Control of stepper motor winding current overlap time - is designed to obtain very high utilisation of active material

摘要

The system is used for the control of a stepper motor (1). At low step frequencies the overlap time between the current flow in one phase and the next is controlled to a very small value approaching zero. Typically the time is one millisecond. With a short overlap time the power loss in the windings is greatly reduced when compared with a constant ratio overlap. The loss reduction permits the use of a higher current at low speeds, and at low speeds, and hence a higher torque for the same heating affect. Alternatively the amount of active material can be reduced for a given torque.