Method for determining a rotor position in a permanent magnet motor
First Claim
1. A method for determining the absolute position of a rotor in a PMSM motor having a rotor which includes at least one north pole, at least one south pole, and a stator having windings arranged about a core, wherein each winding is arranged such that when a current passes through the winding, the current generates flux in the core, the method comprising the steps of:
- (a) applying a short duration voltage pulse of to the stator windings at each of a plurality of successively spaced electrical angle sample points;
(b) sampling a current at the end of each voltage pulse;
(c) identifying an electrical angle segment between a first and a second successive electrical angle sample point that includes a maximum current;
(d) evaluating a magnitude of the current in the identified electrical angle segment to locate the peak current; and
(e) determining an angle of the peak current, wherein the angle of the peak current correlates to a rotor position.
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Accused Products
Abstract
A method for determining the position of a rotor in a permanent magnet synchronous motor includes applying voltage pulses to the windings at successive electrical angles while the motor is at a standstill. The resultant current is sampled. The position of a maximum current is determined by identifying an segment of an electrical cycles which includes the maximum current, and using a spline interpolation to model the current flow in this segment. The maximum current is then correlated to the position of the rotor.
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Citations
24 Claims
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1. A method for determining the absolute position of a rotor in a PMSM motor having a rotor which includes at least one north pole, at least one south pole, and a stator having windings arranged about a core, wherein each winding is arranged such that when a current passes through the winding, the current generates flux in the core, the method comprising the steps of:
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(a) applying a short duration voltage pulse of to the stator windings at each of a plurality of successively spaced electrical angle sample points; (b) sampling a current at the end of each voltage pulse; (c) identifying an electrical angle segment between a first and a second successive electrical angle sample point that includes a maximum current; (d) evaluating a magnitude of the current in the identified electrical angle segment to locate the peak current; and (e) determining an angle of the peak current, wherein the angle of the peak current correlates to a rotor position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A drive system comprising:
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a PMSM motor having a rotor which includes at least one north pole, at least one south pole, and a stator having windings arranged about a core, wherein each winding is arranged such that when a current passes through the winding, the current generates flux in the core; an inverter including switching devices connected to corresponding windings to apply voltage pulses to the windings; a current sensor associated with each of the windings; and a controller connected to the inverter and the current sensor for controlling voltage pulses to the windings and sampling current, the controller being programmed to; (a) activate the switching devices to apply a short duration voltage pulse of to the stator windings at each of a plurality of successively spaced electrical angle sample points; (b) sample a current at the end of each voltage pulse at the current sensor; (c) identify an electrical angle segment between a first and a second successive electrical angle sample point that includes a maximum current; (d) evaluate a magnitude of the current in the identified electrical angle segment to locate the peak current; and (e) determine an angle of the peak current, wherein the angle of the peak current correlates to a rotor position. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification