High-Power Electronics Cooling
High-power electronics present some of the most challenging thermal management problems in modern engineering. Power converters, motor drives, inverters, and other power electronic systems routinely handle kilowatts or even megawatts of electrical energy, with even small inefficiencies translating into substantial heat generation. Effectively removing this heat while maintaining junction temperatures within safe operating limits requires sophisticated thermal design and often multiple cooling technologies working in concert.
The thermal challenges in high-power electronics are compounded by several factors: extremely high power densities concentrated in small semiconductor die areas, pulsed operating modes that create thermal cycling, high operating voltages requiring electrical isolation of cooling systems, and demanding reliability requirements in critical applications such as transportation, renewable energy, and industrial automation. Success requires understanding not only heat transfer fundamentals but also the specific characteristics and thermal behaviors of power semiconductor devices.
Power Semiconductor Thermal Characteristics
IGBT Thermal Management
Insulated Gate Bipolar Transistors (IGBTs) combine high voltage capability with fast switching speeds, making them the workhorse of medium to high power applications. IGBT modules can dissipate hundreds of watts in packages ranging from a few square centimeters to large power modules. The thermal design challenge centers on efficiently conducting heat from the small silicon die through multiple material interfaces to an external cooling system.
Modern IGBT modules use direct bonded copper (DBC) substrates to minimize thermal resistance between the die and the module baseplate. The DBC consists of a ceramic layer (typically aluminum nitride or aluminum oxide) with copper layers bonded to both sides. This structure provides both electrical isolation and a low-resistance thermal path. Junction temperatures must typically be maintained below 125-150°C under continuous operation, with transient ratings allowing brief excursions to 175°C.
Cooling system design for IGBTs must account for both steady-state and transient thermal behavior. The thermal time constants of the die, substrate, and baseplate create a multi-stage thermal response. Short-duration overloads may be permissible if the thermal mass can absorb the energy without excessive temperature rise. Sophisticated thermal models incorporating thermal capacitance networks help predict dynamic thermal behavior under realistic operating conditions including PWM switching patterns and load variations.
Thyristor and High-Power Diode Cooling
Thyristors and high-power diodes, commonly used in phase-controlled rectifiers, high-voltage DC transmission, and electric arc furnaces, can handle enormous power levels—individual devices may conduct thousands of amperes at voltages exceeding several kilovolts. The power dissipation, though typically only 1-2% of the handled power, can reach several kilowatts per device due to on-state voltage drop and switching losses.
These devices are typically packaged in disc or stud-mounted configurations designed for direct mounting to substantial heatsinks. The large thermal mass of the package helps smooth temperature variations during AC half-cycle operation. Junction-to-case thermal resistance is a critical specification, typically in the range of 0.01 to 0.1 K/W depending on device size and package style. Achieving low thermal resistance requires proper mounting pressure, high-quality thermal interface materials, and flat, parallel mounting surfaces.
Thermal design for high-power thyristors often involves calculating the required heatsink thermal resistance based on maximum expected forward current, junction temperature limit, ambient temperature, and thermal resistance from junction to case. For critical applications, double-sided cooling using two heatsinks (one on each face of the disc device) may be employed to reduce overall thermal resistance and improve reliability.
Power Module Thermal Design
Power modules integrate multiple semiconductor devices (IGBTs, MOSFETs, diodes) in a single package to form complete converter stages or subsystems. These modules present complex thermal design challenges because multiple heat sources with different power levels and duty cycles share a common thermal path. Thermal crosstalk between adjacent devices must be carefully analyzed to ensure that heat from one device doesn't push neighboring devices beyond their temperature limits.
Advanced power modules use innovative substrate technologies to improve thermal performance. Direct copper bonding provides lower thermal resistance than traditional die attach methods. Silicon nitride (Si3N4) substrates offer better thermal conductivity than alumina while maintaining excellent electrical isolation. Some high-performance modules incorporate integrated cooling structures such as microchannel cold plates built directly into the module baseplate.
Thermal cycling reliability is a critical concern for power modules. The different coefficients of thermal expansion among silicon, copper, ceramic, and solder create thermomechanical stresses during temperature cycling. Modern modules use advanced die attach techniques such as sintered silver or copper, which offer better thermomechanical reliability than traditional solder while also providing improved thermal conductivity. Some designs eliminate bond wires in favor of pressure contact or spring-loaded connections to improve reliability under thermal cycling.
