No description available.

Developments in automotive (particularly hybrid electric vehicles), aerospace, and energy production industries over the recent years have led to expanding research interest in integrated circuit (IC) design toward high-temperature applications. A high-voltage, high-temperature SOI process allows for circuit design to expand into these extreme environment applications. Nearly all electronic devices require a reliable supply voltage capable of operating under various input voltages and load currents. These input voltages and load currents can be either DC or time-varying signals. In this work, a stable supply voltage for embedded circuit functions is generated on chip via a voltage regulator circuit producing a stable 5-V output voltage. Although applications of this voltage regulator are not limited to gate driver circuits, this regulator was developed to meet the demands of a gate driver IC. The voltage regulator must provide reliable output voltage over an input range from 10 V to 30 V, a temperature range of −50 ºC to 200 ºC, and output loads from 0 mA to 200 mA. Additionally, low power stand-by operation is provided to help reduce heat generation and thus lower operating junction temperature. This regulator is based on the LM723 Zener reference voltage regulator which allows stable performance over temperature (provided proper design of the temperature compensation scheme). This circuit topology and the SOI silicon process allow for reliable operation under all application demands. The designed voltage regulator has been successfully tested from −50 ºC to 200 ºC while demonstrating an output voltage variation of less than 25 mV under the full range of input voltage. Line regulation tests from 10 V to 35 V show a 3.7-ppm/V supply sensitivity. With the use of a high-temperature ceramic output capacitor, a 5-nsec edge, 0 to 220 mA, 1-µsec pulse width load current induced only a 55 mV drop in regulator output voltage. In the targeted application, load current pulse widths will be much shorter, thereby improving the load transient performance. Full temperature and input voltage range tests reveal the no-load supply current draw is within 330 µA while still providing an excess of 200 mA of load current upon demand.

Developments in automotive (particularly hybrid electric vehicles), aerospace, and energy production industries over the recent years have led to expanding research interest in integrated circuit (IC) design toward high-temperature applications. A high-voltage, high-temperature SOI process allows for circuit design to expand into these extreme environment applications. Nearly all electronic devices require a reliable supply voltage capable of operating under various input voltages and load currents. These input voltages and load currents can be either DC or time-varying signals. In this work, a stable supply voltage for embedded circuit functions is generated on chip via a voltage regulator circuit producing a stable 5-V output voltage. Although applications of this voltage regulator are not limited to gate driver circuits, this regulator was developed to meet the demands of a gate driver IC. The voltage regulator must provide reliable output voltage over an input range from 10 V to 30 V, a temperature range of −50 ºC to 200 ºC, and output loads from 0 mA to 200 mA. Additionally, low power stand-by operation is provided to help reduce heat generation and thus lower operating junction temperature. This regulator is based on the LM723 Zener reference voltage regulator which allows stable performance over temperature (provided proper design of the temperature compensation scheme). This circuit topology and the SOI silicon process allow for reliable operation under all application demands. The designed voltage regulator has been successfully tested from −50 ºC to 200 ºC while demonstrating an output voltage variation of less than 25 mV under the full range of input voltage. Line regulation tests from 10 V to 35 V show a 3.7-ppm/V supply sensitivity. With the use of a high-temperature ceramic output capacitor, a 5-nsec edge, 0 to 220 mA, 1-µsec pulse width load current induced only a 55 mV drop in regulator output voltage. In the targeted application, load current pulse widths will be much shorter, thereby improving the load transient performance. Full temperature and input voltage range tests reveal the no-load supply current draw is within 330 µA while still providing an excess of 200 mA of load current upon demand.

Les travaux de thèse portent sur la conception et la réalisation d'un circuit intégré de commande rapprochée générique pour les transistors à grille isolée comme les MOSFETs et les IGBTs dans les structures de conversion d'énergie de l'électronique de puissance. L'objectif principal est de concevoir un système de commande simple à mettre en oeuvre, compact et configurable pouvant servir un panel varié d'applications dites multi-transistors. Le mémoire de thèse se structure en quatre chapitres : état de l'art de la commande rapprochée des transistors à grille isolée, présentation et validation d'une nouvelle topologie de commande rapprochée à base de transformateur d'impulsion, présentation et validation d'une version améliorée pour travailler à large spectre de fréquence et de rapport cyclique, conception et validation du driver intégré générique. Les champs d'application de ce concept du driver sont multiples, celui-ci favorise la simplicité de la conception et de la mise en oeuvre des système de commande pour l'électronique de puissance. / The thesis work focuses on the design and the implementation of a generic integrated gate driver circuit for power transistors such as MOSFETs and IGBTs in power conversion structure. The main objective is to design a control system which is simple to implement, compact and can be configurable to serve several multi-transistors applications. The thesis is structured into four chapters: state of the art of the gate driver for power transistor, presentation and validation of a new gate driver topology based on pulse transformer, presentation and validation of an upgraded version enable to work with wider range of frequency and duty cycle, design and validation of a generic integrated driver. The fields of application of this driver concept are multiples; it promotes the simplicity of the design and implementation of control system for power electronics.

