| 摘要 |
PURPOSE:To halve the number of power transistors by a method wherein a neutral point of three-phase stator winding is connected to one end of a power source, and each other end of the stator winding is connected to three transistors conducted and controlled successively. CONSTITUTION:A flip-flop 37 turns on the transistors 29, 32 and Trs 30, 31 alternately, depending upon rotor position detecting pulses outputted from a position detecting pulse generator 38, thus supplying currents to field winding 28. The number of revolution of the three-phase brushless synchronous motor 27 is controlled by the on-off of the power Trs 21-23 controlled by means of a ternary digit ring counter 40 being subject to the output of a pulse oscillator 39 for controlling frequency. The frequency of the pulse oscillator 39 at that time is controlled by the output of a phase comparator 41 comparing the phase of the output of the oscillator and the output of the position detecting pulse generator 38, thus synchronizing the changes of the polarity of a stator and the field winding 28. |
