Optimal Switching Control of Series Custom Power Device for Voltage Quality Improvement

This paper reports the component design and analysis of a series-custom power device (Se-CPD) for voltage quality improvement in single-phase system using the finite control set-model predictive control (FCS-MPC) switching technique. The Se-CPD configuration employs two power semiconductor switching devices only, forming a half-bridge inverter connected in series with the ac mains without transformer for coupling. Thus, the resulting structure is known to be a transformerless series custom power device (TLSe-CPD). The system's control strategy encapsulates the positive fundamental component estimator (PFCE), reference load voltage calculation, and FCS-MPC switching technique. The utility synchronization signals can be generated with the phase-locked-loop free concept. The TLSe-CPD provides better voltage sag, swell, and harmonics ride-through capabilities with the embedded FCS-MPC switching technique. The MATLAB/Simulink is used to validate the performance of TLSe-CPD for specific loads under sag, swell, and distorted terminal voltage.