This paper presents the effect of LED panel placement on the impedance measurement of photovoltaic (PV) panels for light intensity modulated impedance spectroscopy. The impact of height between LED panels and a PV panel on irradiance distribution and the subsequent PV panel response has been analysed. The research has employed a 200W PV panel in conjunction with sixteen LED panels positioned at different heights to validate the impacts on irradiance patterns, such as specific dips and irregularities in distribution. The obtained distribution patterns have demonstrated the accuracy of the proposed model and experimental results shows that the most uniform distribution was obtained at a height of 17.27cm.

This article explores the behavior of lithium-ion (Li-ion) batteries in underwater temperature environments and develops a thermal management system to control the battery's temperature. When the battery is operating at low temperature conditions, the life span of the battery is shortened due to increasing internal resistance and results in reduced capacity. A Li-ion battery pack was tested inside a thermal chamber to simulate underwater conditions, which maintained room temperature during high discharge rates, but decreased to the environment temperature at low discharge rates. To maximize battery performance, a heat pad and thermal control mechanism is proposed. The thermal management system was able to reduce the internal resistance of the battery, thereby reducing the power loss. From this result, we expect the battery lifespan to increase with this method. The proposed system was tested with a 18Ah, 14.8V, 4 series 6 parallel 18650 Li-ion battery pack in a water-tight enclosure inside the thermal chamber simulating underwater temperature conditions.

This paper presents the integration of electrochemical impedance spectroscopy (EIS) in the battery management system (BMS) with reduced number of components. The functions of BMS in this paper are to equalize the batteries’ state-of-charge (S0C) and to internally heat the batteries through the internal resistance of the batteries during the winter condition. The EIS method is to inject the periodically current signal and measure the output voltage in the terminal of the battery. Then, the battery impedance can be obtained by calculating the comparison of voltage and current in the battery. The impedance data processing will be used to estimate the condition of the battery-related to the state of health (SoH) or lifetime. The internally heating mechanism will be used during the winter or sub-zero temperature conditions to heat up the battery. The equalizer is needed to balance the SOC in each battery and to prevent over-charging and over-discharging which can lead to thermal runaway. Batteries 18650 will be used in the proposed method for PSIM simulation.

AC equivalent circuit parameters of photovoltaic modules can be utilized to quantify a module’s aging and overall performance degradation. I-V curve testing can quantify power conversion efficiency but cannot extract impedance information or equivalent circuit parameters in PV modules. This paper presents an approach for measuring the impedance of PV modules, and an algorithm to extract equivalent circuit parameters. The proposed approach uses a 100W white LED array driven by a current-controlled synchronous buck converter to optically perturb the PV module in order to measure the AC impedance. Through this, AC equivalent circuit parameters are extracted based on impedance data.