Performance Comparison between PI based Control and Model Predictive Control of Voltage Source Inverter under Load Variations

Now-a-days, advancement of control logic for DC-AC converter, i.e., an inverter become important in stand-alone applications. This converter is essential for multi-purposes, such as, to convert outputs of different renewable sources, to provide variable frequency and/or voltage for industrial motor-drive system, to provide back-up power supply etc. In the applications, proper selection of controller is very much essential for achieving improved dynamic performance of inverter. In this regard, different control logics for three-phase two level voltage source inverter have been examined. Here, comparative studies between conventional closed loop current control using proportional-integral (PI) regulator and model predictive current control method have been done under variable loading conditions on inverter. This is appearing from observations of various studies that dynamic behaviours of load current have been enhanced in case of model predictive control (MPC) than that of PI controller based logic. Also, harmonic distortion in load current is reduced under MPC logic.