Linear motor
US4595870A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 7, 1984 |
| Grant date | Jun 17, 1986 |
| Priority date | — |
| Expiry date | Aug 7, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/64
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.