A Study on Output Voltage Regulation of Single-Phase Inverter Using Robust Tracking Control

This thesis presents a robust control strategy for a single-phase DC-AC inverter with output LC-filter. The control method using dq-synchronous frame is commonly used for three-phase systems but it is quite challenging for single-phase systems. In this thesis, an all-pass filter is utilized to create an artificial β-signal so that the proposed controller can be simply used in dq-synchronous frame. The proposed robust controller utilizes a state feedback control with integral action in the dq-synchronous frame. A linear matrix inequality-based optimization scheme is used to determine stabilizing of the controllers to maximize the convergence rate to steady state in the presence of uncertainties. The uncertainties of the system are described as the potential variation range of the inductance and capacitance in the LC-filter. These uncertainties are expressed as possible ranges of the capacitor and inductor values. The proposed control method yields good tracking performance for regulating and stabilizing the inverter’s output voltage after a step change in the inverter load and low total harmonic distortion (THD). The efficacy of the proposed controller is verified through PSIM simulation and experiment. The procedure of experiment was implemented on DSP (TMS320F28335) in the control board to control the single-phase inverter system.