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
Again in Figure 15-42 the current reached the maximum safe current of this motor of 6 A, but this time for a longer period of time. However, the time in which forced angle is applied is still under one electrical cycle. It can also be seen that we are approaching the limits of the estimator, as the measured frequency shows 2.38 Hz, where the commanded speed is 2 Hz, effectively a difference of about 6 RPM.
The estimated flux shows some error and a transient (Figure 15-43), although is still comparable to what we got in other tests running at 2 Hz. The difference in flux compared to a rated flux of 0.5 v/Hz is the reason of the difference of actual electrical frequency compared to estimated electrical frequency.
The angle estimation shows a forced angle of just under one electrical cycle (Figure 15-44).
Zooming in the angle, it can be seen how the first cycle is less than one second before it changes frequency (Figure 15-45). Once the motor angle and estimated angle are aligned, the torque production is much higher, causing a motor acceleration beyond the target speed of 30 RPM. This is why the cycle right after the forced angle cycle has a much higher frequency than the following cycle.
The speed overshoot can be seen in Figure 15-46. It can also be seen that the motor spins backwards for a small period of time before accelerating to the commanded direction.
The estimated torque in Figure 15-47 shows the same behavior as the previous example: a transient at the beginning due to the error in the estimated flux, and a steady state error possibly due to measurements inaccuracies and motor heating up.
The last plot in this example (Figure 15-48) shows the current Iq, which actually shows a torque production of over 4 A, generating a higher torque than the previous example.