| 摘要 |
PURPOSE: To detect the rotor position accurately regardless of the load and to realize optimal conduction switching of the armature winding. CONSTITUTION: When a DC power supply is switched at an inverter section 4 in order to apply a voltage to the armature winding of a brushless motor 3, the inverter section 4 is driven based on the detected rotor position of the brushless motor 3 to switch conduction of the armature winding. In such a control method for the brushless motor, a comparison circuit 10a compares the terminal voltage (induced voltage) of the armature winding with a reference voltage and delivers a position signal (e) variable at an intersection determined by the comparison results to a control circuit 11. The control circuit 11 calculates the times corresponding to predetermined phase angles ((300-α) deg., (90-α) deg., (150-α) deg. or a table data) from the variation point of the position signal (e). Furthermore, the calculation times (the times corresponding to ((30-α) deg., (90-α) deg., (150-α) deg.) are measured and conduction of the armature winding of the brushless motor 3 is switched at the end of time measurement. |
