With the rapid advancement of urban infrastructure maintenance and aerial robotics, high-end bridge inspection Electric Vertical Take-Off and Landing (eVTOL) aircraft have become critical tools for ensuring structural safety. Their propulsion and onboard power management systems, serving as the "core muscles and nervous system" of the aircraft, demand extremely high efficiency, reliability, and power density to handle mission-critical loads like multi-rotor motors, high-power sensor suites, and communication payloads. The selection of power MOSFETs and IGBTs directly determines the system's thrust-to-weight ratio, flight endurance, electromagnetic compatibility (EMC) in noisy environments, and operational safety. Addressing the stringent requirements of inspection eVTOLs for efficiency, reliability, weight, and robustness, this article centers on scenario-based adaptation to reconstruct the power semiconductor selection logic, providing an optimized solution ready for direct implementation.
I. Core Selection Principles and Scenario Adaptation Logic
Core Selection Principles
High Voltage & Robustness: For typical high-voltage battery buses (400V-800V), semiconductor voltage ratings must have a safety margin ≥50% to handle regenerative braking spikes, switching transients, and potential overvoltage conditions.
Ultra-Low Loss & High Power Density: Prioritize devices with minimal on-state resistance (Rds(on)) and switching losses (Qgd, Qrr) to maximize efficiency, reduce heat sink size, and extend flight time. Low thermal resistance packages are crucial.
High Current Capability & Ruggedness: Devices must deliver high continuous and pulse currents for motor drives, with excellent SOA (Safe Operating Area) and avalanche energy ratings for harsh operational environments.
System-Level Reliability: Components must meet rigorous standards for vibration resistance, thermal cycling, and continuous operation under varying climatic conditions.
Scenario Adaptation Logic
Based on the core electrical systems within a bridge inspection eVTOL, power semiconductor applications are divided into three primary scenarios: High-Voltage Main Propulsion Inverter (Thrust Core), High-Current Auxiliary Actuator & PDU (Power Distribution), and Specialized High-Power Payload Control (Mission-Specific). Device parameters are matched to the unique demands of each scenario.
II. MOSFET/IGBT Selection Solutions by Scenario
Scenario 1: High-Voltage Main Propulsion Inverter (20kW-100kW per motor) – Thrust Core Device
Recommended Model: VBL155R13 (Single-N, 550V, 13A, TO-263, Planar)
Key Parameter Advantages: High 550V voltage rating is ideal for 400V+ DC bus systems, providing ample margin. Planar technology offers proven reliability and robust performance in high-voltage switching.
Scenario Adaptation Value: The TO-263 package provides excellent power dissipation capability necessary for high-power motor drives. Its high-voltage rating ensures system resilience against back-EMF spikes from large brushless motors, a critical factor for stable multi-rotor control during precise inspection hovering and maneuvering.
Applicable Scenarios: Phase legs in multi-level or two-level inverters for core propulsion motors.
Scenario 2: High-Current Auxiliary Actuator & PDU – Power Distribution & Control Device
Recommended Model: VBFB1402 (Single-N, 40V, 120A, TO-251, Trench)
Key Parameter Advantages: Exceptionally low Rds(on) of 2mΩ @10V minimizes conduction loss. Ultra-high continuous current rating of 120A handles significant auxiliary power paths.
Scenario Adaptation Value: The low-voltage, ultra-low Rds(on) characteristic makes it perfect for non-isolated DC-DC converters (e.g., 48V to 12V/5V), landing gear actuator control, and main power distribution unit (PDU) switching. High current capability in a TO-251 package offers an excellent balance of performance and power density, reducing weight.
Applicable Scenarios: High-current load switches, synchronous rectification in low-voltage-high-current DC-DC converters, servo/actuator drives.
Scenario 3: Specialized High-Power Payload Control – Mission-Specific Device
Recommended Model: VBMB16I20 (IGBT with FRD, 600/650V, 20A, TO-220F, SJ (Super Junction))
Key Parameter Advantages: 600V/650V rating suitable for high-power off-board systems. Integrated Fast Recovery Diode (FRD) simplifies circuit design. Low VCEsat of 1.7V @15V reduces conduction loss.
