Driven by the advancement of urban air mobility (UAM), high-end short-haul eVTOL air taxis represent the future of transportation. Their powertrain and electrical power distribution systems, serving as the "heart and arteries" of the aircraft, must deliver exceptionally efficient, reliable, and safe power conversion and control for critical loads such as lift/propulsion motors, high-voltage battery management, and avionics. The selection of power semiconductors (MOSFETs/IGBTs) directly determines the system's power density, efficiency, thermal performance, safety redundancy, and ultimately, flight endurance and reliability. Addressing the stringent requirements of eVTOLs for weight, efficiency, safety, and electromagnetic compatibility (EMC), this article centers on scenario-based adaptation to reconstruct the power device selection logic, providing an optimized solution ready for direct implementation.
I. Core Selection Principles and Scenario Adaptation Logic
Core Selection Principles
High Voltage & Safety Margin: For high-voltage battery buses (typically 400V-800V DC), power devices must have voltage ratings with significant margin (≥50-100%) to withstand switching transients, regenerative braking spikes, and operational fluctuations.
Ultra-Low Loss & High Efficiency: Prioritize devices with low conduction losses (low Rds(on) or VCEsat) and optimized switching characteristics to maximize powertrain efficiency, directly extending flight range.
High Power Density & Robust Packaging: Select packages (TO-247, TO-220, DFN) that offer an optimal balance of high current capability, excellent thermal dissipation, mechanical robustness, and minimal weight/volume.
Ultra-High Reliability & Redundancy: Components must be rated for harsh operational environments, exhibiting superior thermal stability, avalanche robustness, and long-term reliability for critical flight systems.
Scenario Adaptation Logic
Based on the core electrical systems within a 2-seater eVTOL, power semiconductor applications are divided into three main scenarios: Main Propulsion Motor Drive (High-Power Core), High-Voltage Battery & Power Distribution (Safety-Critical), and Auxiliary System & Avionics Power Management (Functional Support). Device parameters and technologies are matched accordingly.
II. Power Semiconductor Selection Solutions by Scenario
Scenario 1: Main Propulsion Motor Drive Inverter (20-50 kW range) – High-Power Core Device
Recommended Model: VBM16I20 (IGBT with FRD, 650V, 20A, TO-220)
Key Parameter Advantages: Utilizes Field Stop (FS) technology, offering a low VCEsat of 1.65V at 15V drive, optimizing conduction loss. The 650V voltage rating is suitable for 400V bus systems with ample margin. The integrated Fast Recovery Diode (FRD) ensures robust freewheeling and reverse recovery performance.
Scenario Adaptation Value: The TO-220 package provides excellent thermal interface for heatsinking, crucial for managing high inverter losses. IGBT technology offers a good balance of cost, robustness, and switching performance at the high voltage/current levels typical for compact eVTOL motor drives. The 20A rating allows for parallel use in phases to achieve higher power levels.
Applicable Scenarios: Phase legs in the main traction inverter for lift/cruise motors, requiring high reliability and efficient power handling.
Scenario 2: High-Voltage Battery Management & Primary DC Power Distribution – Safety-Critical Device
Recommended Model: VBFB185R05 (N-MOSFET, 850V, 5A, TO-251)
Key Parameter Advantages: Very high 850V drain-source voltage rating, providing exceptional margin for 400V-600V battery systems and protecting against high-voltage transients. Planar technology ensures stable performance.
Scenario Adaptation Value: The high voltage rating makes it ideal for pre-charge circuits, main contactor driving, or high-side switches in the primary high-voltage distribution unit (PDU). Its TO-251 package offers a compact footprint with good power handling for these auxiliary but critical control functions, ensuring safe isolation and connection of the high-voltage bus.
Applicable Scenarios: Solid-state switching in battery disconnect units (BDU), pre-charge circuit control, and high-voltage auxiliary load switches.
Scenario 3: Auxiliary System & Avionics Power Management (DC-DC Converters, Low-Voltage Loads) – Functional Support Device
Recommended Model: VBQA1152N (N-MOSFET, 150V, 53.7A, DFN8(5x6))
Key Parameter Advantages: Utilizes Trench technology, achieving a very low Rds(on) of 15.8mΩ at 10V Vgs. High continuous current rating of 53.7A. The 150V rating is perfect for intermediate bus voltages (e.g., 48V, 96V) or the output side of high-power DC-DC converters.
