## 4 Discussion  
From the analysis performed on the basis of the system modeling, it appears that the difference in the absorbed active power is underestimated by 1.63 kW in the case of the DCP architecture neglecting the dynamic aspects, compared to the case in which the dynamic effects are taken into account. This difference is significant, which is why the following considerations take into account the dynamic DCP architecture. The introduction of regeneration in the directly controlled valve leads to a reduction in the average active power consumption by 50.5%. In architectures 3, 4, and 5, regeneration is kept as a common element, so the differences in active power consumed are determined only by the differences in the configurations. From the results summarized in Table 13, it appears that the high-low, VDP, and DCP solutions achieve higher energy efficiency for the plant than the purely renewable architecture. In fact, in all three cases there is a more or less pronounced decrease in the active electric power absorbed from the grid. The solutions that achieve the greatest savings in terms of active power consumption are, in order, the high-low configuration, followed by DCP, and finally VDP. The difference between the high-low configuration and DCP is very small (1.8%). The particular efficiency of the high-low architecture for this application is due to the nature of the variable speed industrial process. In fact, the high-low architecture is particularly well suited for operation with phases in which high oil flow rates at low pressure alternate with phases of low liquid flow rates at high pressure. This is typically the case with punching. The lower energy efficiency of the solution with VDP is caused by the additional control oil flow that must be continuously ensured to maintain the flow rate control of the axial piston pump. Comparing the VDP configuration with the DCP configuration, it can be seen that the DCP configuration provides savings in power consumption, even if the savings are small in the case considered. It can be concluded that the DCP solution is slightly more advantageous than the VDP solution from the point of view of absorbing the average active electric power during the duty cycle, or that the VDP solution is in no way better than the DCP solution. Figure 19: Active and active electrical power absorbed by the real blanking press with DCP power architecture. (**a**) Active electrical current absorbed [A] by the architecture with DCP over time [s]. The measurement is made upstream of the frequency converter and is related to a single phase. To get the total current just multiply by \(\sqrt{3}\). (**b**) Active electrical power absorbed [K\(W\)] by the architecture with DCP over time [s]. The measurement is made upstream of the frequency converter. From the data referring to the active electrical power parameter (Figure 13 and Table 13), the solution with DCP realized a marked advantage over the standard architecture, a slight advantage over the VDP configuration, and a comparable, or even slightly lower, result than the high-low solution. If, on the other hand, the comparison is made using the cost parameter for electrical energy (based on Italian energy prices), the DCP architecture is significantly cheaper, even compared to the high-low and VDP solutions. This is due to the reactive power component of the electric power (Table 14), for which there are economic disadvantages when there is a high absorption of reactive power from the power grid. In the DCP architecture, these economic disadvantages do not exist. This is ensured by the effect of the capacitor bank present in the drive, which brings the absorbed electrical reactive energy (inductive) below 50% of the active energy or lowers the power factor below the value of 0.9. Therefore, taking into account the contributions of both active and reactive power, the DCP solution is the most advantageous among the solutions studied in terms of energy operating costs, which also results in a saving of 15% compared to the high-low architecture.