**6. Circuit Design**

The block diagram of the standalone renewable energy system is illustrated in Figure 12. As can be easily seen, the whole system is broadly composed of a power generator (wind turbines and PV array), an uploading circuit, a three-phase rectifier bridge, an interleaved Buck circuit, a DC/DC conversion circuit, a switch circuit, a power supply circuit, an amplifier, a driver circuit, a voltage and current monitoring, a load, battery units, and a control system. The electric energy generated by the wind turbine converts into direct current through the three-phase rectifier bridge, and concentrates with the electric energy generated by the photovoltaic power generator. Then the electric energy generated by the wind energy and the solar energy are converted into stable direct currents to loads and the battery units by the interleaved Buck circuit. The wind turbine side is designed with an unloading circuit to prevent excessive output power from damaging the equipment under high wind conditions. The bus voltage is 24 V and the battery voltage is 12 V, thus, a DC/DC conversion circuit is designed. The model's parameters of circuits were chosen by empirical and commercial general specifications, which is a common method in circuit design.

**Figure12.** Blockdiagramofthestandalonerenewableenergysystembyhybridsolar–windsystem.
