How use Three-Phase Dynamic Load block to generate Power data?

Hi there!

I am trying to model a three phase power system, with measured data of active and reactive power using Simscape, as shown below.

I am trying to use the external control for the module, since I already have the data measured and I just need to get that data into the load. The Active and Reactive power are vectors with the value I want as the load, as shown below.

At the end, it is given mee two errors, due two the size of the matrix, but I cannot figure out what I am doing wrong.

[Salma Al abri]

Hello Enmanuel, Did you mange to figure out how to solve this problem! Because I have been fasing similar issue and havent got to the soluion yet.

Answer 1

[Vasco Lenzi]

Hi Enmanuel

you need to feed P&Q as a timeseries, and not as a vector of elements. In total you will feed a vecotr of size 2, varying over time to change P&Q at different times:

So you need to use a block such as the repeating sequence in which you can define values at a certain time:

Answer 2

[Jorge Luis Arrúa Gines]

Hola, pueden ayudarme a montar lo descripto por Vasco? gracias

[Vasco Lenzi]

hi Jorge, where do you need more information?

If you wnat to simulate a linear increase in P and Q you can simply use the ramp source block in simulink:

there are many source block available to customize your input into the model. Choose one, create a vector together with another one for Q and feed into the PQ input port. It doesn't need to be a ramp, it can be a mat file, a MATLAB time series (from Workspace) or even an hand-drawn signal in the signal editor block!

Answer 3

[Evode RWAMURANGWA]

I have the same issue, when i use the P&Q data from outside to the dynamic load, the current from the source becomes zero and the voltage signals are really bad. what should be the reason?

[Evode RWAMURANGWA]

[Evode RWAMURANGWA]

What might be the reason of having that zero current from the source and distortion from the voltage source

Answer 4

[Vasco Lenzi]

Hi Evode

It's a limitation of the dynamic load block of the specialized power system libraries. See this example and this comment:

As the dynamic load is a nonlinear model simulated by current sources, it cannot be connected to an inductive network (R-L in series). Therefore, a small resistive load (1 MW) has been added in parallel with the dynamic load.

Dynamic Load and Programmable Voltage Source

[Evode RWAMURANGWA]

Hi! Vasco! Thank you very much for the answer! However, I am a bit confused, the example you gave require no external source power. How to include work?

[Evode RWAMURANGWA]

So that it doesn't cause any distortion in the voltage source sigapll

[Vasco Lenzi]

Hi Evode

If you open that example and click on the "3-phase dynamic load" block, you can tick the "External Control of PQ" option. This will give you the ability to add an external signal as power.

What this model shows, is that you need to have a parallel small resistor to avoid the problem you saw.You an add such block in your original model as well to avoid the sources going to 0.