Nonlinear control of a bidirectional dc-dc converter operating with boost-type Constant-Power Loads

In order to address the voltage control problem in a dc distribution system (dc-microgrid) with renewable sources and energy storage devices, in this paper we propose a new Sliding Mode Controller for a dc-dc bidirectional power converter to control the dc bus voltage under instantaneous Constant Power Loads (CPLs). This type of loads introduce a destabilizing nonlinear effect on the converter through an inverse voltage term that can lead to significant oscillations in the dc bus voltage. A simplified scheme based on two cascaded converters was considered to validate the proposed voltage controller. Simulation and experimental results are shown to verify the performance of the proposed controller.