Method and device for controlling position sensorless motor

A device for controlling a position sensorless motor which is provided with a synchronized operation and a position sensorless operation and has operation mode-switching means for switching between such operations, comprising:

• stator coil drive means which excites stator coils of the motor in synchronization with a position command signal when the synchronized operation is selected by the operation mode-switching means and, when the position sensorless operation is selected, detects the rotation position of the rotor based on counter electromotive forces produced in the stator coils, and excites the stator coils in synchronization with the detected rotation position of the rotor;
• deviation calculation means which determines a deviation between a target position and the present position from the position command signal and the detected rotation position of the rotor when the position sensorless operation is selected by the operation mode-switching means;
• control means which controls the drive of the stator coil drive means according to the deviation determined by the deviation calculation means when the position sensorless operation is selected by the operation mode-switching means;
• and
• bias control means which adds a predetermined bias to the deviation determined by the deviation calculation means immediately after the selection of the position sensorless operation by the operation mode-switching means and decreases the bias with a lapse of time.

A method for controlling a position sensorless motor which is provided with a synchronized operation and a position sensorless operation and has operation mode-switching means for switching between such operations, comprising the steps of:

• exciting stator coils of the motor in synchronization with a position command signal during the synchronized operation to rotate a rotor;
• detecting a rotation position of the rotor based on counter electromotive forces produced in the stator coils during the position sensorless operation, exciting the stator coils in synchronization with a rotor rotation position signal indicating the detected rotation position of the rotor to rotate the rotor;
• determining a deviation between a target position and the present position from a target rotation position and the detected rotation position of the rotor according to the position command signal, adding an integral value of the determined deviation to the deviation, determining a rotor rotational speed on the basis of the rotor rotation position signal, making a position sensorless close loop drive on the basis of a value obtained by subtracting the rotor rotational speed from an added value of the deviation and the integral value of the deviation;
• and
• setting a predetermined initial value for the integral value of the deviation when the synchronized operation is switched to the position sensorless operation by the operation mode-switching means.

A device for controlling a position sensorless motor which is provided with a synchronized operation and a position sensorless operation and has operation mode-switching means for switching between such operations, comprising:

• stator coil drive means which excites stator coils of the motor in synchronization with a position command signal when the synchronized operation is selected by the operation mode-switching means and, when the position sensorless operation is selected, detects the rotation position of the rotor based on counter electromotive forces produced in the stator coils to excite the stator coils in synchronization with a rotor rotation position signal indicating the detected rotation position of the rotor;
• deviation calculation means which determines a deviation between a target position and the present position from a target rotation position according to the position command signal and the detected rotation position of the rotor when the position sensorless operation is selected by the operation mode-switching means;
• integration means for determining an integral value of the deviation determined by the deviation calculation means;
• rotational speed detection means for determining a rotor rotational speed on the basis of the rotor rotation position signal;
• control means which controls the drive of the stator coil drive means on the basis of a value obtained by adding an integral value of the deviation to the deviation and subtracting the rotor rotational speed from the added value of the deviation and the integral value of the deviation;
• and
• initial value setting means for setting a predetermined initial value as the integral value of the deviation by the integration means when the synchronized operation is changed to the position sensorless operation by means of the operation mode-switching means.

A device for controlling a position sensorless motor, comprising:

• position detection means for producing a rotor position signal indicating a rotation position of a rotor by comparing counter electromotive forces produced in stator coils of the motor with a predetermined voltage;
• clocking means for detecting a moment of change in the rotor position signal produced by the position detection means and measuring a time between the detected moments of changes;
• energization changeover timing decision means which adds a delay time with reference to the moments of changes detected by the clocking means to decide the energization changeover timing of the stator coils and uses as the delay time the measuring time corresponding to the positive and negative periods of the counter electromotive forces among the measured times by the clocking means;
• and
• exciting means for flowing an electric current to the stator coils with the energization changeover timing decided by the energization changeover timing decision means.

A device for controlling a motor, comprising:

• position detection means for producing a rotor position signal indicating a rotation position of a rotor by comparing counter electromotive forces produced in stator coils of the motor with a predetermined voltage;
• exciting means for flowing an electric current to the stator coils on the basis of the rotor position signal produced by the position detection means;
• rotational speed detection means which sequentially detects a moment of the change from the rotor position signal produced by the position detection means, measures a time between the detected moments of the change, and determines a rotational speed of the rotor from the average of the two times corresponding to the plus and minus periods of the counter electromotive forces among the measured times;
• and
• control means for controlling the exciting means so to have the rotational speed determined by the rotational speed detection means agreed with a target value.

A device for controlling a position sensorless motor, comprising:

• position detection means for producing a rotor position signal indicating a rotation position of a rotor by comparing counter electromotive forces produced in stator coils of the motor with a predetermined voltage;
• clocking means which detects a moment of change of the rotor position signal produced by the position detection means and measures a time between the detected moments of change;
• energization changeover timing decision means which adds a delay time with reference to the moments of change detected by the clocking means to decide the energization changeover timing of the stator coils and uses as the delay time the time corresponding to the plus and minus periods of the counter electromotive forces among the times measured by the clocking means;
• exciting means for flowing an electric current to the stator coils with the energization changeover timing decided by the energization changeover timing decision means;
• rotational speed detection means which determines the rotational speed of the rotor from the average of the two times corresponding to the plus and minus periods of the counter electromotive forces among the times measured by the clocking means;
• and
• control means for controlling the exciting means so to have the rotational speed determined by the rotational speed detection means agreed with a target value.