*5.3. Power Supply Strategy*

The prerequisite for stable operation of the wind–solar hybrid power system is to maintain the energy balance between power generation and power consumption. If the power converted by wind and solar is less than the actual load, the battery plays the role to supply power to the load. On the contrary, if the power converted by wind and solar is greater than the actual load, the battery stores excess electrical energy. The flowchart of the power supply strategy is given in Figure 11.

After the energy assessment, three energy supply methods were selected: (1) Wind energy available; (2) Wind and solar energy available; (3) Solar energy available. After the SOC estimation was completed, whether the output power of the generator (wind turbine and PV array) can meet the load was calculated and evaluated. In all three energy supply methods, when the energy output is greater than the load, the output power of the generator can supply the load. If SOC < 90%, the output power of the generator should charge the battery. Otherwise, the battery does not need to be charged. When the energy output is less than the load, as long as SOC is greater than 10%, the battery and the power generator can directly provide the power of the load. If SOC < 10%, the power supply of a part of the load should be cut off to ensure the power generator and the battery providing power to the remaining load.

**Figure 11.** The flowchart of the power supply strategy.
