Linear motor, linear motor control apparatus, and linear motor control method

Abstract

A linear motor control apparatus for controlling at least one of torque, speed and position of a linear motor includes circuitry that receives at least one of a magnetic pole position value, torque command signal, and speed command signal, and imparts a high-frequency voltage to at least one of a d-axis and a q-axis and impart a load current to the q-axis based on the at least one of the magnetic pole position value, torque command signal, and speed command signal. The d-axis is an axis extending in a central direction of a stator tooth of a stator, and the q-axis is an axis extending in a direction offset 90 degrees from the central direction in an electrical angle.

What is claimed is: 
     
         1 . A linear motor control apparatus for controlling at least one of torque, speed and position of a linear motor, comprising:
 circuitry configured to   receive at least one of a magnetic pole position value, torque command signal, and speed command signal, and   impart a high-frequency voltage to at least one of a d-axis and a q-axis and impart a load current to the q-axis based on the at least one of the magnetic pole position value, torque command signal, and speed command signal,   wherein the d-axis is an axis extending in a central direction of a stator tooth of a stator, and the q-axis is an axis extending in a direction offset 90 degrees from the central direction in an electrical angle.   
     
     
         2 . The linear motor control apparatus according to  claim 1 , wherein the linear motor comprises the stator, and a mover comprising a mover iron core, a plurality of teeth formed in the mover iron core such that the plurality of teeth is protruding toward the stator, a plurality of field magnets positioned in the plurality of teeth, respectively, and a plurality of armature windings wound around the plurality of teeth respectively such that each of the armature windings is housed in a slot formed between adjoining teeth of the plurality of teeth, and the plurality of teeth includes at least one tooth having a first hole formed in the slot housing a respective one of the armature windings. 
     
     
         3 . The linear motor control apparatus according to  claim 2 , wherein the tooth is formed such that the first hole is formed at a position apart from an end of the tooth facing the stator. 
     
     
         4 . The linear motor control apparatus according to  claim 3 , wherein the mover iron core comprises two sub-teeth formed at end positions in a moving direction of the mover, respectively, such that the mover does not have the armature windings on the sub-teeth, and each of the teeth adjoining the sub-teeth has the first hole formed only in the slot on an opposite side with respect to a respective one of the sub-teeth. 
     
     
         5 . The liner motor control apparatus according to  claim 4 , wherein the first hole of the tooth is formed such that a respective one of the field magnets in the tooth magnetically saturates the tooth at a position of the first hole when the armature winding is in a non-energized state and the tooth is facing a stator tooth formed in the stator in a magnetic gap direction. 
     
     
         6 . The linear motor control apparatus according to  claim 5 , wherein the mover iron core comprises a yoke connecting the plurality of teeth together and has a plurality of magnet insertion holes extending in the plurality of teeth toward the yoke in the magnetic gap direction such that the plurality of field magnets is positioned in the plurality of magnet insertion holes, respectively, and the yoke of the mover iron core is formed such that each of the magnet insertion holes has at least one second hole formed in the moving direction of the mover. 
     
     
         7 . The linear motor control apparatus according to  claim 6 , wherein the second hole is formed in a respective one of the magnetic insertion holes such that the second hole is positioned at an end portion of the respective one of the magnetic insertion holes on an opposite side with respect to the stator. 
     
     
         8 . The linear motor control apparatus according to  claim 7 , wherein the teeth adjoining the sub-teeth have the magnet insertion holes formed such that each of the magnet insertion holes has the second hole formed only on the opposite side with respect to the respective one of the sub-teeth. 
     
     
         9 . The linear motor control apparatus according to  claim 8 , wherein the second hole of the tooth is formed such that the respective one of the field magnets magnetically saturates a portion of the tooth between the second hole and the first hole when the armature winding is in a non-magnetized state and the tooth is facing the stator tooth formed in the stator in the magnetic gap direction. 
     
     
         10 . The linear motor control apparatus according to  claim 2 , wherein the first hole formed in the tooth is forming a thin tooth portion such that the thin tooth portion has a cross-sectional area which is smaller than a cross-sectional area of an end portion of the tooth facing the stator. 
     
     
         11 . A linear motor control method for controlling at least one of torque, speed and position of a linear motor, comprising:
 receiving at least one of a magnetic pole position value, torque command signal, and speed command signal; and   imparting a high-frequency voltage to at least one of a d-axis and a q-axis and imparting a load current to the q-axis based on the at least one of the magnetic pole position value, torque command signal, and speed command signal,   wherein the d-axis is an axis extending in a central direction of a stator tooth of a stator, and the q-axis is an axis extending in a direction offset 90 degrees from the central direction in an electrical angle.   
     
     
         12 . The linear motor control method according to  claim 11 , wherein the linear motor comprises the stator, and a mover comprising a mover iron core, a plurality of teeth formed in the mover iron core such that the plurality of teeth is protruding toward the stator, a plurality of field magnets positioned in the plurality of teeth, respectively, and a plurality of armature windings wound around the plurality of teeth respectively such that each of the armature windings is housed in a slot formed between adjoining teeth of the plurality of teeth, and the plurality of teeth includes at least one tooth having a first hole formed in the slot housing a respective one of the armature windings. 
     
     
         13 . The linear motor control method according to  claim 12 , wherein the tooth is formed such that the first hole is formed at a position apart from an end of the tooth facing the stator. 
     
     
         14 . The linear motor control method according to  claim 13 , wherein the mover iron core comprises two sub-teeth formed at end positions in a moving direction of the mover, respectively, such that the mover does not have the armature windings on the sub-teeth, and each of the teeth adjoining the sub-teeth has the first hole formed only in the slot on an opposite side with respect to a respective one of the sub-teeth. 
     
     
         15 . The liner motor control method according to  claim 14 , wherein the first hole of the tooth is formed such that a respective one of the field magnets in the tooth magnetically saturates the tooth at a position of the first hole when the armature winding is in a non-energized state and the tooth is facing a stator tooth formed in the stator in a magnetic gap direction. 
     
     
         16 . The linear motor control method according to  claim 15 , wherein the mover iron core comprises a yoke connecting the plurality of teeth together and has a plurality of magnet insertion holes extending in the plurality of teeth toward the yoke in the magnetic gap direction such that the plurality of field magnets is positioned in the plurality of magnet insertion holes, respectively, and the yoke of the mover iron core is formed such that each of the magnet insertion holes has at least one second hole formed in the moving direction of the mover. 
     
     
         17 . The linear motor control method according to  claim 16 , wherein the second hole is formed in a respective one of the magnetic insertion holes such that the second hole is positioned at an end portion of the respective one of the magnetic insertion holes on an opposite side with respect to the stator. 
     
     
         18 . The linear motor control method according to  claim 17 , wherein the teeth adjoining the sub-teeth have the magnet insertion holes formed such that each of the magnet insertion holes has the second hole formed only on the opposite side with respect to the respective one of the sub-teeth. 
     
     
         19 . The linear motor control method according to  claim 18 , wherein the second hole of the tooth is formed such that the respective one of the field magnets magnetically saturates a portion of the tooth between the second hole and the first hole when the armature winding is in a non-magnetized state and the tooth is facing the stator tooth formed in the stator in the magnetic gap direction. 
     
     
         20 . The linear motor control method according to  claim 12 , wherein the first hole formed in the tooth is forming a thin tooth portion such that the thin tooth portion has a cross-sectional area which is smaller than a cross-sectional area of an end portion of the tooth facing the stator.