VFD Cooling Methods for the Extreme Oil and Gas Installation Conditions

Offshore oil and gas industry is always targeting more efficient systems to optimize production platforms. The use of high power Variable Frequency Drives (VFD) become attractive in this scenario, as losses decrease and impact of transient conditions is minimized during startup of big motors or short circuit contribution. Nevertheless, VFD typically requires controlled acclimatized ambient, affecting directly the platform HVAC system. Therefore, offshore applications focus on drives as smaller and efficient as possible to minimize impact on platform layout and utility systems. These opposing necessities have a direct relation with the efficiency of the VFD cooling system. This paper examines the cooling methods for high power converters applied to VFD's. The heatsink characteristics of water-cooled and air-cooled converters are evaluated. The pros and cons of each cooling method, including requirements and applicability depending on installation conditions are also analyzed. Additionally, a case study on the choice of heatsink and cooling method for a 2.4MW 4.16kV VFD driving an offshore water injection pump is presented.