Modular reconfigurable electrical AC/DC converter

An electrical converter (10, 20) for converting between an AC signal and a DC signal, the electrical converter comprising:

• a plurality of AC terminals (a, b, c, g, N), a first and a second DC terminal (DC+, DC−),
• a plurality of converter modules (11, 21, 22), wherein each of the plurality of converter modules comprises:
• an AC node (a1, 111),
• a first capacitor (C), wherein the AC node (a1, 111) is connected to a first terminal of the first capacitor and the second DC terminal (DC−) is connected to a second terminal of the first capacitor opposite the first terminal, such that the second DC terminal forms a common node of the first capacitors (C) of the plurality of converter modules,
• a first converter stage (12) comprising a first switch node (A), a first active semiconductor switch (T1) connecting the first terminal of the first capacitor to the first switch node (A) and a second active semiconductor switch (T2) connecting the second terminal of the first capacitor to the first switch node (A),
• a second converter stage (13) comprising a second switch node (B), a third active semiconductor switch (T3) connecting the first DC terminal to the second switch node (B) and a fourth active semiconductor switch (T4) connecting the second DC terminal to the second switch node (B),
• a first inductor (L), wherein the first and second switch nodes are connected to opposite terminals of the first inductor,
• wherein a connection between the AC nodes (a1, 111) of the plurality of converter modules and the plurality of AC terminals is reconfigurable allowing the electrical converter to operate according to a first mode of operation configured to convert between a first AC signal having a first plurality p1≥2 of phase voltages and the DC signal and according to a second mode of operation configured to convert between a second AC signal having a single-phase voltage and the DC signal, such that the plurality of converter modules (11, 21, 22) contributing to converting between the first AC signal and the DC signal in the first mode of operation contribute to conversion between the second AC signal and the DC signal or to an active capacitive energy storage (CPPB) in the second mode of operation,
• wherein the plurality of converter modules comprise at least p1k converter modules, k being a positive integer equal to or larger than two, wherein in the first mode of operation, the p1k converter modules are grouped in p1 first groups (101, 102, 103), and wherein in the second mode of operation, the p1k converter modules are rearranged in two second groups (104, 105) with a larger number of the plurality of converter modules assigned to a first one (105) of the two second groups and with at least two of the plurality of converter modules assigned to a second one (104) of the two second groups, wherein the electrical converter is configured to operate multiple converter modules assigned to a same group of the first groups and the second groups in parallel,
• wherein the second mode of operation comprises a boost mode of operation in which the electrical converter is configured to operate the plurality of converter modules assigned to the first one (105) of the two second groups via pulse width modulation, and to operate the plurality of converter modules assigned to the second one (104) of the two second groups according to an unfolder operation, such that the first active semiconductor switch (T1) is switched to clamp the first switch node (A) to the respective AC node and the third active semiconductor switch (T3) and one or both of the second and the fourth active semiconductor switches (T2, T4) are switched to clamp the second switch node (B) alternatingly to respectively the first and the second DC terminal at half a fundamental period of the second AC signal.