This paper presents an overview of the synchronization stability of converter-based resources under a wide range of grid conditions. The general grid-synchronization principles for grid-following and grid-forming modes are reviewed first. Then, the small-signal and transient stability of these two operating modes are discussed, and the design-oriented analyses are performed to illustrate the control impact. Lastly, perspectives on the prospects and challenges are shared.

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Grid-Synchronization Stability of Converter-Based Resources - An Overview

Wide bandgap (WBG) device-based power electronics converters are more efficient and lightweight than silicon-based converters. WBG devices are an enabling technology for many motor drive applications and new classes of compact and efficient motors. This paper reviews the potential applications and advances enabled by WBG devices in ac motor drives. Industrial motor drive products using WBG devices are reviewed, and the benefits are highlighted. This paper also discusses the technical challenges, converter design considerations, and design tradeoffs in realizing the full potential of WBG devices in motor drives. There is a tradeoff between high switching frequency and other issues such as high dv/dt and electromagnetic interference. The problems of high common mode currents and bearing and insulation damage, which are caused by high dv/dt , and the reliability of WBG devices are discussed.

Wide Bandgap Devices in AC Electric Drives: Opportunities and Challenges

Driving solutions for power semiconductor devices are experiencing new challenges since the emerging wide bandgap power devices, such as silicon carbide (SiC), with superior performance become commercially available. Generally, high switching speed is desired due to the lower switching loss, yet high $dv/dt$ and $di/dt$ can result in elevated electromagnetic interference (EMI) emission, false-triggering, and other detrimental effects during switching transients. Active gate drivers (AGDs) have been proposed to balance the switching losses and the switching speed of each switching transient. The review of the in-existence AGD methodologies for SiC devices has not been reported yet. This review starts with the essence of the slew rate control and its significance. Then, a comprehensive review categorizing the state-of-the-art AGD methodologies is presented. It is followed by a summary of the AGDs control and timing strategies. In this work, using AGD to reduce the EMI noise of a 10-kV SiC MOSFET system is reported. This work also highlights other capabilities of AGDs, including reliability enhancement of power devices and rebalancing the mismatched electrical parameters of parallel- and series-connected devices. These application scenarios of AGDs are validated via simulation and experimental results.

A Review of Switching Slew Rate Control for Silicon Carbide Devices Using Active Gate Drivers

Along with the increasing maturity for the material and process of the wide bandgap semiconductor silicon carbide (SiC), the insulated gate bipolar transistor (IGBT) representing the top level of power devices could be fabricated by SiC successfully This article presents a thorough review of development of SiC IGBT in the past 30 years The progresses of models, structure design, and performance in SiC IGBT are summarized The challenges resulting from fabrication process and switching characteristics are discussed and analyzed in detail The experimental results and existing problems in SiC IGBT-based applications are summarized in the end

A Review of SiC IGBT: Models, Fabrications, Characteristics, and Applications

With features such as faster switching frequency and higher breakdown voltage, wide bandgap power devices are key enablers to address the increasing demand for higher power density and higher efficiency in future medium-voltage converters. The 10-kV SiC MOSFET is one of such devices; yet, to fully utilize its benefits, a gate-drive power supply capable of meeting the necessary insulation (voltage) and isolation ( dv/dt voltage slew rate) requirements is needed. To this end, this article presents the complete design and optimization of such a power supply meeting four critical objectives: 1) high power density with high-voltage (HV) insulation; 2) minimum input–output capacitance; 3) fault ride-through capability; and 4) good voltage regulation. To this end, a GaN-based inductor-capacitor-capacitor-inductor (LCCL)- LC resonant converter switching at 1 MHz was used to produce a resonant current source and to supply multiple isolated loads (gate-drivers) through the single-turn primary winding loop. Experimental results are shown demonstrating the attained power density (6.3 W/in3), input–output capacitance (1.67 pF), peak efficiency (86.0%), short- and open-circuit fault withstanding capacity, and insulation rating (partial discharge inception voltage of 12 kV).

High-Density Current-Transformer-Based Gate-Drive Power Supply With Reinforced Isolation for 10-kV SiC MOSFET Modules

Medium-voltage (MV) silicon carbide (SiC) devices have opened up new areas of applications which were previously dominated by silicon-based IGBTs From the perspective of a power converter design, the development of MV SiC devices eliminates the need for series connected architectures, control of multilevel converter topologies which are necessary for MV applications, and the inherent reliability issues associated with it However, when SiC devices are used in these applications, they are exposed to a high peak stress (5–10 kV) and a very high $dv/dt$ (10–100 kV/ $\mu$ s) Using these devices calls for a gate driver with a dc–dc isolation stage that has ultralow coupling capacitance in addition to be able to withstand the high isolation voltage This paper presents a new MV gate driver design to address these issues while maintaining a minimal footprint for the gate driver An MV isolation transformer is designed with a low interwinding capacitance, while maintaining the clearance, creepage, as well as insulation standards A dc isolation test has been performed to validate the integrity of the insulating material The key features include low input common mode current, and a short-circuit protection scheme specifically designed for 10 kV SiC mosfet s The performance of the gate driver is evaluated using double pulse tests and continuous tests Experimental results validate the advantages of the gate driver and its application for MV SiC devices exhibiting very high $dv/dt$  The proposed gate driver concept is aimed at providing an efficient and reliable method to drive MV SiC devices

