With the rapid development of urban air mobility, AI-powered electric vertical takeoff and landing aircraft for instant delivery (50kg payload) have emerged as a transformative solution. The propulsion and power management systems, serving as the "heart and thrust" of the entire vehicle, provide efficient power conversion and precise control for key loads such as multi-phase propulsion motors, high-voltage auxiliary systems, and critical flight controllers. The selection of power MOSFETs directly determines system efficiency, power density, thermal performance, and operational reliability. Addressing the stringent requirements of eVTOLs for high thrust-to-weight ratio, safety, endurance, and compactness, this article focuses on scenario-based adaptation to develop a practical and optimized MOSFET selection strategy.
I. Core Selection Principles and Scenario Adaptation Logic
(A) Core Selection Principles: Four-Dimensional Collaborative Adaptation
MOSFET selection requires coordinated adaptation across four dimensions—voltage, loss, package, and reliability—ensuring precise matching with harsh aerial operating conditions:
High Voltage & Robustness: For high-voltage propulsion buses (e.g., 400V-600V), select devices with sufficient voltage margin (≥20-30%) to handle regenerative braking spikes and system transients. Prioritize technologies like Super Junction (SJ) for high-voltage blocking capability.
Ultra-Low Loss for Maximum Efficiency: Prioritize devices with extremely low Rds(on) and optimized gate charge (Qg) to minimize conduction and switching losses. This is critical for extending flight endurance and reducing thermal management burden.
Package for Power Density & Cooling: Choose packages with excellent thermal performance (low RthJC) and low parasitic inductance (e.g., TOLL, DFN) for motor drives. Balance power handling and board space for auxiliary systems.
High Reliability & Ruggedness: Meet stringent aviation-grade durability requirements. Focus on high junction temperature capability, avalanche robustness, and high Vgs tolerance to ensure operation under thermal and electrical stress.
(B) Scenario Adaptation Logic: Categorization by Load Criticality
Divide loads into three core scenarios: First, Multi-phase Propulsion Motor Drive (Thrust Core), requiring very high current, ultra-low loss, and parallel operation capability. Second, High-Voltage DC Link & Auxiliary Power Distribution (System Power Backbone), requiring high voltage blocking and robust switching. Third, Safety-Critical & Redundant System Control (Flight Assurance), requiring compact, dual-channel devices for reliable load switching and isolation.
II. Detailed MOSFET Selection Scheme by Scenario
(A) Scenario 1: Multi-phase Propulsion Motor Drive (~10-30kW per phase) – Thrust Core Device
Propulsion motors demand handling extremely high continuous and peak phase currents with minimal loss to maximize thrust efficiency and power density.
Recommended Model: VBGQT1801 (Single N-MOS, 80V, 350A, TOLL)
Parameter Advantages: SGT technology achieves an ultra-low Rds(on) of 1.0mΩ at 10V. Continuous current of 350A supports high-power motor phases. TOLL package offers superior thermal resistance and very low parasitic inductance, essential for high-frequency PWM and parallel operation.
Adaptation Value: Drastically reduces conduction loss. For a phase current of 150A, conduction loss is only ~22.5W per device. Enables efficient operation at high switching frequencies (50-100kHz), contributing to smoother motor control, reduced torque ripple, and higher system power density.
Selection Notes: Requires careful parallel configuration for multi-phase bridges. Implement aggressive thermal management with a dedicated cold plate. Must be paired with high-current gate drivers with desaturation protection.
(B) Scenario 2: High-Voltage DC Link & Auxiliary Power Distribution – System Power Backbone Device
This scenario involves managing the main high-voltage bus (e.g., 400V) for DC-DC conversion and distributing power to auxiliary systems, requiring high voltage blocking and reliable switching.
Recommended Model: VBL16R31SFD (Single N-MOS, 600V, 31A, TO263)
Parameter Advantages: Super Junction Multi-EPI technology provides excellent 600V blocking capability with an Rds(on) of 90mΩ. TO263 (D2PAK) package offers a good balance of power handling, thermal performance, and mountability.
Adaptation Value: Provides a reliable switch for high-voltage DC-DC converters (e.g., 400V to 48V/12V) with sufficient margin. Can be used in PFC stages or as a main contactor driver, ensuring stable high-voltage bus management.
Selection Notes: Ensure gate drive voltage is sufficient (typically 12V) for full enhancement. Pay attention to layout to minimize high-voltage node ringing. Adequate heatsinking is required for continuous operation.
(C) Scenario 3: Safety-Critical & Redundant System Control – Flight Assurance Device
Critical systems like redundant flight controllers, servo actuators, or safety isolation switches require compact, dual-channel switches for reliable and independent control.
