# US 11,444,559 B2 · Operational mode control of a motor

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- Number: US 11,444,559 B2
- Document ID: US11444559B2
- Status: Granted
- Kind: B2
- Application number: 17/148,245
- Filed: 2021-01-13
- Published: 2021-05-06
- Granted: 2022-09-13
- Earliest claimed: 2018-06-15
- Assignees: Texas Instruments Incorporated
- Applicants: Texas Instruments Incorporated
- Inventors: Kristen N. Mogensen
- Web page: https://patentgrep.com/patent/US11444559B2

## CPC

- H02P 6/182: using back-emf in windings
- H02P 6/21: Open loop start
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

One example is a system for controlling a motor during startup. The system includes measurement logic, pattern detection logic, and mode logic. The measurement logic monitors a back-electromotive force (BEMF) signal representing a BEMF of an electric motor and the pattern detection logic monitors this signal to detect instances of the monitored BEMF signal exhibiting a predetermined pattern. The mode logic enables control of the electric motor according to a plurality of modes of control. In some examples, the mode logic initially employs a first mode of control and switches from the first mode of control to a second mode of control in response to the pattern detection logic detecting that a BEMF signal exhibits the predetermined pattern over a plurality of commutation states.

## Claims

### Claim 1

A method comprising:
receiving, by pattern detection logic, a signal generated by a motor having a plurality of commutation states and operating in a first control mode;
determining, by the pattern detection logic, a predetermined signal pattern in the signal generated by the motor;
incrementing, by the pattern detection logic, a count value based on a number of times over a set of the plurality of commutation states that the predetermined signal pattern is determined in the signal; and
in response to the count value exceeding a count threshold, selecting, by the pattern detection logic, a second control mode to operate the motor.

### Claim 2 (depends on 1)

The method of claim 1, wherein:
the signal comprises a back-electromotive force (BEMF) signal; and
the signal corresponds to the BEMF signal crossing a predetermined voltage during a selected commutation state of the plurality of commutation states.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
initializing, by a motor control logic, the motor, wherein the initializing includes starting the motor in the first control mode and increasing a commutation frequency of the motor from a first commutation frequency until the motor generates the signal.

### Claim 4 (depends on 3)

The method of claim 3, further comprising:
determining, by the motor control logic, whether an overcurrent condition with the motor exists.

### Claim 5 (depends on 4)

The method of claim 4, further comprising:
in response to the overcurrent condition existing with the motor, placing, by the motor control logic, the motor in a fault condition.

### Claim 6 (depends on 5)

The method of claim 5, further comprises:
in response to placing the motor in the fault condition, switching, by the motor control logic, the motor to the first commutation frequency.

### Claim 7 (depends on 3)

The method of claim 3, further comprising:
in response to determining the predetermined signal pattern is not determined in the signal, resetting the count value; and
increasing, by the motor control logic, the commutation frequency.

### Claim 8 (depends on 1)

The method of claim 1, wherein:
the count threshold is set in response to a user input.

### Claim 9 (depends on 1)

The method of claim 1, further comprising:
sampling, by a measurement logic, the signal periodically; and
converting, by the measurement logic, the signal into a digital signal.

### Claim 10 (depends on 9)

The method of claim 9, wherein:
the sampling includes a plurality of measurements of the signal of a respective floating phase of one or more commutation periods of the motor.

### Claim 11

A system comprising:
measurement logic operable to measure a signal associated with a motor having a plurality of commutation states;
pattern detection logic operable to:
receive the signal;
compare the signal to a predetermined signal pattern;
based on the comparison, increment a count value; and
in response to the count value exceeding a count threshold, generate a motor control selection to switch operation of the motor from a first control mode to a second control mode; and
mode logic operable to:
receive the motor control selection; and
operate the motor based on the motor control selection.

### Claim 12 (depends on 11)

The system of claim 11, wherein the measurement logic is operable to:
measure the signal periodically.

### Claim 13 (depends on 11)

The system of claim 11, wherein:
the signal comprises an analog signal; and
the measurement logic is operable to convert the analog signal to a digital signal.

### Claim 14 (depends on 11)

The system of claim 11, wherein the measurement logic is operable to:
measure the signal for a respective floating phase as the signal travels through one or more commutation periods of the motor.

### Claim 15 (depends on 11)

The system of claim 11, wherein:
the pattern detection logic includes a comparator.

### Claim 16 (depends on 11)

The system of claim 11, wherein the mode logic is operable to:
operate the motor in open-loop control in the first control mode; and
operate the motor in closed-loop control in the second control mode.

### Claim 17 (depends on 11)

The system of claim 11, wherein the mode logic is operable to:
operate the motor in a first closed-loop control in the first control mode; and
operate the motor in a second closed-loop control in the second control mode.

### Claim 18

A device, comprising:
pattern detection logic configured to:
receive a signal generated by a motor having a plurality of commutation states and operating in a first control mode;
compare the signal in a number of the plurality of commutation states with a predetermined signal pattern;
based on the comparison, increment a count value; and
in response to the count value exceeding a count threshold, selecting a second control mode to operate the motor.

### Claim 19 (depends on 18)

The device of claim 18, wherein:
the count value is increased in response to the signal matching the predetermined signal pattern over a set of the plurality of commutation states.

### Claim 20 (depends on 18)

The device of claim 18, wherein:
the count threshold is selected from one of a default value and a programmable value.