Showing papers on "Power module published in 2020"

A Review of SiC Power Module Packaging Technologies: Challenges, Advances, and Emerging Issues

Abstract: Power module packaging technologies have been experiencing extensive changes as the novel silicon carbide (SiC) power devices with superior performance become commercially available. This article presents an overview of power module packaging technologies in this transition, with an emphasis on the challenges that current standard packaging face, requirements that future power module packaging needs to fulfill, and recent advances on packaging technologies. The standard power module structure, which is a widely used current practice to package SiC devices, is reviewed, and the reasons why novel packaging technologies should be developed are described in this article. The packaging challenges associated with high-speed switching, thermal management, high-temperature operation, and high-voltage isolation are explained in detail. Recent advances on technologies, which try to address the limitations of standard packaging, both in packaging elements and package structure are summarized. The trend toward novel soft-switching power converters gave rise to problems regarding package designs of unconventional module configuration. Potential applications areas, such as aerospace applications, introduce low-temperature challenges to SiC packaging. Key issues in these emerging areas are highlighted.

Review of Packaging Schemes for Power Module

Abstract: SiC devices are promising for outperforming Si counterparts in high-frequency applications due to its superior material properties. Conventional wirebonded packaging scheme has been one of the most preferred package structures for power modules. However, the technique limits the performance of a SiC power module due to parasitic inductance and heat dissipation issues that are inherent with aluminum wires. In this article, low parasitic inductance and high-efficient cooling interconnection techniques for Si power modules, which are the foundation of packaging methods of SiC ones, are reviewed first. Then, attempts on developing packaging techniques for SiC power modules are thoroughly overviewed. Finally, scientific challenges in the packaging of SiC power module are summarized.

10-kV SiC MOSFET Power Module With Reduced Common-Mode Noise and Electric Field

Abstract: The advancement of silicon carbide (SiC) power devices with voltage ratings exceeding 10 kV is expected to revolutionize medium- and high-voltage systems. However, present power module packages are limiting the performance of these unique switches. The objective of this research is to push the boundaries of high-density, high-speed, 10-kV power module packaging. The proposed package addresses the well-known electromagnetic and thermal challenges, as well as the prominent electrostatic and electromagnetic interference (EMI) issues associated with high-speed, 10-kV devices. The high-speed switching and high voltage rating of these devices causes significant EMI and high electric fields. Existing power module packages are unable to address these challenges, resulting in detrimental EMI and partial discharge that limit the converter operation. This article presents the design and testing of a 10-kV SiC mosfet power module that switches at a record 250 V/ns without compromising the signal and ground integrity due to an integrated screen reduces the common-mode current by ten times. This screen connection simultaneously increases the partial discharge inception voltage by more than 50%. With the integrated cooling system, the power module prototype achieves a power density of 4 W/mm3.

Automotive Power Module Packaging: Current Status and Future Trends

Abstract: Semiconductor power modules are core components of power electronics in electrified vehicles. Packaging technology often has a critical impact on module performance and reliability. This paper presents a comprehensive review of the automotive power module packaging technologies. The first part of this paper discusses the driving factors of packaging technology development. In the second section, the design considerations and a primary design process of module packaging are summarized. Besides, major packaging components, such as semiconductor dies, substrates, and die bonding, are introduced based on the conventional packaging structure. Next, technical details and innovative features of state-of-the-art automotive power modules from major suppliers and original equipment manufacturers are reviewed. Most of these modules have been applied in commercial vehicles. In the fourth part, the system integration concept, printed circuit board embedded packaging, three-dimensional packaging, press pack packaging, and advanced materials are categorized as promising trends for automotive applications. The advantages and drawbacks of these trends are discussed, and it is concluded that a preferable overall performance could be achieved by combining multiple technologies.

