Harmonics Minimization in PUC Type Solar Multilevel Converter with Multicarrier Switching Schemes

This paper presents the power quality investigation of a seven-level three-phase packed U-cell (PUC) converter with multicarrier switching schemes. This system is grid-connected, and each phase has two solar PV arrays of different voltages. Various modulation schemes are available for switching the multilevel converter, and level-shifted multicarrier pulse width modulation is widely used for easy implementation. A new modified carrier-based modulation technique is introduced for solar PV array fed PUC inverter. The main aim is to reduce the harmonic content in the seven-level output voltage. It also increases the magnitude of the fundamental component of the converter voltage. The comparison of the presented technique shows its advantages over other existing modulation schemes. Closed-loop control is implemented with the inclusion of a modified switching scheme for switching the three-phase PUC converter. The proportional resonant controller provides excellent dynamic performance to feed the power into the grid. Modeling and simulation of the system are done in MATLAB/Simulink. Furthermore, obtained simulation results verify the effectivity of the switching scheme towards minimizing total harmonic distortion. The overall system is validated in the real-time simulator for steady-state and dynamic environmental conditions.