Application-Specific Cooling Solutions
Motor Drive Cooling Systems
Variable frequency drives and motor controllers must maintain reliable operation across a wide range of load conditions, from light load to 150% overload for short durations. The cooling system must handle not only the steady-state losses but also the additional heating during motor starting and overload conditions. Most industrial drives use forced air cooling with temperature-controlled fans that adjust speed based on heatsink temperature.
The electrical environment in motor drives creates additional cooling system design constraints. High levels of electromagnetic interference (EMI) from fast-switching power semiconductors require careful routing of fan power cables and may necessitate filtered fan supplies. Conducted emissions through the cooling system must be minimized. In some cases, the cooling fan motor itself must meet specifications for operation in hazardous locations or high-vibration environments.
Larger motor drives (above approximately 100 kW) often use liquid cooling to achieve higher power density and reduce acoustic noise. Closed-loop liquid cooling systems circulate a coolant mixture through cold plates mounted to power module baseplates, with a remote heat exchanger rejecting heat to ambient air or facility water systems. Liquid cooling enables operation in high-temperature environments where air cooling would be inadequate and allows for more compact drive enclosures.
Inverter Thermal Design
Inverters for renewable energy applications, uninterruptible power supplies, and electric vehicles face unique thermal challenges. Solar inverters must operate reliably in outdoor environments with ambient temperatures potentially reaching 50°C or higher while converting kilowatts to megawatts of DC power to AC. Automotive traction inverters must fit within tight packaging constraints while handling peak power levels exceeding 100 kW, all while meeting stringent reliability and lifetime requirements.
Many solar inverters use passive cooling designs that eliminate fans to improve reliability and reduce maintenance. Large aluminum extrusions serve as both structural chassis and heatsinks, with power modules mounted on internal surfaces. Computational fluid dynamics (CFD) analysis optimizes the fin geometry and orientation to maximize natural convection heat transfer. The inverter enclosure design must balance thermal performance against ingress protection requirements, often achieving IP65 or higher ratings against dust and water.
Electric vehicle inverters employ liquid cooling almost exclusively due to the extreme power density requirements. Coolant typically circulates through cold plates in thermal contact with power module baseplates, with the coolant then flowing to a radiator integrated with the vehicle's thermal management system. Some advanced designs use direct cooling where refrigerant flows through passages in the power module baseplate itself, enabling even higher heat flux removal. Junction temperature estimation algorithms provide real-time thermal monitoring and can implement protective derating to prevent overtemperature conditions.
Power Supply Cooling
Switch-mode power supplies range from low-power adapters dissipating a few watts to high-power industrial supplies handling tens of kilowatts. Thermal design approaches vary dramatically across this range. Small power supplies typically rely on natural convection and heat spreading through the PCB and enclosure. As power levels increase, forced air cooling becomes necessary, with the airflow path carefully designed to cool all heat-generating components including switching transistors, rectifiers, inductors, and transformers.
High-power supplies (above approximately 1-2 kW) use finned heatsinks for primary power semiconductors, with baseplate or through-hole mounting configurations that conduct heat directly to the heatsink. The heatsink is positioned in the forced air stream to maximize convective heat transfer. Fan selection balances cooling performance against acoustic noise, particularly important for equipment used in office or residential environments. Variable-speed fans controlled by temperature sensing provide adequate cooling while minimizing noise during light load operation.
Server and telecom power supplies face additional challenges related to redundancy and hot-swap capability. Multiple power supplies operate in parallel, each with independent cooling. The mechanical design must ensure that removing or inserting a supply doesn't disrupt airflow to remaining units. High-reliability designs may use redundant fans within each supply. Efficiency optimization at light loads has become increasingly important, as data centers often operate well below maximum capacity, making part-load efficiency a key metric for reducing overall energy consumption.
Battery Thermal Management
Lithium-ion battery packs require precise thermal management to maximize performance, ensure safety, and extend operational lifetime. Unlike power electronics where heat removal is the primary goal, battery thermal management must both remove heat during high-rate charging or discharging and also maintain temperature uniformity across all cells in the pack. Temperature differences as small as 5°C between cells can lead to uneven aging and capacity loss over thousands of charge cycles.