Design of a High-Efficiency, High Specific-Power Three-Level T-Type Power Electronics Building Block for Aircraft Electric-Propulsion Drives

Abstract: The electric propulsion drives for the more-electric aircraft need lightweight and high-efficiency power converters. Moreover, a modular approach to the construction of the drive ensures reduced costs, reliability, and ease of maintenance. In this article, the design and fabrication procedure of a modular dc–ac three-level t-type single phase-leg power electronics building block (PEBB) rated for 100-kW, 1-kV dc-link is reported for the first time. A hybrid switch (HyS) consisting of a silicon insulated-gate bipolar junction transistor (IGBT) and silicon carbide metal–oxide–semiconductor field-effect transistor (MOSFET) was used as an active device to enable high switching frequencies at high power. The topology and semiconductor selection were based on a model-based design tool for achieving high conversion efficiency and lightweight. Due to the unavailability of commercial three-level t-type power modules, a printed circuit board (PCB) and off-the-shelf discrete semiconductor-based high-power switch was designed for the neutral-point clamping. Also, a nontrivial aluminum-based multilayer laminated bus bar was designed to facilitate the low-inductance interconnection of the selected active devices and the capacitor bank. The measured inductance indicated symmetry of both current commutation loops in the bus bar and value in the range of 28–29 nH. The specific power and volumetric power density of the block were estimated to be 27.7 kW/kg and 308.61 W/in3, respectively. The continuous operation of the block was demonstrated at 48 kVA. The efficiency of the block was measured to be 98.2%.

Accurate Temperature Estimation of SiC Power mosfet s Under Extreme Operating Conditions

Abstract: Electrothermal modeling of silicon carbide (SiC) power devices is frequently performed to estimate the device temperature in operation, typically assuming a constant thermal conductivity and/or heat capacity of the SiC material. Whether and by how much the accuracy of the resulting device temperature prediction under these assumptions is compromised has not been investigated so far. Focusing on high-temperature operating conditions as found under short circuit (SC), this paper presents a comprehensive analysis of thermal material properties determining the temperature distribution inside SiC power mosfet s. Using a calibrated technology computer-aided design (TCAD) electrothermal model, it is demonstrated that the temperature prediction of SiC power devices under SC operation when neglecting either the top metallization or the temperature dependence of the heat capacity is inaccurate by as high as 25%. The presented analysis enables to optimize compact electrothermal models in terms of accuracy and computational time, which can be used to assess the maximum temperature of SiC power mosfet s in both discrete packages and multichip power modules exposed to fast thermal transients. A one-dimensional thermal network of a SiC power mosfet is proposed based on the thermal material properties, the size of the active area of the device, and its thickness.

Impact of Power Module Parasitic Capacitances on Medium-Voltage SiC MOSFETs Switching Transients

Abstract: Increased switching speeds of wide bandgap (WBG) semiconductors result in a significant magnitude of the displacement currents through power module parasitic capacitances that are inherent in packaging design. This is of increasing concern, particularly in case of newly emerging medium-voltage (MV) SiC MOSFETs since the magnitude of the displacement currents can be several order higher due to the fast switching transients and increased voltage magnitudes of the SiC MOSFETs compared to their Si counter parts. The severity intensifies when the magnitude of the displacement current becomes comparable to a significant fraction of SiC MOSFETs rated current, leading to the worsened impact on the converter electromagnetic interference (EMI) as well as performance in terms of switching losses. The key objective of this article is to provide a detail insight into the impact of the module parasitic capacitances on the SiC MOSFET switching dynamics and losses. To realize this, a well-defined approach to dissect the switching energy dissipation is proposed, based on which the detailed analysis and quantitative measurements of the module parasitic capacitance impact on terms of added switching energy losses, and common-mode currents are investigated using a custom-packaged 10-kV half-bridge SiC MOSFET power modules. The theoretical analysis and experimental results obtained from dynamic as well as static characterization reveal that the impact of the module parasitic capacitance on the switching energy dissipation is twofold and substantially adverse such that it cannot be overlooked considering its intended application in the high-power MV power electronic converters.

Estimation, Minimization, and Validation of Commutation Loop Inductance for a 135-kW SiC EV Traction Inverter

