The rapid development of urban air mobility and specialized logistics, such as chemical transport, places extreme demands on electric Vertical Take-Off and Landing (eVTOL) aircraft. Their propulsion and power management systems, serving as the core of thrust generation and energy distribution, directly determine the aircraft's payload capacity, flight endurance, operational safety, and overall reliability. Power semiconductors (MOSFETs/IGBTs), as the critical switching components in these high-power systems, profoundly impact system efficiency, power density, thermal performance, and ruggedness through their selection. Addressing the unique requirements of high-voltage bus systems, stringent safety standards, and demanding weight constraints in chemical transport eVTOLs, this article proposes a complete, actionable semiconductor selection and design implementation plan with a scenario-oriented and systematic approach.
I. Overall Selection Principles: High Voltage, High Efficiency, and Robustness
Selection must prioritize a balance among voltage rating, conduction/switching losses, current handling, and package thermal performance, tailored to the rigorous aviation environment.
Voltage and Current Margin Design: Based on typical high-voltage bus architectures (e.g., 400V, 600V, 800V), select devices with a voltage rating margin ≥30-50% above the maximum bus voltage to withstand regenerative braking spikes and transients. Current rating must support continuous and peak thrust demands with significant derating for thermal management.
Loss Minimization for Range and Cooling: For motor drives, low conduction loss (low Rds(on) for MOSFETs, low VCEsat for IGBTs) is critical for efficiency. For high-switching-frequency applications (auxiliaries), low gate charge (Q_g) and output capacitance (Coss) are key to reducing switching loss and enabling higher frequencies.
Package and Thermal Management Coordination: High-power propulsion requires packages with very low thermal resistance (e.g., TO-247, TO-3P) for effective heatsinking. Weight-saving and space-constrained areas may use TO-220F or TO-252. Thermal interface materials and advanced cooling techniques (liquid cold plates) are often necessary.
Reliability and Environmental Ruggedness: Operation in varying atmospheric conditions and under continuous high stress demands devices with high junction temperature ratings, strong avalanche energy capability, and stable parameters over lifetime. Safety-critical designs may require adherence to relevant automotive or aerospace quality standards.
II. Scenario-Specific Semiconductor Selection Strategies
The powertrain of a chemical transport eVTOL can be categorized into main propulsion motors, high-power auxiliary pumps/compressors, and critical safety & distribution loads.
Scenario 1: Main Propulsion Motor Drive (High-Power, High-Voltage)
This is the most demanding application, requiring maximum efficiency, high power density, and ultimate reliability for lift and cruise.
Recommended Model: VBP17R47S (Single-N MOSFET, 700V, 47A, TO-247)
Parameter Advantages:
Super-Junction (SJ_Multi-EPI) technology offers an excellent balance of high voltage (700V) and remarkably low on-resistance (80 mΩ @10V), minimizing conduction losses.
High current rating (47A) suits multi-phase motor drive legs in parallel configurations.
TO-247 package provides superior thermal dissipation capability for managing high power.
Scenario Value:
Enables high-efficiency motor drive inverters, directly extending flight range and payload capacity.
The high voltage rating provides headroom for 600V+ bus systems, enhancing system safety margin.
Design Notes:
Must be driven by high-current gate driver ICs with reinforced isolation.
Requires meticulous PCB layout with low-inductance power loops and strategic placement of DC-link capacitors.
Scenario 2: High-Power Auxiliary Loads (Chemical Pump/Compressor Control)
These loads (e.g., for cargo environment management) require robust switching, high continuous current, and good efficiency at slightly lower frequencies than main motors.
Recommended Model: VBMB16I20 (IGBT+FRD, 600/650V, 20A, TO-220F)
Parameter Advantages:
Field Stop (FS) IGBT technology offers low saturation voltage (VCEsat=1.65V @15V) at medium frequencies, ideal for switch-mode pump drives.
Integrated Fast Recovery Diode (FRD) simplifies design and improves reliability in inductive switching.
