With the rapid advancement of urban air mobility (UAM), AI-powered electric vertical take-off and landing (eVTOL) air taxis represent the future of short-haul transportation. Their propulsion and power management systems, serving as the "heart and muscles" of the aircraft, demand exceptionally high efficiency, power density, and reliability for critical loads such as lift/cruise motors, flight control actuators, and avionics. The selection of power MOSFETs directly determines the system's conversion efficiency, thermal performance, weight, and operational safety. Addressing the stringent requirements of eVTOLs for weight, efficiency, thermal management, and safety redundancy, this article centers on scenario-based adaptation to reconstruct the power MOSFET selection logic, providing an optimized solution ready for direct implementation.
I. Core Selection Principles and Scenario Adaptation Logic
Core Selection Principles
High Voltage & Sufficient Margin: For typical high-voltage DC bus systems (e.g., 540V or 800V), MOSFET voltage ratings must have a significant safety margin (≥20-30%) to handle regenerative braking spikes, switching transients, and ensure robustness.
Ultra-High Efficiency & Power Density: Prioritize devices with low on-state resistance (Rds(on)) and optimized package thermal impedance to minimize losses and cooling system weight, maximizing thrust-to-weight ratio.
Aerospace-Grade Reliability: Devices must exhibit excellent thermal stability, high avalanche energy rating, and proven reliability under vibration and varying atmospheric conditions for mission-critical operation.
Package & Thermal Suitability: Select packages like TO-3P, TO-263, TO-220F that offer superior heat dissipation and are compatible with aerospace cooling methods (e.g., cold plates).
Scenario Adaptation Logic
Based on the core power chain of a 2-seater eVTOL, MOSFET applications are divided into three main scenarios: High-Power Propulsion Inverter (Thrust Core), High-Voltage DC Power Distribution & Protection (Power Backbone), and High-Efficiency Auxiliary Power Conversion (System Support). Device parameters are matched to the specific voltage, current, and switching demands of each scenario.
II. MOSFET Selection Solutions by Scenario
Scenario 1: High-Power Propulsion Motor Inverter (~20-50 kW per motor) – Thrust Core Device
Recommended Model: VBPB17R11S (Single N-MOS, 700V, 11A, TO-3P)
Key Parameter Advantages: A 700V rating provides a robust margin for 540V bus systems. The TO-3P package offers extremely low thermal resistance for high heat dissipation. Utilizing SJ_Multi-EPI technology ensures a good balance between low Rds(on) (450mΩ) and high voltage capability.
Scenario Adaptation Value: The high voltage rating is crucial for safety and overshoot tolerance in motor drives. The robust TO-3P package facilitates direct mounting to a cooling plate, managing significant switching and conduction losses from high-frequency PWM. Its parameters are well-suited for paralleling in multi-phase inverter bridge legs to achieve the required current rating for motor drive.
Applicable Scenarios: Phase legs in lift and cruise motor drive inverters, requiring high voltage, robust thermal performance, and parallel-ability.
Scenario 2: High-Voltage DC Power Distribution & Protection – Power Backbone Device
Recommended Model: VBE19R08S (Single N-MOS, 900V, 8A, TO-252)
Key Parameter Advantages: Very high 900V drain-source voltage, ideal for 800V bus systems or as a primary protection switch on 540V buses with huge margin. The SJ_Multi-EPI technology provides stable performance at high voltages.
Scenario Adaptation Value: The high VDS is critical for solid-state circuit breakers (SSCBs), load disconnect switches, and backup power path selection in the high-voltage distribution unit (HPDU). It provides reliable isolation and fault interruption capability. The TO-252 package offers a good compromise between isolation, power handling, and board space.
Applicable Scenarios: Solid-state switching in main HV distribution, battery disconnect units, and protection circuits for critical high-voltage loads.
