Current controller for a bidirectional boost input stage equipped with an LCL (inductance–capacitance–inductance) filter

• A controller to an LCL filter used in dc–dc boost converters is introduced.
• Active damping of the LCL filter is achieved.
• The controller only measures the source current.

A control strategy for a low resonance frequency LCL (inductance–capacitance–inductance) filter used in the input stage of dc–dc bidirectional boost converters is proposed. When compared with the classical L filter, an LCL filter allows to obtain a cheaper topology. However, with an LCL topology, damping is needed for guaranteeing the system stability. In this paper an active damping strategy is designed. The needed damping is achieved via a dynamic controller. The controller consists of a simple PI (proportional-integral) controller plus a linear filter added in series with the PI integrator term. The modified PI controller achieves the active damping of the LCL filter and allows to arbitrarily place the system closed-loop poles. The proposed strategy only requires measurement of the variable to be controlled, the source current. Simulation and experimental results validate the proposed controller and show its effectiveness.