Brushless DC motor coupled directly to AC source and electric apparatus using the same motor
First Claim
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1. A brushless DC motor coupled directly to an AC source, the motor comprising:
- (a) a stator including a stator coil;
(b) a rotor including a rotor magnet;
(c) a magnetic flux sensor for sensing magnetic-flux of the rotor magnet;
(d) an inverter circuit including a plurality of switching elements coupled in a full-wave bridge having an upper arm and a lower arm;
(e) a plurality of AC source couplers;
(f) a rectifier for full-wave rectifying a voltage of the AC source;
(g) a DC voltage converter for converting a rectified voltage supplied from the rectifier into a low DC voltage, and for applying the low DC voltage to the inverter circuit as a power supply;
(h) a controller for controlling the inverter circuit based on a signal supplied from the magnetic flux sensor such that the low DC voltage is supplied to the stator coil in a full-wave driving method; and
(i) a current controller for regulating an average current value applied to the inverter circuit constantly at a set current;
(j) a set current changer for changing the set current regulated by the current controller;
wherein the set current changer changes the set current regulated by the current controller in response to which terminals of the AC source couplers are coupled to the AC source.
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Abstract
A brushless DC motor is disclosed, in which a commercial AC source is full-wave rectified by a rectifier and then converted into a generally flat and low DC voltage not more than 45V by a DC voltage converter. The low DC voltage is applied in a full-wave driving method to a stator coil via an inverter circuit formed of switching elements in a bridge configuration. This structure allows obtaining the brushless DC motor coupled directly to the AC source, and the torque ripples and uneven rotation of the motor are suppressed.
28 Citations
9 Claims
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1. A brushless DC motor coupled directly to an AC source, the motor comprising:
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(a) a stator including a stator coil; (b) a rotor including a rotor magnet; (c) a magnetic flux sensor for sensing magnetic-flux of the rotor magnet; (d) an inverter circuit including a plurality of switching elements coupled in a full-wave bridge having an upper arm and a lower arm; (e) a plurality of AC source couplers; (f) a rectifier for full-wave rectifying a voltage of the AC source; (g) a DC voltage converter for converting a rectified voltage supplied from the rectifier into a low DC voltage, and for applying the low DC voltage to the inverter circuit as a power supply; (h) a controller for controlling the inverter circuit based on a signal supplied from the magnetic flux sensor such that the low DC voltage is supplied to the stator coil in a full-wave driving method; and (i) a current controller for regulating an average current value applied to the inverter circuit constantly at a set current; (j) a set current changer for changing the set current regulated by the current controller; wherein the set current changer changes the set current regulated by the current controller in response to which terminals of the AC source couplers are coupled to the AC source. - View Dependent Claims (2, 3)
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4. A brushless DC motor coupled directly to an AC source, the motor comprising:
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(a) a stator including a stator coil; (b) a rotor including a rotor magnet; (c) a magnetic flux sensor for sensing magnetic-flux of the rotor magnet; (d) an inverter circuit including a plurality of switching elements coupled in a full-wave bridge having an upper arm and a lower arm; (e) an AC source coupler; (f) a rectifier for full-wave rectifying a voltage of the AC source; (g) a DC voltage converter for converting a rectified voltage supplied from the rectifier into a low DC voltage, and for applying the low DC voltage to the inverter circuit as a power supply; (h) a controller for controlling the inverter circuit based on a signal supplied from the magnetic flux sensor such that the low DC voltage is supplied to the stator coil in a full-wave driving method; (i) a current instructing means for instructing the average current value for supplying to the inverter circuit; (j) a current controller for regulating the average current value supplied to the inverter circuit constantly at a instructed value; and (k) an output means for outputting a signal of a motor rpm based on a signal supplied from the magnetic flux sensor; wherein the current instructing means instructs the average current value for supplying to the inverter circuit in response to the motor rpm. - View Dependent Claims (5, 6, 7, 8, 9)
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Specification