| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect a rotor position precisely based on an electromotive force induced in an excitation coil without masking a counter electromotive force induced in the excitation coil. <P>SOLUTION: With regard to the voltages across a U phase stator coil 101U, a V phase stator coil 101V and a W phase stator coil 101W provided in the stator of a motor 100, i.e. a brushless DC motor, first reference voltage, second reference voltage and third reference voltage are set in descending order within the range from 0 V to the input voltage of these coils. For each coil, a decision is made that the electromotive force induced in a corresponding coil has risen if the voltage across the coil exceeds the second reference voltage and the first reference voltage, and a decision is made that the electromotive force induced in a corresponding coil has fallen if the voltage across the coil is less than the second reference voltage and the third reference voltage thus estimating the rotor position of the motor 100. <P>COPYRIGHT: (C)2008,JPO&INPIT |
