Experimentally evaluation and comparison of control methods applied to three phase four-leg inverter for stand-alone applications

In three phase stand-alone applications, due to intermittent nature of loads, unbalanced loading condition is unavoidable. To supply unbalanced loads, four-leg inverter is a suitable and beneficial topology. However, the control system must be selected and designed properly to have advantages of the four-leg inverter. Among different control methods, nonlinear and digital control methods attract high attention due to simplicity and ease of implementation. In this paper, two high performance control methods, deadbeat and sliding mode control (SMC) methods are presented to control the output voltage of the four-leg inverter. Experimental results on a 3kW prototype are provided to evaluate the performance of control methods. Finally, a complete comparison between two methods is provided through different quality parameters such as THD%, Ev%, efficiency, etc.