A piezoelectric generator in public transportation captures energy from vehicle vibrations through the principle of piezoelectricity. Piezoelectricity is a phenomenon in which certain materials generate an electric charge in response to mechanical stress or vibrations. This property allows piezoelectric materials to convert mechanical energy into electrical energy and vice versa.
Here's how a piezoelectric generator works in the context of public transportation:
Placement of Piezoelectric Materials: Piezoelectric materials, such as crystals or ceramics, are strategically placed in areas of the vehicle where vibrations and mechanical stress are prevalent. These could include the chassis, suspension system, seats, floors, and even the wheels.
Vibration and Mechanical Stress: As the vehicle moves, it encounters various vibrations and mechanical stress due to the road conditions, engine operation, braking, acceleration, and interactions with passengers. These vibrations cause the piezoelectric materials to experience deformation or displacement.
Generation of Electric Charge: When the piezoelectric materials experience deformation or displacement due to vibrations, they generate electric charges at their surfaces. This charge separation is a direct result of the piezoelectric effect. The generated charges accumulate on opposite sides of the material.
Harvesting and Storing Energy: The electric charges generated by the piezoelectric materials are collected and channeled through an electrical circuit. This circuit typically includes rectifiers and energy storage devices like capacitors or batteries. The rectifiers convert the alternating current (AC) generated by the piezoelectric material into direct current (DC) suitable for charging batteries or capacitors. These energy storage devices store the harvested energy for later use.
Utilization of Captured Energy: The harvested electrical energy can be used to power various components of the public transportation system. This could include lighting, displays, sensors, communication systems, or other low-power electrical devices. In some cases, the harvested energy might also contribute to the vehicle's overall power supply, potentially reducing the load on the primary power source.
It's important to note that while piezoelectric generators can indeed capture energy from vehicle vibrations, the amount of energy generated is typically quite small compared to the overall energy needs of the vehicle. However, when integrated into a larger energy harvesting system alongside other technologies (such as regenerative braking systems), these small amounts of harvested energy can contribute to the overall energy efficiency of the vehicle and reduce its environmental impact.