Current-type Power Hardware in the Loop (PHIL) evaluation for smart transformer application

The development of power electronics and power systems due to the massive integration of renewable energy sources is challenging the distribution grids. Among several concepts, the Smart Transformer (ST), a solid-state transformer with advanced control and communication capabilities, has been investigated by several researchers. A great challenge of this kind of system is the possibility to test the effectiveness of the physical system under a broad spectrum of operating conditions. For this reason, the Power Hardware in the Loop (PHIL) concept can be adopted to emulate the behavior of a distribution grid connected to the ST. In this case, because the low-voltage stage of the ST is voltage controlled, the test setup must be current-controlled. In this paper, the current-controlled PHIL setup is analyzed. The theorethical analysis is carried out and preliminary results obtained with the PHIL facilities are presented, highlighting how the current-controlled PHIL can be an effective means to study the ST.