Piezoelectric energy harvesting is a process that involves converting mechanical energy, such as vibrations or mechanical stress, into electrical energy using piezoelectric materials. Piezoelectric sensors play a crucial role in this energy harvesting process. Here's how they work:
Piezoelectric Material: The piezoelectric sensor is made from a piezoelectric material, which possesses a unique property: when mechanical stress or pressure is applied to the material, it generates an electric charge across its surface. Conversely, when an electric field is applied to the material, it undergoes mechanical deformation.
Mechanical Energy Input: In the context of energy harvesting, the piezoelectric sensor is mechanically connected to a source of mechanical energy, such as vibrations, movement, or pressure. For example, in some applications, the sensor might be attached to a vibrating structure or a rotating mechanical part.
Generation of Electric Charge: As the mechanical energy is applied to the piezoelectric material, it causes the material to deform slightly, creating an electric charge across its surface. This charge is proportional to the amount of mechanical stress applied to the material.
Electrical Energy Output: The electric charge generated by the piezoelectric sensor is collected and stored for later use. To do this, the sensor is connected to an electrical circuit that includes a rectifier and an energy storage device, such as a capacitor or a battery. The rectifier converts the alternating current (AC) output of the piezoelectric sensor into direct current (DC) suitable for charging the energy storage device.
Cycle of Energy Conversion: The process of energy harvesting with a piezoelectric sensor is cyclical. As long as the mechanical energy source continues to apply stress to the piezoelectric material, the sensor will continuously generate electric charge, which is then converted and stored as electrical energy for practical applications.
Piezoelectric energy harvesting has gained popularity in various fields, especially in applications where there are ambient vibrations or mechanical movements that can be harnessed to power low-energy electronic devices or to extend the battery life of wireless sensors in remote or hard-to-reach locations.