TO-220F package offers a good balance of power handling and mounting flexibility.
Scenario Value:
Provides a cost-effective and robust solution for controlling several-hundred-watt auxiliary motors or pumps.
IGBT characteristics are favorable for lower switching frequency drives, simplifying EMC filtering.
Design Notes:
Gate drive voltage must be adequately supplied (typically 15V) for optimal VCEsat.
Consider snubber circuits for managing voltage overshoot during turn-off.
Scenario 3: Critical Safety & Power Distribution Loads (Rapid Switching, Lower Voltage)
These include battery disconnect units, fan controllers, or heater controls that require fast switching, low loss, and high reliability, often on lower voltage rails (e.g., 48V, 100V).
Recommended Model: VBFB1102N (Single-N MOSFET, 100V, 50A, TO-251)
Parameter Advantages:
Extremely low on-resistance (19 mΩ @10V) using Trench technology, ensuring minimal voltage drop and power loss in conduction.
High continuous current (50A) in a compact TO-251 package, offering excellent power density.
Lower voltage rating (100V) is perfect for secondary power distribution networks.
Scenario Value:
Enables highly efficient, compact solid-state power switching modules for safety-critical load shedding or power routing.
Low Rds(on) reduces heat generation in confined spaces, improving system reliability.
Design Notes:
Can often be driven directly by MCUs or via simple driver stages due to standard gate threshold.
Ensure proper PCB copper area for heat dissipation despite the small package.
III. Key Implementation Points for System Design
Drive Circuit Optimization: Use isolated, high-speed gate drivers for main propulsion MOSFETs/IGBTs. Pay critical attention to gate resistance selection to balance switching speed and EMI. Implement advanced protection features (DESAT, short-circuit, undervoltage lockout).
Thermal Management Design: Employ liquid cooling or large forced-air heatsinks for main inverters using TO-247 devices. Use thermal vias and exposed pads effectively for surface-mount or TO-220 packages. Perform detailed thermal simulation under worst-case flight profiles.
EMC and Reliability Enhancement: Implement comprehensive DC-link filtering with film capacitors. Use RC snubbers or clamp circuits across power devices to suppress voltage spikes. Employ common-mode chokes and shielded cables to mitigate conducted EMI. Integrate redundant protection circuits (current sensing, temperature monitoring) for fault-tolerant operation.
IV. Solution Value and Expansion Recommendations
Core Value:
High-Efficiency Propulsion: The combination of low-loss SJ MOSFETs and optimized IGBTs maximizes powertrain efficiency, crucial for mission range.
Enhanced Safety & Reliability: Rugged devices suitable for high-voltage environments, combined with robust protection designs, ensure safe operation during chemical transport missions.
Optimized Power Density: Selection of devices with high current capability and compact packages contributes to overall system weight reduction.
Optimization and Adjustment Recommendations:
Higher Power Scaling: For larger eVTOLs, consider paralleling VBP17R47S devices or exploring higher-current module solutions.
Integration Upgrade: For auxiliary drives, consider intelligent power modules (IPMs) that integrate IGBTs, drivers, and protection.
Extreme Environment: For operation in wide temperature ranges or high vibration, specify devices screened for enhanced robustness or consider potting critical power modules.
Future Technology: Monitor the adoption of Silicon Carbide (SiC) MOSFETs for the main inverter to achieve even higher frequency, efficiency, and power density.
Conclusion
The selection of power semiconductors is a cornerstone in the design of high-performance, reliable eVTOL propulsion and power systems for demanding applications like chemical transport. The scenario-based selection and systematic design methodology proposed herein aim to achieve the optimal balance among power density, efficiency, safety, and ruggedness. As eVTOL technology matures, the adoption of wide-bandgap semiconductors like SiC will further push the boundaries of performance, supporting the next generation of efficient and safe low-altitude logistics platforms.

Detailed Topology Diagrams