Tempco provided the CERN in Geneva a cooling unit system for deionized water to be supplied to IGBT testing equipments. The IGBT are insulated-gate bipolar transistors, three-terminal power semiconductor devices primarily employed in high power applications, mounted on NPC converters (Neutral Point Clamped).

The testing platform required is used in the CERN Technology department dedicated to EPC and PHC, Electric power converters and High power converters. The aim of the testing platform was to test damaged components after reparation before they are put back into operation in NPC power stacks converters. The Power stacks tester comprises two DC sources connected in series, with a cooling unit to provide the necessary water flow to cool the power stacks.

Technical specifications required a water/water cooling unit rated 40 kW, with water as cooling liquid on both primary and secondary side. A crucial element was the presence of a deionizing circuit, because the water on the secondary circuit gets directly in contact with the conductors. In addition, the cooling unit layout required the presence of some sensors, a flow rate sensor, a conductivity sensor and a temperature sensor on the output of the secondary circuit. As well as a pressure sensor placed in the vicinity of the expansion tank.

All parts in contact with the secondary circuit water have been realized in AISI 316 stainless steel, and the same material was employed for all fittings and valves. EPDM elastomer has been employed for all gaskets.

CERN is the European organization for Nuclear research that designs, builds and operates particle accelerators, actually used by more than 11.000 scientific users from research institutes all over the world. The flagship of the accelerator complex at CERN is the Large Hadron Collider (LHC), the world’s larger accelerator consisting of a 27 km ring of superconducting magnets and accelerating structures.