A method for charging a capacitance connected between DC poles of a three-phase active rectifier/inverter and a converter apparatus comprising a three-phase active rectifier/inverter (10) having a capacitance (CDC) connected between DC poles thereof, a three-phase filter (20) and a three-phase stepdown transformer (T), wherein the active rectifier/inverter (10) is configured to charge the capacitance (CDC) connected between the DC poles of the active rectifier/inverter with a rectified secondary voltage of the transformer (T) until a voltage of the capacitance reaches a first predetermined threshold voltage, and, in response to the voltage of the capacitance (CDC) connected between the DC poles of the active rectifier/inverter (10) reaching the first predetermined threshold voltage, to charge the capacitance (CDC) with a boosted rectified secondary voltage of the transformer (T) until the voltage of the capacitance (CDC) reaches a second predetermined threshold voltage higher than the first predetermined threshold voltage.