Abstract: With growing interests in low-inductance silicon carbide (SiC)-based power module packaging, it is vital to focus on system-level design aspects to facilitate easy integration of the modules and reap system-level benefits. To effectively utilize the low-inductance modules, busbar and interconnects should also be designed with low stray inductances. A holistic investigation of the flux path and flux cancellations in the module-busbar assembly, which can be treated as differentially coupled series inductors, is thus mandatory for a system-level design. This article presents a busbar design, which can be adopted to effectively integrate the CREE’s low-inductance 1.2-/1.7-kV SiC power modules. This article also proposes a novel measurement technique to measure the inductance of the module-busbar assembly as a whole rather than deducing it from individual components. The inductance of the overall commutation loop of the inverter that encompasses the SiC power module, interconnects, and printed circuit board (PCB) busbar has been estimated using finite-element analysis (FEA). Insights gained from FEA provided the guidelines to decide the placement of the decoupling capacitors in the busbar to minimize the overall commutation loop inductance from 12.8 to 7.4 nH, which resulted in a significant reduction in the device voltage overshoot. The simulation results have been validated through measurements using an impedance analyzer (ZA) with less than 5% difference between the extracted loop inductance from FEA and measurements. The busbar design study and the measurement technique discussed in this article can be easily extended to other power module packages. Finally, the 135-kW inverter has been compared to a similar high-power inverter utilizing a laminated busbar to highlight the performance of the former.

Design and Experimental Validation of a Wire-Bond-Less 10-kV SiC MOSFET Power Module

Abstract: Wide bandgap (WBG) power devices with voltage ratings exceeding 10 kV have the potential to revolutionize medium- and high-voltage systems due to their high-speed switching and lower ON-state losses. However, the present power module packages are limiting the performance of these unique switches. The objective of this article is to push the boundaries of high-density, high-speed, 10-kV power module packaging. The proposed package addresses the well-known electromagnetic and thermal challenges, as well as the more recent and prominent electrostatic and electromagnetic interference (EMI) issues associated with high-speed, 10-kV devices. The module achieves low and balanced parasitic inductances, resulting in a record switching speed of 250 V/ns with negligible ringing and voltage overshoot. An integrated screen reduces the common-mode (CM) current that is generated by these fast voltage transients by ten times. This screen connection simultaneously increases the partial discharge inception voltage (PDIV) by more than 50%. A compact, medium-voltage termination and system interface design is also proposed in this article. With the integrated jet-impingement cooler, the power module prototype achieves a power density of 4 W/mm3. This article presents the design, prototyping, and testing of this optimized package for 10-kV SiC MOSFETs.

Combined geometrical techniques and applying nonlinear field dependent conductivity layers to address the high electric field stress issue in high voltage high-density wide bandgap power modules

Abstract: Wide bandgap (WBG) power modules made from materials such as SiC and GaN (and soon Ga 2 O 3 and diamond), which can tolerate higher voltages and currents than Si-based modules, are the most promising solution for reducing the size and weight of power electronics systems. In addition to the higher blocking voltages of WBG power modules, their volume has been targeted to be several times smaller than that of Si-based modules. This translates into higher electric stress within the module and, in turn, a higher risk for unacceptable partial discharge (PD) activities, leading to aging and degradation of both the ceramic substrate and the silicone gel. Due to the small dimensions of power module geometry, in the mm or μm (for protrusions) range, and due to its extremely non-uniform electric field geometry, conventional high voltage testing electrode geometries cannot simulate real conditions. On the other hand, university-based laboratories often cannot provide testing samples under manufacturing/factory conditions and with high-quality materials. Thus, it is difficult to determine the efficacy of electric field and PD control methods. To address this issue, an electric field criterion based on precise dimensions of a power module and its PD measurement is introduced. Then, combined geometrical techniques and the application of nonlinear field-dependent conductivity (FDC) layers are proposed, for the first time, to address the high electric field issue in an envisaged 25 kV high-density WBG power module. Electric field modeling and simulations are carried in COMSOL Multiphysics where various electric field reduction methods proposed in this paper can be used as a guideline and reference to design the insulation system for next-generation WBG power modules, meeting both the one-minute insulation and PD tests based on IEC 61287-1.

Stepwise Design Methodology and Heterogeneous Integration Routine of Air-Cooled SiC Inverter for Electric Vehicle

