With the rapid development of urban air mobility, electric Vertical Take-Off and Landing (eVTOL) aircraft for island commuting have become a key solution for efficient transportation. The propulsion inverter, battery management, and auxiliary power systems, serving as the "heart and energy core" of the entire vehicle, provide high-fidelity power conversion and distribution for critical loads such as propulsion motors, battery packs, and avionics. The selection of power MOSFETs and IGBTs directly determines system efficiency, power density, thermal performance, and mission reliability. Addressing the stringent requirements of eVTOL for extreme weight efficiency, safety, high voltage, and operational robustness, this article focuses on scenario-based adaptation to develop a practical and optimized semiconductor selection strategy.
I. Core Selection Principles and Scenario Adaptation Logic
(A) Core Selection Principles: Multi-Dimensional Co-optimization
Power device selection requires coordinated adaptation across key dimensions—voltage, loss, package, and reliability—ensuring precise matching with the harsh operating conditions of aviation:
High Voltage with Margin: For high-voltage battery buses (typically 400V-800V DC), select devices with rated voltages exceeding the maximum bus voltage by ≥50% to withstand voltage spikes during regenerative braking and fault conditions. Prioritize devices with ≥900V-1200V ratings for 400V-800V systems.
Ultra-Low Loss Priority: Prioritize devices with minimal conduction loss (low Rds(on)/Vce(sat)) and switching loss (low Qg, Eoss). This is critical for maximizing flight time (energy efficiency), reducing heat sink weight, and managing thermal stress in confined spaces.
Package for Power Density & Cooling: Choose packages like TO-247, TO-3P, or TO-247-4L that offer excellent thermal performance (low RthJC) for main propulsion inverters. For distributed systems, compact packages like TO-252 or TO-220F are preferred to save weight and space while ensuring adequate heat dissipation.
Aviation-Grade Reliability: Devices must operate reliably under vibration, wide temperature swings, and continuous high stress. Focus on high junction temperature capability (Tj max ≥ 175°C), robust gate oxide, and high immunity to dv/dt and di/dt stresses.
(B) Scenario Adaptation Logic: Categorization by System Function
Divide applications into three core scenarios: First, Main Propulsion Motor Drive (high-power core), requiring very high voltage, current, and switching frequency. Second, High-Voltage Auxiliary & Battery Management Systems (functional and safety critical), requiring efficient switching for DC-DC conversion and contactor control. Third, Low-Voltage Distribution & Protection (high-current power path), requiring ultra-low conduction loss for power distribution and protection circuits.
II. Detailed Device Selection Scheme by Scenario
(A) Scenario 1: Main Propulsion Motor Inverter (High-Power Core)
Propulsion motors demand the highest power levels, requiring devices capable of handling high DC link voltages (≥800V) and large currents with utmost efficiency and high-frequency switching to minimize motor and filter weight.
Recommended Model: VBP112MC60-4L (SiC MOSFET, 1200V, 60A, TO247-4L)
Parameter Advantages: Utilizes advanced SiC (Silicon Carbide) technology, offering a remarkably low Rds(on) of 40mΩ (at 18V Vgs). The 1200V rating provides ample margin for 800V bus architectures. The TO247-4L (Kelvin source) package minimizes gate loop inductance, enabling cleaner, faster switching crucial for SiC.
Adaptation Value: Drastically reduces both conduction and switching losses compared to Si counterparts. Enables inverter switching frequencies >50 kHz, allowing for smaller, lighter motor filters and magnetics. Directly contributes to extended range and higher power density. High-temperature operation capability eases cooling system requirements.
Selection Notes: Requires a dedicated high-performance gate driver with negative turn-off voltage capability (as per Vgs min of -10V). PCB layout must minimize power loop inductance. Active or advanced forced cooling (liquid cooling) is typically required.
(B) Scenario 2: High-Voltage Auxiliary Power & Battery System Switch
This includes high-voltage DC-DC converters for avionics and battery pack isolation contactors. Requirements are high voltage blocking, good efficiency, and compact size for distributed placement.
Recommended Model: VBE165R08SE (Super-Junction MOSFET, 650V, 8A, TO252)
Parameter Advantages: Deep-Trench Super-Junction technology offers a balanced low Rds(on) of 460mΩ and robust 650V rating. The compact TO252 (DPAK) package saves significant board space and weight while providing good thermal performance via its exposed pad.
Adaptation Value: Ideal for auxiliary DC-DC converters (e.g., 400V to 28V/12V) or as a solid-state switch for battery module isolation. Its efficiency improves overall system energy conversion, and its small footprint allows integration near point-of-load.
Selection Notes: Confirm RMS and peak current requirements for the specific converter topology. Ensure adequate PCB copper area for heat sinking. Gate driving is straightforward with standard drivers.
