# US 2017/0288581 A1 · Method and circuit for controlling or starting a u-shape single phase synchronous permanent magnet motors

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2017/0288581 A1
- Document ID: US20170288581A1
- Status: Published application
- Kind: A1
- Application number: 15/623,512
- Filed: 2017-06-15
- Published: 2017-10-05
- Earliest claimed: 2015-12-15
- Assignees: Whirlpool Corporation
- Applicants: Whirlpool Corporation
- Inventors: KEVIN J. FITZPATRICK; BIAO HE; QIANG MEI; YING XIAO
- Web page: https://patentgrep.com/patent/US20170288581A1

## CPC

- H02P 6/182: using back-emf in windings
- A47L 15/4214: {Water supply, recirculation or discharge arrangements; Devices therefor}
- H02P 6/26: Arrangements for controlling single phase motors
- H02P 23/12: Observer control, e.g. using Luenberger observers or Kalman filters
- H02P 23/14: Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
- H02P 25/04: Single phase motors, e.g. capacitor motors
- H02P 1/465: {for starting an individual single-phase synchronous motor}
- H02P 6/22: in a selected direction of rotation
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- A47L: DOMESTIC WASHING OR CLEANING (brushes A46B; cleaning quantities of bottles or of other hollow articles of one kind B08B9/00; laundry D06F); SUCTION CLEANERS IN GENERAL (cleaning in general B08)

## 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.

## Claims

### Claim 1

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.

### Claim 2 (depends on 1)

The method of claim 1 wherein estimating back-EMF includes continuously estimating back-EMF.

### Claim 3 (depends on 1)

The method of claim 1 wherein estimating back-EMF includes estimating back-EMF more than 120 times per second.

### Claim 4 (depends on 1)

The method of claim 1 wherein estimating back-EMF occurs at a time scale independent of the single phase AC power source frequency.

### Claim 5 (depends on 1)

The method of claim 1 further comprising estimating a rotational speed of the motor and a position of the rotor based on the estimates of the back-EMF.

### Claim 6 (depends on 5)

The method of claim 5 wherein triggering the switch to supply power to the motor is further based on the estimates of the rotation speed of the motor and the position of the rotor.

### Claim 7 (depends on 1)

The method of claim 1 wherein the feedback signal representative of the voltage across the U-SPSPM motor leads is measured by a voltage sensing circuit coupled to a microcontroller, and configured to send the feedback signal to the microcontroller.

### Claim 8 (depends on 1)

The method of claim 1 wherein the feedback signal representative of the current through the U-SPSPM motor is measured by a current sensing circuit coupled to a microcontroller, and configured to send the feedback signal to the microcontroller.

### Claim 9 (depends on 1)

The method of claim 1 wherein the feedback signal indicative of a zero-crossing of the single phase AC power source is measured by a phase sensor connected between the AC power source a microcontroller, and configured to send the feedback signal to the microcontroller.

### Claim 10 (depends on 1)

The method of claim 1 wherein the switch is a triac and further comprising adjusting a trigger angle of the triac based on at least one of the back-EMF and a rotational speed of the motor and a position of the rotor.

### Claim 11 (depends on 1)

The method of claim 1 further comprising comparing the speed of the rotor with a predetermined synchronous speed for the U-SPSPM motor.

### Claim 12 (depends on 11)

The method of claim 11 further comprising adjusting the switch if the speed of the rotor is greater than or less than the synchronous speed.

### Claim 13 (depends on 12)

The method of claim 12 wherein adjusting the switch includes decreasing a trigger angle of a triac.

### Claim 14 (depends on 12)

The method of claim 12 wherein adjusting the switch includes increasing a trigger angle of a triac.

### Claim 15 (depends on 1)

The method of claim 1 wherein the triggering includes setting the switch ON when polarity of the rotor is north and the phase value is greater than or equal to zero, or if polarity is south and the phase value is less than or equal to zero.

### Claim 16 (depends on 1)

The method of claim 1 wherein the triggering includes setting the switch OFF when polarity of the rotor is north and the phase value is not greater than or equal to zero, or if polarity is south and the phase value is not less than or equal to zero.

### Claim 17

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.

### Claim 18 (depends on 17)

The circuit of claim 17 in a dishwasher where the U-SPSPM motor is associated with one of a wash pump or a drain pump.

### Claim 19

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.

### Claim 20 (depends on 19)

The method of claim 19 wherein estimating back-EMF includes estimating back-EMF of the motor during the set of pulses.