Solid-state switch-mode rectification converters have reached a matured level for improving power quality in terms of power-factor correction (PFC), reduced total harmonic distortion at input AC mains and precisely regulated DC output in buck, boost, buck-boost and multilevel modes with unidirectional and bidirectional power flow. This paper deals with a comprehensive review of improved power quality converters (IPQCs) configurations, control approaches, design features, selection of components, other related considerations, and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of IPQC technology to researchers, designers and application engineers working on switched-mode AC-DC converters. A classified list of more than 450 research publications on the state of art of IPQC is also given for a quick reference.

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A review of single-phase improved power quality AC-DC converters

DC–DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which fundamental energy storing elements (inductors and capacitors) and/or transformers in conjunction with switch(es) and diode(s) are utilized in the circuit. These techniques include switched capacitor (charge pump), voltage multiplier, switched inductor/voltage lift, magnetic coupling, and multistage/-level, and each has its own merits and demerits depending on application, in terms of cost, complexity, power density, reliability, and efficiency. To meet the growing demand for such applications, new power converter topologies that use the above voltage-boosting techniques, as well as some active and passive components, are continuously being proposed. The permutations and combinations of the various voltage-boosting techniques with additional components in a circuit allow for numerous new topologies and configurations, which are often confusing and difficult to follow. Therefore, to present a clear picture on the general law and framework of the development of next-generation step-up dc–dc converters, this paper aims to comprehensively review and classify various step-up dc–dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc–dc converters are presented and summarized with comparative study of different voltage-boosting techniques.

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Step-Up DC–DC Converters: A Comprehensive Review of Voltage-Boosting Techniques, Topologies, and Applications

The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300/spl deg/C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog VLSI in this temperature range. However practical operation of silicon power devices at ambient temperatures above 200/spl deg/C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

High-temperature electronics - a role for wide bandgap semiconductors?

The continuously increasing demand for electric power and the economic access to remote renewable energy sources such as off-shore wind power or solar thermal generation in deserts have revived the interest in high-voltage direct current (HVDC) multiterminal systems (networks). A lot of work was done in this area, especially in the 1980s, but only two three-terminal systems were realized. Since then, HVDC technology has advanced considerably and, despite numerous technical challenges, the realization of large-scale HVDC networks is now seriously discussed and considered. For the acceptance and reliability of these networks, the availability of HVDC circuit breakers (CBs) will be critical, making them one of the key enabling technologies. Numerous ideas for HVDC breaker schemes have been published and patented, but no acceptable solution has been found to interrupt HVDC short-circuit currents. This paper aims to summarize the literature, especially that of the last two decades, on technology areas that are relevant to HVDC breakers. By comparing the mainly 20+ years old, state-of-the art HVDC CBs to the new HVDC technology, existing discrepancies become evident. Areas where additional research and development are needed are identified and proposed.

HVDC Circuit Breakers: A Review Identifying Future Research Needs

Silicon carbide (SiC) power devices have been investigated extensively in the past two decades, and there are many devices commercially available now. Owing to the intrinsic material advantages of SiC over silicon (Si), SiC power devices can operate at higher voltage, higher switching frequency, and higher temperature. This paper reviews the technology progress of SiC power devices and their emerging applications. The design challenges and future trends are summarized at the end of the paper.

https://ieeexplore.ieee.org/ielaam/41/8031005/7815312-aam.pdf

Review of Silicon Carbide Power Devices and Their Applications

Silicon offers multiple advantages to power circuit designers, but at the same time suffers from limitations that are inherent to silicon material properties, such as low bandgap energy, low thermal conductivity, and switching frequency limitations. Wide bandgap semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN), provide larger bandgaps, higher breakdown electric field, and higher thermal conductivity. Power semiconductor devices made with SiC and GaN are capable of higher blocking voltages, higher switching frequencies, and higher junction temperatures than silicon devices. SiC is by far the most advanced material and, hence, is the subject of attention from power electronics and systems designers. This paper looks at the benefits of using SiC in power electronics applications, reviews the current state of the art, and shows how SiC can be a strong and viable candidate for future power electronics and systems applications.

