With the rapid development of unmanned aerial logistics and the demand for sustainable transportation, electric vertical take-off and landing (eVTOL) vehicles have become key enablers for rural express low-altitude delivery. Their propulsion and power management systems, serving as the core of energy conversion and control, directly determine the vehicle’s flight efficiency, payload capacity, operational safety, and endurance. The power MOSFET, as a critical switching component in these systems, significantly impacts overall performance, power density, thermal management, and reliability through its selection. Addressing the high-power, variable-load, and harsh-environment requirements of eVTOL applications, this article proposes a practical, scenario-oriented power MOSFET selection and design implementation plan.
### I. Overall Selection Principles: System Compatibility and Balanced Design
MOSFET selection should balance electrical performance, thermal characteristics, package size, and reliability to match stringent eVTOL system demands.
- Voltage and Current Margin Design: Based on typical battery voltages (e.g., 48V, 72V, or higher), select MOSFETs with a voltage rating margin ≥50% to handle regenerative braking spikes and voltage transients. Continuous and peak current ratings must exceed load requirements with a derating factor of 60–70% for reliable operation.
- Low Loss Priority: Focus on low on-resistance (Rds(on)) to minimize conduction loss and low gate charge (Q_g) and output capacitance (Coss) to reduce switching loss, enabling higher frequency operation and improved efficiency.
- Package and Heat Dissipation Coordination: Choose packages with low thermal resistance and parasitic inductance for high-power stages (e.g., TOLL, TO263) and compact packages for auxiliary circuits (e.g., SOT89). PCB copper area and thermal vias are essential for heat spreading.
- Reliability and Environmental Adaptability: For outdoor and varying weather conditions, prioritize devices with wide junction temperature ranges, high ESD resistance, and robust surge immunity to ensure long-term reliability.
### II. Scenario-Specific MOSFET Selection Strategies
eVTOL power systems typically involve propulsion motor drives, battery management, and auxiliary control loads. Each scenario demands tailored MOSFET selection.
Scenario 1: Main Propulsion Motor Drive (High Power, 5–20 kW per motor)
The propulsion motor requires high efficiency, high current capability, and fast switching to ensure thrust response and flight stability.
- Recommended Model: VBGQT1801 (Single-N, 80V, 350A, TOLL)
- Parameter Advantages:
- Utilizes SGT technology with extremely low Rds(on) of 1 mΩ (@10 V), drastically reducing conduction loss.
- High continuous current of 350A and peak capability support high-torque demands during take-off and climbing.
- TOLL package offers low thermal resistance and low parasitic inductance, suitable for high-frequency PWM operation.
- Scenario Value:
- Enables efficient motor drive with conversion efficiency >98%, extending battery life and flight range.
- Supports switching frequencies above 50 kHz, allowing compact motor design and reduced acoustic noise.
- Design Notes:
- Pair with high-current gate drivers (≥2 A) to minimize switching losses.
- Implement extensive copper pours and thermal vias on PCB; consider heatsinks for sustained high power.
Scenario 2: Battery Management and Power Distribution (Moderate Power, 1–3 kW)
This includes battery protection, DC-DC conversion, and load switching, requiring bidirectional control and compact integration.
- Recommended Model: VBI5325 (Dual-N+P, ±30V, ±8A, SOT89-6)
- Parameter Advantages:
- Integrated N and P-channel MOSFETs with low Rds(on) (18 mΩ N-channel @10 V, 32 mΩ P-channel @10 V) for minimal voltage drop.
- Low gate threshold voltage (Vth ≈ ±1.6 V) allows direct drive by low-voltage MCUs (3.3 V/5 V).
- SOT89-6 package saves board space and simplifies power path design.
- Scenario Value:
- Ideal for bidirectional current control in battery protection circuits and synchronous rectification in DC-DC converters.
- Enables efficient power switching for auxiliary systems, reducing standby consumption.
- Design Notes:
- Add gate resistors (10–100 Ω) to dampen ringing and ensure stable switching.
- Use symmetrical layout for parallel channels to balance current and thermal distribution.
Scenario 3: Auxiliary Actuator and Servo Control (Medium Power, 500 W–2 kW)
This covers flight control surfaces, landing gear actuators, and cooling fans, needing reliable switching and moderate current handling.
- Recommended Model: VBPB1101N (Single-N, 100V, 100A, TO3P)
- Parameter Advantages:
- Low Rds(on) of 9 mΩ (@10 V) ensures high efficiency in medium-power applications.
- High current rating of 100A accommodates peak loads from inductive actuators.
- TO3P package provides robust thermal performance and mechanical durability.
- Scenario Value:
- Suitable for driving servo motors and electromechanical actuators with fast response and low loss.
- Enhances system reliability in vibration-prone environments due to sturdy package.
- Design Notes:
- Implement TVS diodes and freewheeling diodes for inductive load protection.
- Ensure proper mounting with thermal interface material for heat dissipation.
### III. Key Implementation Points for System Design
- Drive Circuit Optimization:
- For VBGQT1801: Use dedicated high-current driver ICs with dead-time control to prevent shoot-through and minimize switching losses.
- For VBI5325: When driven by MCUs, include level-shifting circuits for P-channel gates and RC filters for noise immunity.
- For VBPB1101N: Add gate series resistors and possibly bootstrap circuits for high-side configurations if needed.
- Thermal Management Design:
- Tiered approach: VBGQT1801 requires heatsinks or cold plates; VBPB1101N uses PCB copper plus thermal vias; VBI5325 relies on natural convection with local copper pours.
- Derate current usage in high-altitude or high-temperature conditions (>50°C ambient).
- EMC and Reliability Enhancement:
- Place high-frequency capacitors (100 pF–10 nF) near MOSFET drain-source terminals to suppress voltage spikes.
- Incorporate TVS diodes at gates for ESD protection and varistors at power inputs for surge suppression.
- Implement overcurrent and overtemperature protection with fast shutdown mechanisms.
### IV. Solution Value and Expansion Recommendations
- Core Value:
- High Efficiency and Extended Range: Low-loss MOSFETs contribute to overall system efficiency >95%, maximizing payload and flight duration.
- Compact and Lightweight Design: Selected packages optimize power density, crucial for eVTOL weight constraints.
- Robust Operation: Margin design and protection features ensure reliability in rural and variable environments.
- Optimization and Adjustment Recommendations:
- Power Scaling: For higher voltage systems (e.g., 400V bus), consider SJ_Multi-EPI devices like VBPB15R47S (500V) or VBMB16R34SFD (600V).
- Integration Upgrade: For space-critical areas, explore dual MOSFETs in DFN packages (e.g., VBQA3638 for dual N-channel needs).
- Harsh Environment Adaptation: For extreme temperatures or humidity, specify automotive-grade variants or apply conformal coating.
- Future Trends: As technology advances, consider wide-bandgap devices (e.g., GaN) for even higher frequency and efficiency in next-generation eVTOL designs.
In conclusion, careful selection of power MOSFETs is pivotal for the success of rural delivery eVTOL power systems. The scenario-based approach and systematic design outlined here achieve an optimal balance of efficiency, reliability, and lightweight construction, supporting the evolution of autonomous aerial logistics in challenging environments.

Detailed Topology Diagrams