Several cooling architectures are used in battery systems. Air cooling, common in hybrid vehicles and stationary energy storage, circulates air through channels between cell modules. Liquid cooling, used in most modern electric vehicles, circulates coolant through cold plates in contact with cell modules or through cooling channels integrated into the pack structure. Phase change materials provide an alternative approach, absorbing heat during high-rate operation and releasing it slowly during periods of lower demand.
Battery thermal management systems must handle both steady-state and transient conditions. During fast charging, the system must remove heat quickly to prevent cells from exceeding temperature limits that could trigger charge rate reduction or safety shutdowns. During cold weather operation, some systems incorporate heating elements to warm the pack to optimal operating temperature before allowing full power discharge or charge. Advanced battery management systems use distributed temperature sensing and thermal models to optimize cooling system operation while minimizing parasitic power consumption.
Advanced Cooling Technologies
Direct Substrate Cooling
Direct substrate cooling eliminates the thermal resistance of a baseplate by flowing coolant directly against the back of the power module substrate. This approach can reduce junction-to-coolant thermal resistance by 30-50% compared to conventional cold plate cooling, enabling higher power density or lower junction temperatures. The technique is particularly valuable in traction inverters and other applications where space constraints limit heatsink size.
Implementation of direct substrate cooling requires careful attention to several design considerations. The cooling structure must provide uniform flow distribution across the substrate area to prevent hot spots. Pressure drop must be minimized to reduce pump power requirements. The substrate-to-cooling structure interface requires a thermal interface material that maintains performance under thermal cycling while also providing electrical isolation. Reliability testing must verify that thermal cycling and vibration don't degrade the thermal interface or create coolant leaks.
Some advanced designs integrate microchannels directly into the substrate or baseplate structure, creating extremely high heat transfer coefficients through very high flow velocity in small passages. These designs can achieve heat fluxes exceeding 300 W/cm², but require careful design to manage pressure drop and ensure flow stability. Computational fluid dynamics analysis is essential for optimizing channel geometry and predicting thermal performance under various operating conditions.
Gradient Heat Spreaders
Gradient heat spreaders address the thermal interface challenge between small, high-power-density semiconductor die and larger cooling structures. These devices use materials with very high in-plane thermal conductivity to spread heat laterally before conducting it through the thickness of the package. Pyrolytic graphite, with thermal conductivity exceeding 1000 W/m-K in-plane, provides exceptional spreading performance. Vapor chamber heat spreaders use the latent heat of evaporation and condensation to achieve effective thermal conductivities even higher than solid copper.
The effectiveness of heat spreading depends on the geometric spreading resistance ratio—the ratio of heat source area to heatsink area. When a 1 cm² die is cooled by a 100 cm² heatsink, effective spreading can reduce the thermal resistance by a factor of 2-3 compared to direct conduction through a uniform material. The benefit is greatest for small heat sources and large spreading areas, making this technique particularly valuable for high-power semiconductor cooling.
Advanced power modules increasingly incorporate vapor chambers integrated into the module baseplate. These custom-designed heat spreaders match the geometry of the power module, with wicking structures and internal channel geometry optimized for the specific heat flux distribution. The vapor chamber effectively equalizes the temperature across the baseplate, reducing thermal gradients and improving cooling system effectiveness. Some designs use multiple independent vapor chambers to separately manage heat from different sections of the module.
Wireless Charging Thermal Design
Wireless power transfer systems for electric vehicle charging and industrial applications present unique thermal challenges. The power electronics must handle tens of kilowatts while fitting within the limited space available in a ground-mounted charging pad or vehicle-mounted receiver. Additionally, the magnetic coupling coils themselves dissipate power due to AC resistance and core losses, creating distributed heat sources that must be cooled effectively.
The ground assembly (transmitter pad) typically uses liquid cooling for the power electronics and either liquid or forced air cooling for the coil. The pad must withstand outdoor environmental conditions including rain, snow, and vehicle traffic while maintaining thermal performance. The vehicle assembly (receiver pad) faces even tighter packaging constraints, competing for limited under-vehicle space with other components. Most designs use liquid cooling integrated with the vehicle's thermal management system.
Thermal design must account for the coupling between thermal performance and system efficiency. Higher coil temperatures increase electrical resistance, reducing power transfer efficiency and increasing losses in a potentially unstable feedback loop. Aluminum coil conductors, while lighter than copper, require more aggressive cooling due to higher resistivity. Some systems use temperature monitoring to adjust power level or pause charging if thermal limits are approached, balancing charging speed against thermal constraints.
