Single-Phase UPS Inverter Using Offset-Free Optimizing Control with Digital All-Pass Filter

This study adopts a linear matrix inequalities (LMI)-based optimization approach to formulate a systematic control design for an LC-filtered single-phase DC-AC inverter. The proposed study’s optimization criteria define the LMI problems to provide fast output voltage response by reducing the time to steady state. Then, the stabilizing control gain is computed based on the LMI optimization criterion with help from the MATLAB toolbox. Integral control to eliminate offset error and state feedback control to provide closed-loop stability to the inverter system are the two features that make up the controller in this paper. In addition, an all-pass filter is employed for generating artificial voltage and current so that the states of the system can all be transformed and controlled in the dq-rotating frame. The proposed control technique is implemented in PSIM using a 10 kHz sampling rate. The results are then verified in an experimental setting using a TMS320F28335 Texas Instrument DSP-equipped single-phase inverter prototype. The single-phase inverter has outstanding performance in terms of both steady-state and dynamic response. Furthermore, the proposed control method effectively minimizes the total harmonic distortion.