Article
Engineering, Electrical & Electronic
Zheyuan Yi, Kai Sun, Hanyu Liu, Guoen Cao, Shilei Lu
Summary: This article proposes an insulation design method for the medium-voltage medium-frequency transformer in solid-state transformers (SSTs). The method adopts a novel insulation structure to improve reliability and heat dissipation performance. Finite-element method (FEM) simulations are conducted to optimize the insulation distance parameters. Experimental results validate the improved performances with the proposed insulation design method.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2022)
Article
Automation & Control Systems
Rachit Agarwal, Hui Li, Zhehui Guo, Peter Cheetham
Summary: The medium-frequency (MF) transformer in a phase-shift modulated dc solid-state transformer (SST) is susceptible to partial discharge (PD), which affects system reliability and lifetime. The close proximity and spiral geometry of tightly packed MF transformer windings carrying pulsewidth modulation (PWM) voltages create favorable conditions for PD inception. Phase-shift modulation results in a peak potential condition between adjacent posterior conductors of the primary and secondary windings, leading to PD at lower than expected operating voltages. This article investigates the effects of PWM voltages with high dv/dt switching transients on PD and lifetime characteristics of the MF transformer in a dc SST, and presents a nonintrusive PD detection strategy using high-speed optical sensors.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Yuxin Liu, Xin Liu, Fei Gao, Dong Liu, Patrick Wheeler
Summary: Auxiliary power supply (APS) plays a crucial role in medium voltage (MV) solid state transformers (SSTs) by providing power to auxiliary units. A new design for isolated APS of an input-series output-parallel (ISOP) SST is proposed in this article. The distributed MV APSs are galvanically isolated by flybacks, and the centralized APS is supplied from the MV APSs via a decoupling four-port medium frequency transformer. A dual-loop control scheme based on APS-fluctuating is proposed to solve the issue of input voltage imbalance in the ISOP system. The proposed system's small-signal model, start-up strategy, and parameter design are investigated, and a 500 V/2.2 kW lab prototype of SST with APS is built with an overall system efficiency of 95.1%.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Rui Lu, Chushan Li, Jianxiong Yu, Yinan Yao, Wuhua Li, Xiangning He
Summary: In this study, an analytic model for the eddy current loss of the multiple-layer shielding structure at high frequency is established. An improved shielding structure is proposed based on the loss model to minimize the additional loss while ensuring the shielding effect. Experimental results confirm that this structure significantly reduces transformer loss while ensuring shielding effectiveness.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Liran Zheng, Rajendra Prasad Kandula, Deepak Divan
Summary: This article presents the issue of additional device voltage stress due to grounding-loop current in current-source solid-state transformers, using the soft-switching solid-state transformer as an example. It proposes a voltage-stress mitigation scheme using additional grounding capacitors and damping resistors. The effectiveness of the proposed scheme is verified experimentally on a prototype with parameter variations.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Chunmeng Xu, Jia Wei, Liran Zheng, Xiangyu Han, Maryam Saeedifard, Rajendra Prasad Kandula, Karthik Kandasamy, Deepak Divan, Lukas Graber
Summary: This article discusses the challenges of insulation coordination design for the deployment of solid-state transformers in medium-voltage distribution systems. Two challenges, including the mismatch between protective levels and insulation strength, and the incompatibility of standard impulse tests, are identified. The article presents solutions, such as a novel lightning protection scheme and comprehensive evaluation of surge withstand capability, to address these challenges. By addressing these challenges, the field deployment of SSTs can be facilitated.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2022)
Article
Computer Science, Artificial Intelligence
Pradeep Ammasaikutti, Kannan Palanisamy
Summary: This study proposes a single phase Soft Switching-Solid State Transformer (SS-SST) design with H-bridge topology as an alternative solution for low (or) medium grid power applications. An optimization of Cuckoo Search Firefly (CSF) algorithm is used to find the optimum switching angle and duty cycle in the bridge circuit unit. The proposed SS-SST (MS4T) model achieves maximum efficiency for medium/low power frequency applications. The design has applications in electric aircraft, ship power systems, battery energy storage systems (BESS), and fast charging electric vehicles (EV) in medium-voltage DC (MVDC) networks. The proposed MS4T design offers benefits such as low conduction loss, low EMI, and high efficiency through the H-bridge converter circuit. MATLAB platform is used to validate the effectiveness of the present investigations.