Design Methodology and Analysis
Thermal Network Modeling
Thermal network modeling provides a computationally efficient method for predicting temperatures in power electronic systems. The technique represents the thermal system as an electrical analog circuit where temperatures correspond to voltages, heat flows to currents, thermal resistances to electrical resistances, and thermal capacitances to electrical capacitances. This approach enables rapid analysis of steady-state and transient thermal behavior without requiring detailed CFD simulation.
For power semiconductor cooling, the thermal network typically includes nodes representing junction temperature, case temperature, heatsink temperature, and ambient temperature, connected by thermal resistances. Additional nodes may represent intermediate layers such as thermal interface materials, baseplates, or cold plates. Thermal capacitances at each node capture thermal mass effects, enabling transient analysis. The model can be solved using circuit simulation tools or specialized thermal analysis software.
Accuracy of thermal network models depends on proper characterization of thermal resistances and capacitances. Junction-to-case thermal resistance is typically specified by the device manufacturer under defined test conditions. Case-to-heatsink resistance must account for thermal interface material properties, contact pressure, and surface roughness. Heatsink-to-ambient resistance depends on airflow conditions and must be characterized through testing or CFD analysis. Validating the model against physical measurements ensures that predictions are reliable for design optimization.
Thermal Imaging and Testing
Infrared thermal imaging provides invaluable insight into the actual temperature distribution in operating power electronic systems. Modern thermal cameras can measure temperature with accuracy better than ±2°C and spatial resolution of a few millimeters, enabling identification of hot spots, assessment of cooling system effectiveness, and validation of thermal models. However, interpreting thermal images requires understanding emissivity—the efficiency with which a surface radiates infrared energy.
Different materials and surface finishes have dramatically different emissivities. Black-anodized aluminum has emissivity near 0.9, making it read accurately with default camera settings. Bare copper or aluminum, with emissivities around 0.1, appears much cooler than its actual temperature unless the emissivity setting is corrected. Applying a coating of flat black paint to surfaces of interest can simplify accurate temperature measurement. Some thermal cameras can store emissivity settings for different regions of interest, enabling accurate measurement of different materials in a single image.
Thermal transient testing provides another powerful characterization technique. By applying a step change in power dissipation and recording the junction temperature response, the thermal impedance curve can be determined. This curve reveals the individual time constants associated with different layers in the thermal path—fast time constants correspond to die and die attach, intermediate time constants to substrates and baseplates, and slow time constants to heatsinks and ambient thermal coupling. The technique enables quality control testing of thermal interface assembly and can detect degradation from thermal cycling.
Reliability and Derating
Junction temperature directly affects the reliability and lifetime of power semiconductor devices. The Arrhenius relationship quantifies this effect: for every 10°C increase in operating temperature, the failure rate approximately doubles. This exponential temperature sensitivity means that relatively modest improvements in cooling system effectiveness can translate to dramatic improvements in device lifetime and system reliability.
Conservative thermal design practice employs derating—operating devices at junction temperatures below their absolute maximum ratings to improve reliability. A common approach limits maximum junction temperature to 100-110°C even though the device might be rated for 150°C or higher. This 40-50°C margin provides substantial reliability improvement while also leaving thermal headroom for ambient temperature variation, aging of thermal interface materials, and partial cooling system failures such as fan degradation.
Thermal cycling creates thermomechanical stress due to coefficient of thermal expansion (CTE) mismatch between materials. The number of thermal cycles to failure depends on both the temperature swing magnitude and the mean temperature. Reducing junction temperature swing by 20°C can increase thermal cycling life by a factor of 2-4 depending on the package construction. For applications with frequent load variations, thermal cycling lifetime may be the limiting reliability factor, making it even more important to minimize both peak temperature and temperature swing through effective thermal design.
Practical Design Considerations
Thermal Interface Materials Selection
The thermal interface material (TIM) between power semiconductors and heatsinks critically affects overall thermal resistance. Even apparently smooth machined surfaces have microscopic roughness that creates air gaps when placed in contact. Thermal interface materials fill these gaps to improve heat conduction. Common TIM options include thermal grease, phase change materials, thermal pads, and gap filler pads, each with distinct characteristics, advantages, and limitations.
