Papers by Keyword: High Voltage

Abstract: This paper reports on the comparative analysis of several 6.5 kV-rated 4H-SiC Junction Barrier Schottky integrated MOSFETs (JBSFETs) and 4H-SiC MOSFET to assess their forward conduction, 3^rd quadrant behavior, and blocking characteristics. Among different JBSFET architectures, the Island P+ JBSFET achieved nearly identical specific on-resistance (R_on,sp) to the nominal MOSFET while delivering superior 3^rd quadrant conduction and maintaining a high breakdown voltage. Further optimization of Schottky width demonstrated a trade-off between leakage suppression and 3^rd quadrant conduction efficiency that underscores the Island P+ JBSFET’s potential as a reliable high-voltage SiC power device for next-generation applications.

Abstract: We have demonstrated an integrated 3.3 kV 4H-SiC vertical planar bidirectional (BD) conventional (Conv) power DMOSFET in common-drain (CD) configuration using two commercially available power DMOSFET dies and study its operation down to 77 K (-196 °C) to evaluate its cryogenic static and switching performance. The BD conduction and blocking are achieved down to 77 K. The measured specific on-resistance (R_ON,sp) of the BD MOSFET at room temperature (RT) is 26 mΩ-cm², approximately twice that of the unidirectional device. It increases by 54% when cooled to 77 K due to a substantial increase in channel and possibly JFET on-resistance components. In addition, the extracted specific switching losses (E_ON,sp and E_OFF,sp) increases by 33% (13%) at 195K (–77 °C) and by 83% (88%) at 77 K, relative to their RT values. These increases are primarily attributed to the substantial rise in R_ON,sp at 77 K. As a result, the implemented BD Conv DMOSFET exhibits degradation in both on-state and switching performance under cryogenic operation, driven mainly by the significant increase in channel and JFET resistance components.

Abstract: This study investigates a cost-effective semi-Superjunction (SSJ) solution for 3.3 kV silicon carbide (SiC) MOSFETs, comparing planar and trench configurations. The semi-SJ method, utilizing side-wall implantation and silicon oxide trench refill, offers a practical alternative to the more complex multi-epitaxial growth approach. Through TCAD simulations, the planar semi-SJ MOSFET (planar-SSJ) achieved a 48 % reduction in specific on-state resistance (7.5 mΩ.cm²) and a 4.5 % improvement in maximum blocking voltage (4210 V) compared to conventional planar MOSFET. The trench semi-SJ MOSFET (trench-SSJ), depending on the deep trench angle, can further reduce the specific on-state resistance by 52 % (7.0 mΩ.cm²) and improve the maximum blocking voltage by 6 % (4285 V), while also providing a wider implantation window and a lower gate-oxide electric field.

Abstract: This paper presents for the first time a comparison between experimental measurements of Optical Beam Induced Current (OBIC) and finite element simulations on high-voltage bipolar diodes. Two peripheral protection structures were chosen: a simple MESA protection and a MESA + JTE combination. Comparable experimental and simulated results were obtained in both cases.

Abstract: In this paper, the static and dynamic characterization of a High Voltage (10kV) 4H-SiC Bipolar Junction Transistor (BJT) is presented. Using a high-voltage source in vacuum conditions, a breakdown voltage of 11 kV was measured. Results showed that both large and small BJTs exhibit similar on-state resistance per unit area and collector current density of 55 A.cm^-2. The current gain increases with a decrease in temperature, indicating reduced charge carrier recombination at lower thermal energies. Also, BJT have been characterized in switching mode at 1 kV. The study concludes that 4H-SiC BJT demonstrates promising electrical performance for high-efficiency applications in harsh environments.

Abstract: High voltage overhead transmission line is a transmission tower used to conduct electricity with a voltage of 35 kV to 230 kV. In the installation of the HV overhead transmission line tower structure, one of the main things that need to be considered is the installation of stub that can affect the sturdiness of the tower. This research aims to design and make a stub setting fixture on the HV overhead transmission tower installation. The research process began with data observation and literature study of tower stub installation in the 150kV 2xZebra Andolo – Kasipute Sec.1 installation project of PT. PLN Persero UIP South Sulawesi, then designed the stub setting fixture components, design data analysis, and fixture manufacturing. The results of the analysis of the design structure experienced do not exceed the limits of the material stresses of the component, the analysis of machine elements in the stub setting fixture is able to withstand the loads experienced by the component. It is expected that there will be improvements and development of fixture in the form of more efficient forms of construction and operation, and can use analog and digital controls in terms of fixture operation in subsequent development and research.

