and the performance of the proposed PCB Rogowski coil current sensor was verified.

Owing to its obvious advantages such as high control flexibility, no commutation failure and strong dy-namic reactive power support capability, the voltage sourced converter based high-voltage direct-current (VSC-HVDC) transmission technology has been widely applied in scenarios including point-to-point transmission, back-to-back inter-connections and DC grids. As a core piece of equipment in VSC-HVDC transmission engineering, the VSC valve achieves AC/DC energy conversion through frequent switching of power electronic devices. In this paper, the key design requirements for VSC valves in different application scenarios are systematically summarized by combining with practical experiences accumulated in engineering, the commonly used power devices and VSC valve topologies in VSC-HVDC transmission engineering are compared and analyzed, and their development trends are projected. In addition, different schemes for two typical application scenarios in the future are also compared, providing reference for the applications of VSC-HVDC transmission technology in high-voltage, large-capacity and long-distance transmission scenarios.

The advancements in research on automotive power device packaging have significantly improved the dynamic performance and driving range of electric vehicles, making them more efficient and reliable. With the continuous optimization of automotive power device packaging, the electric vehicle industry is expected to embrace a broader market prospect and development space. In recent years, power device packaging modeling, packaging structure and optimization, thermal management and junction temperature monitoring, gate drive and applications, reliability analysis, and online monitoring have become current research hotspots and have received sustained attention from both the academic and industrial sectors. To promote discussions on the challenges and hot issues related to automotive power devices packaging and their applications, a special issue titled "High Reliability Power Device Packaging and Assistant Technology in EV Application" has been launched in the Journal of Power Supply.

The thermal resistance model of a thyristor converter valve considering its water-cooling circuit is estab-lished by combining the mechanism of a thyristor connected in series with the water-cooling circuit, which can calculate the water temperature at the inlet of each heat sink, as well as the junction temperature of each thyristor accordingly. This model is used to calculate the thermal resistance of each component in the converter valve in an example, and a steady-state thermal resistance model is built to calculate the junction temperature of the thyristor. Calculation results show that the maximum calculation error of thyristor junction temperature can reach 10.81% when considering the differ-ence of coolant temperature in the water-cooling circuit.

As the service environment of power semiconductor devices becomes more and more severe, the third-generation semiconductor represented by silicon carbide (SiC) has become the mainstream of industry applications owing to its excellent high-temperature performance. However, the lack of bounding materials which not only match with SiC chips but also have a low cost and a high melting point has become a bottleneck in the development of the industry. Cu-Sn intermetallic compounds (IMCs) are considered to be ideal bounding materials for SiC chips because of their low cost, good conductivity and characteristics that meet the requirements of low-temperature bonding and high-temperature service. Aimed at the power semiconductor device packaging, the preparation and reliability of Cu-Sn full IMC joints at home and abroad in recent years are analyzed and reviewed, and the problems to be solved at present and the development trend in the future are discussed.

The bidirectional switch is extensively applied in the fields such as state-solid breakers and photovoltaic inverters, and increasing attention is paid to the bidirectional switch of SiC power modules owing to its low power loss and high switching frequency. However, due to the traditional packaging methods for Si power modules, the bidirectional switch of the SiC power module is challenged by the issue of high switching speed. Aimed at the low-inductance packaging requirement, a chip-on-chip 3D packaging method is proposed for the bidirectional switch of the SiC power module. The circuit topology and geometric structure of the 3D packaging are given, and the communication loop and parasitic inductance of the 3D packaging are analyzed. In addition, the process was designed for the 3D packaging, and a prototype of the bidirectional switch of the SiC power module was fabricated. Experimental results of a double-pulse test verified the feasibility and effectiveness of the proposed 3D packaging for the bidirectional switch of the SiC power module.