Hybrid MPC-SHE Technique for Capacitor Voltage Balancing in Single DC-Source Three-Phase Modified PUC Inverter

Capacitor voltage balancing is one of the major challenges of multilevel inverter topologies which must be address in the design process of the circuit topology and switching technique for all operational condition. In this paper, Selective Harmonics Elimination (SHE) has been combined with Model Predictive Control (MPC) to actively balance the dc capacitors voltages of a designed single dc -source three-phase nine-level modified PUC inverter at a fundamental switching frequency operation. According to the proposed MPC-SHE principle, switching angles are pre-calculated using an improved SHE and then are given to a designed MPC as to integrate the redundant switching states in an online approach for each voltage level to balance the dc capacitors voltages at low switching frequency operation. The hybrid MPC-SHE technique has been validated through theoretical and simulation analyses to verify the accurate dc capacitor voltage regulation of the presented single dc -source three-phase nine-level modified PUC inverter under a critical low dynamic condition.