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In this paper, the third quadrant behavior of a high-voltage superjunction mosfet (SJ-FET) in cascode configuration (CC) with a low-voltage silicon mosfet is deeply studied by means of an analytical model and experimental data. The third quadrant dynamic behavior of the SJ-CCs is compared to the standalone counterparts by evaluating their reverse recovery time (tRR), reverse recovery peak current (IRRM), and reverse recovery charge (QRR). An analytical model and experimental results show that the SJ-CC avoids or mitigates the activation of the SJ-FET body diode during the third quadrant operation. As a consequence, the SJ-CC strongly improves the widely used figure-of-merit RON·QRR, which considers the on-state resistance of the transistors (RON). In addition, the results obtained using an SJ-CC are similar or better than those achieved by SJ-FETs with enhanced reverse recovery (i.e., irradiated SJ-FETs). This paper also includes a comparison with commercial wide bandgap switches, concluding that the RON·QRR value provided by the SJ-CC is around eight times higher than that provided by a commercial GaN cascode. [ABSTRACT FROM AUTHOR]

Superjunction MOSFETs in cascode configuration with low-voltage silicon MOSFETs are evaluated in this paper. The proposed structure combines the good switching performance provided by the cascode configuration with the benefits of the silicon technology such as its robustness, maturity, and low cost. This paper aims to explain and to demonstrate the reduction of switching losses of superjunction MOSFETs in cascode configuration with respect to their standalone counterparts (directly driven). A detailed simulation analysis of power loss contributions is carried out under hard-switching operation. Moreover, experimental evidence is provided using a boost converter (100–400 V) operating in continuous conduction mode for different switching frequencies (100–400 kHz) and output power levels (180–500 W). [ABSTRACT FROM AUTHOR]

A converter intended to be used for the interconnection of battery-based energy storage systems with the cells of a multilevel converter is addressed in this paper. High efficiency at light and medium loads is important in these applications and it can be achieved using soft switching techniques. Two control techniques with fixed and variable switching frequency are proposed and compared. The use of silicon carbide (SiC) mosfets provides a higher attainable switching frequency, which is especially interesting in variable frequency control techniques, allowing the operation at high voltages and high switching frequencies, with high efficiencies over a wide power range. A synchronous boost DC/DC converter rated for 400 to 800 V and 10 kW is designed and developed with SiC mosfets obtaining efficiencies higher than 97% from 100% to 3.5% of full load using a variable switching frequency (up to 200 kHz) control. Significant efficiency improvement is achieved at medium and light loads. [ABSTRACT FROM PUBLISHER]

This paper is focused on a high-voltage (400 to 800 V) bidirectional converter, which is intended to be used for the interconnection of battery-based energy-storage systems with the cells of a modular multilevel converter, providing distributed energy-storage capability to a solid-state transformer. This converter must have a high efficiency at medium and light load and also a low current ripple due to the charging and discharging processes. This work takes advantage of the use of SiC MOSFETs into a synchronous boost converter to accomplish the previous requirements. First, the adoption of a variable-switching frequency control to keep the efficiency high is analyzed, and second, the use of a modular converter with different control techniques to provide a current ripple reduction is also addressed in this study. An input-parallel–output-parallel synchronous boost converter, made up with three modules (3 kW per module), is used to validate experimentally the advantages of the use of SiC MOSFETs and to compare different control techniques. [ABSTRACT FROM PUBLISHER]

The new wide band-gap semiconductor devices provide new properties to be explored. Normally on silicon carbide (SiC) JFET power devices have several advantages, in particular low switching losses and the potential capabilities of high temperature and high reverse blocking voltage. Looking for improving the overall efficiency in power converters, new structures based on these power devices might be studied. In this paper, a cascode rectifier based on normally on SiC JFET is presented and analyzed. This rectification structure can be applied as front-end rectifier stage for ac-dc power converters, increasing the overall efficiency of these topologies. A second cascode rectifier based on silicon (Si) MOSFET is also studied, as a low-cost alternative. A simple static forward characterization and a brief dynamic behavior analysis of the proposed cascode rectifier structure are made. Both cascode structures are compared with traditional Si rectifier diodes and front-end rectifiers, using an active power factor corrector (PFC) interleaved boost converter. As a result of this comparison, an efficiency improvement as high as two points is obtained. An additional OR gate based on a diode is also used as second test circuit to compare the proposed structures to the traditional Si rectifiers. A reduction between 75% and 55% of the total loss are obtained in this second experimental test. [ABSTRACT FROM AUTHOR]