Thermal grease offers the lowest thermal resistance (typically 0.1-0.5 K-cm²/W) but requires careful application and proper contact pressure. Too little grease leaves air gaps; too much grease increases thermal resistance because the grease thermal conductivity is much lower than metal. The ideal application uses just enough grease to fill surface irregularities without creating excess thickness. Some greases are silicone-based while others use synthetic oils; selection depends on temperature range, outgassing requirements, and compatibility with other materials.
Phase change materials (PCMs) are solid at room temperature but soften at elevated temperature (typically 45-60°C) to flow into surface irregularities, then remain soft during operation. PCMs are easier to apply than grease and provide consistent performance with less dependence on application technique. Thermal pads offer the convenience of solid, dry installation but have higher thermal resistance than grease or PCMs. Gap filler pads accommodate larger variation in component height and provide some mechanical compliance but typically have the highest thermal resistance of common TIM options. Material selection involves trading off thermal performance against ease of application, reliability, and cost.
Mounting and Assembly Techniques
Proper mounting of power semiconductors to heatsinks is essential for achieving low thermal resistance and reliable operation. Inadequate or uneven mounting pressure can leave air gaps that dramatically increase thermal resistance. Excessive mounting force can crack ceramic substrates or damage semiconductor die. Most power modules specify required mounting torque, typically in the range of 3-6 N-m for common mounting screw sizes.
The mounting surface flatness and finish significantly affect thermal interface performance. Heatsinks should have flatness within 0.05 mm over the mounting area and surface roughness less than 3-6 µm Ra. When mounting multiple power modules to a common heatsink, care must be taken to ensure parallel mounting surfaces so that all modules make proper thermal contact. Some designs use individual mounting blocks for each module to ensure proper interface even if the heatsink base has slight variations in flatness.
Assembly procedures should follow manufacturer recommendations regarding cleaning, TIM application, mounting sequence, and torque specifications. The mounting surface should be cleaned with isopropyl alcohol to remove contaminants that could degrade thermal performance. Mounting screws should be tightened in a cross pattern, gradually increasing torque in multiple steps to ensure even pressure distribution. Some applications require periodic retorquing after thermal cycling to compensate for TIM settling. Documentation of assembly torque values provides traceability and quality assurance.
System Integration and Environmental Factors
Effective thermal design considers the power electronic system within its larger environmental context. Ambient temperature varies with location, season, and whether equipment is indoors or outdoors. Altitude affects air density and therefore cooling performance—forced air systems may lose 3-4% of effectiveness for every 1000 meters of altitude increase. Orientation affects natural convection: heatsinks designed for vertical mounting may perform poorly if mounted horizontally.
Contamination can severely degrade cooling system performance over time. Dust accumulation on heatsink fins reduces airflow and heat transfer effectiveness. Air filters protect internal components but require periodic maintenance to prevent excessive pressure drop. Humid or marine environments may cause corrosion of aluminum heatsinks, potentially degrading thermal performance and creating reliability concerns. Conformal coatings protect electronics from moisture but may add thermal resistance if applied to heat-generating components.
Acoustic noise from cooling fans can be a critical system requirement, particularly for equipment used in office, residential, or medical environments. Larger, slower-speed fans move the same air volume with less noise than smaller, faster fans. Variable-speed fan control reduces noise during light load operation. Acoustic enclosures or foam baffles can reduce noise but may impede airflow, requiring careful design to avoid compromising thermal performance. Some applications achieve acoustic requirements by using liquid cooling with the heat-rejecting radiator located remotely from the electronics.
Emerging Technologies and Future Trends
Wide Bandgap Semiconductors
Silicon carbide (SiC) and gallium nitride (GaN) power semiconductors operate at higher junction temperatures than silicon devices—175-200°C continuously with some devices rated to 250°C—potentially simplifying cooling requirements. However, realizing this benefit requires packaging and thermal interface materials capable of withstanding these elevated temperatures. Additionally, the higher switching frequencies enabled by wide bandgap devices create new thermal challenges: smaller passive components have less thermal mass, and higher frequency operation increases core and copper losses in magnetic components.
