Driving apparatus for a commutatorless DC motor

摘要

A driving apparatus for a commutatorless DC motor decides a next commutation period based on a difference of a reference zero-cross time and an actual zero-cross time such that a rising or falling edge of induced voltage signals is generated at the reference zero-cross time. Rising and falling edges of the induced voltage signals represent zero-cross points of induced voltages that are generated at each phase of drive windings. The actual zero-cross time is an actual time width from a start of a current commutation period till the generation of a rising or falling edge of the induced voltage signals. The reference zero-cross time is a desirable time width from the start of the current commutation period until a rising or falling edge of the induced voltage signals should be generated. The driving apparatus calculates an integrated value of the next commutation period by an integral computation based on the difference and an integrated value of the current commutation period, and decides the next commutation period by a proportional computation based on the difference and the integrated value of the next commutation period. Driving current of each phase of the drive windings is commutation controlled based on the decided commutation period.