(C) Scenario 3: Low-Voltage High-Current Distribution & Protection
This involves power distribution units (PDUs) protecting and routing power from the main low-voltage bus (e.g., 28V or 48V) to various avionics, lighting, and control systems. Ultra-low conduction resistance is paramount.
Recommended Model: VBMB1311 (Trench MOSFET, 30V, 68A, TO220F)
Parameter Advantages: Features an extremely low Rds(on) of 10mΩ (at 10V Vgs), minimizing voltage drop and power loss in high-current paths. The 68A continuous current rating handles substantial loads. The fully plastic TO220F package provides safe isolation and good power handling.
Adaptation Value: When used as a smart fuse or load switch, its low on-state loss minimizes heat generation and voltage sag, improving efficiency of downstream systems. Enables electronic circuit protection (e.g., e-fuse) with fast response versus mechanical breakers.
Selection Notes: Apply within its voltage rating for 28V systems. Gate can be driven directly from 5V or 3.3V MCUs due to low Vth (1.7V). Thermal design is still important for continuous high-current operation.
III. System-Level Design Implementation Points
(A) Drive Circuit Design: Matching Device Characteristics
VBP112MC60-4L (SiC): Pair with isolated gate drivers (e.g., SiC-specific drivers from ADI, TI) capable of fast slew rates and providing negative turn-off voltage (-3 to -5V). Use low-inductance gate resistor networks and careful attention to decoupling.
VBE165R08SE: Standard gate driver ICs are sufficient. Include a small gate resistor to control switching speed and damp ringing.
VBMB1311: Can be driven directly by MCU GPIO for slow switching or via a small buffer MOSFET/NPN for faster turn-off. Include basic RC snubber if inductive load switching is involved.
(B) Thermal Management Design: Critical for Power Density
VBP112MC60-4L: Requires dedicated, advanced cooling. Mount on a liquid-cooled cold plate or a large, forced-air-cooled heatsink. Use thermal interface material (TIM) with high conductivity.
VBE165R08SE: Requires a local PCB copper pad of ≥100mm² with thermal vias. A small clip-on heatsink may be needed for high-duty-cycle operation.
VBMB1311: Mount on a PCB with a generous copper area (≥300mm²) or a small aluminum heatsink, especially for currents near its rating.
Overall: Implement thermal monitoring (NTC/PTC) near key devices. Design cooling airflow path strategically in the avionics bay.
(C) EMC and Reliability Assurance
EMC Suppression:
VBP112MC60-4L: Utilize low-inductance DC-link capacitor banks. Implement RC snubbers across each switch if needed. Shield motor cables.
General: Use common-mode chokes on input power lines. Implement proper filtering for auxiliary power inputs. Maintain strict separation of high dv/dt nodes from sensitive analog circuits.
Reliability Protection:
Derating: Apply conservative derating (e.g., use ≤60-70% of rated voltage/current at max operational temperature).
Overcurrent/SOAP Protection: Implement hardware-based desaturation detection for SiC MOSFETs and IGBTs. Use shunt resistors or current sensors with fast comparators.
Voltage Clamping: Use TVS diodes or varistors on gate drives and at the inputs of all power converters. Protect battery terminals with appropriate high-energy TVS devices.
IV. Scheme Core Value and Optimization Suggestions
(A) Core Value
Maximized Range and Payload: SiC-based propulsion inverter significantly increases system efficiency, directly translating to longer flight time or increased payload capacity.
Enhanced Safety and Power Density: Robust high-voltage devices ensure reliable operation of critical systems. Compact packages contribute to overall weight reduction.
Balanced Performance and Cost: The selected portfolio leverages both cutting-edge SiC for the performance-critical path and cost-optimized, mature Si technologies for auxiliary functions, offering an optimal system-level cost solution.
(B) Optimization Suggestions
Higher Power Propulsion: For larger eVTOLs requiring >100A phase currents, consider paralleling VBP112MC60-4L devices or moving to higher-current SiC modules.
Integration Upgrade: For battery management contactor driving, consider intelligent high-side switch ICs that integrate protection features.
Special Scenarios: For extreme vibration environments, consider additional mechanical securing (potting, brackets) for larger packages like TO-247. For the lowest conduction loss in LV distribution, explore even lower Rds(on) devices in similar packages.
Redundancy Design: For safety-critical distribution paths (avionics power), use two VBMB1311 devices in series or parallel with independent control for redundancy and fault isolation.
Conclusion
Power semiconductor selection is central to achieving the demanding goals of efficiency, power density, and reliability in eVTOL power systems. This scenario-based scheme, leveraging SiC for high-performance propulsion and optimized Si MOSFETs for auxiliary functions, provides a clear technical pathway for eVTOL powertrain development. Future exploration should focus on integrated power modules and wide-bandgap devices with even higher switching speeds, further pushing the boundaries of aerial vehicle performance and safety.

Detailed Topology Diagrams