| 摘要 |
A control system for a motor, including a first detector providing signals indicative of the sign and zero-crossings of a supply voltage, and a second detector providing signals indicative of the sign and the zero-crossings of BEMF developed in the stator winding. A switch is driven to cause a first current pulse through the winding at a first delay relative to the zero-crossing of the supply voltage. The system checks if the BEMF has a first zero-crossing within a predetermined period of time preceding a third zero-crossing of the voltage, and if so, causes an opposite second current pulse through the winding with a second delay relative to the third zero-crossing of the supply. If not, the first current pulse is repeated, reducing or increasing the duration of the first delay if the first zero-crossing of the BEMF took place after or before the predetermined period of time. |
