Model Predictive Control of Transformerless Series Custom Power Device for Voltage Quality Improvement

Abstract

A single-phase series custom power device (Se-CPD), based on model predictive control (MPC), is presented in this paper to compensate for erratic supply voltage conditions such as voltage sag, swell, and harmonics. The control strategy for Se-CPD encapsulates the generation of reference voltage and optimal switching signals for the voltage source inverter (VSI) of the Se-CPD. The reference voltage extraction from the distorted point of common coupling (PCC) voltage is synthesized using a second-order generalized integrator (SOGI) without any phase delay, unlike the case that uses a low-pass filter (LPF). An MPC realizes the generation of optimal switching signals for Se-CPD with its intuitive and straightforward implementation, without any modulation stage, and considers the converter’s switching characteristics in the MPC algorithm itself. The simulation results, using MATLAB/Simulink and the real-time simulation results using the OPAL-RT OP4510 real-time simulator, are presented to validate the SOGI-MPC’s effectiveness for voltage quality improvement.