Trouble in abc to dq0 transform

Hi! I'm trying to simulate a very basic asynchronous motor by the Asynchronous Motor SI Units of the Specialized Power System Toolbox; when I take the stator voltages (ia,ib,ic) from the output and perform an abc to dq0 transform with wt equal to the electrical rotor angle and then confront the result with the motor block id, iq output I obtain a totally different waveform. I'm using a continuous analysis, the block uses the stationary reference frame. I'm pretty positive that the input angle is wrong, but I tried everything that came in mind and never obtained the right answer.

[Nikhil]

Could you share the Simulink model to reproduce the issue?

Also, check the convention used for Park Transform in abc-dq0 block. Refer to this article for more information.

Answer 1

[Aditya]

Hey Carlo,

I understand that you are having trouble with abc to dq0 transform.

When working with the Asynchronous Motor SI Units block in the Specialized Power Systems Toolbox, correctly obtaining the dq0 transformation of the stator voltages requires careful consideration of the reference frames and angle inputs. Here are a few things to check and consider:

1. Reference frame alignment: Ensure that the reference frames of the stator voltages and the dq0 transformation are aligned correctly. The Asynchronous Motor block in the Specialized Power Systems Toolbox typically uses the stationary reference frame, so make sure the dq0 transformation is also in the stationary reference frame.

2. Electrical rotor angle (wt): The electrical rotor angle, wt, represents the position of the rotor flux in the synchronous reference frame. It is important to provide the correct value for wt to correctly perform the dq0 transformation. Verify that the value you are using for wt is appropriate and matches the rotor position.

3. Rotor speed synchronization: The dq0 transformation assumes that the rotor speed is synchronized with the stator frequency. If the rotor speed is not synchronized, the dq0 transformation may not give accurate results. Ensure that the rotor speed is properly synchronized with the stator frequency for accurate transformation.

4. Synchronization method: Check the synchronization method used in the Asynchronous Motor block. The block typically provides options for synchronization, such as "Frequency" or "Rotor Speed." Ensure that you have selected the appropriate synchronization method based on your application.

5. Time step and simulation settings: Verify that the simulation time step and other simulation settings are appropriate for your application. A smaller time step may provide more accurate results, especially when dealing with fast-changing variables.

6. Check connections and units: Double-check that the connections between the blocks are correct, and ensure that the units of the inputs and outputs are consistent. Mismatched units can lead to incorrect results.

Refer this article as well;-Perform transformation from three-phase (abc) signal to dq0 rotating reference frame or the inverse - Simulink (mathworks.com)