@article{huang_huang_yu_liu_yu_2019, title={High-Efficiency and High-Density Single-Phase Dual-Mode Cascaded Buck-Boost Multilevel Transformerless PV Inverter With GaN AC Switches}, volume={34}, ISSN={["1941-0107"]}, DOI={10.1109/TPEL.2018.2878586}, abstractNote={This paper introduces a high-efficiency and high-density single-phase dual-mode cascaded buck–boost multilevel transformerless photovoltaic (PV) inverter for residential application. This inverter topology combines a regulated cascaded H-bridge multilevel inverter stage with an unregulated GaN-based ac boost converter. The cascaded H-bridge inverter and the ac boost share a common inductor. Compared with the traditional cascaded H-bridge PV inverter, this topology significantly enlarges the input voltage range due to the additional ac boost. And, a flexible number of PV panels can be used. To control the multiple dc-link PV voltages and to reduce the switching loss of the ac boost, this paper further introduces a dual-mode operation. The two modes are buck mode and buck–boost mode. To maximize the utilizations of the dc-link voltages, this paper presents a minimized ac boost duty-cycle generation strategy with feedforward. Then, a dual-mode modulation based on the boost feedforward duty-cycle generation is introduced. This paper also uses an indirect current control for this inverter, since the ac boost is an unregulated stage. The ac boost stage is implemented with two interleaved phases and the ac switches based on the 650-V E-mode GaN FETs. Finally, an 8-port 2-kW prototype based on this topology is developed and demonstrated. Compared with the state-of-the-art microinverter-based 2-kW PV inverter system, the developed inverter prototype achieves 40% reduction of the total power loss, 25% improvement of the power density, 37.5% reduction of the power connectors, 50% reduction of the device count, and 87.5% reduction of the main magnetic count. Operating with natural convection cooling, this PV inverter achieves 98.0% efficiency at 60% of load and 97.8% efficiency at full load. The power density of the packaged PV inverter is 5.8 W/in3.}, number={8}, journal={IEEE TRANSACTIONS ON POWER ELECTRONICS}, author={Huang, Qingyun and Huang, Alex Q. and Yu, Ruiyang and Liu, Pengkun and Yu, Wensong}, year={2019}, month={Aug}, pages={7474–7488} }
 @inproceedings{song_huang_liu_zhang_2016, title={1200v/200a freedm-pair: loss and cost reduction analysis}, DOI={10.1109/wipda.2016.7799928}, abstractNote={FREEDM-Pair is an innovative power semiconductor switch which reduces the loss and cost through the hybrid integration of a Si IGBT and a SiC MOSFET. During the turn-off of the FREEDM-Pair, the Si IGBT is turned off first under ZVS condition and after a carefully selected delay time, the Si MOSFET is turn-off. In this way, the IGBT's turn-off loss is significantly reduced due to the ZVS turn-off condition. During the delay time, the current will be carried by the MOSFET only. During the turn-on, the SiC MOSFET and the IGBT can be turned on at the same time. Due to faster turn-on speed of the MOSFET, the IGBT is also turned on under the ZVS condition. Another advantage of the FREEDM-Pair is the better conduction characteristics compared to the Si IGBT by combining both the unipolar and bipolar devices' advantages in current conduction. Therefore the FREEDM-Pair provides an ideal option to realize the tradeoff between the cost and performance, and can be applied to main stream applications which currently use IGBT. Previously, the 6.5-kV FREEDM-Pairs results have been published and analyzed. In this paper, loss and cost reduction of a 1200V/200A FREEDM-Pair is presented and analyzed for the first time.}, booktitle={2016 IEEE 4th Workshop on Wide Bandgap Power Devices and Applications (wipda)}, author={Song, X. Q. and Huang, A. Q. and Liu, P. K. and Zhang, L. Q.}, year={2016}, pages={152–157} }
 @inproceedings{song_huang_zhang_liu_ni_2016, title={15kV/40A FREEDM super-cascode: A cost effective SiC high voltage and high frequency power switch}, DOI={10.1109/ecce.2016.7854643}, abstractNote={High voltage wide bandgap (WBG) semiconductor devices like the 15kV SiC MOSFET have attracted great attentions because of its potential applications in high voltage and high frequency power converters. However, these devices are not commercially available at the moment and their high cost due to expensive material growth and fabrication may limit their widespread adoption in the future. In this paper, a 15kV/40A three terminal power switch, the FREEDM Super-Cascode, is reported for the first time which is based on series connection of 1.2kV SiC power devices. The design and operation principle of the FREEDM Super-Cascode are introduced and the performance including the static blocking capability, conduction characteristics over a wide range of temperatures, and dynamic switching performances are analyzed. In addition, the thermal resistance of the FREEDM Super-Cascode is measured and the power dissipation capability is projected. The FREEDM Super-Cascode costs only one third of the estimated high voltage SiC MOSFETs, and will facilitate early applications of SiC in very high voltage and high frequency power converters.}, booktitle={2016 ieee energy conversion congress and exposition (ecce)}, author={Song, X. Q. and Huang, A. Q. and Zhang, L. Q. and Liu, P. K. and Ni, X. J.}, year={2016} }
