| CPC H02P 25/064 (2016.02) [H02K 11/215 (2016.01); H02K 41/031 (2013.01)] | 10 Claims |
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1. A direct drive system, comprising:
a stator;
a plurality of primary units fixed to the stator and arranged along a length direction of the stator, wherein each primary unit of the plurality of primary units has at least one winding;
a plurality of drivers, wherein each driver of the plurality of drivers is connected to the at least one winding of a respective primary unit;
a controller connected to the plurality of drivers;
a plurality of first position feedback devices fixed to the stator, wherein each first position feedback device of the plurality of first position feedback devices is in correspondence to a respective primary unit and connected to a respective driver;
guide rails fixed to the stator and disposed on either sides of any primary unit of the plurality of primary units; and
a plurality of movers slidably fitted to the guide rails, wherein each mover of the plurality of movers has at least one magnetic steel and a second position feedback device;
wherein the second position feedback device aligns with a respective first position feedback device, and each winding of the at least one winding aligns with a respective magnetic steel;
wherein the at least one winding is configured to generate thrust between the at least one winding and the at least one magnetic steel by generating a traveling-wave magnetic field when the at least one winding is energized, in order to drive a mover to move along the guide rails;
wherein each first position feedback device of the plurality of first position feedback devices is configured to sense a second position feedback device of a respective mover, in order to acquire relative position information between the respective mover and a respective primary unit;
the controller is configured to calculate absolute position information of the respective mover on the guide rails according to the relative position information, and to switch working modes of the respective primary unit according to the relative position information;
wherein the working modes comprise a position mode and a current mode;
when a projection of outer edges of the at least one magnetic steel on the respective primary unit is surrounded by outer edges of the respective primary unit, the working mode of the respective primary unit is switched to the position mode;
when the at least one magnetic steel completely leaves a primary unit preceding the respective primary unit and moves to the respective primary unit, the working mode of the primary unit preceding the respective primary unit is switched to the current mode, and the working mode of the respective primary unit is switched to the position mode;
when the at least one magnetic steel is located between the primary unit preceding the respective primary unit and the respective primary unit, the working modes of the primary unit preceding the respective primary unit and the respective primary unit are both switched to the position mode; or switch the working mode of one primary unit of the primary unit preceding the respective primary unit and the respective primary unit to the position mode, and switch the working mode of the other primary unit to the current mode;
in the position mode, the controller is configured to output a position control instruction according to the absolute position information and predetermined positions of the respective mover within a full range of travel on the guide rails, and a respective driver is configured to adjust current in at least one winding of the respective primary unit according to the position control instruction, in order for the respective mover to move to a predetermined position; and
in the current mode, the controller is configured to output a current control instruction, and the respective driver is configured to provide current to the at least one winding of the respective primary unit according to the current control instruction, in order to compensate a thrust loss occurred in movement of the respective mover.
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