Controller design of grid-connected power conditioning system with energy storage device

The open voltage and short current characteristic of renewable energy source are changed according to environmental factors. For such reasons, Maximum Power Point (MPP) of renewable energy continually changes. Because of this characteristic, power conditioning system must be controlled to track the MPP. The stable control loop is supposed to be designed at MPP of renewable energy. Therefore, the small signal modeling must be done before the compensator design of the feedback control loop. In this paper, a bidirectional converter for charging/ discharging to energy storage is considered. For the controller design, the interaction of dynamic response between boost converter and charger/discharger in parallel should be investigated. According to the small-signal analysis, closed loop controller design was done. Also, verified the model using MATLAB and PSIM simulation. Finally, 1kW hardware prototype of power conditioning system with energy storage device has been implemented for experimental verification of the proposed converter system.