Power system and application thereof

The invention discloses a power system and application thereof. The power system comprises an energy accumulator; an outer oil bag; the inner oil tank is connected with the outer oil bag through an oil path; the first hydraulic cylinder comprises a first piston assembly, a first cavity and a second cavity, the first cavity is connected with the energy accumulator through an oil way, and the second cavity is connected with the outer oil bag through an oil way; the inner oil tank is connected with the second cavity through an oil path; the standby pump is arranged on an oil way between the outer oil bag and the energy accumulator; the second hydraulic cylinder comprises a second piston assembly and a third chamber; and the heat exchanger is connected with the third cavity through an oil path. The standby pump is additionally arranged in the power system, so that the underwater vehicle can complete the change of the buoyancy state from ascending to descending or from descending to ascending in a short time, and