Abstract: Carrying on SiC devices, the air-cooled inverter of the electric vehicle (EV) can eliminate the traditional complicated liquid-cooling system in order to obtain a light and compact performance of the powertrain, which is considered as the trend of next-generation EV. However, the air-cooled SiC inverter lacks strategic design methodology and heterogeneous integration routine for critical components. In this article, a stepwise design methodology is proposed for the air-cooled SiC inverter in the power module, dc-link capacitor, and heat sink levels. In the power module level, an electrical–thermal–mechanical multiphysics model is proposed. The multidimension stress distribution principles in a six-in-one SiC power module are demonstrated. An improved power module is presented and confirmed by using the observed multiphysics design principles. In the dc-link capacitor level, ripple modeling of the inverter and capacitor are created. Considering the tradeoffs among ripple voltage, ripple current, and cost, optimal strategies to determine the material and minimize the capacitance of the dc-link capacitor are proposed. In the heat sink level, thermal resistance of air-cooled heat sink is modeled. Structure and material properties of the heat sink are optimally designed by using a comprehensive electro-thermal analysis. Based on the optimal design results, the prototypes of the customized SiC power module and heterogeneously integrated air-cooled inverter are fabricated. Experimental results are presented to demonstrate the feasibility of the designed and manufactured air-cooled SiC inverter.

Characterization of Nonlinear Field-Dependent Conductivity Layer Coupled With Protruding Substrate to Address High Electric Field Issue Within High-Voltage High-Density Wide Bandgap Power Modules

Abstract: In addition to higher blocking voltages of wide bandgap (WBG) power modules, their volume has been targeted to be several times smaller than that of Si-based modules. This translates into higher electric stress within the module and, in turn, a higher risk for unacceptable partial discharge (PD) activities, leading to aging and degradation of both the ceramic substrate and the silicone gel. Due to the small dimensions of power module geometry, in the mm- or $\mu \text{m}$ (for protrusions)-range, and due to its extremely non-uniform electric field geometry, conventional high-voltage testing electrode geometries cannot simulate real conditions. On the other hand, university-based laboratories often cannot provide manufacturing/factory conditions for testing samples and for high-quality materials. Thus, it is difficult to determine the efficacy of electric field control methods through experiments. In these situations, numerical electric field calculation is the only feasible way to evaluate different electrical insulation designs. To this end, the finite-element method (FEM) models of the electrical insulation system used in WBG power modules are developed in COMSOL Multiphysics. It is shown that the current geometrical techniques alone cannot address the high-electric field issue within high-density WBG modules. To address this issue, for the first time, nonlinear field-dependent conductivity (FDC) materials applied to high-electric stress regions in combination with a recently introduced geometrical technique known as the protruding substrate is proposed. In this regard, the nonlinear FDC layer is characterized and various designs to reduce the electric field are evaluated. Moreover, the effect of the operating frequency on the performance of the solution mentioned above will be studied.

Design, Analysis, and Discussion of Short Circuit and Overload Gate-Driver Dual-Protection Scheme for 1.2-kV, 400-A SiC MOSFET Modules

Abstract: This paper proposes short circuit and overload gate-driver dual-protection scheme based on the parasitic inductance between the Kelvin- and power-source terminals of high-current SiC mosfet modules. The paper presents a comprehensive analysis of the two schemes in question, including worst-case analysis used to assess their parametric dependence due to manufacturing tolerances and temperature variations, as well as the in-depth design procedure that can be generally applied to any power module containing a Kelvin-source. For verification, a compact 1.2-kV, 400-A half-bridge module integrating the two protection circuits was developed. The results obtained demonstrate a response time within tens of nanoseconds, and effectively validate their functionality under short circuit and overload scenarios. Finally, a 100-kW, 400-V dc three-phase voltage-source inverter was used to demonstrate the gate-driver with integrated protection functions under 105°C ambient temperature conditions.

A 10-Level Flying Capacitor Multi-Level Dual-Interleaved Power Module for Scalable and Power-Dense Electric Drives

Abstract: The adoption of cleaner vehicle technologies is predicated on the development of efficient and power-dense electric drives Recent activity in this area has produced several high performance converters geared towards this application While much effort has been focused on improving traditional concepts, others have sought more unconventional topologies to attain high performance as well as system level benefits–such as reduced output current distortion, dv/dt and filter size This work represents the latter approach, using the flying capacitor multilevel topology (FCML) in a high-power, high-voltage, gallium nitride (GaN)-based inverter Specific design considerations are reviewed, and take into account recent developments in component characterization and thermal management, followed by a discussion of start-up and steady-state operation A 10-level prototype FCML inverter is used to demonstrate operation at 1 kV dc input voltage and 134 kW peak output power, with 267 kW/kg and 174 kW/L power densities

Real-Time Monitoring of Thermal Response and Life-Time Varying Parameters in Power Modules

Abstract: This article introduces new technologies for monitoring thermal response and life-time varying parameters of power electronic modules in real time without interrupting normal converter operation. The technologies are embedded in an adaptive thermal observer, which integrates temperature measurements and electrothermal models to estimate device losses and temperatures at reliability-critical locations of the power module. The observer structure includes a model reference adaptive system for adaptively calibrating device switching-loss models. This improves thermal monitoring accuracy, avoids time-consuming offline calibrations, and creates the opportunity for efficiency estimations during power module operation. The adaptive observer together with small-signal loss-excitation and system-identification technologies extract the thermal impedance of the power module in magnitude and phase over multiple frequency decades. This in situ thermal impedance spectroscopy has the unique feature of continuously providing information on the thermal interface of the power devices without interrupting normal inverter operation. The extracted information, i.e., life-time varying electrical and thermal parameters, enables diagnosing power module state-of-health with improved accuracy compared to prior technologies. It even allows separating different degradation effects, such as bond wire lift-off, device and base-plate solder delamination as well as deterioration of the convection process. With these new features, next generation monitoring systems can extract thermal response and degradation and thus protect power modules from severe thermal stress and overload. Furthermore, the obtained state-of-health information can be selectively used to reduce thermal stress and to schedule predictive maintenance leading to a safer and more reliable operation of future converter systems.

Localization and Detection of Bond Wire Faults in Multichip IGBT Power Modules

Abstract: Multichip insulated gate bipolar transistor (mIGBT) power modules (PMs) degrade over power cycling. Bond wire lift–off is one of the major failure modes. This article presents a technique to diagnose bond wire lift-off by analyzing the on -state voltages across collector and emitter terminals and the voltages across collector and Kelvin emitter terminals. The proposed method can indicate the first lift-off out of 37 bond wires in a mIGBT. The main novelty of the proposed technique is that it can locate the chip that has bond wire lift-off(s). In addition, the temperature dependence of the proposed approach is negligible. The article describes the proposed technique in detail and shows results and discussions based on practical tests which are carried out on two mIGBT PMs with different packages.

Study of Current Density Influence on Bond Wire Degradation Rate in SiC MOSFET Modules

Abstract: This paper proposes a separated test method for studying the current effect on the ageing process of a wire-bonded silicon carbide (SiC) MOSFET module under power cycling test (PCT). The separated test method enables testing SiC MOSFET at different load current densities, but under the same temperature swing and average temperature conditions. By analyzing the output characteristics in the linear region, the relationships among the gate voltage, on-state voltage, and junction temperature are revealed. Then, the one-to-one correspondence between gate voltage and conduction power loss can be used to adjust the current density under the same temperature conditions. Two six-pack SiC modules (1200 V/20 A) are tested under 12 and 24 A conditions to experimentally verify the proposed method. The ageing curves show that the high current can speed up the ageing rate of bond wires even under the same temperature conditions (65 °C–125 °C). Moreover, the high current density also has an impact on solder layer degradation as well as on the temperature conditions. Finally, a power device analyzer B1506A and a scanning acoustic microscope (SAM) are used to investigate the degradation of electrical parameters and the solder layer, respectively. The final summary of analytical results shows that the input current has a nonnegligible impact on the degradation process of power modules.

A Power Module for Grid Inverter With In-Built Short-Circuit Fault Current Capability

Abstract: As grid codes evolve, inverter-interfaced renewable generation may be required to take greater responsibility for grid support. It may be obliged to source a large current during a short-circuit fault in the grid and provide large dynamic reactive power, beyond the inverter rating, for voltage recovery after the fault clearance. In this sense, the inverter-interfaced generating system would behave more similarly to a conventional synchronous machine. This is not yet mandatory but current technology cannot readily support it if required in the future, because the power semiconductors would overheat unless they are drastically derated. This study proposes a method to increase the power semiconductor's transient thermal capacity, and hence its short-term over-current capability, by integrating a phase-change material inside the power semiconductor module. Experiment and thermodynamic simulation across different materials are used to illustrate the feasibility of the concept and the factors that should be considered in such a design. The study shows that 1.5 p.u. (per unit) overcurrent could be achieved for 30 s, which is typical of synchronous generators; and 3.0 p.u. fault current could be achieved for 3 s. A custom-made 1200-V, 50-A IGBT half-bridge module integrating a liquid metal as the phase change material is compared with a conventional commercially available module. A validated simulation model is then used to further evaluate the proposal, regarding a 1700-V, 1000-A IGBT module for use in a wind turbine.

