Preface: Building the "Nervous System" for Vertiport Test Infrastructure – Discussing the Systems Thinking Behind Power Device Selection
In the emerging field of vertiport-integrated flying car test benches, an outstanding test system is not merely an integration of power supplies, loads, and data acquisition units. It is, more importantly, a precise, dynamic, and reliable electrical "stress applicator" and "performance probe." Its core capabilities—high-fidelity simulation of both flight and road operational profiles, high-bandwidth dynamic load response, and the reliable coordination of myriad auxiliary sensors and controls—are all deeply rooted in a fundamental module that determines the system's fidelity and safety: the power conversion and management subsystem.
This article employs a systematic and co-design mindset to deeply analyze the core challenges within the power path of flying car test benches: how, under the multiple constraints of extreme voltage/current ratings, high switching frequency for precision, harsh EMI environments, and stringent reliability requirements, can we select the optimal combination of power devices for the three key nodes: high-voltage DC stimulus & energy recovery, high-current actuator/dyno drive, and multi-channel auxiliary system power management?
Within the design of a flying car test bench, the power conversion and switching module is the core determining test accuracy, bandwidth, safety, and uptime. Based on comprehensive considerations of bidirectional energy flow for regenerative braking/fan simulation, transient high-current handling for torque ripple, system isolation, and robust thermal management, this article selects three key devices from the component library to construct a hierarchical, complementary power solution.
I. In-Depth Analysis of the Selected Device Combination and Application Roles
1. The Core of the High-Voltage Stress Stimulus: VBP117MC06 (1700V SiC MOSFET, 6A, TO-247) – Bidirectional High-Voltage DC Source/Sink Main Switch
Core Positioning & Topology Deep Dive: This device is pivotal for simulating the high-voltage DC bus of a flying car's powertrain (often ~800V to 1kV) and managing regenerative energy flow back to the grid or storage. Its 1700V rating provides critical margin for voltage spikes during switching transients and fault conditions inherent in test environments. The SiC technology enables operation at very high switching frequencies (50kHz-200kHz+), crucial for high-bandwidth, high-fidelity power amplifier stages in test systems that must replicate fast transients from propulsors or traction inverters.
Key Technical Parameter Analysis:
Ultra-High Voltage & SiC Advantage: The 1700V VDS safely encompasses the high-voltage DC link with ample derating. SiC's near-zero reverse recovery charge and high-temperature stability drastically reduce switching losses, enabling efficient, compact, and cool-running high-voltage converters.
Low Rds(on) for its Voltage Class: 1500mΩ @ 18V is competitive, keeping conduction losses manageable in medium-current paths typical of stimulus sources.
Selection Trade-off: Compared to series-connected lower-voltage Si IGBTs or MOSFETs (complex balancing, slower), this single SiC MOSFET offers simplicity, superior speed, and efficiency, justifying its cost for mission-critical test accuracy and reliability.
2. The Backbone of High-Current Load Simulation: VBL1615A (60V, 120A, TO-263) – Dynamometer/Actuator Drive Inverter Low-Side Switch
Core Positioning & System Benefit: As the core switch in low-voltage, ultra-high-current three-phase inverter bridges driving dynamometers, mechanical load simulators, or environmental chamber actuators, its exceptionally low Rds(on) of 7mΩ @10V is paramount. This directly determines the conduction loss and current fidelity of the load simulation circuit. Under high-torque, high-cyclic-duty test profiles:
High Efficiency & Power Density: Minimizes energy loss and heat generation within the test bench itself, reducing cooling demands and facility energy costs.
Exceptional Peak Current Capability: The TO-263 package with extremely low internal resistance allows for very high pulsed currents, accurately simulating sudden load demands like landing impact or rapid acceleration.
Enhanced Signal Fidelity: Low conduction loss correlates with minimal distortion, ensuring the load current waveform precisely follows the command signal for accurate device-under-test (DUT) characterization.
Drive Design Key Points: Despite the low Rds(on), its high current rating demands a gate driver capable of high peak current to charge/discharge the significant Ciss rapidly, minimizing switching losses during high-frequency PWM operation for dynamic load simulation.
3. The Intelligent Auxiliary System Butler: VBMB2251K (-250V, -7A, TO-220F) – Multi-Channel Isolated/High-Side Auxiliary Power & Sensor Supply Switch
Core Positioning & System Integration Advantage: This single P-MOSFET in an isolated package is key to achieving intelligent management and fault isolation for medium-voltage auxiliary rails and sensor suites within the test bench. Flying car test benches involve numerous isolated sensors (voltage, current, vibration), safety interlocks, and controller subsystems that require reliable, switched power rails.
Application Example: Enables sequenced power-up of different test stand sections, provides hard-wired emergency shutdown (ESD) control, or isolates faulty sensor clusters without affecting the entire system.
Reason for P-Channel Selection: As a high-side switch for positive rails up to 250V, it can be controlled directly by opto-isolators or low-voltage logic with a simple level shifter, providing a robust and straightforward isolation barrier. This is crucial for safety and noise immunity in the electrically noisy test environment.
Package Benefit: The TO-220F fully isolated package simplifies heatsinking and improves creepage/clearance distances, enhancing reliability in dense, high-potential test equipment.