JOURNAL OF INTELLIGENT & FUZZY SYSTEMS
(2023)
Article
Engineering, Electrical & Electronic
Pablo Bravo, Javier Pereda, Michael M. C. Merlin, Sebastian Neira, Timothy C. Green, Felix Rojas
Summary: This paper presents a customized and simple control method for the Modular Multilevel Matrix Converter (M3C) used in AC substations, and compares it to the back-to-back Modular Multilevel Converter (B2B-MMC). Simulation results demonstrate the performance and advantages of M3C in different operating conditions, while experimental results validate its performance under less ideal conditions.
IEEE TRANSACTIONS ON POWER DELIVERY
(2022)
Article
Engineering, Electrical & Electronic
Liran Zheng, Xiangyu Han, Zheng An, Rajendra Prasad Kandula, Karthik Kandasamy, Maryam Saeedifard, Deepak Divan
Summary: This article introduces a 5-kV SiC-based universal modular solid-state transformer (SST), which can interface either an LVac or LVdc grid with an MVdc grid in single-stage power conversion with high efficiency and robustness. The proposed SST module uses 3.3-kV SiC MOSFETs and diodes, and can serve as a building block in series or parallel for higher voltage higher power systems. The topology of each module is based on the soft-switching solid-state transformer (S4T) with reduced conduction loss and electromagnetic interference, offering high efficiency with full-range zero-voltage switching for main devices and zero-current switching for auxiliary devices.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Energy & Fuels
Essam Hussain, Mohammad Abusara, Suleiman Sharkh
Summary: For integrating large batteries in the medium voltage grid, current fed solid-state transformers offer galvanic isolation and a significant weight and size reduction. A design optimization strategy is proposed in this paper to find the optimum operating frequency and core flux density under practical constraints. Analytical equations for the power losses calculation and the cores design are derived and validated using ANSYS and MATLAB Simulink software packages, and simulation results are presented.
Article
Engineering, Electrical & Electronic
Liran Zheng, Xiangyu Han, Rajendra Prasad Kandula, Deepak Divan
Summary: This article proposes a fast predictive control method and a small dc-link inductor to minimize the dc-link current in a current-source converter based solid-state transformer. It not only improves the steady-state performance but also significantly enhances the dynamic performance, as experimentally validated.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Piotr Czyz, Thomas Guillod, Daifei Zhang, Florian Krismer, Jonas Huber, Raphael Faerber, Christian M. Franck, Johann W. Kolar
Summary: This article investigates the component and system-level performance limits of air-cooled solid-state transformers using either air-core or magnetic-core transformers. Detailed designs of two prototypes are presented, and comprehensive experimental characterizations are conducted to validate the derived performance limits. The results show that both prototypes achieve high efficiencies.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2022)
Article
Chemistry, Multidisciplinary
Abdelrahman Ismail, Mahmoud S. Abdel-Majeed, Mohamed Y. Metwly, Ayman S. Abdel-Khalik, Mostafa S. Hamad, Shehab Ahmed, Eman Hamdan, Noha A. Elmalhy
Summary: This paper selects the integrated DC power distribution network aboard an electric ship as a case study. It proposes a multiport solid-state transformer (SST) based on silicon carbide (SiC) switches/MOSFETs, which can significantly simplify the system structure. At the DC distribution level, a high penetration of renewable generation with energy storage is allowed. Simulations and experiments validate the theoretical findings, providing important theoretical basis for the DC distribution network on electric ships.
APPLIED SCIENCES-BASEL
(2022)
Article
Energy & Fuels
Mehmet Ugras Cuma, Alireze Deljavan Anvari, Murat Mustafa Savrun
Summary: This paper presents an enhanced solid-state transformer topology for a medium-voltage utility grid. The main objective is to develop an improved flyback converter with a high-voltage conversion capability for integration into an MV modular multilevel converter. The system integrates the quasi z-source and flyback converters, with a high-frequency transformer providing isolation between the input and output ports.
Article
Engineering, Electrical & Electronic
Huawei Yuan, Hin Sang Lam, Neha Beniwal, Siew-Chong Tan, Josep Pou, Shu Yuen Ron Hui
Summary: This article proposes a voltage-balancing control solution for the MV-ES system through the cooperation of diode-clamped converters (DCCs) and dual active bridges (DABs). By taking advantage of the DABs in voltage balancing, the DCCs can adopt simple modulation to ensure grid-friendly voltage and current injection into the power grid.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Review
Energy & Fuels
Alvaro Carreno, Marcelo Perez, Carlos Baier, Alex Huang, Sanjay Rajendran, Mariusz Malinowski
Summary: Distribution systems face constant stress from variable operating conditions, impacting distribution transformers and lines and degrading end-user service quality. Hybrid transformers, composed of a conventional transformer and a power converter, offer an interesting alternative to address multiple power quality issues.
Correction
Engineering, Electrical & Electronic
Jiaxing Wei, Siyang Liu, Xiaobing Zhang, Weifeng Sun, Alex Q. Huang
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Zhicheng Guo, Ruiyang Yu, Wei Xu, Xianyong Feng, Alex Q. Huang
Summary: This article presents a design and optimization methodology for a 200-kW medium-frequency transformer based on low-loss magnetic core, achieving high power density and efficiency through a parallel-concentric winding structure and innovative cooling and insulation design.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Yuan Li, Xintian Zhou, Yuanfu Zhao, Yunpeng Jia, Dongqing Hu, Yu Wu, Liqi Zhang, Zibo Chen, Alex Q. Huang
Summary: This article investigates the degradation of SiC MOSFETs under short circuit stress and develops an aging platform for experimental analysis. The study finds bidirectional VTH shift in different types of SiC MOSFETs with varying degradation rates. Device simulation reveals that the damaged region in SiC planar-gate MOSFET is near the channel area, while in SiC trench-gate MOSFET, it is at the trench corner.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Ruiyang Yu, Tianxiang Chen, Pengkun Liu, Alex Q. Huang
Summary: This article introduces a new 3-D parallel winding method with low resistance and low capacitance. Through experimental comparisons and finite element analysis, it demonstrates the effectiveness of this method in improving transformer efficiency and reducing winding loss.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Qingyun Huang, Qingxuan Ma, Pengkun Liu, Alex Q. Huang, Michael A. de Rooij
Summary: This article presents the design and testing of a high-efficiency and high-density 2.5 kW four-level flying capacitor multilevel (FCML) totem-pole bridgeless power-factor-correction (PFC) rectifier with GaN devices, achieving a peak efficiency of 99.25%. The system power density reaches 104 W/in(3) without a heatsink and with forced air cooling.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2021)
Article
Physics, Applied
Atsushi Shimbori, Alex Q. Huang
Summary: This paper discusses the design and fabrication of a 4H-SiC RESURF SBD and proposes optimization methods for the anode and cathode edge structures. The study focuses on minimizing the impact ionization at the edge of the active area and achieving close to ideal RESURF breakdown voltage. Three-dimensional simulations were conducted to optimize the electric field distribution and enable junction isolation between neighboring devices. The findings provide guidance for the development of monolithic SiC high voltage integrated circuits.
