High-Power Closed-Loop SMPC-Based Photovoltaic System Characterization under Varying Ambient Conditions

Abstract

Photovoltaic energy generation potential can be tapped with maximum efficacy by characterizing the source behaviour. Characterization refers to the systematic terminal measurement-based PV modeling which can further facilitate output prediction and fault detection. Most of the existing PV characterization methods fail for high-power PV array due to increased thermal losses in electronic components. Here, we propose a switched-mode power converter-based PV characterization setup which is designed with input filter to limit switching ripple entering into PV array under test, thereby enhancing system life and efficiency. The high resonant frequency input filter ensures its compactness with high-speed characterization capability. To further enhance the system performance, a closed-loop current control of the system is designed for high bandwidth and stable phase margins. Variation of the controller parameters under varying ambient conditions of 200–1000 W/m2 irradiation and 25–70 °C temperature is documented and an adaptive PI controller is proposed. Experimental and simulation results validate the high performance of the closed loop operation of the PV characterization at 1.2 kW range power level in real-time field conditions. Compared to the open loop operation, the closed-loop operation eliminates the waveform ringing by 100% during characterization.

Keywords

• photovoltaic energy conversion
• electric output characterization
• switched mode power converter
• high-frequency input filter
• closed loop operation