Driving control device of motor

1. A driving control device of a motor, comprising:

a motor driving unit, which receives power from a power supply and drives a motor in response to a driving control signal; and

a control unit, which detects a rotational position of a rotor based on a detection signal from a rotation sensor and determines an energization pattern applied to an armature coil based on the detected rotational position of the rotor, wherein the control unit starts rotation control by a preset first energization pattern when activating of the motor,

wherein when a predetermined time period has elapsed since the motor is activated, the control unit determines whether it is an energization pattern switchable timing, which is a timing at which a rising or falling edge of the detection signal is detected and, at which a short of each phase is not caused at switching of the energization pattern, and if it is determined that it is the energization pattern switchable timing, outputs the driving control signal to the motor driving unit so that the rotation control is switched to rotation control of a second energization pattern, wherein the first energization pattern and the second energization pattern are stored in an energization pattern storage unit, with a phase of the first energization pattern being different from a phase of the second energization pattern, and the second energization pattern a predetermined advanced electrical angle amount with respect to the first energization pattern,

wherein the motor driving unit controls driving current flowing through the motor by a PWM signal, which is generated therein, and

wherein the control unit controls the motor driving unit so that, just before switching the energization pattern from the first energization pattern to the second energization pattern, an ON duty of the PWM signal in the first energization pattern is set to be lower than an ON duty of the PWM signal just before the switching and then the energization pattern is switched from the first energization pattern to the second energization pattern.

2. The driving control device of a motor according to claim 1 ,

wherein the predetermined time period is one of a preset elapsed time after the rotation control by the first energization pattern starts or a time at which a preset number of energization switching is performed.

3. The driving control device of a motor according to claim 1 ,

wherein the control unit comprises:

an energization pattern storage unit, which stores therein the first energization pattern and the second energization pattern;

a timer circuit unit, which measures time and outputs measured time information based on a result of the measuring of the time; and

a motor control unit, which checks whether the predetermined time period has elapsed based on the measured time information, selects any one energization pattern from the energization pattern storage unit based on a result of the check and outputs the driving control signal corresponding to the selected energization pattern.

4. The driving control device of a motor according to claim 1 ,

wherein the control unit controls the motor driving unit so that, just before switching the energization pattern from the first energization pattern to the second energization pattern, an ON duty of the PWM signal in the first energization pattern is set to be an ON duty at the steady state where the motor is rotated at a target rotation speed after the switching to the second energization pattern.