Method and circuit for controlling or starting a u-shape single phase synchronous permanent magnet motors
AssigneeWhirlpool Corporation
InventorsKEVIN J. FITZPATRICK, BIAO HE, QIANG MEI, YING XIAO
Life of this patent
Estimating the term…
Abstract
A method and circuit for controlling or starting a U-shape single phase synchronous permanent magnetic motor (U-SPSPM motor) having a rotor and a stator and coupled to a single phase alternating current (AC) power source through a switch, including estimating back electromotive force (back-EMF) of the motor based on an observer model with inputs indicative of the measured signals, and triggering the switch to supply power to the motor based on the estimates of the back-EMF.
Claims20
A method for controlling a U-shape single phase synchronous permanent magnetic motor (U-SPSPM motor) having a rotor and a stator and coupled to a single phase alternating current (AC) power source through a switch, the method comprising:
- measuring a feedback signal representative of voltage across the motor leads;
- measuring a feedback signal representative of current through the motor;
- measuring a feedback signal indicative of a zero-crossing of the single phase AC power source;
- estimating back electromotive force (back-EMF) of the motor based on an observer model with inputs indicative of the measured feedback signals, wherein the estimates of the back-EMF has a higher fidelity than the number of zero-crossings measured;
- and
- triggering the switch to supply power to the motor based on the estimates of the back-EMF.
A circuit for controlling a U-shape single phase synchronous permanent magnetic motor (U-SPSPM motor) comprising:
- an alternating current (AC) power source connected to a U-SPSPM motor having a rotor;
- a microcontroller coupled to the AC power source and to the U-SPSPM motor;
- a phase sensor connected between the AC power source and the microcontroller configured to send a signal representative of zero crossing to the microcontroller;
- a current sensing circuit coupled to the microcontroller configured to send a signal representative of a current value to the microcontroller;
- a voltage sensing circuit coupled to the microcontroller configured to send a signal representative of a voltage value to the microcontroller;
- a triac connected in series between the AC power source and the U-SPSPM motor, and coupled to the microcontroller;
- and
- an observer model in the microcontroller configured to determine back electromotive force (back-EMF), wherein the determination of the back-EMF has a higher fidelity than the number of zero-crossings represented by the phase sensor signal.
A method for starting a U-shape single phase synchronous permanent magnetic motor (U-SPSPM motor) having a rotor and a stator and coupled to a single phase alternating current (AC) power source through a switch, the method comprising:
- controllably enabling a set of pulses through the switch, by a microcontroller;
- estimating back electromotive force (back-EMF) of the motor, by the microcontroller, based on an observer model and the set of pulses;
- integrating the estimated back-EMF, by the microcontroller;
- determining, by the microcontroller, whether the integrated back-EMF satisfies a predetermined threshold;
- determining, by the microcontroller, a start sequence polarity based on the determination whether the integrated back-EFM satisfies the predetermined threshold;
- and
- initiating a start sequence for the U-SPSPM in accordance with the determined start sequence polarity.
Dependencies are inferred from the claim text.