Switch – control hybrid wind and PV power generating system

In order to acquire both wind and solar energy at the same time, the system is config­ured as in Fig. 4. As seen in Fig. 10(a)-(c), the wind to solar charging duty cycle ratio is changed to examine the charging behavior at three wind speeds. Owing to fluctuations in wind speed at 3 m/s, the system sometimes stops outputting the wind charging current, as seen in Fig. 10(a), while the charging of battery by solar energy remains very stable. When wind speed increases to 4 m/s, as shown in Fig. 10(b), the wind charging current contin­ues to charge the battery during its duty cycle, but the current decreases during charg­ing. When the solar charging duration is increased to 3.2 seconds, the wind charging current drops to 2 A, as seen in Fig. 10(c) prior to solar charging. Upon completion of solar charging, i. e. after 3.2 seconds, the wind charging current increases to 4 A and falls gradually back to 2 A This phenomenon can be explained as follows. During solar energy charging, the wind turbine is in a no-load condition. Wind energy is thus converted into mechanical energy, which speeds up the alternator. In other words, owing to the inertial momentum, the wind turbine can store mechanical energy, and solar energy is not best utilized or lost during wind charging. Therefore, the charging duty cycle ratio between wind and solar energy can be adjusted to obtain the maximum energy source.