| 摘要 |
PURPOSE:To drive a brushless motor at variable speed while detecting the position with high accuracy in a brushless motor driving device for switching phase excitation with the control lead angle being zero, by providing a means for correcting the rotor pole position detecting timing detected by a position detecting means. CONSTITUTION:When a sample hold circuit 6 performs sampling and holding, respectively, during ON and OFF times of transistors T1-T3, terminal voltage Sva is obtained. The terminal voltage Sva is compared with the neutral point voltage Vn through a position detecting circuit 3 and a phase excitation switching position signal P1 is taken out. If the matching point exists in the OFF interval of the voltage waveform Sv, detection of position is delayed. In this case, a correcting circuit 7 operates and calculates the detecting time point correctly. |
