Introduction

The invention refers to an electronic circuit and to a method for optimizing the extraction of the electrical power from a resonant electromagnetic vibration energy harvester. The objective of the proposed system is to increase the efficiency of the harvester at vibration frequencies different from its mechanical resonance frequency. The increase of the power generated by energy harvesting systems, eliminates the need for wired electrical power supply, and the maintenance costs and the environmental impact of disposable batteries, in Internet of Things applications.

Technical features

Resonant electromagnetic vibration energy harvesters efficiently operate only when vibrations frequency is coincident with their resonance frequency. The aim  of  this system is to increase the efficiency of such harvesters at vibration frequencies different from the resonance. The optimization of the extracted power is obtained by injecting a proper current into an additional coil, by means of a power electronic circuit, in order to emulate a suitable spring-mass-damper system with a significantly higher efficiency at a desired vibration frequency, even if different from the harvester resonance frequency. The addition of the proposed system to a standard vibration harvester, allows a power gain higher than 80%. In energy harvesting systems, the increase of the generated power allows both the supply of more performing Internet of Things devices (with higher power consumptions and higher service quality levels), and the reduction of the harvester size (and hence of the system initial cost) for the same Internet of Things device to be supplied.

Possible Applications

• Power supply of Internet of Things devices;
• Power supply of nodes of wireless sensor networks;
• Power supply of monitoring sensors in railway, automotive, aerospace, industrial, infrastructure, biomedical and home automation applications.

Advantages

• Supply of Internet of Things devices with higher service quality levels;
• Reduction of the harvesting system initial cost;
• No wired electrical power supply or disposable batteries required;
• Environmentally friendly.