Silicon Carbide (SiC) is revolutionizing the power electronics field by delivering exceptional efficiency, increased power density, and improved thermal performance, especially in automotive applications such as main drives, onboard chargers, and battery charging stations. SiC’s dielectric strength is ten times that of silicon, enabling the creation of high-voltage devices that meet the demands of charging infrastructure and smart grids. Its high switching frequency also allows for reduced physical sizes of inductors and transformers.
SiC power devices are widely used in electric vehicle power conversion, industrial motor drives, and renewable energy generation systems. To fully leverage SiC, design methodologies must adapt, often resulting in significant changes to PCBs, reduced auxiliary components, lower costs, and saved space. Therefore, having tools that can quickly and accurately test new designs and assess device reliability is crucial.
A modular design toolkit provides an ecosystem of building blocks to streamline the SiC device evaluation process, enabling fast and comprehensive system-level testing of various SiC products, thereby accelerating the design workflow for engineers, designers, and manufacturers. Before actual hardware design commences, engineers can simultaneously test and optimize MOSFETs and their gate drivers.
The evaluation platform comprises a main circuit board, power modules, gate driver modules, and optional control modules, supporting testing of various discrete devices up to 1,200V. This platform accommodates a wide range of voltages, package styles, and power topologies, allowing users to set testing parameters via a computer graphical interface, eliminating the need for external function generators. This offers firmware engineers opportunities to develop and test custom firmware for high-voltage/high-power designs.
The main board features a low-inductance layout, with screw terminal power connections designed for efficient testing of SiC devices. The power daughter card is customized for each device package, utilizing coaxial connectors for VGS and VDS measurements to ensure optimal signal integrity, while high-bandwidth current sensing allows precise switching loss measurement.
This modular design enables the evaluation of various SiC devices, from surface-mounted TOLL devices to TO-247 packages. The central board primarily adopts a half-bridge configuration, equipped with slots for gate driver cards, power daughter cards, and optional control cards, integrating cooling fans and DC bus capacitors.
Custom daughter card gate driver boards, developed in collaboration with leading gate driver companies, facilitate comprehensive testing of the full range of SiC MOSFETs. These cards play a crucial role in the analysis and optimization of SiC devices, especially concerning challenges posed by parasitic inductance and capacitance at high dV/dt and di/dt. The gate driver directly influences the switching performance of SiC MOSFETs.
Each gate driver card features two isolated driver outputs and corresponding bias supplies, supporting half-bridge power daughter card driving. In applications requiring short-circuit protection, these cards optimize response times and performance validation. The gate driver cards in the evaluation platform help engineers measure QRR and switching losses, determining timing parameters to optimize device performance under various operating conditions.
The power daughter card adopts a half-bridge configuration, incorporating high-side and low-side SiC MOSFETs with high-bandwidth current sensing capabilities. They enable high-fidelity current measurements in double-pulse tests or operation in forced air-cooled continuous power converters. Engineers can select their preferred gate driver to test devices, perform measurements, and optimize SiC MOSFETs and their drivers.
The power daughter card supports solderless replacement of SiC devices, maintaining low-inductance connections to the DC bus. The platform accommodates various packages of SiC MOSFETs for applications up to 1,200V, allowing engineers to adjust gate resistance for optimal switching behavior and conduct high-power thermal testing under practical operating conditions. Hardware testing is supported by modular SPICE models, facilitating comparison with simulation results for enhanced design accuracy.
Furthermore, the SPICE system models provide estimates of key parasitic components, assisting engineers in effectively managing these elements to improve the efficiency of SiC MOSFETs. The evaluation kit also includes buck-boost boards for testing across different power levels, with custom air-core inductors ensuring accurate double-pulse testing to support optimized converter design. With the buck-boost filter board, applications can operate at full power while measuring thermal data and converter efficiency.
As the demand for high power density energy-efficient conversion continues to grow, the importance of SiC device evaluation in power electronics is increasingly recognized. Utilizing the SpeedVal kit for modular SiC device evaluation allows engineers to quickly execute critical tests without the need for new designs for each test, saving time and costs. Additionally, the design files of the SpeedVal kit are reusable, reducing design risk.
The modular evaluation design provides a comprehensive solution, including necessary components such as gate drivers and control boards, allowing for testing across different voltage ranges before hardware launch. Its low-inductance power loop and current sensing design streamline the process of precise switching measurements. Importantly, the modular features enable engineers to select different modules based on specific application needs, customizing testing conditions.
As the industry continues to pursue efficiency, size, weight, and cooler designs, the application of SiC components will continue to grow. The modular evaluation approach is an effective strategy for achieving optimized designs, offering vast potential for the future of power electronics
