Archives

External

commutation

In the past, external sine commutation was a technology that gave analog drives the ability to commutate motors sinusoidally.  With today’s processors, servo drives no longer need an external controller to produce sinusoidal commutation.  Therefore this discussion is for informational purposes or for cases where specialized control is needed. External sine commutation was developed to External

Sinusoidal

commutation

Sinusoidal commutation smoothly transitions the current between all three phases as the motor turns resulting in reduced torque ripple. Advantages Results in reduced cogging / torque ripple in low speed applications Output power is constant through the entire electrical cycle ADVANCED Motion Controls’ Capabilities DigiFlex® Performance™ servo drives provide sinusoidal output via Field Oriented Control (FOC) as Sinusoidal

Trapezoidal

commutation

Trapezoidal commutation steps through 6 different commutation states per electrical cycle to transition the current between phases. Current passes through 2 phases at any given moment while the 3rd phase has zero output. Advantages Results in increased overall torque but with more torque ripple at low speeds Compatible with low resolution Hall sensors for motor Trapezoidal