Electrical power conversion system and associated method

An electrical power conversion system configured for converting three-phase AC power to DC power and DC power to three-phase AC power, comprising:

• a controller;
• a DC side with a positive terminal (DC1) and a negative terminal (DC2);
• an AC side with a first terminal and a second terminal for each of the three phases (R, S, T);
• a primary conversion block (1);
• a secondary conversion block (2);
• and
• a transformer block (3) comprising at least one primary winding (3.1) connected to the primary conversion block (1) and three secondary windings (3.2R, 3.2S, 3.2T) connected to the secondary conversion block (2), each secondary winding (3.2R, 3.2S, 3.2T) being associated with a respective AC phase (R, S, T), wherein:
• the primary conversion block (1) comprises the positive terminal (DC1) and the negative terminal (DC2) of the DC side and a plurality of controllable switches to enable controlling a flow of electrical power between the positive terminal and the negative terminal and the transformer block (3),
• the secondary conversion block (2) comprises the first terminal and the second terminal of the AC side per phase (R, S, T) and the plurality of controllable switches associated with each phase (R, S, T) to enable controlling the flow of electrical power, in each case, between corresponding terminals and the transformer block (3),
• the controller (4) communicates with the controllable switches of the primary conversion block and the secondary conversion block and configured to cause opening and closing of said switches in a controlled and coordinated manner to perform power conversion,
• the secondary conversion block (2) comprises a secondary sub-block (2S, 2R, 2T) for each of the phases (R, S, T), each secondary sub-block (2S, 2R, 2T) comprising a first output terminal and a second output terminal for a corresponding phase (R, S, T) and the plurality of controllable switches communicated with the controller (4),
• the each secondary sub-block (2S, 2R, 2T) being connected to a respective secondary winding (3.2R, 3.2S, 3.2T) of the transformer block (3), each of the secondary windings (3.2R, 3.2S, 3.2T) of the transformer block (3) comprising a first end connected to the first output terminal of a corresponding secondary sub-block (2R, 2S, 2T) and a second end connected to the second output terminal of said corresponding secondary sub-block (2R, 2S, 2T),
• the each secondary sub-block (2R, 2S, 2T) comprising a first switching block (1MS) which is connected to a corresponding secondary winding (3.2R, 3.2S, 3.2T) of the transformer block (3) and to at least one of the first or second output terminals of said secondary sub-block (2R, 2S, 2T) and comprising at least one controllable switch communicated with the controller (4), and a second switching block (2MS) comprising at least one controllable switch communicated with the controller (4), and
• the second switching block (2MS) is connected between the first output terminal and the second output terminal of said secondary sub-block (2R, 2S, 2T) and comprises a first end that is directly connected to the first output terminal of said secondary sub-block (2R, 2S, 2T) and a second end that is directly connected to the second output terminal of said secondary sub-block (2R, 2S, 2T),
• wherein the first switching block is configured to isolate the secondary winding from the first output terminal and second output terminal when in an open state and the secondary switching block is configured to short circuit the first output terminal and second output terminal when in a closed state,
• wherein the first terminal and the second terminal of the secondary sub-block are output terminals.