User Manual

Table Of Contents
Sinusoidal Commutation
Advanced Digital Motor Controller User Manual 119
Field Oriented Control is available on most models of Roboteq motor controllers. It uses a
classical implementation as described in the figure 8-11. The current in the motor phase is
captured, along with the rotor’s angle. From this are computed the useful Iq and wasteful
Id. Two Proportional-Integral (PI) regulators then work to control the power output so that
the desired Torque (Iq) and Flux (Id) currents are met. The desired Flux current is typically
set to 0, and so the regulator will work to totally eliminate the Flux current.
Both PI regulator have user-settable gains. They can be changed from the menus in the
RoborunPlus utility.
Or by sending the configuration command for single Channel Controllers:
^KPF 1 nn = Proportional Gain for Channel 1 Flux
^KPF 2 nn = Proportional Gain for Channel 1 Torque
^KIF 1 nn = Integral Gain for Channel 1 Flux
^KIF 2 nn = Integral Gain for Channel 1 Torque
Or by sending the configuration command for dual Channel Controllers:
^KPF 1 nn = Proportional Gain for Channel 1 Flux
^KPF 2 nn = Proportional Gain for Channel 2 Flux
^KPF 3 nn = Proportional Gain for Channel 1 Torque
^KPF 4 nn = Proportional Gain for Channel 2 Torque
^KIF 1 nn = Integral Gain for Channel 1 Flux
^KIF 2 nn = Integral Gain for Channel 2 Flux
^KIF 3 nn = Integral Gain for Channel 1 Torque
^KIF 4 nn = Integral Gain for Channel 2 Torque
Where nn = Gain * 1000000, e.g. 12500000 = 12.5 (on version 2.x of firmware)
FOC Gains Determination & Tuning
Good PI gains are important for the controller to quickly reach and stabilize the desired Id
and Iq current. A very good approximation of the gain values can be calculated from the
motor’s Resistance and Inductance using the formulas:
Flux Proportional gain = Motor Phase Inductance(Henry) * Bandwidth
Flux Integral gain = Motor Phase Resistance(Ohm) * Bandwidth