PSpice-COMSOL-Based 3-D Electrothermal–Mechanical Modeling of IGBT Power Module

Abstract: The behavior of the insulated gate bipolar transistor (IGBT) module results in the electric field, temperature field, and stress field, and there are strong coupling effects among its electrical, temperature, and mechanical characteristics. Meanwhile, the packaging failure of IGBT module is also the interaction results of multi-physical fields coupling. In this article, a multi-physical fields transient modeling method based on PSpice and COMSOL is proposed. This method synthesizes the advantages of the physical model and the finite-element model. According to the time constants of different physical fields, continuous simulation analysis is carried out on different timescales. Through flexible multispeed simulation strategy, the dynamic characteristics of IGBT devices at different timescales can be accurately characterized. First, the electric-thermal–mechanical coupling mechanism of IGBT is described. Then, the electrical model and thermomechanical coupling model of IGBT are constructed in PSpice and COMSOL, respectively, and the multi-physical fields simulation in multi-timescale is realized through the control file of MATLAB script. The proposed modeling approach is verified by a short-circuit test of Starpower 1200-V/50-A IGBT module. Finally, an example of multi-time-scale simulation analysis under short-circuit condition is given, and the reasons for module failure under multi-field coupling effect are studied.

Reconfigurable equilibrium circuit with additional power supply

Abstract: The invention provides a reconfigurable equalization circuit with an additional power supply, and the circuit comprises a battery cell module, an energy storage battery pack, an additional power module and a load. The battery cell module comprises two switches and one battery, and can determine the working state of a battery cell through controlling the operation of the corresponding switch. The energy storage battery pack is formed by the series connection of battery cells. The additional power module consists of three switches, one additional power supply, and one DC converter, and maintainsthe constant end voltage of the load through a corresponding control method. Through the adding of elements at lower cost, the circuit can maintain the end voltage of the load under the condition that the high flexibility and high conversion efficiency of the reconfigurable equalization circuit are maintained in an equalization process during the equalization of the energy storage battery pack orwhen some batteries have faults.

Finite Control Set Model Predictive Control With Secondary Problem Formulation for Power Loss and Thermal Stress Reductions

Abstract: Thermal stress has been identified as one of the major failure causes in power modules. Generated from the power loss, thermal stress accelerates the degradation of semiconductor devices and downgrades the system reliability. This article presents a finite control set model predictive control (FCS-MPC) oriented to reduce the power loss over the mission profile and relieve the thermal stress in power modules. Conventional control approaches including the switching frequency regulation, the reactive power injection, and the dc-bus voltage adaption show an effective progress. However, the increased control loops and complicated modulation schemes limit the system performance and practical implementation. In the proposed FCS-MPC, a secondary problem formulation is defined to reduce the power loss for the thermal stress reduction in power modules. It is simply integrated with the primary problem formulation in order to achieve the power flow control and power loss reduction simultaneously. An energy-based loss model is proposed for the loss prediction. The impact of the weightings between primary and secondary problem formulations is investigated and a most efficient weighting curve with a weighting-zones strategy is presented to design the proposed FCS-MPC. The proposed FCS-MPC is validated in the simulations and experiments. A 2.5-kW grid-tied inverter prototype is developed for the hardware testing and validation.

A High-Performance Embedded SiC Power Module Based on a DBC-Stacked Hybrid Packaging Structure

Abstract: Silicon carbide (SiC) devices have the advantage of high switching speed. However, the switching speed is limited by the high parasitic inductance which could cause high voltage overshoot, parasitic turn-on, oscillation, and electromagnetic interference (EMI) issues. Thus, the parasitic inductance of the SiC power module has to be reduced for better performance. This paper proposed an integrated half-bridge (HB) power module based on a direct bonding copper (DBC)-stacked hybrid packaging structure. This packaging structure utilizes two DBC substrates to stack together, which form a 3-D power commutation loop. The SiC chips are embedded on the top of the bottom DBC substrate to reduce the thermal resistance. Based on an optimized mutual inductance cancellation design, the proposed DBC-stacked hybrid packaging structure has only 1.8-nH commutation power loop inductance for a 1200-V, 120-A HB power module. Moreover, the geometrical parameters of the laminated power terminal have been analyzed and optimized for the symmetrical current sharing in the multichip paralleled power module. A compact 1200-V, 120-A full SiC HB power module with integrated decoupling capacitors has been fabricated and the dc-link capacitor board, gate drivers can be integrated on the power module compactly. Finally, the static and dynamic characteristics of the proposed module have been tested. The results of double pulse test (DPT) under zero external driver resistor indicate that the voltage overshoot of the proposed module is reduced by approximately 55% compared to the commercial power module, and the total switching energy is only 43% of the commercial module. Moreover, the loss of the 5.5-kW single-phase inverter based on the proposed module is reduced by 28.3% compared with the inverter based on the commercial module under 120-kHz switching frequency.

Analysis and Cancellation of Leakage Current Through Power Module Baseplate Capacitance

Abstract: The fast edge rates achievable by wide-bandgap semiconductors can produce significant common-mode (CM) leakage currents through the baseplates of encompassing power modules, which are known to produce elevated electromagnetic signatures for power electronic applications. This article provides a theoretical treatment of this CM behavior for a typical silicon carbide half-bridge multichip power module in the context of an example system consisting of a half-bridge inverter. A CM equivalent model is produced that quantitatively relates the distribution of the parasitic baseplate capacitance across the module terminals to the amplitude of the leakage current through the module baseplate for the converter under study. The model predicts that this leakage current can be canceled out by achieving a prescribed distribution of said baseplate capacitance. These predictions are validated by a set of empirical studies in which the model predictions are shown to be in excellent agreement with the measured behavior of this system. Through these demonstrations, the theoretical treatment provided in this article is shown to be a useful tool to identify simple and effective means for mitigation of CM behavior within power electronic systems. As such, this approach is expected to be of significant interest to system designers seeking to optimize the performance of applications with respect to CM behavior.

A Soft-Switched Power Module With Integrated Battery Interface for Photovoltaic-Battery Power Architecture

Abstract: In conventional photovoltaic (PV)-battery systems, a centralized battery storage system (BSS) is typically connected through a separate bidirectional converter at the common dc link to support the PV system. It is known that a bidirectional converter typically requires more switches than a unidirectional converter, and hence, a complete PV-battery power interface will result in a high-cost system and will suffer high power losses. This paper proposed an integrated battery storage interface with soft-switching capability for module-integrated PV systems. In the proposed system, a multi-input converter (MIC) structure that consists of an integrated soft-switched quasi-resonant (QR) Cuk- and flyback-based circuit is presented. In this approach, the battery charging circuit is integrated with the input side of the PV power optimizer while the battery discharging circuit of the proposed system shares the output filter of the PV power optimizer, resulting in a compact and efficient system. The proposed converter is capable of tracking the maximum power point (MPP) and following the charging profile (constant voltage and constant current) of the battery. Moreover, all the switches in the proposed converter are able to achieve soft-switched turn on and turn off for different operating conditions. The operating principles and the theoretical analysis of the proposed system are presented. Experimental results on a 175-W proof-of-concept prototype are presented to demonstrate the features of the proposed converter.

A Double-Sided Cooling 650V/30A GaN Power Module with Low Parasitic Inductance

Abstract: This paper presents a compact double-sided cooling Gallium Nitride (GaN) power module with low parasitic parameters. The GaN bare dies are sandwiched between two ceramic substrates with high thermal conductivity to achieve efficient double-sided cooling capability. Through careful design and layout optimization, the bus decoupling capacitors and core drive components are successfully integrated into the module to reduce critical parasitic parameters. The thermal and parasitic characteristics of the module are analyzed and optimized. Finally, a double-pulse-test platform is built based on the presented 650V/30A GaN power module. The results show that the power loop inductance is reduced to 0.95 nH and the gate loop inductance is reduced to about 2nH. The dv/dt of the drain-source voltage can be as high as 150V/ns, while the overshoot is only 10%.

