Brushless DC motor control system responsive to control signals generated by a computer or the like

In a system for controlling a brushless DC motor of the type having a multiphase winding and a rotor mounted on a shaft, the combination which comprises:

• (a) shaft position-sensing means for deriving shaft position signals indicative of the angular position of the motor shaft;
• (b) commutation signal-generating means responsive to the shaft position signals for generating commutation signals representative of each commutation period for each phase winding;
• (c) driving means individually associated with each phase winding for selectively applying current to the associated winding;
• (d) control signal-generating means for generating independent control signals for each phase winding;
• and
• (e) gating means individually connected to the driving means for each phase winding and responsive to the commutation and control signals for the respective phase winding for enabling the driving means associated with each phase winding to thereby apply current to the respective winding only upon the occurence of the commutation signal and control signal for said winding, whereby the motor shaft can be incrementally advanced to a selected position.

In a system for controlling the torque delivered by a brushless DC motor of the type having a multiphase wound stator, a permanent magnet rotor mounted on a shaft and arranged so that each phase winding, when energized, will generate torque for a predetermined number of degrees of shaft rotation, the combination which comprises:

• (a) shaft position-sensing means for producing a shaft position signal for each predetermined number of degrees of shaft rotation required to provide a complete rotation of the shaft;
• (b) commutation signal-generating means responsive to the shaft position signals for generating commutation signals representative of the commutation time for each phase winding;
• (c) torque-regulating signal generating means coupled to the commutation signal-generating means for generating a torque-regulating signal having a repetition rate which is higher than the highest repetition rate of the commutation signals for one phase winding and having a duty cycle which bears a relationship to the repetition rate of the commutation signals for said one phase winding;
• (d) driving means individually associated with each phase winding for selectively applying current to the associated winding;
• and
• (e) gating means individually connected to the driving means for each phase winding and responsive to commutation signals and the torque-regulating signal for enabling the driving means associated with each phase winding upon the occurrence of the commutation signal for said winding and in accordance with the duty cycle of the torque-regulating signal whereby the instantaneous generated torque is proportional to the instantaneous duty cycle of the torque-regulating signal.

In a system for synchronizing the motion of a plurality of brushless DC motors wherein each motor includes a rotor and a multiphase wound stator with each phase winding being arranged to be energized in succession to provide a rotating magnetic field;

• a commutation signal generator responsive to the position of the rotor for generating commutation signals representative of commutation time for each phase winding;
• a driving circuit individually associated with each phase winding for selectively applying current to the associated winding;
• and a gating circuit individually connected to the driving circuit for each phase winding and responsive to the commutation signals and to an input control signal for enabling the driving circuit associated with each phase winding upon the occurrence of the commutation signal and the input control signal, the combination which comprises:
• (a) gating means individually responsive to the commutation signals associated with each respective phase winding of each motor for producing an output signal when each commutation signal for an associated phase winding is completed;
• and
• (b) input control signal-generating means for applying said input control signal to the driving circuit associated with the next succeeding phase winding to be energized in response to an output signal from the gating means.