| 摘要 |
PURPOSE:To reduce the number of lines required and man-hour for wiring and prevent the erroneous insertion of connectors with respect to a rotor position detecting circuit. CONSTITUTION:The method for detecting rotor position is based on the terminal voltage of a brushless motor 1. A first and a second induced voltage period waveform detecting sections 13, 20 detect the waveform of terminal voltages U, V. A voltage adjusting section 14 divides the maximum voltage of terminal voltage U, and a first and a third comparing sections 15, 21 compare the waveform with the divided voltage to extract a virtual neutral point. A first and a second frequency detecting section 16, 22 detect the frequency of a signal using the extracted virtual neutral point as reference. Saw-tooth wave generating sections 17, 23 generate a first and a second saw-tooth signals according to the detected frequency. A first and a second comparison voltage generating sections 18, 24 converts the frequency of the virtual neutral point into a voltage and divide it. A second and a fourth comparing sections 19, 25 compare the first and second saw-tooth signals with the divided voltages to obtain specified timing pulses. A combining section 26 combines them to form a position detection signal. |