Scenario 3: High-Efficiency Auxiliary Power Conversion (AVIONICS, ECS) – System Support Device
Recommended Model: VBQF1615 (Single N-MOS, 60V, 15A, DFN8(3x3))
Key Parameter Advantages: Very low Rds(on) (10mΩ @10V) using Trench technology. The DFN8 package provides minimal footprint and low parasitic inductance. Low gate charge (Qg) enables high-frequency switching.
Scenario Adaptation Value: Perfect for high-frequency, high-efficiency DC-DC converters (e.g., 48V to 12V/28V) that power avionics, environmental control systems (ECS), and servo actuators. The ultra-low conduction loss maximizes converter efficiency, reducing thermal load. The compact size supports high power density in tightly integrated auxiliary power units (APUs).
Applicable Scenarios: Synchronous rectification and primary switching in multi-kilowatt isolated/non-isolated DC-DC converters for low-voltage bus generation.
III. System-Level Design Implementation Points
Drive Circuit Design
VBPB17R11S: Requires a high-current, isolated gate driver IC capable of fast switching to minimize losses. Careful attention to gate loop layout is critical.
VBE19R08S: Gate drive must be robust and include overvoltage clamp protection. Desaturation detection is recommended for protection functions.
VBQF1615: Can be driven by standard PWM controller outputs. Optimize layout for high-frequency operation to minimize ringing.
Thermal Management Design
Hierarchical Strategy: VBPB17R11S must be mounted on a liquid-cooled cold plate or high-performance heatsink. VBE19R08S requires a dedicated heatsink. VBQF1615 relies on PCB thermal vias and copper pours connected to the system cold plate.
Derating & Margins: Apply stringent aerospace derating rules (e.g., 50% voltage, 50-60% current at max rated temperature). Junction temperature must be kept far below maximum under all flight profiles.
EMC and Reliability Assurance
EMI Suppression: Use low-inductance busbars and RC snubbers across DC-link capacitors for inverter MOSFETs (VBPB17R11S). Proper shielding and filtering for all gate drives.
Protection & Redundancy: Implement comprehensive protection: short-circuit, overcurrent, overtemperature, and overvoltage for all switches. Consider paralleling devices or using redundant paths for critical distribution functions (VBE19R08S). Use TVS diodes and ferrite beads for surge and noise immunity.
IV. Core Value of the Solution and Optimization Suggestions
This high-voltage power MOSFET selection solution for eVTOL air taxis, based on scenario adaptation, achieves comprehensive coverage from megawatt-level propulsion to kilowatt-level auxiliary power. Its core value is reflected in:
Weight & Efficiency Optimization: Selecting the VBPB17R11S with a balance of voltage and thermal performance minimizes heatsink mass. The VBQF1615 maximizes auxiliary converter efficiency, reducing waste heat and cooling demands. This holistic approach contributes directly to extended range and payload capacity.
Safety-Critical Reliability: The use of the ultra-high-voltage VBE19R08S in distribution ensures an immense safety margin against transients, enhancing system-level fault tolerance. The robust packages and technologies (SJ, Trench) selected are proven for demanding environments, forming a foundation for certifiable systems.
Scalability and Integration Path: The chosen devices represent practical, commercially mature technologies that balance performance and cost for initial vehicle programs. The solution architecture allows for future seamless integration of next-generation wide-bandgap devices (like SiC MOSFETs for the main inverter) as they become more cost-competitive, enabling a clear path to higher efficiency and power density.
In the design of power systems for AI urban eVTOL air taxis, power MOSFET selection is a cornerstone for achieving the necessary efficiency, power density, and unwavering reliability. This scenario-based solution, by precisely matching devices to the distinct demands of propulsion, distribution, and conversion, provides a actionable technical foundation. As eVTOLs evolve towards higher voltages, greater intelligence, and stringent certification, future focus will shift towards integrated power modules and the adoption of SiC/GaN to further push the boundaries of performance, paving the way for safe, efficient, and scalable urban air transportation. In the dawn of the UAM era, robust and intelligent power electronics are the bedrock of flight safety and operational viability.

Detailed Topology Diagrams