FOC in Simulink for induction motor: Te = 0 and only one PWM phase reaches Vdc

I'm developing a Field Oriented Control (FOC) system for an Induction Motor (IM) in Simulink. The model includes:

• Inverter driven by a PWM block
• Rotor position and speed measurement or estimation
• Clarke and Park transformations
• PID controllers for Id and Iq
• Reference inputs for rotor flux and rotor angle (θ_r)
• The PID controllers are configured with standard parameters and anti-windup enabled

Issue:

• The electromagnetic torque Te stays at zero, even when a non-zero speed reference is applied
• Only one of the PWM output voltages reaches Vdc; the other two remain very low or close to zero

Checks already performed:

• The motor feedback currents seem correct
• Iq ≠ 0 and Id = 0, as expected
• The inverter output voltages toward the motor appear to be valid
• The reference signals reach the PID controllers properly

Attached:

• A picture of the full FOC model in Simulink
• Parameter settings of the induction motor
• Scopes showing Te and the PWM input signals

Answer 1

[Supraja]

Hi Alessio,

I understand that you are observing discrepancy in the output while performing FOC of IM.

Please follow the below troubleshooting steps:

1. Inspect the Inverse Park Transformation and PWM Block Inputs
2. Check the Rotor Angle (θr​) Input
3. Verify PID Controller Outputs and Scaling
4. Examine the PWM Modulation Block Configuration
5. Check the FOC Reference Frame Transformations

Also, please refer to the documentation below for more examples on FOC of IM:

Field-Oriented Control of Induction Motors with Simulink - Video Series - MATLAB & Simulink

[Alessio]

Hi,

I've already tried those checks, and I can give you a few more details:

The rotor speed wm drops to zero after about 10 seconds, and the rotor angle tetar keeps decreasing until it reaches around –3.5.

I’ve tried changing both the blocks and parameters, but nothing seems to change—I can’t figure out what I’m doing wrong.

I also used the Model Advisor, but it didn’t report anything meaningful.

Thanks a lot for your reply.