**2. Design and Modeling of the Energy Harvester**

#### *2.1. Configuration*

Figure 1 depicts the setup of the developed harvester. It consists of a flexible structure (i.e., the counterpart of transmission lines with a length of 0.42 m) that aims to receive wind energy from incoming flows, a supporting frame where the flexible structure is fixed, and a wind direction regulator that is mainly composed of a spindle and a deflector. The two ends of the flexible structure are respectively connected with the rigid body of

the supporting frame, and the free end of a cantilever beam where a piezoelectric film is adhered. The cantilever beam is made of 0.3 mm × 150 mm stainless steel. The piezoelectric film, i.e., the PVDF (Polyvinylidene Fluoride) film (IPS-17020, ZHINK TECHNOLOGY) has dimensions of 30 mm (length) × 12.1 mm (width) × 0.28 μm (depth), and the density is 1.78 × 103 kg/m3. The spindle is fixed with the supporting frame and the deflector rigidly. Due to the guiding effects of the deflector, incoming wind flows tend to blow in a direction that is perpendicular to the windward surface of the flexible structure. When the wind speed exceeds a certain value, the flexible structure can vibrate up and down severely, i.e., galloping occurs. The vibrating flexible structure then drives the cantilever and therefore the PVDF film to sway, which fulfills the conversion of wind energy into electricity.

**Figure 1.** Schematic diagram of energy harvester.

When the energy harvester faces the incoming wind, the flexible bluff body swings around the plane and causes the thin wire to generate tension. The tension at one end of the thin wire directly drives the cantilever beam to produce periodic alternating strain. At the same time, the piezoelectric film is deformed. A certain charge is generated, which effectively converts the flow energy of the air into electric energy. The energy harvester has a simple structure and low manufacturing costs, and is very suitable for the surrounding windy environment all year round. Compared with various forms of energy harvesters, this paper's harvester is not affected by wind direction and is suitable for any wind direction angle. Since the designed energy harvester has excellent parameters, and the critical wind speed generated is small, the flexible structure is prone to galloping and improves the efficiency of energy harvesting.
