A method for controlling an active neutral-point clamped, ANPC, three-level converter , wherein the ANPC three-level converter comprises at least one bridge leg , each of the at least one bridge leg comprises a plurality of input terminals , an output terminal , and a plurality of switches connected between the plurality of input terminals and the output terminal , the plurality of input terminals comprise a first input terminal , a second input terminal , and a third input terminal , the plurality of switches comprise a first external switch , a first internal switch , a second internal switch , a second external switch , a first clamp switch , and a second clamp switch , where the first external switch , the first internal switch , the second internal switch , and the second external switch are sequentially connected in series, an end of the first external switch is connected to the first input terminal , and another end of the first external switch is connected to the first internal switch , an end of the first clamp switch is connected to the second input terminal , and another end of the first clamp switch is connected to a connection point of the first external switch and the first internal switch , an end of the second external switch is connected to the third input terminal , and another end of the second external switch is connected to the second internal switch , an end of the second clamp switch is connected to the second input terminal , and another end of the second clamp switch is connected to a connection point of the second external switch and the second internal switch , the output terminal is connected to a connection point of the first internal switch and the second internal switch , characterized in that the method comprises: in response to receiving an instruction of starting operation, controlling (S1501) the first clamp switch and the second clamp switch in each bridge leg to turn on, and simultaneously or after a first delay time, recovering normal control signals of the first internal switch and the second internal switch in each bridge leg ; after a second delay time, recovering (S1503) normal control signals of the first clamp switch and the second clamp switch in each bridge leg ; and after a third delay time, recovering (S1505) the normal control signals of the first external switch and the second external switch in each bridge leg ; wherein said normal control signals are recovered according to a predetermined sequence such that the converter is recovered to the normal working state, wherein before receiving the instruction of starting operation, the first external switch , the first internal switch , the second internal switch , the second external switch , the first clamp switch , and the second clamp switch are all in an off state. in response to receiving an instruction of starting operation, controlling (S1501) the first clamp switch and the second clamp switch in each bridge leg to turn on, and simultaneously or after a first delay time, recovering normal control signals of the first internal switch and the second internal switch in each bridge leg ; after a second delay time, recovering (S1503) normal control signals of the first clamp switch and the second clamp switch in each bridge leg ; and after a third delay time, recovering (S1505) the normal control signals of the first external switch and the second external switch in each bridge leg ; said normal control signals are recovered according to a predetermined sequence such that the converter is recovered to the normal working state, wherein before receiving the instruction of starting operation, the first external switch , the first internal switch , the second internal switch , the second external switch , the first clamp switch , and the second clamp switch are all in an off state. <EOS>