High efficiency solar cells - such as passivated emitter and back contact (PERC) cells, heterojunction Technology (hjt) cells and interdigital back contact (IBC) cells - are increasing in production and market share.but, the solar simulators used in many production lines cannot accurately measure the maximum power and other featuresUsually, the maximum power is underestimated, resulting in manufacturers selling their products at less power than necessary, thereby reducing the price.
Due to the well passivated surface and efficient minority carrier lifetime, these architectures store a large amount of charge in the device. Therefore, when a short flash pulse is applied, charging and discharging the device during the flash test will distort the measured I-V curve and maximum power.
The capacitance compensation (CAC) method developed by ends measures the capacitance of PV cells or modules based on the current and voltage recorded during normal flash pulses. By observing the behavior of the measured current when the device is charged by forward scanning and discharged by continuous reverse scanning, this method can accurately measure the capacitance of the device. Once the capacitance is known, the influence of capacitive elements is eliminated, and the steady-state I-V curve and maximum power are constructed.
Capacitance Compensation for high efficiency CPV modules,High efficiency solar cells with an open circuit voltage of 720 mV. A linear sweep of the output voltage with a duration of 20 ms is applied in both the forward (from short circuit to open circuit) and reverse directions. Compared with the simulated steady-state I-V curve, the measurement artifacts caused by capacitive charge storage in solar cells can be seen near the maximum power point (MP) as underestimated output current during forward scanning and overestimated output current during reverse scanning.Capacitance Compensation for high efficiency CPV modules have access to a solar simulator to accurately measure the I-V curve and power of high-efficiency photo voltaic (PV) product with a flash pulse of under forty milliseconds