PV Module Bypass Diode Thermal Test System (IEC 61215-2, MQT 18).

The PV Module Bypass Diode Thermal Test System performs the bypass diode test of IEC 61215-2 (MQT 18). With the module held at 75 °C, the system passes the short-circuit current and then 1.25 × the short-circuit current through the module, and confirms each bypass diode operates and that its junction temperature stays below the diode maker's rated value.

Junction temperature is found by the calibration-curve method: a short (≤1 ms) current pulse is applied and the diode forward voltage is captured by high-speed data acquisition, against a forward-voltage-versus-temperature calibration. The system controls the module and junction-box temperature to the 75 °C ± 5 °C target — commanding an environmental chamber — and tests the selected bypass diodes the 2021 edition calls for.

ULMEKA designs and manufactures this system. The pulse current source, acquisition channels, calibration scope and chamber integration are built to the module and the applicable standard; the exact configuration is defined during the quotation stage.