초록 ▼

A linear motor separates the functions of commutating into a first function for enabling a subset of coils in a linear stator which are within the magnetic influence of permanent magnets in the movable element and a second function for applying the drive power to the enabled subset. One pair of sens

A linear motor separates the functions of commutating into a first function for enabling a subset of coils in a linear stator which are within the magnetic influence of permanent magnets in the movable element and a second function for applying the drive power to the enabled subset. One pair of sensors produces sine and cosine signals to maintain a controd coils, the fiabout the phase of power which should be applied to the enabled subset. Another sensor produces a proportional signal which varies linearly between zero and one over each electrical quadrant with a short non-changing interval at maximum and minimum. The control system employs the sine, cosine and proportional signals to synthesize a pair of quasi-sinusoidal waveforms for application to alternate coils in the enabled subset of coils. The short non-changing intervals in the proportional signal are employed to ensure that polarity changeover to the enabled coils takes place at zero volts for bumpless drive. A balanced version of the linear motor is disclosed for reducing the load on the structure supporting the movable element.

대표청구항 ▼

A linear motor system comprising: a linear motor; said linear motor including a stator and a movable element; said stator including a plurality of coils wound thereon effective for producing a plurality of magnetic poles having alternating magnetic polarities; said movable element including at least

A linear motor system comprising: a linear motor; said linear motor including a stator and a movable element; said stator including a plurality of coils wound thereon effective for producing a plurality of magnetic poles having alternating magnetic polarities; said movable element including at least one permanent magnet having at least one permanent magnetic pole facing said stator; means for sensing first and second phase positions of said at least one permanent magnetic pole with respect to said plurality of magnetic poles; means for enabling a subset of said plurality of coils within a substantial magnetic influence of said at least one pemanent magnetic pole; and means in said control system responsive at least to said phase positions for producing a first driving signal for application to alternate ones of said enabled coils and a second driving signal for application to a remainder of said enabled coils, said first and second driving signals having polarities and amplitudes effective for applying a desired force to said movable element.