Differentiation Power Control of Modules in Second-Life Battery Energy Storage System Based on Cascaded H-Bridge Converter

Abstract: There is a possibility that second-life power batteries, which can store and deliver substantial energy, could satisfy the requirements of stationary energy storage applications. In this article, split second-life battery modules with good performance have been directly introduced to the dc sides of the H-bridges in cascaded H-bridge converter (CHBC) without complex manual dismantling, screening, and recombination of the battery cells. However, the severe discrepancies of the second-life battery modules’ parameters can lead to overcharge, overdischarge, and underutilization of some battery modules’ effective capacity simultaneously. To suitably integrate and control these widely different battery modules, a differentiation power control strategy based on the online battery parameter estimation method is proposed. Real-time online power allocation of the independent power modules according to the parameters of the battery modules is conducted by the strategy, which ensures that the charging/discharging trajectories of the second-life battery modules during a charging/discharging cycle will all arrive at their maximum/minimum values at the same time, whether the battery modules are in the same phase or different phases. The control range and capability of the strategy are also analyzed quantitatively. Finally, modeling, analysis, and experimental validation are performed on a downscaled prototype in the laboratory.

Characterization and Extraction of Power Loop Stray Inductance With SiC Half-Bridge Power Module

Abstract: The power loop stray inductances of the silicon carbide (SiC) half-bridge power module (HBPM) must be included in the circuit simulation model to predict the power device switching characteristics and the power bus noise caused by the power converter. Instead of a full equivalent circuit model of the SiC HBPM, a simplified but accurate three-terminal equivalent circuit model is presented in this article. Based on the simplified model, a novel frequency-domain impedance measurement method based on the two-port network technique is proposed to extract the power loop inductances through direct measurement. By using the extracted power loop inductances of a 1.2-kV 300-A SiC HBPM, a three-terminal equivalent model of the HBPM is obtained, and its accuracy is validated by the finite element method and experiments.

High Current Medium Voltage Bidirectional Solid State Circuit Breaker using SiC JFET Super Cascode

Abstract: DC power systems found in electric transport, data centers and residential microgrid applications maintain a demand for fast, reliable and efficient power electronics in the Medium Voltage (MV) range. DC systems are inherently more sensitive to faults due to low system impedance and voltage sensitivity of accompanying power electronics creating a need for a fast all Solid State approach to system protection. This paper proposes a Bidirectional Solid State Circuit Breaker (BSSCB) utilizing the SuperCascode topology as the breaking element and has parallel transient energy absorption circuitry comprising of MOVs and snubbers to denergize the line upon fault. The paper discusses critical design points in breaker design, advantages of SuperCascode switch for breaker applications and power stage scaling calculations of the transient absorption circuitry. For packaging, a novel Epoxy Resin Composite Dielectric (ERCD) is considered as an alternative to metal-clad ceramic (DBC) substrate for higher reliability. The paper studies transient heat transfer in the power module using finite element analysis (FEA) and proposes a thermally defined and digitally controlled fuse curve for breakers. A design example of 10kV/100 A BSSCB is provided which holds 10x rated current for a 5ms dwell. A scaled-down 6kV/10A SSCB prototype using TO-247 packaged dies is demonstrated and is capable of withstanding 7x over-current for 1μs and short circuit interruption in approximately 60 ns.

Overview of Digital Design and Finite-Element Analysis in Modern Power Electronic Packaging

Abstract: Wide band gap (WBG) semiconductors require packaging with reduced parasitic inductance and capacitance. To achieve this, new packaging solutions are proposed that increase integration. This causes difficulty in measurement of voltages, currents, and device temperature, and therefore, designers must rely more heavily on simulations to gain insight in the operation of the developed prototypes. Additionally, the use of the digital design may reduce the number of physical prototype iterations, and thereby, reduces the development time. Gaining fidelity of three-dimensional multiphysics simulations, reduced order modeling, and system simulation aids in the design of working prototypes and pushes performance of new power modules based on WBG semiconductor devices. This article provides an overview and discusses the recent advances in the use of finite-element analysis and simulation tools within the topic of power module packaging. The main aspects covered are extraction of electrical parasitics, simulation of transient thermal response, and issues related to evaluation of electric fields. An example of a simulation software roadmap is presented that enables accurate electro-thermal simulation of new packaging structures that combine the conventional power module technology with integrated printed circuit boards. The future challenges for utilizing the potential of the digital design are discussed.