Brushless, permanent magnet d-c pulse current controlled, essentially uniform torque dynamo electric machine, particularly motor

Claim 2

Brushless d-c motor comprising a stator support; a permanent magnet rotor having first and second essentially annular magnetic regions, wherein the first region defines n poles of alternating polarity, and the second region defines 2n poles of alternating polarity, wherein n is an even number; magnetically-actuable rotor position sensing means (53) supported on the stator support and arranged to be magnetically actuated by the first magnetic region to provide, as a consequence of said actuation, rotor position information, including information relating to the position of one of said magnetic regions of the rotor to the sensing means; stator pole means located on said stator support and positioned for electromagnetic coupling and interaction with the rotor, including two winding means, wherein the stator pole means extends over at least a part of the first and second magnetic regions of the rotor and has an angular extent, in the direction of rotation, over both the first and second regions of approximately two-thirds, or integral multiples thereof, of one pole pitch of the first magnetic region; and controlled switching means, selectively connecting a selected one of said winding means to a source of electrical power in dependence on said rotor position information to provide, in operation, controlled current flow through the selected one of the windings for effecting electromagnetic interaction with the magnetic regions of the rotor.

Claim 3

Brushless d-c motor comprising a stator support; a permanent magnet rotor having first and second essentially annular magnetic regions, wherein the first region defines n poles of alternating polarity, said poles of the first region having essentially trapezoidal magnetization, and the second region defines 2n poles of alternating polarity, wherein n is an even number; magnetically-actuable rotor position sensing means (53) supported on the stator support and arranged to be magnetically actuated by the first magnetic region to provide, as a consequence of said actuation, rotor position information, including information relating to the position of one of said magnetic regions of the rotor to the sensing means; stator pole means located on said stator support and positioned for electromagnetic coupling and interaction with the rotor, including two winding means, wherein the stator pole means extends over at least a part of the first and second magnetic regions of the rotor and has an angular extent, in the direction of rotation, over both the first and second regions of approximately two-thirds, or integral multiples thereof, of one pole pitch of the first magnetic region; and controlled switching means, selectively connecting a selected one of said winding means to a source of electrical power in dependence on said rotor position information to provide, in operation, controlled current flow through the selected one of the windings for effecting electromagnetic interaction with the magnetic regions of the rotor.

Claim 4

Brushless d-c motor comprising a stator support; a permanent magnet rotor having first and second essentially annular magnetic regions, wherein the first region defines n poles of alternating polarity, said poles of the first region having essentially trapezoidal magnetization, and the second region defines 2n poles of alternating polarity, wherein n is an even number; magnetically-actuable rotor position sensing means (53) supported on the stator support and arranged to be magnetically actuated by the first magnetic region to provide, as a consequence of said actuation, rotor position information, including information relating to the position of one of said magnetic regions of the rotor to the sensing means; stator pole means located on said stator support and positioned for electromagnetic coupling and interaction with the rotor, including two winding means, wherein the stator pole means extends over at least a part of the first and second magnetic regions of the rotor and has an angular extent, in the direction of rotation, over both the first and second regions of approximately two-thirds, or integral multiples thereof, of one pole pitch of the first magnetic region; and controlled switching means, selectively connecting a selected one of said winding means to a source of electrical power in dependence on said rotor position information to provide, in operation, controlled current flow through the selected one of the windings for effecting electromagnetic interaction with the magnetic regions of the rotor.

Claim 5

Brushless d-c motor comprising a stator support; a permanent magnet rotor having first and second essentially annular magnetic regions, wherein the first region defines n poles of alternating polarity, and the second region defines 2n poles of alternating polarity, wherein n is an even number; magnetically-actuable rotor position sensing means (53) supported on the stator support and arranged to be magnetically actuated by the first magnetic region to provide, as a consequence of said actuation, rotor position information, including information relating to the position of one of said magnetic regions of the rotor to the sensing means; stator pole means located on said stator support and positioned for electromagnetic coupling and interaction with the rotor, including two winding means, wherein the stator pole means extends over at least a part of the first and second magnetic regions of the rotor and has an angular extent, in the direction of rotation, over both the first and second regions of approximately two-thirds, or integral multiples thereof, of one pole pitch of the first magnetic region; and controlled switching means, selectively connecting a selected one of said winding means to a source of electrical power in dependence on said rotor position information to provide, in operation, controlled current flow through the selected one of the windings for effecting electromagnetic interaction with the magnetic regions of the rotor; wherein the second magnetic region of the permanent magnet rotor comprises an equal number of shorter poles and longer poles, in which the longer poles have an angular extent which is approximately twice that of the shorter poles, and the shorter poles of the second magnetic region, together with adjacent pole portions of the first magnetic region, form dipole zones, which are relatively dimensioned and arranged to provide, in absolute values, an approximately equal magnetic flux in an air gap separating said poles from the stator pole means.

