Motor drive control device
View Patent ↗A motor drive control device drives a motor including a plurality of phase coils and a rotor rotatably supported with respect to the plurality of phase coils, and the motor drive control device includes a controller, which generates a drive control signal; a motor driver, which outputs a drive signal to each of the phase coils of the motor, based on the drive control signal; and a back-electromotive-voltage detector, which is connected to each of the phase coils and includes resistive voltage dividing circuits having respectively different voltage-dividing ratios, wherein the back-electromotive-voltage detector detects a rotational position of a rotor for sensorless driving by using the resistive voltage dividing circuits.
1. A motor drive control device that drives a motor including a plurality of phase coils and a rotor rotatably supported with respect to the plurality of phase coils, the motor drive control device comprising:
a controller, which generates a drive control signal;
a motor driver, which outputs a drive signal to each of the phase coils of the motor, based on the drive control signal;
a back-electromotive-voltage detector, which is connected to each of the phase coils and includes resistive voltage dividing circuits having respectively different voltage-dividing ratios, wherein the back-electromotive-voltage detector detects a rotational position of a rotor for sensorless driving by using the resistive voltage dividing circuits;
wherein the controller includes:
a back-electromotive-voltage comparator, which generates phase signals of respective phases due to cross timing of a zero-cross reference voltage and a back electromotive voltage of the each of the phase coils;
a rotational speed determination unit, which inputs the phase signals of the respective phases and outputs rotational speed information;
a selection circuit, which selects and outputs any one of the phase signals of the respective phases depending on the rotational speed information; and
an energization signal generator, which generates the drive control signal based on the phase signal output from the selection circuit.
2. The motor drive control device according to claim 1 ,
wherein the controller performs the sensorless driving based on the rotational position of the rotor detected by the back-electromotive-voltage detector, and
wherein the controller performs control to synchronize with a phase having an optimum advance angle depending on a rotational speed of the motor.
3. The motor drive control device according to claim 2 ,
wherein the controller switches the phase, which is to be synchronized, to a further advanced angle, as the rotational speed is increased.
4. The motor drive control device according to claim 2 ,
wherein the controller determines the rotational speed based on at least one of a winding voltage and a winding current of each of the phase coils.