Power converters present unique challenges in electronic packaging and heat management. Their concentration of electrical energy, propensity for electromagnetic interference generation, integration of heavy, irregularly shaped magnetic components, and requirements for uncompromised reliability and affordable cost require careful consideration. This paper outlines these challenges and traces the evolution of packaging techniques utilizing liquid cooling to address them. This evolution has led to latest generation designs that achieve unsurpassed levels of thermal management, packaging density and product reliability.
Historically, most power conversion solutions have utilized either natural or forced convection cooling. However, certain application situations, such as high power levels or the need for protection from environmental contaminants, may dictate conduction cooling to a liquid-cooled heat dissipation element as the preferred solution.
When considering packaging and component options for a liquid-cooled power conversion solution, several basic questions need to be addressed. These include the electrical topology to be employed; power converter modularity along with incremental converter size and power rating; physical environment size constraints; temperature rating of components; and ease of manufacturing and repeatability for quality and system cost control.
Each of these will be considered in the following sections of this paper, along with a review of the historical approaches to address them. Finally, latest generation liquid-cooling packaging techniques will be discussed, pointing how design evolution has produced new levels of performance and economy.