Controller for electrical machines
First Claim
1. A control system for an electrical machine comprising a rotor and a stator having one or more phase windings for generating a rotating stator magnetic field in a stationary reference frame relative to the stator, the system comprising:
- detection means for monitoring current in at least one of the phase windings;
first calculating means for determining from the monitored current values representative of real and imaginary components (Is—
real, Is—
imag) of the current vector in a rotating reference frame rotating relative to the stationary reference frame;
second calculating means for determining from the monitored current values representative of real and imaginary components (Es—
real, Es—
imag) of the emf vector rotating in the rotating reference frame, the second calculating means serving to determine the ratio of the real and imaginary components Es—
real, Es—
imag) of the emf vector;
estimating means for estimating a value representative of an angular position of the rotating emf vector from said ratio;
error means for determining an angular error signal indicative of the deviation of the estimated angular position from a desired angular position which is in line with the real axis of the rotating reference frame; and
synchronising means for controlling the machine such that the angular error signal tends towards zero.
1 Assignment
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Accused Products
Abstract
The present invention relates to control of synchronous machines. A sensorless control system for an electrical machine is provided comprising a rotor and a stator having one or more phase windings for generating a rotating stator magnetic field. The current in the phase windings is monitored to determine real and imaginary components of the current vector in a rotating reference frame, from which real and imaginary components of the emf vector rotating in the rotating reference frame can also be determined. The ratio of the real and imaginary emf components is calculated, and an angular position of the rotational emf vector is estimated from this ratio. An angular error signal indicative of the deviation of the estimated angular position from a desired position in line with the real axis of the rotating reference frame is determined, and the machine is controlled such that the error signal tends towards zero.
42 Citations
12 Claims
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1. A control system for an electrical machine comprising a rotor and a stator having one or more phase windings for generating a rotating stator magnetic field in a stationary reference frame relative to the stator, the system comprising:
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detection means for monitoring current in at least one of the phase windings; first calculating means for determining from the monitored current values representative of real and imaginary components (Is — real, Is— imag) of the current vector in a rotating reference frame rotating relative to the stationary reference frame;second calculating means for determining from the monitored current values representative of real and imaginary components (Es — real, Es— imag) of the emf vector rotating in the rotating reference frame, the second calculating means serving to determine the ratio of the real and imaginary components Es— real, Es— imag) of the emf vector;estimating means for estimating a value representative of an angular position of the rotating emf vector from said ratio; error means for determining an angular error signal indicative of the deviation of the estimated angular position from a desired angular position which is in line with the real axis of the rotating reference frame; and synchronising means for controlling the machine such that the angular error signal tends towards zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification