| 摘要 |
PURPOSE:To provide a commutatorless DC electric motor which is capable of acceleration drive and deceleration drive without requiring a position detection element. CONSTITUTION:The zero-cross point of back electromotive force induced at stator coil windings 11, 12, and 13 is detected by a back electromotive force detection circuit 1 and a six-phase synthesis signal is created by a position signal synthesis means 4 based on the detection signal. The six-phase synthesis signal is distributed into first and second position signals according to the acceleration/deceleration commands input to a selection circuit 6 and the signals are inputted to a first drive transistor group 5a and a second drive transistor group 5b for conduction control. Especially in deceleration drive state, malfunction of the electromotive force detection circuit can be prevented and a stable acceleration/deceleration drive can be achieved by limiting the level of current. |
