Controller Design of a Novel Power Conditioning System with an Energy Storage Device for Renewable Energy Sources under Grid-Connected Operation

Abstract

As a result of the depletion of fossil fuels and environmental contamination, it has become important to use renewable energy. For the stable utilization of renewable energy sources, energy storage devices must be used. In addition, renewable and distributed power sources with energy storage devices must operate stably under grid-connected mode. This paper proposed dynamic response modeling for renewable power generation systems including a charger/discharger with an energy storage device in order to derive a method to guarantee stable operation while fully utilizing the energy from the energy storage device. In this paper, the principle operation and design guidelines of the proposed scheme are presented, along with a performance analysis and simulation results using MATLAB and PSIM. Finally, a hardware prototype of a 1kW power conditioning system with an energy storage device has been implemented for experimental verification of the proposed converter system.

Dynamic Analysis and Controller Design for Standalone Operation of Photovoltaic Power Conditioners with Energy Storage

“…3. Cascaded two-stage power conditioning system with a renewable source under grid-connected operation [22] Fig. 4.…”

“…Through the bypassing path, energy can be stored and released more efficiently, significantly reducing the conversion loss [22]. The boost converter's power capacity is also the same as the maximum power of the source, due to the bypass of the charging/discharging energy of the storage device.…”

“…1. Conventional Architecture of the power conditioning system with a renewable energy source and an energy storage device under standalone operation (source-connection) [22] and the boost converter in series. Fig.…”

“…If the application were to be extended to grid-connection, the storage could also attenuate the power fluctuation of the renewable energy sources, which fluctuation should be avoided for the stable operation of a conservatively regulated power grid. However, there are no special challenges in the controller design for the gridconnection of the bypass PCS, as mentioned in [22].…”

Implementation of Non-time-varying Duty Ratio Transfer Function for Improvement of Control Characteristics Bi-directional Charger

“…이러한 태양광 발전은 환경에 따라 출력이 불 규칙하여 배터리가 필수적이며, 전기자동차에 대한 관심 과 더불어 배터리 사용의 연구가 많이 이뤄지고 있 다. [1]- [5] 일반적인 제어시스템에서 제어기설계는 입력이 일정 하고 출력이 가변하는 플랜트에 대하여 제어이득을 결 정하게 된다. 그러나 양방향 충전기용 DC/DC 컨버터와 같이 입력전압과 출력전압이 가변하는 시스템에서 기존 제어설계에 의해 설계된 이득을 사용하여 제어를 행할 경우 입력전압의 변동에 따라 제어특성이 가변하게 되 는 문제점이 발생한다.…”