SimPowerSystems

Discretizing the PWM Motor Drive

You might have noticed that the simulation using a variable-step integration algorithm is relatively long. Depending on your computer, it might take some minutes to simulate one second. In order to shorten the simulation time, you can discretize your circuit and simulate at fixed simulation time steps.

Open the Powergui and select Discretize electrical model. Set the Sample Time to 10e-6 s. When you restart the simulation, the power system, including the asynchronous machine, is discretized at a 10 µs sample time.

As there are no more continuous states in the electrical system, you do not need a variable-step integration method to solve this system. In the Simulation --> Simulation parameters --> Solver dialog pane, select the Fixed-step and discrete (no continuous states) options.

Start the simulation. Observe that the simulation is now approximately three times faster than with the continuous system. Results compare well with the continuous system.

Using the Multimeter Block

Performing Harmonic Analysis Using the FFT Tool