Three Phase Inverter with LC Filter

The circuit files for this case are in these two links: circuit_files.tar.gz

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.

Result 1 Result 2

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.

Result 3

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

Result 4

The actual currents will be seen to track the references.

Result 5

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

Result 6 Result 7

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.

Result 8 Result 9