Open-Loop Control to Sensorless FOC of PMSM on Teensy Hardware

R2026b

This example shows a step-by-step workflow for implementing sensorless control of a permanent magnet synchronous motor (PMSM) on Teensy® hardware. The workflow progresses from basic open-loop motor operation to sensorless field-oriented control (FOC). It introduces current sensing and rotor position estimation, which are essential building blocks for closed-loop motor control.

The implementation of a sensorless FOC of a PMSM includes these steps:

1. Run PMSM Motor in Open Loop on Teensy Hardware — Generate three-phase PWM signals and control motor speed using open-loop voltage-frequency (V/F) control.

2. Measure Phase Currents of PMSM Motor in Open Loop Teensy Hardware — Measure motor phase currents through ADC channels, reconstruct the third phase current, and monitor current feedback while the motor runs in open-loop control.

3. Estimate Angle and Speed of PMSM Motor in Open Loop on Teensy Hardware — Use an Extended electromotive force (EMF) Observer to estimate rotor position and speed from measured currents and voltages.

4. Sensorless Field-Oriented Control of PMSM Motor Using Teensy Hardware — Use the estimated rotor position and measured currents to transition from open-loop startup to closed-loop sensorless FOC. The controller starts in open-loop current-to-frequency (I-F) mode and transitions to closed-loop FOC once reliable rotor position estimates are available.