태양광 발전시스템의 전력 진동 감소를 위한 개선된 CPG 제어 기법

Abstract

Photovoltaic(PV) power plants typically use maximum power point tracking(MPPT) control to maximize power supply. However, if the output power from photovoltaic generation surpasses the acceptable capacity of the load, it can lead to issues such as overload and overvoltage. Consequently, a constant power generation(CPG) control is required to limit the PV output power to a certain value. In this case, the combined operation of MPPT and CPG is necessary, with optimized control in both modes. Conventional CPG control imposes limitations on the selection of constant power points, leading to suboptimal control depending on the operational points of photovoltaic panels. To ensure the high-efficiency operation of photovoltaic systems, an optimal control technique is crucial, capable of adapting to variations in the operational points of the photovoltaic panels. This facilitates a swift transition from transient state to steady state while enhancing stability by maintaining minimal power oscillations upon reaching the steady state. In this paper, an improved CPG control algorithm is proposed, featuring fast response speed depending on the operation mode and low power oscillation for both MPPT and CPG operations. The proposed control algorithm can select the operating points and obtain fast tracking speed in transient state as well as low power oscillation in steady state. Additionally, optimized operation is achievable by providing low power oscillation not only in MPPT mode but also in CPG mode. The performance of the proposed control algorithm has been validated through simulation.