An integrated approach to design high performance controllers for PWM VSC converters

The modeling of grid connected voltage source converters results in a MIMO system with cross coupling between the two inputs and the two outputs. The usual approach is to design the two compensation controllers for the direct path and use a feed forward component to compensate the coupling. However, this term can lead to significant errors since the associated parameters can change in time. A controller that can directly handle this coupling term is the best approach to maintain high performance levels. The main purpose of the paper is to present a methodology to design a current controller based on the concept of a controller in the complex domain. The complex controller is obtained using the pole placement method and its extension to high order systems is discussed. Finally, simulation and experimental results are presented, clearly demonstrating the validity of the design approach.