No description available.

With the increasing maturity and flexibility of power electronics-based voltage conversion techniques, DC grids, and distribution systems have gained significant interest. These systems offer advantages such as improved power quality, efficiency, and flexibility. Medium-voltage DC (MVDC) applications, including shipboard, railway systems, distribution networks, and microgrids, are emerging as critical areas of interest. To integrate MVDC systems with existing power grids, MV AC/DC conversion techniques are crucial. Moreover, the lack of mature protection strategies and equipment, particularly DC circuit breakers (DCCB), poses a significant challenge to the development of MVDC systems. Therefore, this thesis aims to address two primary challenges in the field: the improved topologies of MV AC/DC conversion techniques for interfacing MVDC systems with power grids and the development of high power density DCCB for MVDC systems. The traditional modular multilevel converter (MMC) is widely used for medium voltage (MV) AC/DC conversion due to its modularity, scalability, and reliability. However, the presence of numerous semiconductor devices and capacitors in MMCs results in challenges such as low power efficiency and density. To enhance the performance of MMCs, this thesis proposes several novel hybrid MMC (HMMC) topologies, including the three-level HMMC, flying capacitor HMMC, and hybrid-leg MMC. These topologies aim to leverage the advantages of both conventional multilevel converters and MMCs. By replacing the low-voltage (LV) submodule (SM) in MMCs with a simple high-voltage (HV) switch, higher efficiency, a smaller footprint, and lower cost can be achieved. The HV switch operates at line frequency, simplifying device-switching and addressing the challenges of series-connected devices. The introduction of additional HV switches enables alternative connections compared to traditional MMCs, reducing the number of required SMs. Consequently, there is a significant reduction in the number of semiconductor devices, capacitor energy storage, and power losses. Furthermore, an average model is developed for the three-level HMMC to illustrate the additional power flow path between the AC and DC sides, as well as the reduced SM capacitor energy storage requirement. As a result, the proposed HMMCs exhibit substantial potential to replace traditional MMCs, offering higher efficiency and power density. Unidirectional high-voltage (HV) and medium-voltage (MV) rectifiers are essential for applications where power flows exclusively from the AC to the DC side. Examples of such applications include HVDC transmission, front-end converters for electric vehicle (EV) charging stations, and data centers. Therefore, hybrid modular multilevel rectifiers (HMMRs) are proposed for these unidirectional AC/DC applications. Instead of utilizing active devices for HV switches, the HMMR employs HV diode to achieve step-up HMMR, step-down HMMR, and flying capacitor HMMR configurations. As diodes are passive devices that do not require gate driver units, the HMMR design becomes simpler, resulting in cost and volume savings. Additionally, voltage sharing among the HV diode stack becomes more manageable as concerns regarding gate signal mismatch are eliminated. However, it is important to note that diodes lack current interruption capability. This limitation requires further investigation, particularly in non-unity power factor (PF) operations, which may impose restrictions on the operational range of the rectifiers. In terms of medium voltage (MV) DC circuit breakers (DCCB), this paper introduces the concept and design procedure of a high-power-density, modular, and scalable power electronic interrupter (PEI) for MV hybrid circuit breakers (HCB). The analysis includes trade-offs and limiting factors of various components within a single PEI module. A prototype of a 12 kV, 1 kA breaking-capable PEI is constructed, and new staged turn-off strategies are proposed to ensure the balanced distribution of metal-oxide varistor (MOV) energy. The developed PEI achieves a peak power density of 7.4 kW/cm$^3$, much higher than the solution based on the IGBT modules. After integrating the developed PEI into a full-scale HCB, the breaking capability of the developed PEI and the effectiveness of the staged turn-off strategy are validated. Furthermore, the scalability of the HCB is evaluated, which can simplify the design process from a low-voltage HCB to a higher-voltage version. For series-connected devices in SSCB or HCB configurations, the conventional gate driver structure necessitates an individual gate driver unit, fiber-optic, and isolated power supplies for each device. This design increases cost and volume, particularly for this single-pulse application. To address this issue, two new single gate driver structures are proposed to reduce component count and system complexity. The first solution, namely the MOV-coupled structure, employs a metal-oxide varistor (MOV) for the turn-off path. On the other hand, the transformer-coupled structure combines the auxiliary power and gate signal, enabling both simultaneous and staged turn-off