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This article is focused on the design of a high-voltage (800 V) bidirectional boost converter with high efficiency at medium-low power levels. Triangular current mode (TCM) enhances the efficiency of the converter at low power, thanks to soft-switching operation, but it requires variable switching frequency and large current ripple through the inductor. The former can be implemented by using silicon carbide (SiC) mosfets and the latter can be minimized by using interleaved modules. At low power, TCM requires high switching frequency, a minimum negative inductor current, and a minimum deadtime to obtain zero voltage switching. These values vary for different input/output voltage ratios and must be properly selected to reduce deadtime losses, normally neglected in the literature since it is assumed that they have low impact. However, it can be relevant at high frequencies (especially for devices with high reverse conduction voltage drop, such as SiC mosfets). In this article, deadtime losses are included in the proposed losses models and the selection of optimum values of deadtime and minimum inductor current to minimize these deadtime losses are analytically evaluated and experimentally validated. [ABSTRACT FROM AUTHOR]

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]

Quasi-square wave mode with zero voltage switching (QSW-ZVS) is an operation mode in which the switching losses can be minimized. However, a large inductance current ripple is needed in this mode, which limits the maximum attainable power of the topology. A possible way to increase the power managed by a QSW-ZVS mode converter is to use a modular converter. An input parallel output parallel (IPOP) arrangement, in which the current can be shared among the modules, can increase the total power proportionally to the number of modules. This paper addresses two main proposals. The first one is a master–slave technique to extend the QSW-ZVS mode to an IPOP modular converter, achieving an interleaved solution which minimizes the total input current ripple and assures the current balance among the modules. The second one is a comparison of four different control techniques applied to the IPOP modular converter to improve the overall efficiency at light to medium load: balanced master–slave technique, master–slave with phase-shedding, asymmetrical master–slave, and burst mode (or hysteretic control). These four strategies are theoretically analyzed, experimentally validated and compared using a 150–400 V 2 kW modular IPOP prototype made up of four synchronous boost converter operating in QSW-ZVS mode. [ABSTRACT FROM PUBLISHER]

Envelope tracking (ET) is a technique designed to enhance the efficiency of radio frequency power amplifiers (RF PA). It is based on providing the voltage to the RF PA with variations that mimic the shape of the envelope of the communication signal that the RF PA is processing. As the bandwidth of these signals can be around several megahertz, the switching frequency of the switching mode power supply designed for ET applications has to be very high. The good switching characteristics of Gallium Nitride devices makes them suitable for this application. This paper presents two multiphase converters to be used as envelope modulators in envelope tracking applications. [ABSTRACT FROM AUTHOR]

This paper presents a new control strategy for power factor correctors (PFCs) used to drive high-brightness light-emitting diodes (HB-LEDs). This control strategy is extremely simple and is based on the use of standard peak-current-mode integrated controllers (PCMICs), reducing its cost and complexity in comparison to traditional PFC controllers. In fact, this method is an alternative implementation of the one-cycle control to PFCs belonging to the flyback family of converters, without introducing high complexity for reducing the total harmonic distortion. In this case, the use of a simple exponential compensation ramp instead of a linear one is the proposed solution for drawing a sinusoidal input current. Moreover, the line current is cycle-by-cycle controlled, and therefore, the input-current feedback loop is extremely fast, which allows the use of this type of control with high-frequency lines. The proposed idea is to apply this simple control to a one-stage PFC in order to design a low-cost ac–dc HB-LED driver. However, the application of this control strategy to PFC belonging to the flyback family of converters is not obvious. Design-oriented considerations about its implementation in PCMIC will be provided. Finally, an experimental prototype of this driver was developed. [ABSTRACT FROM PUBLISHER]

This paper presents the introduction of problem-based learning (PBL) in a power electronics course at the University of Oviedo, Gijón, Spain, by means of two practical projects: the design and construction of a switching-mode power supply (SMPS) prototype and the static study of a dc–dc converter topology. The goal of this innovation was for students to apply in practice the knowledge they had acquired in theory classes. PBL is known to be a motivating, problem-centered teaching method that brings the real professional world closer to the student. The instructors thus considered PBL to be the most suitable methodology to obtain the desired results. The underlying methodology, task planning, and assessment of these projects will be presented. Furthermore, the influence of the introduction of PBL in practical sessions versus the traditional teaching method will be discussed. Finally, the instructors' reflections and conclusions regarding the application of PBL in this course from 2007–2009 will be presented. [ABSTRACT FROM PUBLISHER]