Three Phase Inverter with LC Filter

The circuit files for this case are in these two links:

The purpose of the control is to regulate the voltages across the filter capacitors Ca, Cb and Cc to be balanced sinusoids and with a magnitude of 150 Volts line to line. The control implemented is an outer voltage loop with a PI controller in synchronously rotating frame of reference which sets the reference for the current in the inner current loop that is also a PI controller in the synchronously rotating frame of reference.

The three-phase voltages are shown in the figures below. The first figure shows the profile while the second one shows the close-up with the quality of the waveforms.

The next figure shows the tracking performance of the controller, where the d component of voltage attains 150 V while the q component of voltage is 0.

The current references produced by the outer voltage loop are shown in the figure below.

The actual currents will be seen to track the references.

The actual three-phase currents are in the following figures.

The simulation allows the user to fine-tune the control parameters, check the control signals for saturation and write control code without worrying about algebraic loops. The only care that must be taken is that when using a control variable, the variable must be defined. Therefore, ensure that a variable is defined at the header of a control file or as a static variable in the descriptor file. The modulation signals are plotted in the next two figures in the d and q domain and as three-phase variables.