II. System Integration Design and Expanded Key Considerations
1. Topology, Drive, and Control Loop
High-Voltage SiC Source & Digital Controller Coordination: The drive for VBP117MC06 must be a high-speed, isolated gate driver with precise dead-time control and desaturation protection. Its switching must be tightly synchronized with the high-bandwidth controller of the programmable DC source/load.
High-Fidelity Control of Load Inverter: As the final execution unit for dynamic load profiles, the switching consistency and speed of VBL1615A are critical for minimizing current ripple and phase delay. Matched, high-current gate drivers are essential.
Intelligent & Safe Auxiliary Management: The gate of VBMB2251K is controlled via isolated digital outputs from the Test Sequencer or Safety PLC, enabling soft-start for capacitive sensor loads and instant shutdown upon fault detection.
2. Hierarchical Thermal Management Strategy
Primary Heat Source (Forced Liquid/Air Cooling): The VBL1615A in the load inverter is the primary heat source due to its very high current, requiring a low-thermal-impedance heatsink, potentially liquid-cooled for high-duty-cycle tests.
Secondary Heat Source (Forced Air Cooling): The VBP117MC06, while efficient, concentrates switching loss at high frequency. It requires a dedicated heatsink with attention to low-inductance mounting to preserve SiC switching benefits.
Tertiary Heat Source (Convection/PCB Conduction): VBMB2251K and its control circuits rely on PCB heatsinking. The isolated package allows direct mounting to a chassis or heatsink for improved heat dissipation.
3. Engineering Details for Reliability Reinforcement
Electrical Stress Protection:
VBP117MC06: In high-speed SiC circuits, careful attention to PCB layout (minimizing loop inductance) is more critical than ever. RC snubbers may be used to dampen ringing caused by parasitic inductance.
VBL1615A: Protection against inductive kickback from motorized loads is essential, using freewheeling diodes and bus capacitors.
VBMB2251K: TVS diodes on the switched output protect against transients from long sensor cable runs.
Enhanced Gate Protection: Robust gate protection for all devices is non-negotiable. Use gate series resistors, clamp Zeners, and strong pull-downs. For SiC (VBP117MC06), a negative turn-off voltage (e.g., -5V) is recommended for enhanced noise immunity.
Derating Practice:
Voltage Derating: VBP117MC06 operating VDS should be below 1360V (80% of 1700V); VBL1615A VDS should have margin above the actuator drive bus voltage; VBMB2251K VDS should be derated for the auxiliary rail voltage.
Current & Thermal Derating: Strictly base current ratings on transient thermal impedance and maximum junction temperature (Tjmax), considering the worst-case test profile durations. SiC devices can run hotter but should be derated according to lifetime expectations.
III. Quantifiable Perspective on Scheme Advantages and Competitor Comparison
Quantifiable Test Bandwidth & Fidelity: Using VBP117MC06 (SiC) in the high-voltage source enables switching frequencies 5-10x higher than IGBT-based solutions, directly translating to higher control bandwidth and more accurate replication of high-frequency components in flight power profiles.
Quantifiable System Efficiency & Uptime: Using VBL1615A (ultra-low Rds(on)) for the load inverter can reduce conduction loss by over 40% compared to standard MOSFETs, reducing thermal stress, cooling system size, and energy consumption during prolonged durability testing.
Quantifiable Safety & Reliability Improvement: Using VBMB2251K for isolated auxiliary power switching provides a clear, reliable isolation barrier and simplifies safety circuit design, reducing the risk of cross-talk and improving overall test stand MTBF.
IV. Summary and Forward Look
This scheme provides a complete, robust power chain for vertiport-integrated flying car test benches, spanning from extreme high-voltage stimulus simulation to ultra-high-current load application and intelligent, isolated auxiliary management. Its essence lies in "matching to extreme demands, optimizing for fidelity and safety":
High-Voltage Stimulus Level – Focus on "Precision & Speed": Leverage SiC technology to achieve the switching speed and voltage robustness needed for high-fidelity aerospace-grade power profile simulation.
High-Current Load Level – Focus on "Fidelity & Density": Invest in ultra-low-loss devices to ensure accurate current reproduction and high power density within the test facility.
Auxiliary Management Level – Focus on "Isolation & Control": Use appropriately rated P-MOSFETs with isolated packages to ensure safe, reliable control of critical test infrastructure power.
Future Evolution Directions:
Enhanced SiC Integration: Transition to SiC MOSFET modules with integrated gate drivers and temperature sensing for the high-voltage and high-current sections, further improving power density and monitoring capabilities.
Wide-Bandgap for Auxiliary Switches: For higher-frequency auxiliary converters within the test bench, consider GaN HEMTs to minimize size and improve efficiency of internal point-of-load converters.
Digital Twin Integration: Embed smarter sensing (current, temperature) at the device level to feed data into a digital twin of the test stand, enabling predictive maintenance and adaptive control.
Engineers can refine and adjust this framework based on specific test bench parameters such as maximum stimulus voltage (e.g., 1kV/1.5kV), peak load current, auxiliary system complexity, and safety certification requirements (e.g., ISO 26262 for automotive, DO-254 for aerospace aspects), thereby designing high-performance, safe, and reliable flying car test and validation systems.

Detailed Power Chain Topology Diagrams