Field Oriented Motor Controllers
Sensorless motor controllers typically use Back EMF for rotor position estimation. This rotor position information is then used for commutation of the windings (read when to turn each winding on to make the motor spin). Back-EMF signals are proportional to the speed of the rotor and as such they perform poorly at low speeds.
Field oriented controllers use a measurement of the phase currents to estimate the rotor position. This method works well for low speed motors with a high torque. Generally motor torque is proportional to the phase current thus as long as sufficient torque is present the rotor position may be estimated.
SloMo V1
This board is a sensorless motor controller designed for low speeds and high torques. V1 is the prototype board and has an operating current of only 5A and voltage of 9-15V.
It uses a single sense resistor to reconstruct mathematically each phase current. The controller is based off an Atmel microcontroller and allows for tuning of the motor model over an FTDI cable. A standard ISP connection is provided allowing custom source code to be loaded.
SloMo V2
In development.