| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the error and detection disabling of a position signal by correcting a detected position signal based on the operation conditions of a brushless DC motor and controlling an inverter based on it. SOLUTION: A voltage is given to the stator coil winding of a brushless DC motor by an inverter, thus generating a rotary magnetic field and forcibly starting a the brushless DC motor. After the DC motor starts rotating, the differential voltage between second and first neutral point voltages is supplied to a position detection circuit. Then, a position detection part 4a outputs the tentative prediction position of a rotor and inputs the differential voltage, and a position correction part 4b calculates the amount of correction of the prediction position and corrects the prediction position based on the amount of correction. In this case, the position detection part 4a detects the zero cross of the differential voltage and obtains the prediction position of the rotor from it before outputting. Also, the position correction part 4b obtains the relationship between the amplitude and phase error of the differential voltage in advance and performs correction to cancel it. |