schemes. Moreover, the cascaded high- and lower-voltage transformer structure simplifies insulation design and demonstrates improved scalability. These proposed gate driver structures aim to streamline the system, reduce component numbers, and simplify control for series-connected devices, leading to cost savings and improved overall performance. / Doctor of Philosophy / The advent of modern power electronics has paved the way for the implementation of medium-voltage (MV) DC systems, which offer advantages such as improved power quality, efficiency, and flexibility. However, the development of advanced AC/DC power conversion techniques and MVDC distribution system equipment, particularly MV DC circuit breakers (DCCBs), poses significant challenges for future MVDC systems. While the modular multilevel converter (MMC) is considered one of the best solutions, it suffers from a large number of devices and submodules (SMs). To overcome this limitation, novel topology concepts are introduced by combining high-voltage (HV) switches with low-voltage SMs, which leverage the benefits of both MMC and conventional multilevel converters. Several Hybrid MMC (HMMC) topologies, such as the three-level HMMC, flying capacitor HMMC, and hybrid-leg MMC, have been proposed. The introduction of additional HV switches enables different configurations over one line cycle, reducing the number of SMs and achieving higher power density and efficiency compared to the traditional MMC. Moreover, for unidirectional power flow, the hybrid modular multilevel rectifiers (HMMRs) can be derived by replacing the HV switch with HV diodes. This modification further reduces cost and volume compared to bidirectional converters. However, the non-unity power factor operation is different from the HMMC version, and more investigation is carried out in this work. As for MV DCCBs, the concept and design procedure of a compact, modular, and scalable power electronic interrupter (PEI) for MV hybrid circuit breakers (HCBs) are discussed. Additionally, two single gate driver structures are proposed to simplify the gate driver design, leading to a significant reduction in component count and cost. These advancements in topology solutions, MV DCCBs, and gate driver structures hold promise for the development of efficient and cost-effective MVDC systems.

Conventional wire bond power modules have limited application for high-current operation, mainly because of their poor thermal management capability. Planar power modules have excellent thermal management capability and lower parasitic inductance, which means that the planar packaging method is desirable for high-power applications. For these reasons, a planar power module for an automotive motor drive system was developed, and a gate-driver circuit with an over-current protection was planned to integrate into the module. This thesis discusses a current-sensing method for the planar module, and the integrated gate driver circuit with an over-current protection. After reviewing several current-sensing methods, it becomes clear that most popular current-sensing methods, such as the Hall-Effect sensor, the current transformer, the Shunt resistor, and Rogowski coils, exhibit limitations for the planar module integration. For these reasons, a giant magneto resistive (GMR) magnetic-field detector was chosen as a current-sensing method. The GMR sensor utilizes the characteristics of the giant magneto resistive (GMR) effect in that it changes its resistance when it is exposed to the magnetic-flux. Because the GMR resistor can be fabricated at the wafer level, a packaged GMR sensor is very compact when compared with conventional current sensors. In addition, the sensor detects magnetic-fields, which does not require direct contact to the current-carrying conductor, and the bandwidth of the sensor can be up to 1 MHz, which is wide enough for the switching frequencies of most of motor drive applications. However, there are some limiting factors that need to be considered for accurate current measurement: • Operating temperature • Magnetic-flux density seen by a GMR resistor • Measurement noise If the GMR sensor is integrated into the power module, the ambient temperature of the sensor will be highly influenced by the junction temperature of the power devices. Having a consistent measurement for varying temperature is important for module-integrated current sensors. An experiment was performed to see the temperature characteristics of a GMR sensor. The measurement error caused by temperature variation was quantified by measurement conditions. This thesis also proposes an active temperature error compensation method for the best use of the GMR sensor. The wide current trace of the planar power module helps to reduce the electrical/thermal resistance, but it hinders having a strong and constant magnetic-field-density seen by the GMR sensor. In addition, the eddy-current effect will change the distribution of the current density and the magnetic-flux-density. These changes directly influence the accurate measurement of the GMR sensor. Therefore, analyzing the magnetic-flux distribution in the planar power module is critical for integrating the GMR