Recommended Model: VBBC3210 (Dual N+N MOSFET, 20V, 20A per channel, DFN8(3x3)-B)
Parameter Advantages: Integrated dual N-channel in a compact DFN8 saves significant PCB space. Low Rds(on) of 17mΩ and very low threshold voltage (Vth=0.8V) allow for efficient low-voltage switching and direct drive from low-voltage logic.
Adaptation Value: Enables independent, fail-safe control of redundant subsystems (e.g., dual sensors, backup actuators). Fast switching and low loss improve response time and efficiency of auxiliary control loops.
Selection Notes: Ideal for 12V or lower safety-critical rails. The low Vth requires careful attention to gate noise immunity. Use individual gate resistors and RC filters for each channel.
III. System-Level Design Implementation Points
(A) Drive Circuit Design: Matching Device Characteristics
VBGQT1801: Requires high-current, isolated gate drivers (e.g., based on SiC/GaN driver ICs) with peak current capability >5A. Implement Kelvin source connection for each device. Use gate resistors to control di/dt and prevent oscillation.
VBL16R31SFD: Use gate drivers with sufficient voltage offset for high-side switching. Incorporate miller clamp functionality to prevent parasitic turn-on.
VBBC3210: Can be driven directly by MCU GPIOs via a series resistor (22-100Ω). For higher reliability, use a buffer stage. Implement separate pull-down resistors on each gate.
(B) Thermal Management Design: Tiered and Aggressive Cooling
VBGQT1801 (TOLL): Must be mounted on a dedicated liquid cold plate or a massive heatsink with forced air. Use thermal interface material with high conductivity. Monitor junction temperature via on-board NTC or driver IC protection.
VBL16R31SFD (TO263): Requires a substantial heatsink, preferably attached to the main structural frame or cooling system. Ensure good thermal path from tab to heatsink.
VBBC3210 (DFN8): Local copper pour (≥100mm² per channel) with multiple thermal vias to an internal ground plane is usually sufficient. Position in areas with adequate airflow.
(C) EMC and Reliability Assurance
EMC Suppression:
Propulsion Bridge (VBGQT1801): Use low-ESR DC-link capacitors very close to the bridge. Implement RC snubbers across each switch or phase output. Shield motor cables.
High-Voltage Switch (VBL16R31SFD): Add snubber circuits across drain-source. Use common-mode chokes on input/output lines.
General: Implement strict PCB zoning (high-power, high-voltage, sensitive analog). Use ferrite beads on gate drive and auxiliary power lines.
Reliability Protection:
Derating: Apply conservative derating (e.g., voltage ≤80% of rating, current ≤60-70% at max expected junction temperature).
Fault Protection: Implement hardware overcurrent protection (shunt + comparator) for each motor phase. Use driver ICs with desaturation detection for VBGQT1801. Incorporate overtemperature shutdown at system level.
Transient Protection: Use TVS diodes on all gate driver supply rails. Implement robust input surge protection (varistors, TVS) at the main power entry.
IV. Scheme Core Value and Optimization Suggestions
(A) Core Value
Maximized Power-to-Weight Ratio: Ultra-low loss devices like VBGQT1801 minimize wasted energy as heat, directly contributing to longer flight time or higher payload capacity.
Enhanced System Safety and Redundancy: The use of dedicated, dual-channel switches (VBBC3210) for critical systems enables robust fault-tolerant architectures essential for flight certification.
Scalable and High-Density Design: The selected package portfolio (TOLL, TO263, DFN) supports both high-power handling and compact layouts, enabling scalable power trains.
(B) Optimization Suggestions
Higher Voltage Adaptation: For 800V+ bus architectures, consider devices like VBP15R33S (500V/33A) in a multi-level topology or seek 900V+ rated SJ MOSFETs.
Integration Upgrade: For motor drives, explore using pre-configured power modules or half-bridge building blocks based on TOLL devices for faster development.
Lightweighting: For non-critical, low-power auxiliary switches (<1A), consider the miniature VB1106K (100V/0.26A, SOT23-3) to save weight and space.
Thermal Performance: For the highest power stages, evaluate using VBGQT3401 (Dual-N, 40V, 350A, TOLL) for even lower parallel resistance and optimized thermal sharing in a dual-die package.
Conclusion
Power MOSFET selection is pivotal in achieving the demanding efficiency, power density, and reliability targets for eVTOL power and propulsion systems. This scenario-based scheme, leveraging devices like the ultra-low-loss VBGQT1801 for thrust, the robust VBL16R31SFD for high-voltage handling, and the compact dual-channel VBBC3210 for safety control, provides a foundational technical guideline. Future exploration should focus on wide-bandgap (SiC, GaN) devices for the highest efficiency segments and advanced intelligent power modules, driving the development of next-generation, high-performance urban air mobility solutions.

Detailed Topology Diagrams