Experiment on Three-phase Inverter with Output LC-filter Using Robust Control

This thesis describes an efficient control technique for a three-phase inverter using a Robust control method with an output LC-filter. Robust control is used in the inverter to provide a well-regulated output voltage, while an LC-filter is employed at the output side to help filter out unnecessary signals. In addition, this proposed robust control utilizes state feedback control combined with integral control to bring stability to the system with zero steady-state error in dq synchronous frame. A Linear Matrix Inequality-based (LMI) optimization is used to compute the stabilizing gain for the system and provide the ability to withstand uncertainties of the inverter system. The system uncertainties can be considered as a variation range of the capacitor and inductor values of the LC-filter. Moreover, the consideration of uncertainty model of this proposed method is to provide the consistency of the output performance even under the variation of the capacitance and inductance value of the filter. Sine Pulse Width Modulation (SPWM) is used in this method to control the switching sequence of the IGBTs. It is expected that total harmonic distortion is improved compared to a classical PI control. For this dissertation, the MATLAB, Microsoft Visual Studio, and PSIM are used as Simulation software. The efficacy of this method is also verified by the experiment on a three-phase inverter prototype using DSP TMS320F28335.