sensor. A GMR sensor is very sensitive to noise, especially when it is sensing current flowing in a wide trace and exposed to external fields, neither of which can be avoided for the operation of power modules. Post-signal processing is required, and the signal-conditioning circuit was designed to attenuate noise. The signal-conditioning circuit was designed using an instrumentation amplifier, and the circuit attenuated most of the noise that hindered accurate measurement. The over-current protection circuit along with the gate driver circuit was designed, and the concept was verified by experiments. The main achievements of this study can be summarized as: • Characterization of conventional current-sensing methods • Temperature characterization of the GMR resistor • Magnetic-flux distribution of the planar power module • Design of the signal-conditioning circuit and over-current protection circuit / Master of Science

The wide-bandgap (WBG) devices, like gallium nitride (GaN) and silicon carbide (SiC) devices have proven to be a driving force of the development of the power conversion technology. Thanks to their distinct advantages over silicon (Si) devices including the faster switching speed and lower switching losses, WBG-based power converter can adopt a higher switching frequency and pursue higher power density and higher efficiency. As a trade-off of the advantages, there also exist the high-frequency-oriented challenges in the adoption of the GaN HEMT under research, including narrow safe gate operating area, increased switching overshoot, increased electromagnetic interference (EMI) in the gate loop and the power stages, the lack of the modules of packages for high current application, high gate oscillation under parallel operation. The dissertation is developed to addressed the all the challenges above to fully explore the potential of the GaN HEMTs. Due to the increased EMI emission in the gate loop, a small isolated capacitor in the gate driver power supply is needed to build a high-impedance barrier in the loop to protect the gate driver from interference. A 2 W dual-output gate driver power supply with ultra-low isolation capacitor for 650 V GaN-based half bridge is presented, featuring a PCB-embedded transformer substrate, achieving 85% efficiency, 1.6 pF isolation capacitor with 72 W/in3 power density. The effectiveness of the EMI reduction using the proposed power supply is demonstrated. The design consideration to build a compact 650 V GaN switching cell is presented then to address the challenges in the PCB layout and the thermal management. With the switching cell, a compact 1 kW 400 Vdc three-phase inverter is built and can operate with 500 kHz switching frequency. With the inverter, the high switching frequency effects on the inverter efficiency, volume, EMI emission and filter design are assessed to demonstrate the tradeoff of the adoption of high switching frequency in the motor drive application. In order to reduce the inverter CM EMI emission above 10 MHz, an active gate driver for 650 V GaN HEMT is proposed to control the dv/dt during turn-on and turn-off independently. With the control strategy, the penalty from the switching loss can be reduced. To build a high current power converter, paralleling devices is a normal approach. The dissertation comes up with the switching cell design using paralleled two and four 650 V GaN HEMTs with minimized and symmetric gate and power loop. The commutation between the paralleled HEMTs is analyzed, based on which the effects from the passive components on the gate oscillation are quantified. With the switching cell using paralleled GaN HEMTs, a 10 kW LLC resonant converter with the integrated litz-wire transformer is designed, achieving 97.9 % efficiency and 131 W/in3 power density. The design consideration to build the novel litz-wire transformer operated at 400 kHz switching frequency is also presented. In all, this work focuses on providing effective solutions or guidelines to adopt the 650 V GaN HEMT in the high frequency, high power density, high efficiency power conversion and demonstrates the advance of the GaN HEMTs in the hard-switched and soft-switched power converters. / Ph. D. / Silicon (Si) -based power semiconductor has developed several decades and achieved numerous outstanding performances, contributing a fast development of the power electronics. While the theatrical limit of the silicon semiconductor is almost reached limiting the progress speed to purse the high-efficiency, high-density high-reliability power conversion, the new material, including gallium-nitride (GaN) and silicon-carbide (SiC), based semiconductor, becomes the driven force to retain the development. Compared with Si-based device, GaN and SiC device own a faster switching speed and a lower on-resistance, enabling the adoption of high switching frequency and the possibility to increase the efficiency, power density and dynamic response. The GaN-based semiconductor is explored to be an even promising game changer than SiC device thanks to a higher theoretical ceiling. However, to adopt GaN-based semiconductors and fully utilize its benefits with high switching frequency, there