With the advancement of electric aviation and the demand for efficient grid maintenance, power inspection eVTOLs have become key tools for aerial monitoring and fault detection. The propulsion and power management systems, serving as the "heart and nerves" of the aircraft, provide precise power conversion for critical loads such as main motors, avionics, and safety subsystems. The selection of power MOSFETs/IGBTs directly determines system efficiency, power density, thermal performance, and operational reliability. Addressing the stringent requirements of eVTOLs for lightweight design, high safety, long endurance, and harsh environment adaptation, this article focuses on scenario-based adaptation to develop a practical and optimized device selection strategy.
I. Core Selection Principles and Scenario Adaptation Logic
(A) Core Selection Principles: Four-Dimensional Collaborative Adaptation
MOSFET/IGBT selection requires coordinated adaptation across four dimensions—voltage, loss, package, and reliability—ensuring precise matching with eVTOL flight and operational conditions:
Sufficient Voltage Margin: For high-voltage propulsion buses (e.g., 400V-800V), reserve a rated voltage withstand margin of ≥50% to handle regenerative spikes and dynamic load variations. For example, prioritize devices with ≥600V for a 400V bus.
Prioritize Low Loss: Prioritize devices with low Rds(on) or VCEsat (reducing conduction loss), low Qg, and low Coss (reducing switching loss), adapting to high-power continuous operation, improving energy efficiency, and extending flight time.
Package Matching: Choose robust packages with low thermal resistance and high power density (e.g., TO247, TO220) for high-power motor drives. Select compact packages like DFN or SOT for auxiliary loads, balancing weight savings and layout complexity.
Reliability Redundancy: Meet aviation-grade durability requirements, focusing on thermal stability, vibration resistance, and wide junction temperature range (e.g., -55°C ~ 150°C), adapting to extreme conditions during power inspection missions.
(B) Scenario Adaptation Logic: Categorization by Load Type
Divide loads into three core scenarios based on function: First, main motor drive (propulsion core), requiring high-voltage, high-current, high-efficiency switching. Second, auxiliary system power supply (avionics support), requiring low-power consumption, bidirectional control, and compact integration. Third, safety-critical control (redundancy and isolation), requiring independent operation and fault tolerance. This enables precise parameter-to-need matching.
II. Detailed MOSFET Selection Scheme by Scenario
(A) Scenario 1: Main Motor Drive (10kW-50kW) – Propulsion Core Device
eVTOL main motors require handling high continuous currents and peak currents during takeoff and landing, demanding efficient, lightweight, and high-voltage drive.
Recommended Model: VBP16I75 (IGBT+FRD, 600/650V, 75A, TO247)
Parameter Advantages: SJ technology achieves a low VCEsat of 1.5V at 15V gate drive, minimizing conduction loss. Continuous current of 75A (with higher peak capability) suits 400V-800V buses. TO247 package offers excellent thermal performance (low RthJC) and mechanical robustness for vibration-prone environments.
Adaptation Value: Enables high-efficiency motor control for propulsion systems. For a 400V/20kW motor, multiple devices can be paralleled to handle higher currents. Supports switching frequencies up to 20kHz for precise speed regulation, enhancing flight stability and control response.
Selection Notes: Verify motor power rating, bus voltage, and peak current demands, reserving ample parameter margin. Implement reinforced heat sinking with thermal interface materials and forced-air cooling. Pair with dedicated gate drivers (e.g., IR2110) featuring desaturation and overtemperature protection.
(B) Scenario 2: Auxiliary System Power Supply – Functional Support Device
Auxiliary systems (sensors, communication modules, BMS circuits) are low-to-medium power (5W-100W) and require stable power distribution with minimal standby loss.
Recommended Model: VBQD5222U (Dual-N+P MOSFET, ±20V, 5.9A/-4A, DFN8(3X2)-B)
Parameter Advantages: Dual N+P configuration in a single package saves over 60% PCB space and enables synchronous rectification or H-bridge topologies. Low Rds(on) of 18mΩ (N-channel) and 40mΩ (P-channel) at 10V reduces conduction loss. DFN package offers low parasitic inductance and good thermal dissipation (RthJA~50°C/W). Low Vth of 1.0V/-1.2V allows direct drive by 3.3V/5V MCUs.
Adaptation Value: Facilitates efficient power management for avionics, such as DC-DC converters or load switches. Enables bidirectional current control in BMS modules, improving system integration and energy utilization.
Selection Notes: Ensure per-channel current does not exceed 70% of rated value. Add 22Ω-47Ω gate series resistors to suppress ringing. Maintain symmetric PCB layout for balanced current sharing between channels.
(C) Scenario 3: Safety-Critical Control – Redundancy and Isolation Device
Safety-critical systems (emergency shutdown, redundant motor drives, fault isolation) require high-current handling, fast response, and reliable operation under harsh conditions.
Recommended Model: VBM1808 (Single-N MOSFET, 80V, 100A, TO220)
Parameter Advantages: High current capability of 100A with ultra-low Rds(on) of 7mΩ at 10V, minimizing conduction loss. 80V withstand voltage suits 48V auxiliary power buses with >65% margin. TO220 package provides robust thermal and mechanical performance, with easy mounting on heat sinks. Trench technology ensures fast switching and low gate charge.
