Control system for synchronous brushless motors utilizing torque angle control

Claim 1

A motor control system for a brushless DC motor comprising: a motor including stator windings and a rotor; a position indicator for providing a signal indicative of the position of said rotor relative to said stator; a speed indicator for providing an indication of the rotor speed; means for generating an indication of the load on said motor; a memory having torque angle factors recorded therein; means for selecting torque angle factors from said memory according to the indications of rotor speed and load, and adding the selected torque angle factor to the indication of rotor position to derive an excitation vector position indication; and excitation current generating means for applying sinusoidal excitation currents to said windings, the excitation currents having controllable phases and having values created incrementally from pre-recorded digital sine values selected in accordance with the excitation vector position indications from said means for selecting torque angle factors and the position indications from said position sensor, such that the torque angle is adaptively controlled as a function of speed and load.