APPLIED PHYSICS LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Wei Xu, Zhicheng Guo, Adithyan Vetrivelan, Ruiyang Yu, Alex Q. Huang
Summary: As PV penetration continues to increase, the integration of PV power generation with battery energy storage is becoming more attractive. This article proposes a PV+BES solid-state transformer (PVS-SST) that eliminates the need for a step-up transformer, reducing costs and complexity. The PVS-SST utilizes a modular SST concept and SiC power MOSFET devices, achieving a high power density. The article also discusses the design challenges of the proposed PVS-SST, including medium-frequency transformer design and control architecture.
IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS
(2022)
Article
Automation & Control Systems
Tianxiang Chen, Ruiyang Yu, Alex Q. Huang
Summary: This article presents a novel GaN-based three-phase grid to 48-V battery energy storage system. The system utilizes a single-stage ac-dc dual-active-bridge converter with dual-phase-shift and variable-frequency control. The effectiveness of this control method is validated through experimental results.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Zhicheng Guo, Alex Q. Huang, Robert E. Hebner, Gian Carlo Montanari, Xianyong Feng
Summary: Partial discharge (PD) is a common phenomenon in insulation system defects that can affect the life and reliability of equipment. This article explores PD behavior under high frequency pulsewidth modulation (PWM) conditions and discusses the suitability of test equipment and the impact of windings and insulation materials.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Editorial Material
Engineering, Electrical & Electronic
Wencong Su, Alex Q. Huang, M. Abul Masrur, Anurag K. Srivastava, Tianshu Bi, Di Shi
IEEE TRANSACTIONS ON SMART GRID
(2022)
Article
Engineering, Electrical & Electronic
Zhicheng Guo, Sanjay Rajendran, Jagadeesh Tangudu, Yasmin Khakpour, Stephen Taylor, Lei Xing, Yue Xu, Xianyong Feng, Alex Q. Huang
Summary: This study proposes a novel insulation and cooling structure for high-power medium frequency transformer (MFT) design, which is successfully applied in a medium voltage solid state transformer. Experimental results demonstrate that this design achieves high power density, partial discharge inception voltage, and superior thermal performance at 100 kW output power.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Automation & Control Systems
Saleh Farzamkia, Houshang Salimian Rizi, Alex Q. Huang, Hossein Iman-Eini
Summary: This article proposes a shared redundancy strategy for improving the reliability and useful lifetime of the modular multilevel converter (MMC) by allowing the flexible utilization of redundant submodules (RSMs) in both upper and lower arms. Simulation and experimental results confirm the effectiveness of this strategy in enhancing the reliability and fault-tolerant capability of MMC.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Automation & Control Systems
Tianxiang Chen, Ruiyang Yu, Alex Q. Huang
Summary: This article introduces a new approach called single-stage series resonant dual-active-bridge (SR-DAB) for grid-connected bidirectional ac-dc energy storage applications. The SR-DAB is connected to the grid with an unfolding bridge on the ac side, and three SR-DABs are used to connect to a three-phase grid. A control scheme that combines dual-phase shifts and variable frequency is proposed to achieve zero voltage switching and power factor correction. A series of comparisons are conducted to prove the advantage of the proposed converter over traditional ones. A GaN-based hardware prototype is developed with a peak efficiency of 97.2%.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Proceedings Paper
Energy & Fuels
Zerui Dong, Luc-Andre Gregoire, Vishnu N. Vipin, Sudipta Chakraborty, Ao Sun, Adithyan Vetrivelan, Xianyong Feng, Alex Q. Huang
Summary: Silicon-carbide based, multi-level converters with dual-active-bridge (DAB) are gaining attention for medium voltage, direct grid-connected, utility-scale photovoltaic (PV) applications due to their higher efficiency and power density. Hardware-in-the-loop techniques are often required to de-risk complex control development for high-voltage and high-power inverters. Real-time simulation tools for higher frequency converters are still in development, but a new co-simulation approach in FPGA can achieve real-time simulation for higher frequency converters.
2021 IEEE 12TH INTERNATIONAL SYMPOSIUM ON POWER ELECTRONICS FOR DISTRIBUTED GENERATION SYSTEMS (PEDG)
(2021)
