- Sensorless Trapezoidal BLDC Motors Control Algorithm based on Back Electromotive Force (BEMF) Zero Crossing.
- Motor start of two types: a) initialize the motor to a known position by powering a phase pair and waiting for the rotor alignment (it causes a rotor initial movement, may be in an opposite to desired direction); b) detect a rotor position and start switching by powering a phase pair accordingly.
- Ramp up begins with “open loop” (very short) and then “close loop” starts with BEMF Zero Crossing synchronization.
- Speed controller implemented to hold pre selected speed regardless external disturbances. I use fuzzy logic to make it simple, fast and reliable without any kind of tuning.
- Switching a revolving direction on a fly that can be used as a regenerative brake to accelerate reaction on a speed down change.
Some helpful links: