Linear position sensing system and coil switching methods for closed-loop control of large linear induction motor systems
First Claim
1. A linear motor control system, comprising:
- a stator including a plurality of individually switched stator coils;
a moving rotor adapted to move down a long axis of the stator;
an inductive-based position sensing system with first components attached to said rotor and second components attached to said stator;
calculation means for determining, based on sensed position data, a proper voltage time delay angle with respect to a voltage source peak voltage for applying current to a next leading coil of said stator coils such that the current in said next coil is at its steady state value immediately after switching.
1 Assignment
0 Petitions
Accused Products
Abstract
A control system for a linear motor adapted to accurately supply a moving window of power to the stator coils. A plurality of individually switched stator coils run the length of a linear motor to move a rotor down the long axis of the stator. Accurate inductive-based position sensors continuously provide position data for the moving rotor. A processing unit calculates a proper time delay from a source voltage peak in order to apply power to the next stator coil in the moving direction of the rotor such that no DC offshoot/undershoot occurs. The linear motor control system optionally includes a failure prevention switching scheme in which pairs of individual stator coils on opposite sides of a double-sided stator are switched together.
83 Citations
20 Claims
-
1. A linear motor control system, comprising:
-
a stator including a plurality of individually switched stator coils; a moving rotor adapted to move down a long axis of the stator; an inductive-based position sensing system with first components attached to said rotor and second components attached to said stator; calculation means for determining, based on sensed position data, a proper voltage time delay angle with respect to a voltage source peak voltage for applying current to a next leading coil of said stator coils such that the current in said next coil is at its steady state value immediately after switching. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method for controlling the application of power to a series of stator coils in a linear motor, comprising the steps of:
-
sensing the instantaneous position of a moving rotor with respect to the stationary stator coils using an inductive sensor; calculating, based on the sensed rotor position, a source voltage phase shift for a next one of said stator coils in the moving direction of the rotor that results in a current in the next one of said stator coils moving immediately to a steady state value; applying source voltage to said next stator coil at said calculated phase shift. - View Dependent Claims (14, 15, 16, 17, 18, 19)
-
-
20. An electromagnetic aircraft launching system, comprising:
-
a double-sided stator assembly including a plurality of individually switched stator coils; a moving rotor assembly adapted to move down a long axis of the stator and further adapted to engage an aircraft; an inductive-based position sensing system with first components loosely coupled to said rotor assembly and second components attached to said stator assembly; a processing unit including a digital signal processor for determining, based on sensed position data, a proper voltage time delay angle with respect to a voltage source peak voltage for applying current to a next leading coil of said stator coils such that a DC offset component of the current supplied to said next leading coil is removed.
-
Specification