SPRUHJ1I January 2013 – October 2021 TMS320F2802-Q1 , TMS320F28026-Q1 , TMS320F28026F , TMS320F28027-Q1 , TMS320F28027F , TMS320F28027F-Q1 , TMS320F28052-Q1 , TMS320F28052F , TMS320F28052F-Q1 , TMS320F28052M , TMS320F28052M-Q1 , TMS320F28054-Q1 , TMS320F28054F , TMS320F28054F-Q1 , TMS320F28054M , TMS320F28054M-Q1 , TMS320F2806-Q1 , TMS320F28062-Q1 , TMS320F28062F , TMS320F28062F-Q1 , TMS320F28068F , TMS320F28068M , TMS320F28069-Q1 , TMS320F28069F , TMS320F28069F-Q1 , TMS320F28069M , TMS320F28069M-Q1
Given a motor's speed loop dynamics without consideration of uncertainties such as resonant mode, sample time, and output saturation, the open loop Bode of a speed loop controlled by SpinTAC is always stable, which can be illustrated by the open loop Bode in Figure 13-2. The phase curve does not cross -180°, which means there is no limit on the gain margin. The phase margin is always positive.
However, most mechanical systems have resonant mode, typically at high frequency, which will cause 180° change in the phase curve and spikes in the magnitude curve.
The output saturation and sample time will also limit the adjustable range of the controller gains in order to keep system stable.