A power system includes N direct current coupling units, N direct current buses, and a main controller. The main controller is configured to: obtain a total network input demand power (a network input power required by the power grid); obtain first amplitude limiting values (indicate a maximum discharging power that can be supplied by each energy unit to the power grid); and determine first network input power values (a power value allocated to each energy unit and that is input to the power grid, and at least one direct current coupling unit is in a first amplitude limiting state) based on the total network input demand power and the first amplitude limiting values, and the first amplitude limiting state is that a first network input power value of direct current coupling unit is equal to a first amplitude limiting value corresponding to the direct current coupling unit.