are numerous high-frequency-oriented challenges, including high frequency oscillation at device termination, increased electromagnetic interference (EMI), the lack of the modules of packages for high current application, high frequency oscillation under parallel operation. The dissertation is developed to address the key high-frequency-oriented challenges to adopt GaN-based semiconductors in the power conversion and come up with the novel design strategy and analysis for high-switching-frequency power conversion using GaN devices. To the reduce the increased EMI emission in the gate loop, a novel PCB-embedded transformer structure is proposed to maintain a low isolation capacitor in the gate driver power supply for the GaN phase leg. With the proposed technique, the dual-output gate driver power supply can achieve high efficiency (85%), ultra-low isolation capacitor (1.6 pF) with high power density (72 W/in³ ). To reduce the high frequency oscillation at the GaN device termination, the strategy to layout GaN devices and its gate driver is proposed with corresponding thermal management. A compact structure for three-phase inverter is then presented, operating with a very high switching frequency (500 kHz). Within the inverter, the high switching frequency effects on the inverter performances are assessed to demonstrate the tradeoff and bottle neck to adopt high switching frequency in the motor drive application. In order to reduce the inverter EMI emission at high frequency ( >10 MHz), an active gate driver for GaN device is proposed for the active dv/dt control strategy. To build a high current power converter, the strategy to parallel GaN devices is proposed in the dissertation with the analysis on the commutation between the paralleled GaN devices. A high-frequency high-current litz-wire transformer structure for LLC resonant converter is presented with modeling and optimization. With the technique, a 10 kW LLC resonant converter achieves high efficiency (97.9 %) and high power density (131 W/in³).

With a higher power rating and broader application, Gallium nitride (GaN) is a promising next-generation power switch. The current four GaN HEMTs in paralleled phase leg that can block 400 V and conduct 200 A current is very beneficial, thus making the protection method on a GaN phase leg an urgent topic. This thesis starts with an overview of shortcircuit robustness among silicon (Si), silicon carbide (SiC) and GaN devices. An approximately safe operation area (SOA) for a GaN power switch will also be determined. The various common shortcircuit protection methods are mentioned. Additionally, current research on a GaN semiconductor is summarized. Among all of the protection methods, desaturation detection is selected and analyzed through simulation and then implemented in a parallel enhancement-mode high-electron-mobility transistor (E-HEMT) GaN phase leg. With this desaturation detection feature, the GaN E-HEMT can be turned off as quickly as 200 ns, and in the worst case, 500 ns, during a shortcircuit test. The phase leg survived a series of shortcircuit tests with shortcircuit protection. For the proposed protection scheme, the best-case reaction time (200 ns) is similar to others in the literature, while the shortcircuit peak current and peak energy are higher. The worst-case performance of this design is limited by both the gate driver and the device shortcircuit robustness. Due to the fast switching speed of the GaN HEMT, the false turn-on phenomenon caused by the Miller effect can be a problem. A shoot through may occur with one switch false turn on. The Miller clamp is added to the phase leg to improve its reliability. After the hardware was implemented, the Miller clamp was tested and verified through a double pulse test (DPT). Compared to the phase leg without the Miller clamp, the gate is better protected from gate voltage overshoot and undershoot. The switching loss is reduced by 20 percent by using a new gate driver IC with higher current driving capability. The degradation effect of GaN power switches in different shortcircuit pulses was also studied. The device passes through the shortcircuit tests, but any degradation effect that may change its parameters and influence its normal operation characteristic need to be addressed. Several GaN devices were selected and characterized after several shortcircuit tests to observe any degradation effect caused by the shortcircuit. The degradation test results reveal a "recovery effect" of the GaN HEMT used in this project. The parameter variations on threshold voltage and on-resistance recover to the original state, several hours after the shortcircuit test. The test results match with the conclusion drawn in degradation test conducts by other research groups that the parameter variation during shortcircuit test is negligible. Also, repetitively fast shortcircuit tests on the GaN HEMT show that the shortcircuit protection limit for this device under 400 V bus should be limited to 300 ns. / Master of Science

