Thermal protection of a brushless motor
AssigneeDyson Technology Limited
InventorTuncay CELIK
Life of this patent
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Abstract
A method of controlling a brushless motor. The method includes storing a power lookup table that comprises a control value for each of a plurality of voltages or speeds, measuring the magnitude of a supply voltage or the speed of the motor, and indexing the power lookup table using the measured voltage or speed to select a control value. The method further includes measuring a temperature of the motor and applying a compensation value to the selected control value in the event that the measured temperature exceeds a threshold. A winding of the motor is then excited with the supply voltage and the selected control value is used to define an attribute of excitation. The compensation value, when applied to the selected control value, causes a reduction in the input power of the motor.
Claims13
A method of controlling a brushless motor, the method comprising:
- storing a power lookup table, the power lookup table comprising a control value for each of a plurality of voltages or speeds;
- measuring the magnitude of a supply voltage or the speed of the motor;
- indexing the power lookup table using the measured voltage or speed to select a control value;
- measuring a temperature of the motor;
- applying a compensation value to the selected control value in the event that the measured temperature is greater than a predefined threshold;
- and
- exciting a winding of the motor with the supply voltage,
- wherein the selected control value is used to define an attribute of excitation, and the compensation value when applied to the selected control value reduces the input power of the motor.
A method of controlling a brushless motor, the method comprising:
- storing a power lookup table, the power lookup table comprising a control value for each of a plurality of voltages or speeds;
- storing a temperature lookup table, the temperature lookup table comprising a compensation value for each of a plurality of temperatures;
- measuring the magnitude of a supply voltage or the speed of the motor;
- measuring a temperature of the motor;
- indexing the power lookup table using the measured voltage or speed to select a control value;
- indexing the temperature lookup table using the measured temperature to select a compensation value;
- applying the selected compensation value to the selected control value to obtain a compensated control value;
- and
- exciting a winding of the motor with the supply voltage, wherein the compensated control value is used to define an attribute of excitation.
A control circuit for a brushless motor, the control circuit being configured to:
- store a power lookup table, the power lookup table comprising a control value for each of a plurality of voltages or speeds;
- measure the magnitude of a supply voltage or the speed of the motor;
- index the power lookup table using the measured voltage or speed to select a control value;
- measure a temperature of the motor;
- apply a compensation value to the selected control value in the event that the measured temperature is greater than a predefined threshold;
- and
- excite a winding of the motor with the supply voltage,
- wherein the selected control value is used to define an attribute of excitation, and the compensation value when applied to the selected control value reduces the input power of the motor.
A control circuit for a brushless motor, the control circuit being configured to:
- store a power lookup table, the power lookup table comprising a control value for each of a plurality of voltages or speeds;
- store a temperature lookup table, the temperature lookup table comprising a compensation value for each of a plurality of temperatures;
- measure the magnitude of a supply voltage or the speed of the motor;
- measure a temperature of the motor;
- index the power lookup table using the measured voltage or speed to select a control value;
- index the temperature lookup table using the measured temperature to select a compensation value;
- apply the selected compensation value to the selected control value to obtain a compensated control value;
- and
- exciting a winding of the motor with the supply voltage, wherein the compensated control value is used to define an attribute of excitation.
Dependencies are inferred from the claim text.