Detection of rotor angle in a permanent magnet synchronous motor at zero speed
AssigneeThe Penn State Research Foundation
InventorTodd D. Batzel
Life of this patent
Estimating the term…
Abstract
The teachings herein comprise a method and apparatus for determining the position of a rotor by applying a voltage across a pair of phases of a motor and using a voltage measurement responsive to the applied voltage and indicative of the distribution of the phase inductances within the phase pair to which a test voltage is applied to determine the rotor position.
Claims12
A method for determining the rotor position in a motor at standstill in a motor having multiple phase windings arranged as a stator and a permanent magnet rotor, comprising the steps of:
- applying a test voltage of a first and second polarity across a first pair of said stator phase windings for selectively establishing a current flow through said first phase pair and holding a remaining phase winding open;
- measuring a voltage response to the application of said test voltage across said first phase pair at said remaining open phase winding;
- applying a test voltage of a first and second polarity across a second pair of said stator phase windings for selectively establishing a current flow through said second phase pair and holding a remaining phase winding open;
- measuring a voltage response to the application of said test voltage across said second phase pair at said remaining open phase winding;
- and
- determining the rotor position of the motor at standstill based on the magnitude of the measured responses across the open phases of said motor in response to said applied voltages.
An apparatus for determining the rotor position in a motor at standstill in a motor having multiple phase windings arranged as a stator and a permanent magnet rotor, said apparatus comprising:
- switching circuitry for applying a test voltage of a first and second polarity across a first pair of said stator phase windings for selectively establishing a current flow through said first phase pair and while holding a remaining phase winding open;
- measurement circuitry for measuring, at said remaining open phase, a voltage response to the application of said test voltage across said first phase pair at said remaining open phase winding;
- switching circuitry for applying a test voltage of a first and second polarity across a second pair of said stator phase windings for selectively establishing a current flow through said second phase pair and holding a remaining phase winding open;
- measurement circuitry for measuring, at said remaining open phase, a voltage response to the application of said test voltage across said second phase pair at said remaining open phase winding;
- and
- control means for controlling the application of the test voltage across said phase pairs, including the polarity and timing of the applied test voltages;
- determination means for determining the rotor position of the motor at standstill based on the magnitude of the measured responses across the open phases of said motor in response to said applied voltages.
Dependencies are inferred from the claim text.