Scenario Adaptation Value: The IGBT is ideal for controlling high-power, mission-specific payloads requiring high voltage and moderate switching frequency, such as heavy-duty pulsed lighting systems for night inspections, heating elements for de-icing, or powerful industrial-grade laser rangefinders. The TO-220F insulated package aids in thermal management and safety isolation.
Applicable Scenarios: Switching control for high-power auxiliary payloads, where robustness and high voltage handling are prioritized over ultra-high switching speed.
III. System-Level Design Implementation Points
Drive Circuit Design
VBL155R13: Requires a dedicated high-voltage gate driver IC with sufficient sink/source current and negative voltage turn-off capability for robust operation. Careful attention to gate loop layout is critical.
VBFB1402: Can be driven by standard gate drivers. Ultra-low gate charge allows for very fast switching, necessitating careful layout to minimize parasitic inductance in the high-current power loop.
VBMB16I20: Requires a standard IGBT gate driver. The integrated FRD eliminates the need for an external anti-parallel diode. Gate resistor selection is key to balance switching loss and EMI.
Thermal Management Design
Aggressive Cooling Essential: All selected packages (TO-263, TO-251, TO-220F) are designed for heatsink attachment. Use thermal interface materials and forced air or liquid cooling to maintain junction temperatures well within limits, especially for the propulsion inverter (VBL155R13 arrays).
Derating for Altitude & Vibration: Apply stringent derating rules (e.g., 60% of current rating for continuous operation) accounting for reduced cooling efficiency at altitude and long-term vibration stress.
EMC and Reliability Assurance
EMI Suppression: Implement comprehensive RC snubbers across switches and bus capacitors. Use laminated busbars for the main inverter to minimize parasitic inductance and voltage overshoot.
Protection Measures: Design in desaturation detection for IGBTs, precise current sensing with fast comparators for overcurrent protection, and robust TVS diodes on all gate drivers and sensitive inputs to protect against airborne electromagnetic interference common near high-voltage power lines on bridges.
IV. Core Value of the Solution and Optimization Suggestions
The power semiconductor selection solution for high-end bridge inspection eVTOLs, based on scenario adaptation logic, achieves optimized performance across the high-voltage propulsion chain, high-current auxiliary systems, and specialized payloads. Its core value is reflected in:
Maximized Flight Endurance and Payload Capacity: By selecting the ultra-low-loss VBFB1402 for distribution and the appropriately rated VBL155R13/IGBT for propulsion and payloads, system-wide efficiency is maximized. This translates directly into extended mission time for bridge scanning or increased allowance for heavier, more advanced inspection sensors.
Uncompromising Safety and Mission Reliability: The high voltage margins of the VBL155R13 and VBMB16I20 ensure resilience against electrical transients. The robust package styles and derated design, combined with stringent protection circuits, create a system capable of reliable 7x24 operation in challenging environments, which is paramount for aerial inspection over critical infrastructure.
Optimal Balance of Performance, Weight, and Cost: The solution leverages mature, high-reliability package technologies (TO-263, TO-220, TO-251) that offer excellent thermal performance without the extreme cost of newer wide-bandgap semiconductors in all areas. This allows engineers to allocate budget towards other critical systems like flight controllers and sensors, while still achieving a high-performance, lightweight, and reliable power architecture.
In the design of propulsion and power systems for high-end bridge inspection eVTOLs, power semiconductor selection is a foundational element for achieving safety, endurance, and mission capability. The scenario-based selection solution proposed herein, by matching device characteristics to the specific demands of propulsion, power distribution, and payload control—and integrating robust drive, thermal, and protection strategies—provides a comprehensive technical roadmap. As eVTOLs evolve towards longer range, greater autonomy, and more complex payloads, the role of efficient and reliable power electronics will only grow. Future development should focus on integrating advanced packaging for even higher power density and the strategic adoption of SiC MOSFETs in the main inverter to push efficiency boundaries further, solidifying the hardware foundation for the next generation of intelligent, indispensable infrastructure guardianship platforms.

Detailed Scenario Topology Diagrams