Adaptation Value: Enables redundant control paths for critical loads, such as backup motor drives or emergency power switches. Fast switching response (<100ns) ensures quick fault isolation, enhancing overall system safety.
Selection Notes: Confirm control voltage compatibility and load current profiles. Use isolated gate drivers (e.g., ISO5851) for high-side switching applications. Incorporate overcurrent detection via shunt resistors and comparator circuits.
III. System-Level Design Implementation Points
(A) Drive Circuit Design: Matching Device Characteristics
VBP16I75: Pair with high-voltage gate drivers offering peak output current ≥2A. Optimize gate drive loop to minimize parasitic inductance (<10nH). Add RC snubbers (e.g., 10Ω + 2.2nF) across collector-emitter to dampen voltage spikes.
VBQD5222U: Direct drive by MCU GPIO pins with 10Ω-47Ω gate series resistors. For high-side P-MOSFET, use NPN transistor level shifters or integrated gate drivers. Add SMF05C TVS diodes on gate pins for ESD protection.
VBM1808: Employ gate driver ICs with adequate current capability (e.g., 1.5A). Implement 1kΩ pull-down resistors on gate pins to prevent accidental turn-on. Include 100pF-1nF gate-source capacitors for enhanced noise immunity.
(B) Thermal Management Design: Tiered Heat Dissipation
VBP16I75: Focus on aggressive heat dissipation. Use extruded aluminum heat sinks with thermal pads (≥3W/m·K). Ensure forced-air cooling with ducted airflow; derate current to 60% at ambient temperatures above 85°C.
VBQD5222U: Local copper pour of ≥50mm² per MOSFET on PCB suffices; utilize thermal vias to inner layers for heat spreading. No additional heat sinking required for typical loads.
VBM1808: Mount on heat sinks via thermal pads; apply ≥300mm² copper area on PCB with multiple thermal vias. For continuous high-current operation, consider auxiliary cooling fans.
Overall, integrate thermal design with eVTOL aerodynamics—place high-power devices near cooling inlets or use liquid cooling plates for compact models.
(C) EMC and Reliability Assurance
EMC Suppression
VBP16I75: Add 100pF-1nF high-frequency capacitors across collector-emitter. Use shielded twisted-pair cables for motor connections and incorporate common-mode chokes (e.g., 10µH) at inverter outputs.
VBQD5222U: Place 100nF ceramic capacitors near power pins for decoupling. Insert ferrite beads (600Ω @ 100MHz) in series with supply lines to filter high-frequency noise.
VBM1808: Add Schottky freewheeling diodes (e.g., 40V/10A) parallel to inductive loads. Implement star grounding and separate power ground from signal ground.
Apply PCB zoning: isolate high-power sections from analog/digital areas. Install EMI filters (π-type) at all power inputs.
Reliability Protection
Derating Design: Ensure voltage and current margins under worst-case conditions (e.g., low atmospheric pressure, -40°C to 125°C temperature swings). Derate VBM1808 current to 70% at 100°C junction temperature.
Overcurrent/Overtemperature Protection: Integrate shunt resistors (0.5mΩ) in load loops with fast comparators (response <2µs). Use driver ICs with built-in overtemperature shutdown for VBP16I75.
ESD/Surge Protection: Add gate series resistors (10Ω-100Ω) combined with TVS diodes (e.g., SMCJ24A) on all external interfaces. Install varistors (MOVs) at power inputs for surge suppression up to 1kV.
IV. Scheme Core Value and Optimization Suggestions
(A) Core Value
High Power Density and Extended Endurance: System efficiency reaches >96%, reducing energy consumption by 15%-20% and increasing flight time for longer inspection sorties.
Enhanced Aviation Safety: Redundant control via independent devices ensures fault tolerance, critical for unmanned power inspection missions.
Robust Environmental Adaptation: Devices with wide temperature ranges and rugged packages withstand vibration, thermal cycling, and altitude variations, ensuring reliable operation in grid harsh environments.
(B) Optimization Suggestions
Power Adaptation: For higher power propulsion (>50kW), parallel multiple VBP16I75 devices or upgrade to VBMB18R05SE (800V/5A) for high-voltage auxiliary converters. For micro-loads (<1W), consider VB2290 (SOT23-3) to minimize footprint.
Integration Upgrade: Adopt intelligent power modules (IPMs) combining IGBTs and drivers for main motor control. Select VBQD5222U variants with integrated current sense for precision BMS applications.
Special Scenarios: For extreme cold environments (-55°C), choose low-Vth devices like VBQD5222U to ensure reliable turn-on. For high-vibration settings, opt for packages with screw mounting (TO220/TO247) and reinforce with potting compounds.
Propulsion System Specialization: Pair main motor drives with SiC MOSFETs (future upgrade) for higher switching frequencies, coordinated with VBP16I75 in hybrid configurations to boost efficiency.
Conclusion
Power device selection is central to achieving high efficiency, reliability, and safety in eVTOL power systems for power inspection. This scenario-based scheme provides comprehensive technical guidance for R&D through precise load matching and system-level design. Future exploration can focus on wide-bandgap devices (GaN/SiC) and integrated smart power modules, aiding in the development of next-generation high-performance eVTOLs to revolutionize grid maintenance and aerial surveillance.

Detailed MOSFET Application Diagrams