What is “Monitoring Mode ” on SOLO, and why does it matter?! 1
Written by SOLO Team
05/12/2020
What is “Monitoring Mode ” on SOLO, and why does it matter?!

Nothing is better than awareness when someone wants to solve a problem! It might be very costly to become aware of the main issues, and the more you know, the better you can dig down to the roots and causes of problems and eventually solve them. That’s the purpose of the “Monitoring Mode” existing on SOLO, full supervision!

The main thing that the “Monitoring Mode” is trying to address is giving the maximum possibility to the users of SOLO for having a complete and comprehensive understanding of the most important phenomenons that are happening in the whole system, while they are trying to test the system and possibly finding the best tunings and settings.

Currently, in the first version of Monitoring Mode, once it’s activated, the user will receive a continuous and simultaneous samples of the most critical parameters of Motor as below, each one sampled with 200Hz:

   1.  VA: 3 phase Motors phase A voltage (BLDC, PMSM, ACIM)
   2.  VB: 3 phase Motors phase B voltage (BLDC, PMSM, ACIM)
   3.  IA: 3 phase Motors phase A Current (BLDC, PMSM, ACIM)
   4.  IB: 3 phase Motors phase B Current (BLDC, PMSM, ACIM)
   5.  VBUS : The power supply voltage ( BUS / Battery voltage )
   6.  IM: The DC motor Current
   7.  VM: The DC motor Voltage
   8.  Iq: The quadrature Current in 3 phase motors ( current acting in torque generation)
   9.  Id: The direct or Magnetizing Current in 3 phase motors
 10.  Speed: The speed measured or estimated by SOLO both in Sensorless and in Sensor-based methods

Beside the mentioned parameters, 2 other parameters can be derived directly from them as below:

  11.  VC = VA + VB: 3 phase Motors phase C voltage (BLDC, PMSM, ACIM)
  12.  IC = IA+IB: 3 phase Motors phase C Current (BLDC, PMSM, ACIM)

This means, SOLO in this type of Monitoring, will provide continuous and simultaneous samples of 12 parameters, but one might ask, why simultaneous sampling matters?

To explain this better you can look at Figure 1 and Figure 2 below, taken while a Brushless motor was abruptly stopped and again forced to go back to 4500RPM, this test was done to depict the “Regenerative Brake” qualities in SOLO.

 

What is “Monitoring Mode ” on SOLO, and why does it matter?! 2

Figure 1 – Regenerative Brake Effect on Battery Voltage Level

What is “Monitoring Mode ” on SOLO, and why does it matter?! 3

Figure 2 – Regenerative Brake Effect and the current returned back to the supply

About these two plots, the most interesting part is, the first peak of returned current to the supply ( negative Iq current of -2.95A) is recorded at sample number “36868” visible in Figure 2, while at the exact same sample we have the peak of supply voltage ( battery) rising to 43.7V from the normal range of 36.5V which is evident in Figure 1, these two phenomenons are very momentary and capturing them requires a fairly high sampling rate that SOLO can offer in Monitoring Mode.

Another example of the use of Monitoring mode is depicted in Figures 3 and 4, in which the difference in two various Tuning of Kp and Ki gains of speed controller on the quality of speed controlling on a brushless motor is shown:

What is “Monitoring Mode ” on SOLO, and why does it matter?! 4

Figure 3 – Speed controller tuned with Kp = 0.3 and Ki=0.001

What is “Monitoring Mode ” on SOLO, and why does it matter?! 5

Figure 4 – Speed controller tuned with Kp = 0.4 and Ki=0.02

In both of these figures the step response of the system, by giving a speed set-point (Red Plot) of 3000 RPM is examined, meaning that while the Motor was standing still, a sudden request to rise the speed to 3000 RPM has been sent to SOLO, so as you can see in the first tuning shown in Figure-3, it’s resulted in smooth but relatively slow increase of the speed until the reference, while in second tuning shown in Figure-4 the speed has risen much faster but with an overshoot of around 400RPM for a short time occurred. Both of these tunings can be acceptable for different systems, for example the first one will be good for soft starting of a motor, and the second tuning will be better for fast tracking of the speed reference for agile systems like Robots or drones.

 

As you can see, using the monitoring mode, the analysis of your systems, and how they are behaving will be much easier and professional, resulting in better and more reliable designs. We will continue to introduce more monitoring modes, focused on other features, like position controlling and so on.

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