Abstract: Nanoparticles have emerged as promising tools for cancer treatment due to their ability to selectively deliver drugs to the tumor site while avoiding significant systemic side effects. Chitosan nanoparticles, among various types of nanoparticles, have gained significant attention due to their biocompatibility, biodegradability, and local drug delivery capacity. The electrospray technique is an efficient method for preparing chitosan nanoparticles, offering reproducibility, scalability, and high drug encapsulation efficiency. This technique has gained popularity due to its ease of use and flexibility in meeting various demands of nanoparticle production. Recent studies have investigated the potential of chitosan nanoparticles prepared by electrospray technique to encapsulate a range of drugs. The method leverages active surface absorption, binding, or complexation with drugs. For example, chitosan-based nanoparticles loaded with DOX and QUE achieved high encapsulation efficiency of 83% and effectively inhibited the growth of HCT-116 cancer cells. Similarly, SNP-CH-DOX-CM nanoparticles showed significant anti-cancer activity against HepG2 tumors. However, it should be noted that the toxicity of nanoparticles is directly related to the concentration of the active substance. Therefore, careful optimization of drug dosing is necessary to minimize any potential toxicity.

Abstract: The major portion power loss in power system occurs in the components of low voltage (LV) networks. Low voltage distribution system (LVDS) configuration has been observed to contribute significantly to power loss and unacceptable voltage drop in the system due to its structure and higher current flow in the network. The adoption of small capacity transformers as high voltage distribution system (HVDS) configuration is increasingly applied to the network for power loss reduction and the improvement of voltage profile. This study aims to evaluate the technical and economic implication of the use of HVDS configuration on Ado-Ekiti 11/0.415 kV power distribution networks and provide necessary recommendations. The network data was obtained and modeled on NEPLAN software for simulation and technical evaluation of the networks. The existing LV lines were upgraded to high voltage (HV) and remodeled with small capacity transformers and comparative analysis of the technical and economic effects of the networks were carried out. The results obtained showed that there could be feeder capacity increase of 92.03 kW and power loss reduction of 347.17 kW and 459.72 kVar following reconfiguration from LVDS to HVDS. The losses in the transformers and lines were significantly reduced by 37.8% for HVDS configuration when compared with the LVDS configuration. The voltage profile was significantly improved with voltage deviations in the range of ± 0.01 to ± 0.03 of bus voltage for the HVDS network when compared to the existing network. The cost of implementation of the HVDS network substation was calculated to be ₦807,238,715.50 and with the combination of annual savings and an increment in tariff of ₦5/kWh in the billing charge of unit energy consumption resulted in a payback period of 2 to 3 years for the estimated capital investment. This study showed that technical performance of HVDS implementation on the Ado-Ekiti network feeder was better than that of the existing network.

Abstract: The 10 kV silicon carbide p-channel insulated gate bipolar transistors (IGBTs) with low forward voltage drop (V_F) have been fabricated and characterized successfully. The novel edge termination structure of Four-Region Multistep Field Limiting Rings (FRM-FLRs) and the optimum JFET region design proposed in our previous work is adopted to improve the blocking performance and the on-state characteristics. The fabricated device with a chip size of 6 mm × 6 mm and an active area of 0.16 cm² exhibits a high blocking voltage of -10 kV with a small leakage current below -200 nA. Meanwhile, a low forward voltage drop of -8 V at the collector current of -10 A with a gate bias of -20 V is obtained at room temperature, corresponding to a current density of 62.5 A/cm². Besides, a lower gate leakage current is measured less than 2 nA at the gate voltage of -30 V. Experimental results demonstrate that a better trade-off between the blocking voltage and the on-state characteristics is achieved for the fabricated device, which is desirable for the high power applications.

Abstract: We have performed detailed dynamic switching measurements for 3kV 4H-SiC Charge-Balanced (CB) junction barrier Schottky (JBS) diodes [1,2] and studied their dependence on device design parameters. We have done forward and reverse recovery characterizations and found unusual switching characteristics in these CB-JBS diodes. These switching characteristics are explained based on the design and layout of the devices.