My research is focused on the optimization of the lifetime cost of the power conversion stages that are used in public low voltage direct current distribution (LVDC). Using DC in low voltage distribution increases the power transmission capacity of the network compared to AC distribution and also provides several interesting possibilities to the controllability, connectivity, and monitoring (i.e. Smart Grid functionalities) of the network due to utilization of power electronic converters. Even at the early stage of development, potential target areas for DC distribution have been identified. However, a wider implementation of the technology is still limited by efficiency of the converters that are required in order to operate the network. The primary focus of my research is to optimize the design of the DC to AC conversion stage in terms of lifetime cost and therefore, further increase the feasibility of the LVDC distribution. Lifetime cost is defined as the running cost of the system and therefore, the design of the conversion stages become an optimization problem that addresses the balance between the investment cost and the cost of the losses.