Pole position detector for motor
AssigneeNissan Motor Co., Ltd.
InventorYuki Nakajima
Life of this patent
Estimating the term…
Abstract
A pole position detector correctly detects a pole position of a permanent magnet motor. Each magnetic sensor (27) provides an electric signal in response to leakage flux from a magnet rotor (17). A computation unit (2) detects a change in the output of the magnetic sensor as a base pole position θ, corrects the base pole position by Δθ according to the base pole position, the magnitude of each stat or current (IU, IV, IW), and a current phase, and calculates correct rotation angles θre and θre′ accordingly. With low-cost magnetic sensors (27), the pole position detector corrects the outputs of the magnetic sensors affected by stat or current and provides a correct pole position or a correct rotor rotation angle.
Claims2
A pole position detector for a motor, comprising:
- a magnetic sensor configured to sense magnetic flux from a magnet rotor, the magnet rotor having plurality of magnets that are oppositely magnetized one after another;
- and
- a computation unit configured to detect a base pole position of the magnet rotor according to changes in the output of the magnetic sensor, detect stator current magnitude and a current phase, and correct the detected base pole position according to the detected base pole position, the stator current magnitude, and the current phase, wherein
- the magnet rotor has magnetic pieces on an end face thereof that crosses a shaft of the magnet rotor;
- each of the magnetic pieces is magnetized by magnetic flux from a corresponding one of the magnets;
- and
- the magnetic sensor is fixed to a casing to face the magnetic pieces.
A pole position detector for a motor, comprising:
- a magnetic sensor configured to sense magnetic flux from a magnet rotor, the magnet rotor having plurality of magnets that are oppositely magnetized one after another;
- and
- a computation unit configured to detect a base pole position of the magnet rotor according to changes in the output of the magnetic sensor, detect stator current magnitude and a current phase, and correct the detected base pole position according to the detected base pole position, the stator current magnitude, and the current phase, wherein
- the computation unit detects the base pole position according to one of rising and falling edges contained in the output of the magnetic sensor, and
- the computation unit limits an electrical angle correction quantity applied to the base pole position below a value obtained by dividing the circumferential angle of a gap between the adjacent magnetic pieces by the number of magnetic poles.
Dependencies are inferred from the claim text.