A high-voltage DC transformation apparatus (1), a power system and a control method of the power system. The high-voltage DC transformation apparatus (1) is electrically connected to at least one high-voltage DC power generator (2). The high-voltage DC transformation apparatus (1) includes at least one bidirectional AC/DC conversion module (11), at least one first transformer (12) and at least one unidirectional rectifier module (13). A DC terminal of the bidirectional AC/DC conversion module (11) is electrically connected to the corresponding high-voltage DC power generator (2). The first transformer (12) includes a first transmission terminal and a second transmission terminal. The first transmission terminal is electrically connected to an AC terminal of the corresponding bidirectional AC/DC conversion module (11). The unidirectional rectifier module (13) includes an input terminal and an output terminal. The input terminal is electrically connected to the second transmission terminal of the corresponding first transformer (12), and the output terminal is electrically connected to a high-voltage grid (3).