Semiconductor switching circuit

There is provided a semiconductor switching circuit (70), for use in a HVDC power converter, comprising: a main current branch (74) including at least one main semiconductor switching element (12) and through which current flows in a first direction when the or each main semiconductor switching element (12) is switched on; an auxiliary current branch (76) connected in parallel with the main current branch (74), the auxiliary current branch (76) including at least one auxiliary semiconductor switching element (72); and a control unit (30) operatively connected to the or each main semiconductor switching element (12) to control switching of the or each main semiconductor switching element (12), the control unit (30) operatively connected via a or a respective voltage isolation device to the or each auxiliary semiconductor switching element (72) to control switching of the or each auxiliary semiconductor switching element (72), wherein the control unit (30) is programmed to switch on the or each auxiliary semiconductor switching element (72) in the auxiliary current branch (76) before, when or after the or each main semiconductor switching element (12) is switched on to selectively create an alternative current path via the auxiliary current branch (76) whereby current flowing in the first direction through the main current branch (74) is diverted to flow through the alternative current path to reduce the rate of change of current flowing through the or each main semiconductor switching element (12) immediately after the or each said main semiconductor switching element (12) is switched on.