Control methods for four-leg voltage source inverter

Four-leg voltage source inverters are more advantageous than 3-leg voltage source inverters in such a way by the greater utilization of DC link voltage, independency of the modulation factor of load current and avoidance of superposition of a DC component with the AC output voltage. Four-leg voltage source inverters require a balanced sinusoidal output voltage for supplying unbalanced and/or nonlinear loads. This requirement is satisfied with the help of Pole Placement Control technique via state feedback in this work. The proposed method is found to be effective in achieving an accurate adjustment of the transient performance of the 4-leg voltage source inverter and in tracking its reference input under steady state conditions. A settling time of 0.58ms is achieved. Also the performance of the proposed controller is compared with that of PI, PID, LQR and State Feedback with Integral Control.