Dynamic Electric Circuit Model for Photovoltaic Panel

• Main Authors: Wei-Chen Liu, 劉瑋宸
• Other Authors: Chin-Sien Moo
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/57412268660596337817

碩士 === 國立中山大學 === 電機工程學系研究所 === 102 === A dynamic electric circuit model is proposed for a photovoltaic (PV) panel with a power electronic converter used for drawing a maximum power with ripple currents. The dynamic circuit model is derived on basis of the static single-diode model, in which the PV diode equation is replaced by a voltage source in series with a resistance standing for the diode’s threshold voltage and conduction loss. In practice, the threshold voltage is approximately identical to the voltage at the maximum power point (MPP). An additional parasitic capacitance is introduced to account for the dynamic characteristics as the instantaneous current goes beyond the MPP. The parasitic capacitance dominates the dynamic voltage-current (V-I) characteristics whereas the PV voltage is less than the threshold, meaning that the diode is at the cut-off state. The circuit parameters of the proposed model can be obtained simply from four test points without the need of the intrinsic parameters of the PV panel given by datasheets. As the light irradiance varies, both the static and dynamic characteristic curves can be easily estimated by stretching along the current axis from the pre-known one. Experimental tests are carried out on a laboratory system with a PV panel attached by a boost converter. The dynamic electric circuit model has been demonstrated to be capable of interpreting the starting transient and the dynamic responses of a PV panel under stable illumination.