With the rapid development of the new energy logistics sector, refrigerated light trucks are facing stringent demands for high efficiency, high power density, and reliable operation in extreme environments. The traction inverter, high-voltage auxiliary systems (e.g., electric compressor for refrigeration), and DC-DC converters serve as the core of the vehicle's "three electric" system. The selection of power switches (MOSFETs/IGBTs) directly determines driving range, refrigeration efficiency, system cost, and long-term reliability. Addressing the key requirements of refrigerated trucks for high torque at low speeds, uninterrupted refrigeration, and robustness under wide temperature ranges, this article develops a scenario-based, optimized device selection strategy.
I. Core Selection Principles and Scenario Adaptation Logic
(A) Core Selection Principles: Multi-Dimensional Collaborative Adaptation
Device selection requires a holistic balance across five dimensions: voltage class, conduction/switching losses, current capability, package thermal performance, and ruggedness.
Sufficient Voltage & Current Margin: For main traction systems (typically 300-400V battery voltage), select devices with a rated voltage ≥600V, reserving ≥50% margin for voltage spikes. Current rating must exceed the motor's peak phase current. For high-voltage auxiliary systems (e.g., 550-700V), consider ≥900V devices.
Ultra-Low Loss for Efficiency: Prioritize devices with low Rds(on) or low VCE(sat) to minimize conduction loss, which is critical for continuous operation. Low switching loss (via optimized gate charge and capacitance) is vital for high-frequency operation in DC-DC converters.
Package & Thermal Management: High-power devices (Traction, PFC) require packages with excellent thermal resistance (e.g., TO-247) for effective heat sinking. Auxiliary system devices can use compact packages (TO-220, TO-263) to save space.
Automotive-Grade Ruggedness: Devices must operate reliably across a wide junction temperature range (e.g., -55°C to 175°C), possess high immunity to avalanche and surge events, and ideally meet AEC-Q101 standards.
(B) Scenario Adaptation Logic: Categorization by System Function
Divide applications into three core scenarios: First, Traction Inverter & Main Drive (High Power Core), requiring high current, high voltage, and ultra-low loss. Second, High-Voltage Auxiliary Systems (e.g., Electric Compressor, PFC), requiring medium power with high voltage withstand. Third, Low-Voltage Auxiliary Power & Control (Functional Support), requiring compact size and logic-level drive for efficient switching.
II. Detailed Device Selection Scheme by Scenario
(A) Scenario 1: Traction Inverter / Main Drive (~30-60kW) – Power Core Device
This scenario handles high continuous and peak currents (during startup/climbing), demanding highest efficiency for maximum range.
Recommended Model: VBP16R67S (N-MOSFET, 600V, 67A, TO-247)
Parameter Advantages: Super-Junction Multi-EPI technology achieves an ultra-low Rds(on) of 34mΩ at 10V. 67A continuous current rating handles high phase currents. 600V rating provides ample margin for 400V bus systems. TO-247 package offers superior thermal dissipation capability.
Adaptation Value: Drastically reduces conduction loss in the inverter bridge. For a 400V/50kW system, per-device conduction loss is minimal, contributing to inverter efficiency >98%. Enables high switching frequencies for compact motor design and smoother torque control.
Selection Notes: Verify motor peak current and inverter topology. Use in parallel pairs per switch if needed. Requires robust gate drivers (e.g., with >2A source/sink current) and careful layout to minimize parasitic inductance. Must be paired with effective liquid or forced-air cooling.
(B) Scenario 2: High-Voltage Auxiliary Systems – Electric Compressor / PFC (3-10kW)
Electric compressors for refrigeration and onboard chargers/PFC circuits require high voltage blocking capability and good efficiency at medium power levels.
Recommended Model: VBMB19R15S (N-MOSFET, 900V, 15A, TO-220F)
Parameter Advantages: 900V drain-source voltage is ideal for 550-700V high-voltage auxiliary buses or PFC stages. Rds(on) of 370mΩ at 10V offers good conduction performance. TO-220F (Full-Pak) package provides enhanced isolation and reliability.
Adaptation Value: Ensures safe and reliable operation of the electric refrigeration compressor, maintaining stable cabin temperature. Its high voltage rating increases system safety margin in high-voltage domains. Suitable for critical switch positions in PFC or LLC resonant converters within the OBC/DC-DC.
Selection Notes: Match device current rating to compressor locked-rotor or PFC inductor peak current. Ensure gate drive voltage is sufficient (typically 12-15V) for full enhancement. Implement overcurrent protection for compressor motor drives.
(C) Scenario 3: Low-Voltage Auxiliary Power & Control – DC-DC Converter / Load Switching (12/24V Systems)
These systems power vehicle control units, sensors, fans, and valves, requiring efficient, compact, and reliably controlled switches.