Claim 6

Brushless d-c motor comprising a stator support; a permanent magnet rotor having first and second essentially annular magnetic regions, wherein the first region defines n poles of alternating polarity, and the second region defines 2n poles of alternating polarity, wherein n is an even number; magnetically-actuable rotor position sensing means (53) supported on the stator support and arranged to be magnetically actuated by the first magnetic region to provide, as a consequence of said actuation, rotor position information, including information relating to the position of one of said magnetic regions of the rotor to the sensing means; stator pole means located on said stator support and positioned for electromagnetic coupling and interaction with the rotor, including two winding means, wherein the stator pole means extends over at least a part of the first and second magnetic regions of the rotor and has an angular extent, in the direction of rotation, over both the first and second regions of approximately two-thirds, or integral multiples thereof, of one pole pitch of the first magnetic region; and controlled switching means, selectively connecting a selected one of said winding means to a source of electrical power in dependence on said rotor position information to provide, in operation, controlled current flow through the selected one of the windings for effecting electromagnetic interaction with the magnetic regions of the rotor; wherein the second magnetic region of the permanent magnet rotor comprises an equal number of shorter poles and longer poles, in which the longer poles have an angular extent which is approximately twice that of the shorter poles, and the shorter poles of the second magnetic region, together with adjacent pole portions of the first magnetic region, form dipole zones, which are relatively dimensioned and arranged to provide, in absolute values, an approximately equal magnetic flux in an air gap separating said poles from the stator pole means.

Claim 7

Motor according to claim 3, wherein the poles of the first magnetic region of the rotor have a substantially trapezoidal magnetization.

Claim 8

Motor according to claim 1, wherein the pole arrangement of said first and second regions are so located relative to each each other that at least one pair of adjacent poles of the second region is positioned adjacent an oppositely poled pair of a portion of said first region to form a dipole zone.

Claim 9

Motor according to claim 5, wherein the magnetic characteristics of the poles of the first and second region in said dipole zone are dimensioned and arranged to provide, in absolute values, an approximately equal magnetic flux in an air gap separating said poles from the stator pole mans.

Claim 10

Motor according to claim 1, wherein the second magnetic region comprises an equal number of shorter poles and longer poles, the longer poles having an angular extent which is approximately twice that of the shorter poles.

Claim 11

Motor according to claim 1, wherein some of the boundaries between adjacent poles of the first magnetic region are in substantial alignment with some of the boundaries between adjacent poles of the second magnetic region; and wherein said stator pole means have end portions which extend over and are substantially parallel to those boundaries which are in alignment.

Claim 12

Motor according to claim 1 or 3, wherein the pole pitch of the first magnetic region is essentially uniform.

Claim 13

Motor according to claim 1 or 2 or 3, wherein adjacent like poles of the first magnetic regions and the second magnetic regions are substantially merged to provide respective pole zones of substantially uniform magnetization.

Claim 14

Motor according to claim 1 or 2 or 3, wherein the rotor position sensing means is arranged to control energization of at least one of said stator winding means at any instant of time during operation of the motor, to provide a substantially constant driving torque essentially free of gaps.

Claim 15

Motor according to claim 1, wherein the range of said second region of magnetization extends over an angle of 180°-el having an extent of about 120°-el of the same polarity of the adjacent first region of magnetization and of about 60°-el of opposite polarity of magnetization.

Claim 16

Motor according to claim 1, further including current switching control means connected to and providing approximately constant current to the respective winding means during the time in which the voltage induced in said winding means, upon rotation of the rotor, is approximately uniform.

Claim 17

A motor according to claim 1, comprising current switching control means providing a decreasing current to one of said winding means, in the range of commutation of current from said winding means to the other of said winding means, while the current in said other winding means is increasing.

Claim 18

A motor according to claim 1, wherein said winding means are positioned on a stator of the motor, such that two magnetically active portions of any one of said winding means, offset from each other by 120°-el+m×360°-el, have current flowing therethrough in opposite directions, and wherein m is an integer of the series 0,1,2 . . . .

