Motor Controller Circuit With Commutation-Locked Speed Control

The patent applies periodic action by resetting the waveform signals (triangular wave and sine wave) at each commutation time point of the motor. This periodic resetting ensures that the duty cycle of the PWM signal remains consistent across commutation cycles, enabling the motor to maintain stable rotational speed. The signal generator circuit continuously generates these periodic waveforms and resets them synchronously with motor commutation, creating a rhythmic control pattern that stabilizes motor speed while allowing operation at lower speeds where noise is minimized.

The patent implements feedback through the commutation detection mechanism. The controller detects the commutation state of the motor and uses this feedback information to reset the waveform signals at the appropriate time points. This feedback loop ensures that the PWM duty cycle remains consistent across commutation cycles, allowing the motor to maintain stable rotational speed even at lower speeds. Consequently, the motor can operate quietly while still providing sufficient cooling performance, as the stable speed prevents erratic operation that would reduce cooling efficiency.

The patent applies preliminary action by pre-generating the triangular wave and sine wave signals before commutation occurs. These waveform signals are reset in advance at each commutation time point, ensuring that the PWM duty cycle is predetermined and consistent for the upcoming commutation cycle. This preliminary preparation of control signals allows the motor to adapt smoothly to commutation while maintaining stable rotational speed, as the duty cycle does not vary unexpectedly during the commutation process.