A current controller for inverters connected to the grid through an LCL filter with low resonance frequency

In this paper, a current controller for an inverter connected to the grid through an LCL filter is proposed. Unlike classical active damping schemes, it is proposed to implement the controller by measuring the injected current only. It can be done irrespectively of the filter resonance frequency. In addition, it is possible to place the closed-loop poles of the system in an arbitrary way. The controller performance is compared with the optimum design of a classic control strategy used in this application. In this comparison, our proposal exhibits a better performance by taking into account both trajectory tracking and disturbance rejection.