Brushless d.c. motor having rotor position-dependent control means
First Claim
Patent Images
1. Brushless d.c. motor comprising:
- a stator (18) having motor winding means (25,
26);
a permanent magnet rotor (11) rotatable relative to said stator;
a source of direct current (27,
53);
a rotor position-dependent semiconductor control means (32) having two pairs of terminals;
amplifying means responsive to said rotor position-dependent control means (32) and coupled to said direct current source and to said motor winding means for commutating the current in the motor winding means such that said motor winding means produces, in operation, an alternating magnetic field;
and a voltage divider (71,
72) having its end terminals coupled to one pair of the output terminals of the rotor position-dependent control means (32);
wherein said amplifying means includes a differential amplifier means (60) coupled to the other pair of output terminals of said semiconductor control means (32), the amplifying means having three output branches (54, 55,
66), two of said branches (54,
55) being coupled to control the currents in said motor winding means (25,
26);
and the voltage division ratio of the voltage divider (71,
72) being set such that the voltage of the tap point (70) of the voltage divider, when the rotor position-dependent control means (32) is subjected to a small or non-existent signal, will control said amplifying means so that current in said two branches tends to zero and current flow to said motor windings is blocked, said third branch substantially taking over and drawing the current of the differential amplifier means (60).
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Abstract
A brushless d.c. motor comprises a stator having stator winding means thereon, a permanent magnet rotor rotatable relative to the stator and a rotor position-dependent semiconductor commutating means coupled to the stator winding means for controlling the currents in the stator winding means. Further provided is means including amplifying means responsive to the outputs of the control means for reducing the currents in the stator winding means at predetermined rotor position ranges to substantially zero. The semiconductor control means is preferably a Hall generator.
56 Citations
50 Claims
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1. Brushless d.c. motor comprising:
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a stator (18) having motor winding means (25,
26);a permanent magnet rotor (11) rotatable relative to said stator; a source of direct current (27,
53);a rotor position-dependent semiconductor control means (32) having two pairs of terminals; amplifying means responsive to said rotor position-dependent control means (32) and coupled to said direct current source and to said motor winding means for commutating the current in the motor winding means such that said motor winding means produces, in operation, an alternating magnetic field; and a voltage divider (71,
72) having its end terminals coupled to one pair of the output terminals of the rotor position-dependent control means (32);wherein said amplifying means includes a differential amplifier means (60) coupled to the other pair of output terminals of said semiconductor control means (32), the amplifying means having three output branches (54, 55,
66), two of said branches (54,
55) being coupled to control the currents in said motor winding means (25,
26);and the voltage division ratio of the voltage divider (71,
72) being set such that the voltage of the tap point (70) of the voltage divider, when the rotor position-dependent control means (32) is subjected to a small or non-existent signal, will control said amplifying means so that current in said two branches tends to zero and current flow to said motor windings is blocked, said third branch substantially taking over and drawing the current of the differential amplifier means (60). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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- 16. Brushless d.c. motor comprising a stator with a winding means, a permanent magnet rotor rotatable relative thereto, a source of direct current, rotor position-dependent semiconductor commutating means and amplifying means capacitively coupled thereto and further coupled to said direct current source, and discharge means associated with and connected to said capacitive coupling means.
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27. Brushless d.c. motor comprising:
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a stator with stator winding means; a permanent magnet rotor rotatable relative to said stator; a source of direct current (27,
53);a rotor position-dependent semiconductor control means; and amplifying means responsive thereto coupled to said direct current source and to said stator winding means for commutating the current in the stator winding means such that said stator winding means produces in operation an alternating magnetic field; wherein said control means comprises a Hall generator (32) having a pair of outputs (50,
51);
said amplifying means including a pair of operational amplifiers (73,
74) respective one inputs of which are connected to responsive outputs of said Hall generator, the other inputs of said operational amplifiers (73,
75) being connected to a potential (70) which differs from the potential of the Hall generator outputs (50,
51) when a small or non-existing magnetic field is acting on the Hall generator (32). - View Dependent Claims (28, 29)
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30. Brushless d.c. motor comprising:
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a stator (18) with stator winding means; a permanent magnet rotor (11) rotatable relative to said stator; a source of direct current (27,
53);a rotor position-dependent semiconductor control means (32); and amplifying means responsive thereto coupled to said direct current source and to said stator winding means for commutating the current in the stator winding means such that said stator winding means produces in operation an alternating magnetic field; wherein said amplifying means includes an amplifier having at least two transistors (54,
55);
said rotor position-dependent semiconductor control means (32) having two outputs controlling said amplifier; and
means (54, 93, 55-94) coupled to said amplifier for reducing the base emitter threshold voltages of said amplifier transistors (54,
55) controlled by said semiconductor control means the inputs of said amplifier transistors (54,
55) being respectively capacitively (77,
78) coupled to said outputs (50,
51) of said semiconductor control means (32). - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. Brushless d.c. motor comprising
a stator with stator winding means (25, 26); -
a permanent magnet rotor (11) rotatable relative to said stator; a source of direct current (27,
53);a rotor position-dependent semiconductor control means (32); amplifying means including two operational amplifiers (73,
74) responsive to said rotor position-dependent semiconductor control means (32) and coupled to said direct current source and to said stator winding means to control commutation of current in the stator winding means such that said stator winding means produces, in operation, an alternating magnetic field;a voltage divider; wherein said rotor position-dependent semiconductor control means (32) has terminals coupled to inputs of said amplifying means and additional terminals coupled to the end terminals of the voltage divider (71,
72),the tap point (70) of said voltage divider being additionally connected to said amplifying means, the voltage division ratio of the voltage divider (71,
72) being set such that the voltage at said tap point of said voltage divider, when a small or non-existing signal is acting on said rotor position-dependent control means (32), provides an output voltage at said additional connection to the amplifying means to tend to control the output voltages of both said operational amplifiers (73,
74) to go to zero so that the current in said motor winding means is effectively blocked. - View Dependent Claims (45, 46)
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47. Brushless d.c. motor comprising a stator (18) having motor winding means (25, 26);
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a permanent magnet rotor (11) rotatable relative to said stator; a source of direct current (27,
53);a rotor position-dependent semiconductor control means (32); amplifying means including controlled switch means and coupled to said rotor position-dependent control means, the amplifying means and said switch means controlling and commutating current in the motor winding means such that said motor winding means produces, in operation, an alternating magnetic field; wherein said amplifying means includes a differential amplifying means (60) coupled to said rotor position-dependent semiconductor control means (32), the amplifying means comprising three branches (54, 55,
66), two of said branches (54,
55) being coupled to control the controlled switch means and hence the currents in said motor winding means (25,
26), and circuit means coupled to said two branches for controlling said third branch and said amplifying means and hence said controlled switch means to block current flow to said motor winding means when a small or non-existing signal acts on said rotor position-dependent control means in a range around the theoretical commutating instant (FIG. 5;
180°
-el, 360°
-el....etc.) as sensed by said rotor position-dependent control means. - View Dependent Claims (48, 49, 50)
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Specification