Synchronous machine pu fundamental solver in 2018b

Hi, everyone,

Trying to convert a model from Simulink 2024b to 2018b.

The models consists of a synchronous machine pu fundamental and thyristors to simulate a load commutated inverter.

The models works perfectly in the version 2024b with a solver configuration Backward Euler robust inside the machine in the section Advanced.

There are more options such as the Trapezoidal solvers but the simulation only works with the Backward Euler robust because of the initial conditions.

When I exported the simulation to Simulink 2018b, the block was also changed and it does not contain the Backward Euler robust solver so I cannot solve the simulation.

Is there a way to change the solver to include Backward Euler robust?

or

is there a solver that can solve the synchronous machine with initial conditions speed and field voltage both equal to 1 pu with opened switches connected to its terminals?

The idea is the opened switches see a voltage across their terminals. That voltage is generated by the machine because of the initial conditions speed and field voltage both equal to 1 pu.

Backwar Euler robust in 2024b can solve this scenario. There is no controller in this simulation. The machine is being deaccelerated by friction. Opened switches can see a voltage across their terminales which is the voltage generated by the machine.

Thank you, I hope there is an answer

Answer 1

[Aishwarya]

Hi Franco,

After going through the Release Notes, I noticed that the "Robust Discrete Solver" was introduced in MATLAB R2019a. This feature allows for the simulation of models without the need for a parasitic load. Therefore, MATLAB R2018b does not support the "Robust Discrete Solver" like the "Backward Euler robust" solver.

Since you are using R2018b, I recommend connecting a resistive parasitic load to the synchronous machine's terminal. This might help avoid the numerical instabilities needed to solve the simulation effectively. You can try connecting resistance load that is large enough to minimize unwanted power loss but small enough to stabilize the solver.

To access the release notes for MATLAB R2019a, which are not available online, you can enter the following in the MATLAB Command Window of R2019a release:

>> web(fullfile(docroot, '/physmod/sps/index.html'))

I hope this helps solve your query!