*USC*: SC voltage;

*Irms*: r.m.s value of the current through the SC.

Figure 4a,b shows the evolution of the power losses in the ESR and the efficiency of the ESS as a function of the current flowing through the SCs and the voltage measured at the terminals. As expected, the higher the current through the capacitors, the higher the power losses in the ESR.

**Figure 4.** (**a**) Power losses in the equivalent series resistance (ESR) as a function of the current and voltage measured in the SC cabinet and (**b**) efficiency map of the module due to ESR losses.
