Motor driver ic choices for high torque motors like RMC2082
Hello ST Community,
I am designing a custom high-power motor controller for an industrial servo motor (RMCS2082) and need advice on component selection, thermal limits, and layout architecture.
System Specifications:
- Nominal Current: 18.7 A (Continuous load)
- Peak / Stall Current: 130 A (Transient spike)
- Battery Operating Voltage: 24 Volts
- Target Enclosure/Board Temperature: Strictly under 50°C to 60°C Max
- Control Method: 20 kHz PWM (generated via external MCU)
The Dilemma & My Analysis:
I evaluated the VNHD7008AY using TwisterSIM. Brief transient simulations show safe temperatures around 45°C. However, calculating steady-state thermal dissipation for an 18.7A continuous load across the integrated H-bridge path (approx 16-24 mΩ hot) results in 6W to 8W+ of pure heat generation. In a standard PCB design, this localized thermal load will quickly cause a massive temperature rise exceeding my 60°C target and trigger thermal shutdown. Furthermore, the 130A motor stall current exceeds the typical internal hardware current limitation threshold of the chip.
Questions for Application Engineers & Experts:
1. Is there any integrated H-bridge IC in the VNH/VNHD series that can mathematically handle 18.7A continuous / 130A peak while meeting a strict <60°C thermal envelope?
2. If an integrated chip is unfeasible, what discrete STripFET MOSFET and matching ST Gate Driver combination do you officially recommend for a 24V system at this power level to split the thermal load?
3. Could anyone confirm if my 45°C TwisterSIM result is purely an artifact of the default short transient simulation duration window?
Thank you for your engineering support and design insights!
