Determining motor position with complementary driving and detection and current injection
AssigneeAllegro MicroSystems, LLC
InventorsYisong Lu, Lyndon Ambruson
Life of this patent
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Abstract
Methods and apparatus for determining a position of a rotor in motor, such as a three-phase motor by determining first and second ones of sectors in which a first one of the magnetic poles of the rotor may be positioned by driving phase pairs with complementary signals and examining a voltage of a floating one of the phases. Embodiments can further include driving first and second currents towards the first and second ones of the sectors and analyzing a time for each of the first and second currents to reach a threshold to identify which of the first and second ones of the sectors is aligned with the first one of the magnetic poles of the rotor.
Claims21
A method of determining a position of a rotor in a three-phase motor having phase A, phase B, and phase C, comprising:
- determining first and second ones of sectors in which a first one of the magnetic poles of the rotor may be positioned, wherein the first and second ones of the sectors are oppositely located, by driving phase pairs A-B, A-C, and B-C with complementary signals and examining a voltage of a floating one of the phases;
- and
- driving first and second currents towards the first and second ones of the sectors and analyzing a time for each of the first and second currents to reach a threshold to identify which of the first and second ones of the sectors is aligned with the first one of the magnetic poles of the rotor.
The method according to claim 10, further including determining the first and second ones of the sectors in which a first one of the magnetic poles of the rotor may be positioned from the encoded outputs.
A system for determining position of a rotor of a three-phase motor, comprising:
- a first module to generate drive signals for the three-phase motor;
- a second module configured to determine first and second ones of sectors in which a first one of the magnetic poles of the rotor may be positioned, wherein the first and second ones of the sectors are oppositely located, by driving phase pairs A-B, A-C, and B-C with complementary signals and examining a voltage of a floating one of the phases;
- and
- a third module configured to generate signals to drive first and second currents towards the first and second ones of the sectors and analyze a time for each of the first and second currents to reach a threshold to identify which of the first and second ones of the sectors is aligned with the first one of the magnetic poles of the rotor.
Dependencies are inferred from the claim text.