Due to the limitations of silicon (Si), there is a paradigm shift in research focusing on wide-bandgap-based (WBG) materials. SiC power semiconductors exhibit superiority in terms of switching speed, higher breakdown electric field, and high working temperature, slowly becoming a global solution in harsh medium-voltage (MV) high-power environments. However, to utilize the SiC MOSFET device to achieve those next-generation, high-density, high-efficiency power electronics converters, one must solve a plethora of challenges. For the MV SiC MOSFET device, a high-performance gate-driver (GD) is a key component required to maximize the beneficial SiC MOSFET characteristics. GD units must overcome associated challenges of electro-magnetic interference (EMI) with regards to common-mode (CM) currents and cross-talk, low driving loop inductance required for fast switching, and device short-circuit (SC) protection. Developed GDs (for 1.2 kV, and 10 kV devices) are able to sustain dv/dt higher than 100 V/ns, have less than 5 nH gate loop inductance, and SC protection, turning off the device within 1.5 us. Even with the introduction of SiC MOSFETs, power devices remain the most reliability-critical component in the converter, due to large junction temperature (Tj) fluctuations causing accelerated wear-out. Real-time (online) measurement of the Tj can help improve long-term reliability by enabling active thermal control, monitoring, and prognostics. An online Tj estimation is accomplished by generating integrated intelligence on the GD level. The developed Tj sensor exhibits a maximum error less than 5 degrees Celsius, having excellent repeatability of 1.2 degrees Celsius. Additionally, degradation monitoring and an aging compensation scheme are discussed, in order to maintain the accuracy of the sensor throughout the device's lifetime. Since ultra high-voltage SiC MOSFET devices (20 kV) are impractical, the modular multilevel converter (MMC) emerged as a prospective topology to achieve MV power conversion. If the kernal part of the power-cell (main constitutive part of the MMC converter) is an SiC MOSFET, the design is able to achieve very high-density and high-efficiency. To ensure a successful operation of the power-cell, a systematic design and assessment methodology (DAM) is explored, based on the 10 kV SiC MOSFET power-cell. It simultaneously addresses challenges of high-voltage insulation, high dv/dt and EMI, component and system protections, as well as thermal management. The developed power-cell achieved high-power density of 11.9 kW/l, with measured peak efficiency of n=99.3 %@10 kHz. It successfully operated at Vdc=6 kV, I=84 A, fsw>5 kHz, Tj<150 degrees Celsius and had high switching speeds over 100 V/ns. Lastly, to achieve high-power density and high-efficiency on the MV converter level, challenges of high-voltage insulation, high-bandwidth control, EMI, and thermal management must be solved. Novel switching cycle control (SCC) and integrated capacitor blocked-transistor (ICBT) control methodologies were developed, overcoming the drawbacks of conventional MMC control. These novel types of control enable extreme reduction in passive component size, increase the efficiency, and can operate in dc/dc, dc/ac, mode, potentially opening the modular converter to applications in which it was not previously used. In order to explore the aforementioned benefits, a modular, scalable, 2-cell per arm, prototype MV converter based on the developed power-cell is constructed. The converter successfully operated at Vdc=12 kV, I=28 A, fsw=10 kHz, with high switching speeds, exhibiting high transient immunity in both SCC and ICBT. / Doctor of Philosophy / In medium-voltage applications, such as an electric grid interface in highly populated areas, a ship dc system, a motor drive, renewable energy, etc., land and space can be very limited and expensive. This requires the attributes of high-density, high-efficiency, and reliable distribution by a power electronics converter, whose central piece is the semiconductor device. With the recent breakthrough of SiC devices, these characteristics are obtainable, due to SiC inherent superiority over conventional Si devices. However, to achieve them, several challenges must be overcome and are tackled by this dissertation. Firstly, as a key component required to maximize the beneficial SiC MOSFET characteristics, it is of utmost importance that the high-performance gate-driver be immune to interference issues caused by fast switching and be able to protect the device against a short-circuit, thus increasing the reliability of the system. Secondly, to prevent accelerated degradation of the semiconductor devices due to high-temperature fluctuations, real-time (online) measurement of the Tj is developed on the gate-driver to help improve long-term reliability. Thirdly, to achieve medium-voltage high-power density, high-efficiency modular power conversion, a converter block (power-cell) is developed that simultaneously addresses the challenges of high-voltage insulation, high interference, component and system protections, and thermal management. Lastly, a full-scale medium-voltage modular converter is developed, exploiting the advantages of the fast commutation speed and high switching frequency offered by SiC, meanwhile exhibiting exceptional power density and efficiency.