Design Considerations and Development of an Innovative Gate Driver for Medium-Voltage Power Devices With High $dv/dt$

For high power medium voltage (MV) grid connected applications LCL filter proves to be an attractive solution to filter out the current harmonics when compared to $L$ or LC filters. The inductance requirement reduces drastically to meet the same Total Harmonic Distortion (THD) standards for grid connections for LC L filters compared to $L$ filter which makes the system dynamics much faster. The increasing use of Silicon Carbide (SiC) based power devices for MV applications has made the effects of the parasitic elements in the filter more prominent, due to the high dv / dt experienced by the passive filter elements during device switching transients. This paper addresses the issues associated with the high dv / dt experienced by the LC L filters for SiC-based MV applications. In order to study these effects, the parasitic elements of the inductor are modeled and analyzed. A suitable solution is proposed to improve the overall system performance. The effect of high dv / dt on the filter and the effectiveness of the proposed solution are validated using simulation. Experimental data is also provided to validate the proposed concept.

Practical Design Considerations for MV LCL Filter Under High dv/dt Conditions Considering the Effects of Parasitic Elements

A conventional transformer can withstand multiple electrical, mechanical and thermal faults which enables it to have a long lifetime. However, its inability to control the power flow through it has led researchers to look for alternate options such as the solid-state transformers. With the Silicon Carbide (SiC) semiconductor devices, it is now possible to go to high switching frequencies in medium voltage applications, which helps in reducing the overall size and weight of the transformer. The advent of medium voltage (MV) SiC devices has enabled the use of simple two-level and three-level topologies for medium voltage power transfer. This paper discusses a basic power topology for a medium voltage mobile utilities support equipment based solid state transformer (MUSE-SST) with the new 10 kV SiC MOS-FETs. A design of the MUSE-SST is presented followed by some of the practical considerations that needs to be taken, including gate driver design and heat sink configurations. Simulation results for a 100 kW, MV MUSE SST system is presented. Experimental results are provided validating the operation of these 10 kV devices in double pulse tests, buck and boost operation. This research helps in providing an overview regarding the usage of the 10 kV SiC devices in grid-interconnection and also discusses various challenges that comes along with it.

Design of a Medium Voltage Mobile Utilities Support Equipment based Solid State Transformer (MUSE-SST) with 10 kV SiC MOSFETs for Grid Interconnection

With the increasing maturity of Silicon Carbide (SiC) semiconductor devices at medium voltage (MV) level, high switching frequencies and low conduction losses in MV applications is possible. Higher switching frequency operation enables the reduction in size and weight of transformers. In an application such as MV-MV or MV-LV grid-interconnection, a solid state transformer offers a multitude of advantages compared to conventional transformers. A reduction in size and weight, in addition to having active and reactive power flow control have made SSTs a lucrative replacement to conventional low frequency (LF) transformers. Lower conduction losses exhibited by SiC devices (as compared to their silicon counterparts) have made it possible to achieve similar efficiencies as compared to conventional LF transformers. This paper aims at providing an overview of a MV MUSE-SST topology. A brief idea on control and monitoring is also provided. Practical design considerations that are required to build a MV system is provided to aid researchers in designing converters for MV applications. The protection aspects of the MV MUSE-SST system is also highlighted. Basic experimental results for the gate driver is also shown. Initial testing results with the Gen3 10 kV SiC MOSFETs and the challenges associated with it are also discussed. This research aims at being a building block for implementation and testing of the medium voltage converter systems.

Mobile Utility Support Equipment based Solid State Transformer (MUSE-SST) for MV Grid Interconnection with Gen3 10 kV SiC MOSFETs

An accurate measurement of switching losses in SiC MOSFETs is necessary in order to design and evaluate the thermal performance of modern converter systems. Conventionally, electrical measurement methods, such as the double-pulse test (DPT) are used for calculating the hard-switching losses. However, with the advent of wide-bandgap devices, which have fast switching transients, it is rather difficult to capture the waveforms accurately during switching transitions, and consequently the measurement of switch loss suffers. This paper presents an accurate calorimetric method for measuring the switching losses. The conventional calorimetric measurement methods can accurately measure the device losses. However, the segregation of the conduction, turn-on and turn-off loss is not possible. This paper addresses this issue and proposes a method that can be used to determine individual loss components. The calorimetric test setup is described and a novel modulation scheme is introduced which enables the separation of turn-on and turn-off switching losses. The experimental test setup has been built and the method has been verified by measuring the losses of a Wolfspeed CMF10120D device.

Yos Prabowo

Papers

Design Considerations and Development of an Innovative Gate Driver for Medium-Voltage Power Devices With High $dv/dt$

Practical Design Considerations for MV LCL Filter Under High dv/dt Conditions Considering the Effects of Parasitic Elements

Design of a Medium Voltage Mobile Utilities Support Equipment based Solid State Transformer (MUSE-SST) with 10 kV SiC MOSFETs for Grid Interconnection

Mobile Utility Support Equipment based Solid State Transformer (MUSE-SST) for MV Grid Interconnection with Gen3 10 kV SiC MOSFETs

An accurate calorimetrie method for measurement of switching losses in silicon carbide (SiC) MOSFETs