Recommended Model: VBA1635 (N-MOSFET, 60V, 8A, SOP8)
Parameter Advantages: Low gate threshold voltage (Vth=1.7V) enables direct drive from 3.3V/5V MCU GPIOs without level shifters. Very low Rds(on) (24mΩ @10V, 32mΩ @4.5V) minimizes voltage drop and loss. SOP8 package saves significant PCB space.
Adaptation Value: Perfect for high-side/low-side load switches in 12/24V systems (e.g., controlling fan motors, solenoid valves). Can serve as synchronous rectifier in low-voltage DC-DC converters, boosting conversion efficiency above 95%. Reduces system complexity and BOM cost.
Selection Notes: Ensure load current is within safe operating area (SOA). Add small gate resistors (e.g., 10-47Ω) to dampen ringing. For inductive loads, incorporate freewheeling paths. Utilize its logic-level capability to simplify control circuitry.
III. System-Level Design Implementation Points
(A) Drive Circuit Design: Matching Device Characteristics
VBP16R67S: Use dedicated high-current, high-speed IGBT/MOSFET driver ICs (e.g., 1EDI series, IRS21814) with negative bias or miller clamp capability. Implement <5cm gate traces with low inductance.
VBMB19R15S: Drive with standard gate driver ICs. Pay attention to high-side bootstrap circuit design for high-voltage floating switches.
VBA1635: Can be driven directly by MCU pins for light loads. For higher frequency or multiple parallel devices, use a small buffer MOSFET or driver IC.
(B) Thermal Management Design: Tiered Approach
VBP16R67S (High Power): Mandatory use of isolated thermal pads and heatsinks, potentially with liquid cooling cold plates. Monitor junction temperature via NTC or model-based estimators.
VBMB19R15S (Medium Power): Mount on a common heatsink via insulating washers. Ensure adequate airflow from vehicle cooling systems.
VBA1635 (Low Power): Rely on PCB copper pour (≥100mm²) for heat dissipation. In high ambient temperature locations inside the cabin, ensure ventilation.
(C) EMC and Reliability Assurance
EMC Suppression:
VBP16R67S: Employ RC snubbers across drain-source or bus bars. Use laminated busbars to minimize switching loop inductance. Shield motor cables.
General: Add ferrite beads on gate drives. Use common-mode chokes at power inputs/outputs of converters. Implement proper PCB grounding and partitioning.
Reliability Protection:
Overcurrent/Short-Circuit: Implement desaturation detection for IGBTs/MOSFETs in traction drives. Use shunt resistors or Hall sensors with fast comparators.
Overtemperature: Integrate temperature sensors on heatsinks and implement derating curves in software.
Voltage Surge/ESD: Place appropriate TVS diodes (e.g., SMCJ series) at battery inputs, motor terminals, and sensitive control ports. Use gate-source TVS or zeners for critical switches.
IV. Scheme Core Value and Optimization Suggestions
(A) Core Value
Optimized System Efficiency & Extended Range: Ultra-low loss devices in the traction inverter and auxiliaries directly reduce energy consumption, increasing the vehicle's operational range per charge.
Enhanced Reliability for Demanding Duty Cycles: Automotive-grade ruggedness and robust thermal design ensure 24/7 operation under varying environmental stresses, critical for冷链 logistics.
Cost-Effective Performance Balance: Selecting optimized devices per power level (SJ-MOSFET for mid-high power, Trench MOSFET for lower power) provides the best performance/cost ratio for mass production.
(B) Optimization Suggestions
Higher Power Traction: For light trucks above 80kW, consider IGBT modules (e.g., VBP112MI75 1200V/75A) for their superior cost-effectiveness at very high currents and lower switching frequencies.
Space-Constrained High-Voltage Auxiliaries: For compact OBC designs, consider VBL165R08S (650V, TO-263) for its lower profile.
Higher Current LV Auxiliaries: For 24V pump motors, VBL1154N (150V, 45A, TO-263) offers higher current handling.
Specialized High-Voltage Switching: For applications requiring very high voltage at low current (e.g., sensing), VBP175R04 (750V) can be an option, though with higher Rds(on).
Conclusion
The strategic selection of power switches is pivotal to achieving the efficiency, reliability, and cost targets for new energy refrigerated light trucks. This scenario-based guide, leveraging devices like the high-efficiency VBP16R67S for traction, the robust VBMB19R15S for high-voltage auxiliaries, and the compact VBA1635 for control, provides a practical framework for system designers. Future development will focus on integration of sensing, wider adoption of SiC technology for ultra-high efficiency, and advanced packaging to further boost power density for the next generation of electric commercial vehicles.

Detailed Power Topology Diagrams