The improved efficiency of SiC and GaN devices (typical 1-2% higher than comparable silicon devices) may seem modest but translates to significant thermal benefit. For a 100 kW system, improving efficiency from 97% to 98% reduces losses from 3 kW to 2 kW—a 33% reduction in cooling requirement. This efficiency advantage is greatest at high switching frequencies, enabling smaller, lighter magnetic components while maintaining or reducing overall system losses and cooling requirements.
Integration of wide bandgap devices challenges traditional thermal design approaches. Some GaN devices use flip-chip mounting with top-side cooling to minimize thermal path length. SiC modules increasingly use sintered silver die attach instead of solder to withstand higher temperature operation and improve thermal cycling reliability. The packaging evolution enables power densities several times higher than possible with silicon IGBTs, but requires concurrent advances in cooling technology to fully exploit the device capabilities.
Additive Manufacturing for Thermal Management
Three-dimensional printing technologies enable creation of complex cooling structures impossible to manufacture using conventional techniques. Conformal cooling channels can follow the shape of heat sources, minimizing thermal resistance. Lattice structures optimize the trade-off between thermal performance and material usage. Multi-material printing could potentially integrate thermal spreaders, heatsinks, and structural components in a single piece.
Metal additive manufacturing using selective laser melting or electron beam melting can produce copper or aluminum heatsinks with internal coolant passages too complex for conventional machining. These designs can incorporate features such as turbulence promoters, varying channel cross-sections, and local enhancement of heat transfer near high-flux regions. The technology is particularly attractive for aerospace and defense applications where the value of weight reduction and performance improvement justifies the currently higher manufacturing cost.
Challenges remain in achieving the surface finish and dimensional accuracy required for some thermal applications. As-printed surfaces are relatively rough, potentially requiring secondary machining of critical surfaces. Material properties of printed metals may differ from wrought or cast materials, particularly thermal conductivity and thermomechanical properties. However, continued advances in additive manufacturing processes and increasing adoption in production applications suggest that 3D printed thermal management components will become increasingly common in high-performance power electronics.
Integrated Thermal Management Systems
Future power electronic systems will increasingly feature thermal management integrated at multiple levels. Power modules will incorporate advanced thermal spreading and potentially embedded cooling channels. Electronics cabinets will use shared cooling infrastructure optimized for the specific heat load distribution. Vehicle and aircraft platforms will implement centralized thermal management coordinating cooling requirements across propulsion, power electronics, avionics, and cabin conditioning.
Intelligent thermal management systems will use distributed temperature sensing, physics-based thermal models, and predictive algorithms to optimize cooling performance while minimizing parasitic losses. Machine learning techniques may identify degradation of cooling system components before failure occurs, enabling predictive maintenance. Dynamic thermal management will adjust power converter operating points based on thermal state, balancing system performance against thermal constraints.
The ongoing electrification of transportation, expansion of renewable energy systems, and growth of data centers ensure that thermal management of high-power electronics will remain a critical engineering challenge. Success requires multidisciplinary expertise spanning semiconductor physics, heat transfer, fluid dynamics, materials science, and control systems. As power densities continue to increase and system requirements become more demanding, innovative thermal solutions will be essential for realizing the performance, efficiency, and reliability required in next-generation power electronic systems.
Summary
High-power electronics cooling represents a critical intersection of thermal science, power electronics, and systems engineering. The extreme power densities in modern power semiconductors demand sophisticated thermal design employing multiple cooling technologies, advanced materials, and careful attention to every element of the thermal path from junction to ambient. Success requires understanding both fundamental heat transfer principles and the specific thermal characteristics of power devices including IGBTs, thyristors, and emerging wide bandgap semiconductors.
Application-specific requirements drive thermal solution selection and design. Motor drives, inverters, power supplies, and battery systems each present unique combinations of power levels, environmental conditions, size constraints, and reliability requirements. Effective thermal design balances multiple considerations including thermal performance, cost, acoustic noise, weight, and manufacturability. Advanced technologies such as direct substrate cooling, vapor chamber heat spreaders, and additive manufacturing continue to push the boundaries of achievable thermal performance.
As power densities increase and system requirements become more demanding, thermal management will remain a fundamental challenge in power electronics design. Engineers who master the principles and practices of high-power electronics cooling will be well-equipped to develop the reliable, efficient, and high-performance systems required in renewable energy, electric transportation, industrial automation, and other critical applications driving the electrification of our society.