Scenario Adaptation Value: The DFN8(5x6) package offers very low parasitic inductance and excellent thermal performance via a large exposed pad, enabling high-frequency, high-efficiency switching. Its low Rds(on) minimizes conduction loss in high-current paths. Ideal for synchronous rectification in high-power DC-DC converters (e.g., stepping down from the high-voltage bus to 48V/28V) or for controlling high-current auxiliary loads like actuators or cabin heaters.
Applicable Scenarios: Synchronous rectifiers in high-power isolated DC-DC converters, primary switches in non-isolated point-of-load (POL) converters, and high-current load switches in the low-voltage distribution system.
III. System-Level Design Implementation Points
Drive Circuit Design
VBM16I20 (IGBT): Requires a dedicated high-current gate driver IC with negative turn-off voltage capability for robust operation. Careful attention to gate loop layout is critical to prevent cross-talk and ensure fast, clean switching.
VBFB185R05 (High-Voltage MOSFET): Use isolated or level-shifted gate drivers capable of handling the high common-mode voltage. Implement strong gate drive to minimize switching losses despite higher gate charge typical of high-voltage planar MOSFETs.
VBQA1152N (Low-Voltage MOSFET): Can be driven by standard gate driver ICs. Optimize layout for minimal power loop inductance to exploit its fast switching capability.
Thermal Management Design
Graded Heat Dissipation Strategy: VBM16I20 and VBFB185R05 will require dedicated heatsinks (possibly liquid-cooled for the IGBT in the main inverter). VBQA1152N relies on a high-quality thermal interface between its exposed pad and a large PCB copper plane, potentially augmented with a heatsink.
Derating Design Standard: Apply stringent derating rules consistent with aerospace or high-reliability applications (e.g., 50% voltage derating, current derating based on worst-case junction temperature). Target maximum junction temperatures well below the rated maximum for enhanced lifetime.
EMC and Reliability Assurance
EMI Suppression: Utilize snubber circuits and carefully placed DC-link capacitors for the IGBT inverter. Implement RC snubbers or ferrite beads for the high-voltage MOSFET switches. The DFN package of VBQA1152N inherently benefits from low loop inductance.
Protection Measures: Implement comprehensive overcurrent, overtemperature, and short-circuit protection at the system level. Use TVS diodes and RC networks on gate drives for all devices for ESD and voltage spike protection. Ensure proper creepage and clearance distances for high-voltage nodes.
IV. Core Value of the Solution and Optimization Suggestions
The power semiconductor selection solution for eVTOL air taxis proposed in this article, based on scenario adaptation logic, achieves full-chain coverage from the core high-power propulsion inverter to the high-voltage distribution and down to the auxiliary power management. Its core value is mainly reflected in the following three aspects:
Optimized Performance-Weight-Power Density Trade-off: By selecting a cost-effective and robust IGBT for the main drive, an ultra-high-voltage MOSFET for safety-critical isolation, and a high-current-density MOSFET for auxiliary power, the solution optimizes performance, weight, and volume across different subsystems. This contributes directly to maximizing the payload and range of the eVTOL.
Layered Safety and Reliability Architecture: The use of specialized devices for each voltage/power tier—with appropriate voltage margins and robust packages—creates a layered electrical architecture. This facilitates fault containment, where an issue in an auxiliary system is less likely to propagate to the critical propulsion or high-voltage bus, enhancing overall system safety.
Balance of Advanced Performance and Design Maturity: The selected devices leverage proven technologies (FS IGBT, Trench MOSFET) with established reliability data and supply chains. This reduces technical risk compared to adopting the very latest wide-bandgap devices (SiC/GaN) across the board, while still delivering the high efficiency and performance required for a competitive eVTOL platform. It provides a solid foundation for future incremental technology upgrades.
In the design of the powertrain and power management system for high-end eVTOL air taxis, power semiconductor selection is a cornerstone for achieving the necessary efficiency, power density, safety, and reliability. The scenario-based selection solution proposed in this article, by accurately matching the distinct requirements of the propulsion, primary distribution, and auxiliary systems, and combining it with rigorous system-level design practices, provides a comprehensive, actionable technical reference for eVTOL development. As eVTOLs evolve towards higher voltages, higher efficiencies, and certified airworthiness, the selection of power devices will increasingly focus on qualification to aerospace standards, integration of health monitoring, and the adoption of next-generation WBG devices. Future exploration will logically focus on the application of SiC MOSFETs in the main inverter and the development of integrated power modules, laying a solid hardware foundation for creating the next generation of safe, efficient, and commercially viable urban air mobility solutions.

Detailed Topology Diagrams