The method according to the invention is implemented in a vehicle comprising an electronic control unit (15), vehicle sensors, a data communications bus (16) and an onboard electrical network. The micro-hybrid system (1) comprises at least one rotary electrical machine (2) equipped with a rotation detection means (8), power circuits (14) comprising an inverter (7) and an excitation circuit (4) supplying the rotary electrical machine (2), and a rectifier (11) supplied by the rotary electrical machine (2), energy conversion circuits (12) connected to an energy storage means (9) supplied by the rectifier (11), a first operating circuit (13) for the power circuits (14), and a second operating circuit (25) for the energy conversion circuits (12). The method generates control signals (Dd. Exe, Dd. Ond, Auth. Exe, Auth. Ond) from first information signals (Capt. Véh.) representative of a vehicle operating status originating from vehicle sensors; and generates, by means of the first operating circuit (13), operating signals (Cd. Exe, Cd. Ond.) for operating the power circuits (14) on the basis of diagnostic signals (Diag2. Exe, Diag2. Ond.) representative of a system operating status. According to the invention, the method also generates the control signals (Dd. Exe, Dd. Ond, Auth. Exe, Auth. Ond) by means of the second operating circuit (25) under the control of the electronic control unit (15).