Sensorless control systems and methods for permanent magnet rotating machines
View Patent ↗Systems and methods for controlling a rotating electromagnetic machine. The rotating machine, such as a permanent magnet motor or hybrid switched reluctance motor, includes a stator having a plurality of phase windings and a rotor that rotates relative to the stator. A drive is connected to the phase windings for energizing the windings. A controller outputs a control signal to the drive in response to an input demand such as a demanded speed or torque. Control methods (which can be implemented separately or in combination) include varying the gain of an estimator as a function of a demanded or estimated speed to position control system poles at desired locations, de-coupling control system currents to achieve a constant torque with motor speed, compensating flux estimates of the estimator for saturation operation of the stator, estimating rotor position using averages of sample values of energization feedback, and calculating a trim adjusted speed error from a plurality of speed estimates.
1. A method of estimating rotor position in a sensorless control system for a permanent magnet rotating machine, the machine including a stator and a rotor situated to rotate relative to the stator, the stator having a plurality of energizable phase windings situated therein, the method comprising:
sampling energization feedback from the machine to obtain a plurality of samples;
averaging a pair of the plurality of samples to produce an average sample value;
estimating the rotor position using the average sample value; and
utilizing the estimated rotor position to control energizing of the phase windings to operate the permanent magnet rotating machine.
2. The method of claim 1 wherein averaging includes averaging a successive pair of the plurality of samples.
3. The method of claim 1 wherein averaging includes averaging each successive pair of the plurality of samples to produce a plurality of average sample values, and estimating includes estimating the rotor position using the plurality of average sample values.
4. A permanent magnet rotating machine and controller assembly configured to perform the method of claim 1 .
5. A climate control system comprising the assembly of claim 4 .
6. The climate control system of claim 5 wherein the system includes an air handler and wherein the air handler includes said assembly.
7. A method of controlling a permanent magnet rotating machine, the machine including a stator and a rotor situated to rotate relative to the stator, the stator having a plurality of energizable phase windings situated therein, the method comprising:
producing a first rotor speed estimate;
producing a second rotor speed estimate;
calculating a trim-adjusted speed error using the first rotor speed estimate and the second rotor speed estimate; and
utilizing the trim-adjusted speed error to control energizing of the phase windings to operate the permanent magnet rotating machine.
8. The method of claim 7 wherein calculating includes producing a trim value by calculating a difference between the first rotor speed estimate and the second rotor speed estimate.
9. The method of claim 8 wherein calculating further includes producing a raw speed error by calculating a difference between a demanded rotor speed and an estimated rotor speed.
10. The method of claim 9 wherein calculating further includes adding the trim value or a filtered trim value to the raw speed error.
11. The method of claim 7 wherein the first rotor speed estimate is produced using modeled motor parameters.
12. The method of claim 11 wherein the second rotor speed estimate is produced using zero crossings detected from energization feedback from the machine.