A generator , comprising an active cooling circuit (A) and a passive cooling circuit (B) which are isolated from each other, wherein the active cooling circuit (A) is in communication with a closed space (S), and the passive cooling circuit (B) is in communication with an external environment; wherein the active cooling circuit (A) comprises mutually communicating chambers located at two axial ends of the generator , an air gap between a rotor and a stator of the generator, and radial channels spaced apart along an axial direction (X) of the stator , and a cooling device in communication with the closed space (S) is provided in the active cooling circuit (A), and the stator is fixed on a fixed shaft through a stator bracket ; wherein the passive cooling circuit (B) comprises a first axial channel running through the stator in the axial direction (X), a second axial channel running through the stator bracket , and an outer surface of the generator ; wherein a heat exchanger is further arranged inside the generator , the heat exchanger is in communication with the radial channels and the second axial channel , respectively; and wherein the stator comprises a plurality of iron core assemblies arranged at intervals along the axial direction (X), the radial channels are formed between every two adjacent iron core assemblies ; the first axial channel comprises stator axial channels running through the plurality of iron core assemblies along the axial direction (X), each of the iron core assemblies comprises a yoke portion and a tooth portion integrally formed with the yoke portion , a plurality of tooth grooves arranged at intervals in a circumferential direction (Z) of each iron core assembly is provided on the tooth portion , the yoke portion is provided with a through hole corresponding to the tooth grooves , and a casing in communication with the through hole is arranged between each two adjacent iron core assemblies , and the stator axial channel is formed by the through hole and the casing . wherein the active cooling circuit (A) comprises mutually communicating chambers located at two axial ends of the generator , an air gap between a rotor and a stator of the generator, and radial channels spaced apart along an axial direction (X) of the stator , and a cooling device in communication with the closed space (S) is provided in the active cooling circuit (A), and the stator is fixed on a fixed shaft through a stator bracket ; wherein the passive cooling circuit (B) comprises a first axial channel running through the stator in the axial direction (X), a second axial channel running through the stator bracket , and an outer surface of the generator ; wherein a heat exchanger is further arranged inside the generator , the heat exchanger is in communication with the radial channels and the second axial channel , respectively; and wherein the stator comprises a plurality of iron core assemblies arranged at intervals along the axial direction (X), the radial channels are formed between every two adjacent iron core assemblies ; the first axial channel comprises stator axial channels running through the plurality of iron core assemblies along the axial direction (X), each of the iron core assemblies comprises a yoke portion and a tooth portion integrally formed with the yoke portion , a plurality of tooth grooves arranged at intervals in a circumferential direction (Z) of each iron core assembly is provided on the tooth portion , the yoke portion is provided with a through hole corresponding to the tooth grooves , and a casing in communication with the through hole is arranged between each two adjacent iron core assemblies , and the stator axial channel is formed by the through hole and the casing . <EOS>