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Motor Control

How to Tune fwcurmax on ZombieVerter VCU

Field weakening demagnetizing current (negative). MUST be negative!

Quick Reference

Param ID

144

Unit

A

Range

-1000 — 0

Default

-100

🔍 See a sample config →

📖 What Does It Do?

Field weakening demagnetizing current (negative). MUST be negative!

This parameter controls an aspect of your ZombieVerter VCU's behavior. Getting it right is important for safe and reliable operation of your EV conversion.

🎯 Recommended Values

Default value: -100

Valid range: -1000 to 0

Tuning Strategy

Start with the default value and adjust in small increments. Monitor vehicle behavior after each change before making further adjustments.

💡 Tuning Tips

⚠️ **MUST BE NEGATIVE!** Positive values STRENGTHEN the field, reducing top speed.

How it works: injects negative Id to cancel magnet flux, reducing back-EMF so motor spins faster.

TYPICAL VALUES:

  • Default: -100 (conservative)
  • Nissan Leaf EM57: -450A
  • Prius/GS450H: -200 to -400

    • 🛑 Bench testing: set to 0 to prevent unloaded motor overspeeding!

    Only has effect ABOVE fweak (base speed). Below fweak it does nothing.

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    🔗 Related Parameters

    Other parameters in the Motor Control category that work together with fwcurmax:

    fmax

    Hz

    Maximum motor frequency. RPM = fmax × 60 / polepairs.

    boost

    dig

    Voltage at 0 RPM — controls starting torque. Higher = stronger launch.

    fweak

    Hz

    Field weakening start frequency. Above this, motor enters constant-power region.

    numimp

    ppr

    Speed sensor pulses per revolution.

    polepairs

    Motor pole pairs. CRITICAL — set this correctly for your motor.

    fslipmax

    Hz

    Maximum slip frequency (induction motors). Sets full-throttle torque.

    snsm

    enum

    Motor temperature sensor type. Must match your motor's actual sensor.

    fslipmin

    Hz

    Minimum slip frequency (induction motors). Sets creep torque.

    encmode

    enum

    Encoder/position sensor type. This is your motor's 'eyes' — it tells the inverter where the rotor is.

    dirchrpm

    rpm

    RPM below which direction change is allowed.
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