PURPOSE: To facilitate speed detection and speed control of every section obtained by dividing one turn by a method wherein the individual speeds of the respective sections are determined in accordance with a rotation angle detecting signal obtained by supplying a voltage corresponding to a half of a DC source voltage and the voltage of an artificial neutral point to a comparator and a voltage value detecting signal synchronized with the rotation angle detecting signal.
CONSTITUTION: A judgement device 15 is an A/D converter with a sample hold which maintains an artificial neutral potential when the detection output of a position detector 14 is changed and transmits the artificial neutral potential value to a controller 7. A microcomputer is used as the controller 7 and, when the signal is inputted from the position detector 14, the input from the judgement device 15 is compared with a threshold to obtain a right-or-wrong judgement signal and sectional speeds are detected and PWM signals given to transistors 1-6 are determined. With this constitution, the accuracy of detecting speeds of the respective sections obtained by subdividing one turn of the motor can be improved and the speeds of the respective sections can be controlled.
USHIJIMA KAZUFUMI
HIRATSUKA KAZUHIRO
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