Marine propulsion device and marine vessel
A marine propulsion device includes a controller configured or programmed to calculate a rotation speed of a rotor based on a magnetic flux density detected by a detector, and correct a deviation in a calculated magnet position of the rotor due to an eddy current generated in a metal based on the calculated rotation speed of the rotor.
1 . A marine propulsion device comprising:
a duct including a stator;
a propeller including a rim including a rotor radially inward of the stator and facing the stator, and blades radially inward of the rim;
a detector facing the rotor via a metal to detect a magnetic flux density generated by a magnet of the rotor; and
a controller configured or programmed to calculate a magnet position of the rotor based on the magnetic flux density detected by the detector, and perform a control to apply a current to the stator at a timing at which the rotor is able to obtain a maximum torque based on a calculated magnet position of the rotor; wherein
the controller is configured or programmed to calculate a rotation speed of the rotor based on the magnetic flux density detected by the detector, and correct a deviation in the calculated magnet position of the rotor due to an eddy current generated in the metal based on the calculated rotation speed of the rotor.
2 . The marine propulsion device according to claim 1 , wherein the detector is adjacent to the stator in an axial direction of the rotor, and faces the rotor.
3 . The marine propulsion device according to claim 2 , wherein the detector is accommodated in a space inside a storage area defined by the metal and located in an upper portion of the duct.
4 . The marine propulsion device according to claim 3 , further comprising:
a housing above the duct; wherein
the controller is accommodated in a space inside the housing; and
the space inside the storage area in which the detector is accommodated is connected to the space inside the housing in which the controller is accommodated.
5 . The marine propulsion device according to claim 1 , wherein
three-phase AC power is supplied to the stator;
the detector includes three detectors to detect three-phase magnetic flux densities generated by the magnet of the rotor, respectively; and
the controller is configured or programmed to calculate the rotation speed of the rotor based on one of the three-phase magnetic flux densities detected by the three detectors, respectively, and correct deviations in magnet positions of the rotor calculated based on the three-phase magnetic flux densities, respectively, based on the calculated rotation speed of the rotor.
6 . The marine propulsion device according to claim 5 , wherein
the three detectors are aligned along an alignment direction perpendicular to an axial direction of the rotor in a horizontal plane; and
a thickness of the metal between the rotor and one of the three detectors located at a center in the alignment direction is different from a thickness of the metal between the rotor and another one of the three detectors located on a first side in the alignment direction and a thickness of the metal between the rotor and another one of the three detectors located on a second side in the alignment direction.
7 . The marine propulsion device according to claim 1 , further comprising:
a storage to store correction information indicating a relationship between the rotation speed of the rotor and a correction value to correct the deviation in the calculated magnet position of the rotor; wherein
the controller is configured or programmed to correct the deviation in the calculated magnet position of the rotor based on the calculated rotation speed of the rotor and the correction information.
8 . The marine propulsion device according to claim 7 , wherein the storage is operable to store the correction information for an entire range of the rotation speed of the rotor.
9 . The marine propulsion device according to claim 7 , wherein the storage is operable to store the correction information represented by a mathematical formula, a map, or a table.
10 . The marine propulsion device according to claim 9 , wherein
the storage is operable to store the correction information represented by the mathematical formula; and
the controller is configured or programmed to calculate the correction value based on the calculated rotation speed of the rotor and the correction information represented by the mathematical formula, and correct the deviation in the calculated magnet position of the rotor based on the calculated correction value.
11 . A marine vessel comprising:
a hull; and
a marine propulsion device attached to the hull; wherein the marine propulsion device includes:
a duct including a stator;
a propeller including a rim including a rotor radially inward of the stator and facing the stator, and blades radially inward of the rim;
a detector facing the rotor via a metal to detect a magnetic flux density generated by a magnet of the rotor; and
a controller configured or programmed to calculate a magnet position of the rotor based on the magnetic flux density detected by the detector, and perform a control to apply a current to the stator at a timing at which the rotor is able to obtain a maximum torque based on the calculated magnet position of the rotor; and
the controller is configured or programmed to calculate a rotation speed of the rotor based on the magnetic flux density detected by the detector, and correct a deviation in the calculated magnet position of the rotor due to an eddy current generated in the metal based on the calculated rotation speed of the rotor.
12 . The marine vessel according to claim 11 , wherein the detector is adjacent to the stator in an axial direction of the rotor and faces the rotor.
13 . The marine vessel according to claim 12 , wherein the detector is accommodated in a space inside a storage area defined by the metal and located in an upper portion of the duct.
14 . The marine vessel according to claim 13 , wherein
the marine propulsion device further includes a housing above the duct;
the controller is accommodated in a space inside the housing; and
the space inside the storage area in which the detector is accommodated is connected to the space inside the housing in which the controller is accommodated.
15 . The marine vessel according to claim 11 , wherein
three-phase AC power is supplied to the stator;
the detector includes three detectors to detect three-phase magnetic flux densities generated by the magnet of the rotor, respectively; and
the controller is configured or programmed to calculate the rotation speed of the rotor based on one of the three-phase magnetic flux densities detected by the three detectors, respectively, and correct deviations in magnet positions of the rotor calculated based on the three-phase magnetic flux densities, respectively, based on the calculated rotation speed of the rotor.
16 . The marine vessel according to claim 15 , wherein
the three detectors are aligned along an alignment direction perpendicular or substantially perpendicular to an axial direction of the rotor in a horizontal plane; and
a thickness of the metal between the rotor and one of the three detectors located at a center in the alignment direction is different from a thickness of the metal between the rotor and another one of the three detectors located on a first side in the alignment direction and a thickness of the metal between the rotor and another one of the three detectors located on a second side in the alignment direction.
17 . The marine vessel according to claim 11 , wherein
the marine propulsion device further includes a storage to store correction information indicating a relationship between the rotation speed of the rotor and a correction value to correct the deviation in the calculated magnet position of the rotor; and
the controller is configured or programmed to correct the deviation in the calculated magnet position of the rotor based on the calculated rotation speed of the rotor and the correction information.
18 . The marine vessel according to claim 17 , wherein the storage is operable to store the correction information for an entire range of the rotation speed of the rotor.
19 . The marine vessel according to claim 17 , wherein the storage is operable to store the correction information represented by a mathematical formula, a map, or a table.
20 . The marine vessel according to claim 19 , wherein
the storage is operable to store the correction information represented by the mathematical formula; and
the controller is configured or programmed to calculate the correction value based on the calculated rotation speed of the rotor and the correction information represented by the mathematical formula, and correct the deviation in the calculated magnet position of the rotor based on the calculated correction value.