| 摘要 |
A motor system (100) having a stationary assembly (104) including a winding and a rotatable assembly (106) in magnetic coupling relation to the stationary assembly. A power supply link (132,136,140) having upper and lower rails supplied by a power supply (134) provides power to the motor winding. The power supply link has power switches (132) responsive to a motor control signal for selectively connecting the rails to the winding to energize the winding with a motor current whereby an electromagnetic field is produced for rotating the rotatable assembly. The power switches include a set of upper power switches and a set of lower power switches. Each of the power switches has a conducting state and a nonconducting state. The system includes a disable circuit (172,174) for selectively generating a disable signal and a control circuit (122) for generating the motor control signal to control the power switches (132). The control circuit is responsive to the disable signal for controlling the power switches so that the lower power switches become conducting and the upper power switches become nonconducting, or vice-versa, thereby deenergizing the winding to disable the motor. Other features are also disclosed including circuitry for commutating the motor in advance of zero crossings of the back electromotive force, correcting asymmetries in the commutation intervals and reversing the motor. <IMAGE> |