Claim 19

A motor according to claim 1, wherein said winding means has magnetically active portions which, upon coincidence with a boundary between two poles of the first magnetic region, at least in part extend at least approximately parallel to the boundary.

Claim 20

A motor according to claim 4, comprising a differential amplifier connected between said rotor position sensing means and current switching control means for controlling current in said winding means, to control commutation of current therethrough.

Claim 21

Motor according to claim 1, wherein the motor is an axial air gap motor, and the stator windings are air core or coreless windings.

Claim 22

Motor according to claim 1, wherein the motor is a cylindrical air gap motor, and the stator includes a slotless stator structure.

Claim 23

A motor according to claim 19, wherein the first magnetic region has four poles, said winding means having four symmetrically arranged stator coils, respective coils having a winding pitch of about 240°-el., with reference to the first magnetic region.

Claim 24

A motor according to claim 19, wherein the first magnetic region has four poles, said winding means having four symmetrically arranged stator coils having a winding pitch of about 120°-el., with reference to the first magnetic region.

Claim 25

A motor according to claim 1, wherein said winding means has magnetically active portions of a width between about 10° to 60°-el., with reference to the first magnetic region.

Claim 26

A motor according to claim 1, wherein said winding means has relieved corners formed by chamfering the corners in those regions in which they are within the first magnetic region of the rotor.

Claim 27

A motor according to claim 1, wherein said winding means has stator coils in the shape of an approximate five-cornered polygon with one tip of the polygon pointing in the direction of the first magnetic region of the rotor.

Claim 28

A motor according to claim 1, further comprising a tacho generator winding located in an air gap in the motor and positioned for interaction with the magnetic flux derived from either the first or second magnetic region.

Claim 29

A motor according to claim 25, wherein the tacho generator winding is located for interaction with the magnetic flux from substantially the second magnetic region only.

Claim 30

A motor according to claim 25, wherein the tacho generator winding comprises a plurality of series connected winding loops having the same direction of winding.

Claim 31

A motor according to claim 27, wherein at least three 3p winding loops are provided in a motor having a number of 2p poles in the first magnetic region.

Claim 32

A motor according to claim 27, wherein the winding width of the separate loops of the tacho generator winding is approximately 60°/p.

Claim 33

A motor according to claim 25, wherein the tacho generator winding is a wave or meander winding.

Claim 34

A motor according to claim 30, wherein the meander winding is an essentially flat meander and the radial sections have a distance of about 60°/p for a motor having a number of 2p poles, in the first magnetic region.

Claim 35

A motor according to claim 31, wherein a plurality of meander windings are provided, and individual ones of the meander windings are electrically and mechanically offset with respect to each other to provide an multi-phase tacho generator system.

Claim 36

A brushless d-c motor comprising: a permanent magnet rotor having first and second, essentially annular magnetic regions, the first region defining n poles of alternating polarity and the second region defining 2n poles of alternating polarity, wherein n is an even number; magnetically actuable rotor position sensing means arranged to be magnetically actuated by the first magnetic region and to provide, as a consequence of said actuation, rotor position information; stator pole means which is arranged to interact with the rotor, including two winding means connectable alternately to a current source in dependence upon said information and wherein the stator pole means extends over at least a part of both the first and second regions and has an angular extent, over both the first and second regions, of approximately two-thirds, or approximately integral multiples thereof, of one pole pitch of the first magnetic region.

Claim 37

A brushless d-c motor comprising: a permanent magnet rotor having first and second, essentially annular magnetic regions, the first region defining n poles of alternating polarity and the second region defining 2n poles of alternating polarity, wherein n is an even number; magnetically actuable rotor position sensing means arranged to be magnetically actuated by the first magnetic region and to provide, as a consequence of said actuation, rotor position information; stator pole means which is arranged to interact with the rotor, including two winding means connectable alternately to a current source in dependence upon said information and wherein the stator pole means extends over at least a part of both the first and second regions and has an angular extent, over both the first and second regions, of approximately two-thirds, or approximately integral multiples thereof, of one pole pitch of the first magnetic region.

Claim 38

Motor according to claim 1 or 2 or 3 or 33, wherein the motor is an axial air gap motor.

Claim 39

Motor according to claim 1 or 2 or 3 or 33, wherein the motor is a cylindrical air gap motor.