Synchronization of sequential phase switchings in driving stator windings of a multiphase sensorless brushless motor at sub BEMF-detectability speeds
First Claim
1. A method of synchronizing sequential phase switchings in driving stator windings of a multiphase sensorless brushless motor through a sequence of drive configurations of the stator windings, with reconstructed information on a current angular position of a magnetic rotor, the method comprising:
- sampling on a currently non-conductive stator winding a voltage induced thereon by a resultant magnetic field produced by a drive current forced through currently conductive stator windings that inverts its sign when the magnetic rotor transitions across a plurality of angular positions, at which orthogonality between the resultant magnetic field and a magnetic axis of the non-conductive winding verifies; and
comparing the sign of the sampled voltage induced on the currently non-conductive winding with an expected sign upon reaching an angular position of inversion of the sign of the sampled voltage by the magnetic rotor for a current drive configuration, for consequentially switching to a next drive configuration of the sequence upon verifying conformity of the sign of the sampled voltage with the expected sign at the sign inversion.
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Accused Products
Abstract
The method of synchronizing sequential phase switchings in driving stator windings of a multiphase sensorless brushless motor with a reconstructed information on the current angular position of a permanent magnet rotor, includes sampling on a currently non-conductive stator winding a voltage induced thereon by the resultant magnetic field produced by the drive current forced through currently conductive stator windings that inverts its sign when the rotor transitions across a plurality of significant angular positions, at which orthogonality between the resultant magnetic field and a magnetic axis of the non-excited winding verifies. The sign of the sampled voltage induced on the currently non-excited winding is compared with the sign that is expected upon transiting across the angular position of inversion by the moving rotor for the current phase drive configuration to sequentially switch to the next phase drive configuration upon verifying conformity of the sign of the sampled voltage with the expected sign.
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Citations
26 Claims
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1. A method of synchronizing sequential phase switchings in driving stator windings of a multiphase sensorless brushless motor through a sequence of drive configurations of the stator windings, with reconstructed information on a current angular position of a magnetic rotor, the method comprising:
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sampling on a currently non-conductive stator winding a voltage induced thereon by a resultant magnetic field produced by a drive current forced through currently conductive stator windings that inverts its sign when the magnetic rotor transitions across a plurality of angular positions, at which orthogonality between the resultant magnetic field and a magnetic axis of the non-conductive winding verifies; and comparing the sign of the sampled voltage induced on the currently non-conductive winding with an expected sign upon reaching an angular position of inversion of the sign of the sampled voltage by the magnetic rotor for a current drive configuration, for consequentially switching to a next drive configuration of the sequence upon verifying conformity of the sign of the sampled voltage with the expected sign at the sign inversion. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of controlling a multiphase sensorless brushless motor having a rotor and a plurality of stator windings, the method comprising:
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sequentially driving the plurality of stator windings according to a plurality of phase drive configurations producing a drive current in a stator winding tap and exiting another stator winding tap while placing stator windings that are not driven to a high impedance state, under closed loop control conditions; and obtaining a feedback signal by sampling on a currently non-conductive stator winding a voltage induced thereon by a resultant magnetic field produced by the drive current in the currently conductive stator windings that inverts its sign when the rotor transitions across a plurality of angular positions, at which orthogonality between the resultant magnetic field and a magnetic axis of the non-conductive winding verifies; and comparing the sign of the sampled voltage induced on the currently non-conductive winding with the expected sign upon reaching the angular position of inversion of the sign of the sampled voltage by the rotor for the current phase drive configuration, for consequentially switching to the next phase drive configuration of the sequence upon verifying conformity of the sign of the sampled voltage with the expected sign at the sign inversion. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A device for synchronizing sequential phase switchings in driving stator windings of a multiphase sensorless brushless motor through a sequence of drive configurations of the stator windings, with reconstructed information on a current angular position of a magnetic rotor, the device comprising:
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a control circuit configured to sample a voltage induced on a currently non-conductive stator winding by a resultant magnetic field produced by a drive current forced through currently conductive stator windings that inverts its sign when the magnetic rotor transitions across a plurality of angular positions, at which orthogonality between the resultant magnetic field and a magnetic axis of the non-conductive winding verifies; wherein the control circuit is configured to compare the sign of the sampled voltage induced on the currently non-conductive winding with an expected sign upon reaching an angular position of inversion of the sign of the sampled voltage by the magnetic rotor for a current drive configuration, for consequentially switching to a next drive configuration of the sequence upon verifying conformity of the n of the sampled voltage with the expected sign at the sign inversion. - View Dependent Claims (24, 25, 26)
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Specification