Silicon carbide benefits and advantages for power electronics circuits and systems

Recent progress in silicon carbide (SiC) material has made it feasible to build power devices of reasonable current density This paper presents recent results including a comparison with state-of-the-art silicon diodes Switching losses for two silicon diodes (a fast diode, 600 V, 50 A, 60 ns Trr), an ultra-fast silicon diode (600 V, 50 A, 23 ns Trr) and a 4H-SiC diode (600 V, 50 A) are compared The effect of diode reverse recovery on the turn-on losses of a fast WARP/sup TM/ IGBT are studied both at room temperature and at 150/spl deg/C At room temperature, SiC diodes allow a reduction of IGBT turn-on losses by 25% compared to ultra-fast silicon diodes and by 70% compared to fast silicon diodes At 150/spl deg/C junction temperature, SiC diodes allow a turn-on loss reduction of 35% and 85% compared to ultra-fast and fast silicon diodes respectively The silicon and SiC diodes are used in a boost power converter with the WARP/sup TM/ IGBT to assess the overall effect of SiC diodes on the power converter characteristics Efficiency measurements at light load (100 W) and full load (500 W) are reported Although SiC diodes exhibit very low switching losses, their high conduction losses due to the high forward drop dominate the overall losses, hence reducing the overall efficiency Since this is an ongoing development, it is expected that future prototypes will have improved forward characteristics

A Comparative Evaluation of New Silicon Carbide Diodes and State-of-the-Art Silicon Diodes for Power Electronic Applications

Recent progress in silicon carbide (SiC) material has made it feasible to build power devices of reasonable current density. This paper presents recent results including a comparison with state-of-the-art silicon diodes. Switching losses for two silicon diodes (a fast diode, 600 V, 50 A, 60 ns Trr), an ultra-fast silicon diode (600 V, 50 A, 23 ns Trr) and a 4H-SiC diode (600 V, 50 A) are compared. The effect of diode reverse recovery on the turn-on losses of a fast WARP/sup TM/ IGBT are studied both at room temperature and at 150/spl deg/C. At room temperature, SiC diodes allow a reduction of IGBT turn-on losses by 25% compared to ultra-fast silicon diodes and by 70% compared to fast silicon diodes. At 150/spl deg/C junction temperature, SiC diodes allow a turn-on loss reduction of 35% and 85% compared to ultra-fast and fast silicon diodes respectively. The silicon and SiC diodes are used in a boost power converter with the WARP/sup TM/ IGBT to assess the overall effect of SiC diodes on the power converter characteristics. Efficiency measurements at light load (100 W) and full load (500 W) are reported. Although SiC diodes exhibit very low switching losses, their high conduction losses due to the high forward drop dominate the overall losses, hence reducing the overall efficiency. Since this is an ongoing development, it is expected that future prototypes will have improved forward characteristics.

A comparative evaluation of new silicon carbide diodes and state-of-the-art silicon diodes for power electronic applications

In this paper, a dc/dc power converter for distributed photovoltaic (PV) plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter allows for a simplified maximum power point tracker design using fewer measurements. The stability analysis of the distributed PV system comprised of the proposed dc/dc converters confirms the stable operation even with a large number of deployed converters. The experimental results show a composite weighted efficiency of 98.22% with very high maximum power point tracking efficiency.

An Efficient Partial Power Processing DC/DC Converter for Distributed PV Architectures

A soft switching active snubber is proposed to reduce the turn-off losses of the IGBT in a current-mode controlled buck power converter. The soft switching snubber provides zero-voltage switching for the IGBT, thereby reducing the high turn-off losses of the IGBT due to the current tailing. The proposed snubber uses an auxiliary switch to discharge the snubber capacitor. This auxiliary switch also operates at zero-voltage and zero-current switching. The size of the auxiliary switch compared to the main switch makes this snubber a good alternative to the conventional snubber or even to passive low-loss snubbers. The use of the soft switching active snubber permits the IGBT to operate at high frequencies, with low EMI and an improved RBSOA. The use of an active snubber allows recovery of part of the energy stored in the snubber capacitor during the turn-off. Finally, a generic snubber cell is identified for all the nonisolated DC/DC power converters (buck, boost, buck-boost, Cuk, Sepic, Zeta). >

Ahmed Elasser

Papers

Silicon carbide benefits and advantages for power electronics circuits and systems

A Comparative Evaluation of New Silicon Carbide Diodes and State-of-the-Art Silicon Diodes for Power Electronic Applications

A comparative evaluation of new silicon carbide diodes and state-of-the-art silicon diodes for power electronic applications

An Efficient Partial Power Processing DC/DC Converter for Distributed PV Architectures

Soft switching active snubbers for DC/DC converters