Sensorless position detection for electric machine
AssigneeDiscovery Energy, LLC
InventorsIsaac S. Frampton, Adam Larson, Jonathan Bykowski
Life of this patent
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Abstract
An electric machine includes a rotor, a stator, at least one measurement circuit, and a controller. The rotor includes a plurality of salient poles arranged radially around a rotation axis of the electric machine and spaced apart from the rotation axis of the electric machine. The stator includes a plurality of coils configured to selectively align with the plurality of salient poles of the rotor. The at least one measurement circuit is configured to measure at least one current through at least one of the plurality of coils. The measured current includes a current ripple. The controller is configured to compute a position of the rotor based on a characteristic of the current ripple.
Claims20
An electric machine, comprising:
- a rotor having a plurality of poles;
- a stator having a plurality of coils configured to selectively align with the plurality of poles of the rotor;
- a first measurement circuit configured to measure a first current ripple of a first coil of the plurality of coils of the stator;
- a second measurement circuit configured to measure a second current ripple of a second coil of the plurality of coils of the stator;
- and
- a controller configured to assess a position of the rotor by determining which of the first or second current ripples is greatest.
A method of operating an electric machine, the method comprising:
- providing an electric machine comprising a rotor having a plurality of poles and a stator having a plurality of phases of stator windings;
- measuring current values for first and second phases of the plurality of phases of stator windings;
- calculating first and second current ripples based on the current values for the first and second phases;
- and
- estimating a position of the electric machine based on the first and second current ripples, the position determined at least in part by selecting the highest value between the first current ripple and the second current ripple.
A hybrid device, comprising:
- an engine having a crankshaft;
- and
- an electric machine comprising:
- a rotor having a plurality of poles, the rotor rotationally coupled to the crankshaft of the engine;
- a stator having a plurality of coils;
- first and second measurement circuits configured to measure first and second current ripples of first and second coils of the plurality of coils of the stator;
- and
- a controller configured to determine a position of the engine by identifying a highest reluctance path based on the first current ripple and the second current ripple and compute a rotor position based on the highest reluctance path, the rotor position corresponding to the position of the engine.
Dependencies are inferred from the claim text.