 @inproceedings{guo_liu_yu_zhang_huang_2016, title={Analysis and loss comparison of megahertz high voltage isolated dc/dc converters utilizing integrated sic mosfet module}, DOI={10.1109/wipda.2016.7799955}, abstractNote={Silicon Carbide (SiC) MOSFETs are being increasingly utilized in medium and high power electronics converters (>1 kW) because of the significantly lower switching and conduction losses when compared with conventional power switches such as the Si IGBT. SiC MOSFET based converters operating at high frequency can achieve high efficiency and high power density at the same time. Minimum switching loss can be achieved in the SiC MOSFET with carefully designed gate driving condition and DC link layout, such as the integrated SiC MOSFET module discussed in this paper. Multi-megahertz switching frequency could be realized by the proposed SiC MOSFET module with proper soft switching topology. This paper analyzes three isolated DC/DC converters, namely the asymmetrical half bridge converter, phase shift full bridge converter, and LLC resonant converter. The loss model of the SiC MOSFET is developed and utilized in the analysis. Comparisons are carried out from the device loss and soft switching requirement point of view. The LLC resonant converter is deemed more suitable for multi-megahertz application. A 4.5 kW 1.2 MHz LLC resonant converter prototype is developed and it demonstrates a peak efficiency of 97% at 4 kW.}, booktitle={2016 IEEE 4th Workshop on Wide Bandgap Power Devices and Applications (wipda)}, author={Guo, S. X. and Liu, P. K. and Yu, R. Y. and Zhang, L. Q. and Huang, A. Q.}, year={2016}, pages={291–296} }
 @inproceedings{tan_song_pcng_liu_huang_2016, title={Hierarchical protection architecture for 380v dc data center application}, DOI={10.1109/ecce.2016.7855145}, abstractNote={The DC distribution system is becoming an appealing spot due to its higher energy efficiency in recent years. Nowadays, it has been already applied in data centers, commercial buildings, electrical vehicles charger station and DC micro grid systems, etc. However, there are a lot of challenges in DC application which is not critical in traditional AC system, such as arcing, capacitive charging and discharging, etc. All of them make the protection strategy and architecture an important issue for DC application. In this paper, one 3-level hierarchy circuit protection architecture is proposed with developed solid state circuit protection hardware. It is designed with considering the power rating for DC data center load conditions. Analysis and experimental results based on 380V DC voltage have been conducted and discussed.}, booktitle={2016 ieee energy conversion congress and exposition (ecce)}, author={Tan, K. and Song, X. Q. and Pcng, C. and Liu, P. and Huang, A. Q.}, year={2016} }
 @inproceedings{liu_zhang_huang_guo_lei_2016, title={High bandwidth current sensing of sic mosfet with a si current mirror}, DOI={10.1109/wipda.2016.7799937}, abstractNote={SiC Intelligent Power Module (IPM) with high bandwidth integrated current sensors is a future trend to improve the device protection capability and chip utilization. In this work, an integrated current sensing scheme for Silicon Carbide (SiC) MOSFET power module using a Si MOSFET current mirror is proposed, analyzed and tested. The use of Si MOSFET not only lowers the overall cost, but compensates the temperature variation as well. The influence of device mismatching on sensing accuracy are discussed. Optimal selection and trade-off of sensing resistor value are calculated. Discrete device circuit and conceptual DBC-based module are tested to verify the scheme's feasibility and performance. The results show good steady state accuracy and high bandwidth performance.}, booktitle={2016 IEEE 4th Workshop on Wide Bandgap Power Devices and Applications (wipda)}, author={Liu, P. K. and Zhang, L. Q. and Huang, A. Q. and Guo, S. X. and Lei, Y.}, year={2016}, pages={200–203} }
 @inproceedings{tan_liu_ni_peng_song_huang_2016, title={Performance evaluation of multiple Si and SiC solid state devices for circuit breaker application in 380VDC delivery system}, DOI={10.1109/apec.2016.7467990}, abstractNote={The DC power delivery system is becoming an appealing research topic and real world solution due to its higher energy efficiency compare with AC delivery system. It has already been applied in data centers, commercial buildings, electrical vehicle charge stations and micro grid systems, etc. Among many new issues that need to be addressed for the DC power delivery system, ultra-fast and accurate protection is one of them. The 1200V SiC devices has been developed by many manufacturers in recent years which makes them good candidates in DC circuit breaker application. In this paper, the 380V DC circuit breaker employing solid state devices for DC power delivery system has been proposed and introduced. The criteria of device characteristics particularly for DC solid state circuit breaker application is discussed and defined. Characteristics of 4 different Si and SiC solid state devices in similar power rating have been compared based on defined criteria. The pros and cons of different devices candidates is introduced with test results for DC circuit breaker application.}, booktitle={Apec 2016 31st annual ieee applied power electronics conference and exposition}, author={Tan, K. and Liu, P. K. and Ni, X. J. and Peng, C. and Song, X. Q. and Huang, A. Q.}, year={2016}, pages={983–989} }
 @inproceedings{tan_peng_liu_song_huang_2016, title={Zero standby power high efficiency hot plugging outlet for 380VDC power delivery system}, DOI={10.1109/apec.2016.7467863}, abstractNote={The DC power delivery system is becoming an appealing research topic and real world solution due to its higher energy efficiency compared with AC delivery system. It has already been applied in data centers, commercial buildings, electrical vehicle charge stations and micro grid systems, etc. However, the electrical arc and related potential for fire and human injury is a main safety concern for the DC system. Besides, the inrush current caused by the load capacitance when hot plugged in to the DC system is also a major issue that must be considered when designing DC system. In this paper, a smart hot plugging outlet is proposed and developed by embedding solid state device into the DC outlet. Besides, over temperature and dual threshold over current protections have been also integrated to realize current limiting and trip function for each outlet. Analysis and experimental results based on 380V DC, which is a common voltage level adopted in data centers and DC micro grids, are discussed and presented.}, booktitle={Apec 2016 31st annual ieee applied power electronics conference and exposition}, author={Tan, K. and Peng, C. and Liu, P. K. and Song, X. Q. and Huang, A. Q.}, year={2016}, pages={132–137} }