Voltage control for VSI using load current observer

This paper proposes a voltage controller with disturbance observer for VSI. A discrete time dead-beat inner current loop is used to regulate and limit the inverter current. The outer voltage control loop includes the closed loop dynamic of the current controller and, in order to reduce the THD of the output voltage under non-linear loads, a load current observer is included. The controller and observers have their dynamic behavior set through the DLQR. An interactive scan of the DLQR's Q and R matrices values is implemented to optimize the obtained gains. HIL results are given to support the theoretical analysis and to demonstrate the performance of the system.